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Dwell angle, electronic ignition
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Paul Hovnanian P.E.
Apr 29, 2012, 1:51:02 PM4/29/12
to
Back when dwell angle meant anything (when we all had points in our ignition
systems), 30% dwell meant that the points were closed and the coil
conducting for 30% of the time. As RPM went up and down, the dwell stayed
constant. Which meant the coil conducted for a longer period of time at low
RPM than at high.
I've got a project involving building a new electronic ignition module for a
vehicle, and I've never looked into how electronic ignitions handle the
dwell issue.
Once a coil has 'charged up' so to speak (the DC current has risen to a
steady state value given the coil's primary inductance), allowing it to
conduct for a longer period of time until the points open buys you nothing.
The stored energy in the coil is the same.
Back in the days of points, it made more sense just to let the closed time
track up and down inverse to the RPM. A simple cam will suffice. But now,
its possible (and actually easier) to build a one-shot circuit that breaks
the coil primary for a fixed period of time regardless of RPM. Of course,
that lets the dwell angle go all over the place. But as long as the coil
conducts for the requisite minimum amount of time, there should be no
problem. In fact, such a system is a back door way of implementing a speed
governor. Once the RPM goes so high that the fixed 'open' time exceeds the
time needed between sparks, the engine effectively shuts down (the crank
angle sensor keeps resetting the one-shot before it can time out and close
the circuit).
So, how do modern electronic systems work? Still constant dwell angle?
Constant time? Granted, the ECU controlled ignition could easily be
implement some sort of active coil current control. But that's going a bit
overboard for my needs.
--
Paul Hovnanian mailto:Pa...@Hovnanian.com
------------------------------------------------------------------
Ban the bomb. Save the world for conventional warfare.
systems), 30% dwell meant that the points were closed and the coil
conducting for 30% of the time. As RPM went up and down, the dwell stayed
constant. Which meant the coil conducted for a longer period of time at low
RPM than at high.
I've got a project involving building a new electronic ignition module for a
vehicle, and I've never looked into how electronic ignitions handle the
dwell issue.
Once a coil has 'charged up' so to speak (the DC current has risen to a
steady state value given the coil's primary inductance), allowing it to
conduct for a longer period of time until the points open buys you nothing.
The stored energy in the coil is the same.
Back in the days of points, it made more sense just to let the closed time
track up and down inverse to the RPM. A simple cam will suffice. But now,
its possible (and actually easier) to build a one-shot circuit that breaks
the coil primary for a fixed period of time regardless of RPM. Of course,
that lets the dwell angle go all over the place. But as long as the coil
conducts for the requisite minimum amount of time, there should be no
problem. In fact, such a system is a back door way of implementing a speed
governor. Once the RPM goes so high that the fixed 'open' time exceeds the
time needed between sparks, the engine effectively shuts down (the crank
angle sensor keeps resetting the one-shot before it can time out and close
the circuit).
So, how do modern electronic systems work? Still constant dwell angle?
Constant time? Granted, the ECU controlled ignition could easily be
implement some sort of active coil current control. But that's going a bit
overboard for my needs.
--
Paul Hovnanian mailto:Pa...@Hovnanian.com
------------------------------------------------------------------
Ban the bomb. Save the world for conventional warfare.
jim beam
Apr 29, 2012, 3:52:14 PM4/29/12
to
to threshold. i believe most of the time this is done in a local
ignition module, bit some also do it at the ecu end since there's more
computational horsepower depending on how much you want to manage the
coil[s].
the advantage is, and this is very important, is that this has a
material impact on coil heating, or more accurately, limiting heat
build-up. modern potted coils can't dump heat like older oil bathed
ones since there is no convection possible.
i should check, but iirc, there's some code for this on the megasquirt
engine management project.
--
nomina rutrum rutrum
hls
Apr 29, 2012, 4:49:27 PM4/29/12
to
"Paul Hovnanian P.E." <pa...@hovnanian.com> wrote in message
> So, how do modern electronic systems work? Still constant dwell angle?
> Constant time? Granted, the ECU controlled ignition could easily be
> implement some sort of active coil current control. But that's going a bit
> overboard for my needs.
>
> --
> Paul Hovnanian mailto:Pa...@Hovnanian.com
> ------------------------------------------------------------------
> Ban the bomb. Save the world for conventional warfare.
means
little or nothing unless you are using a Kettering system.
On electronic systems, traditional capacitive discharge systems used high
voltage DC systems to charge the capacitor(s) to a high value, then the
high voltage charged was dumped through a coil or coils to generate a
strong spark. Studies showed that one good hot spark was all that was
needed to ignite the fuel, but, even so, some companies engineered
systems with multiple spark discharges (MSD). IMHO they are good,
but no better than simple CD systems.
Since we dont know what your needs are, it is hard to comment further.
Steve W.
Apr 29, 2012, 5:05:23 PM4/29/12
to
mixture of fuel. The multiple spark serves to ignite overly rich pockets
of fuel when the ignition pulse breaks them down and mixes them better.
On a modern vehicle with port injection they don't work as well because
the mix is much better and more evenly dispersed.
Modern ignitions have advanced a LONG way from the old Kettering system.
Current vehicles use the crank/cam sensors to not only tell the ECM when
to fire but also look for the power pulse and duration to determine IF
the cylinder fired properly.
--
Steve W.
jim beam
Apr 29, 2012, 6:10:23 PM4/29/12
to
On 04/29/2012 01:49 PM, hls wrote:
>
> "Paul Hovnanian P.E." <pa...@hovnanian.com> wrote in message
>
>> So, how do modern electronic systems work? Still constant dwell angle?
>> Constant time? Granted, the ECU controlled ignition could easily be
>> implement some sort of active coil current control. But that's going a
>> bit
>> overboard for my needs.
>>
>> --
>> Paul Hovnanian mailto:Pa...@Hovnanian.com
>> ------------------------------------------------------------------
>> Ban the bomb. Save the world for conventional warfare.
>
> There are several different systems, Paul. As you stated, dwell angle means
> little or nothing unless you are using a Kettering system.
>
> On electronic systems, traditional capacitive discharge systems used high
> voltage DC systems to charge the capacitor(s) to a high value, then the
> high voltage charged was dumped through a coil or coils to generate a
> strong spark.
you're confused. most electronic ignition systems are not capacitive
>
> "Paul Hovnanian P.E." <pa...@hovnanian.com> wrote in message
>
>> So, how do modern electronic systems work? Still constant dwell angle?
>> Constant time? Granted, the ECU controlled ignition could easily be
>> implement some sort of active coil current control. But that's going a
>> bit
>> overboard for my needs.
>>
>> --
>> Paul Hovnanian mailto:Pa...@Hovnanian.com
>> ------------------------------------------------------------------
>> Ban the bomb. Save the world for conventional warfare.
>
> There are several different systems, Paul. As you stated, dwell angle means
> little or nothing unless you are using a Kettering system.
>
> On electronic systems, traditional capacitive discharge systems used high
> voltage DC systems to charge the capacitor(s) to a high value, then the
> high voltage charged was dumped through a coil or coils to generate a
> strong spark.
discharge, they're inductive discharge. two very different concepts in
terms of spark energy and duration.
> Studies showed that one good hot spark was all that was
> needed to ignite the fuel,
trying to fire a muzzle-loader with an improperly primed firing cap, a
low energy spark, regardless of voltage, will only achieve partial
ignition. you need a high /energy/ spark to achieve good ignition.
inductive discharge can provide not only ignition voltage, but current
over time as its magnetic flux decays, and thus the energy delivery
required. indeed, that's why it's used on almost all oem ignition
systems. cd ignition uses a transformer [not coil] to step up the
capacitive voltage, but it has little energy and poor duration.
dumbed down explanation here:
<http://www.magnecor.com/magnecor1/truth.htm>
> but, even so, some companies engineered
> systems with multiple spark discharges (MSD). IMHO they are good,
> but no better than simple CD systems.
the advantage of being able to offer multiple sparks per cycle at low
rpm's, they suck at high rpms because their spark energy is low.
>
> Since we dont know what your needs are, it is hard to comment further.
the knowledge to comment on the needs of others.
--
nomina rutrum rutrum
Scott Dorsey
Apr 30, 2012, 12:07:04 PM4/30/12
to
Paul Hovnanian P.E. <pa...@hovnanian.com> wrote:
>
>I've got a project involving building a new electronic ignition module for a
>vehicle, and I've never looked into how electronic ignitions handle the
>dwell issue.
I recommend a copyu of Carroll A. Brant's _Transistor Ignition Systems_.
>
>I've got a project involving building a new electronic ignition module for a
>vehicle, and I've never looked into how electronic ignitions handle the
>dwell issue.
Like all TAB books it's full of typos and errors (including some in schematics)
but the wwaveforms seem okay. It is phenomenally dated but still useful.
>So, how do modern electronic systems work? Still constant dwell angle?
>Constant time? Granted, the ECU controlled ignition could easily be
>implement some sort of active coil current control. But that's going a bit
>overboard for my needs.
fine at low speeds, but becomes a problem at high speed. Some systems
use constant angle but with a minimum time threshold.
Take a look at megasquirt, it does some interesting goofiness as I recall,
and the source code is there for your perusal.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Paul Hovnanian P.E.
Apr 30, 2012, 10:04:34 PM4/30/12
to
hls wrote:
[snip]
> Since we dont know what your needs are, it is hard to comment further.
I'm building a new ignition module for a 33 year old vehicle whose old
module is getting a bit flaky (intermittent).
Its a 1979 Toyota Landcruiser with a reluctor pickup and solid state
ignition. Replacement (original) parts can occasionally be found for $350.
So I figured I'd build one.
I've seen several DIY conversions for points systems, but since I've already
got the pickup in the distributor, I'm one step ahead of those projects.
If I can keep the existing system running, I can throw an oscilloscope on it
to see what it does, but that's sort of iffy. And I don't like hooking my
(non automotive) electronics gear up to ignition systems. The inductive
kick (even on the primary) can blow the input stage out of some expensive
gear pretty fast.
--
Paul Hovnanian mailto:Pa...@Hovnanian.com
------------------------------------------------------------------
Free the Mallocs!
[snip]
> Since we dont know what your needs are, it is hard to comment further.
module is getting a bit flaky (intermittent).
Its a 1979 Toyota Landcruiser with a reluctor pickup and solid state
ignition. Replacement (original) parts can occasionally be found for $350.
So I figured I'd build one.
I've seen several DIY conversions for points systems, but since I've already
got the pickup in the distributor, I'm one step ahead of those projects.
If I can keep the existing system running, I can throw an oscilloscope on it
to see what it does, but that's sort of iffy. And I don't like hooking my
(non automotive) electronics gear up to ignition systems. The inductive
kick (even on the primary) can blow the input stage out of some expensive
gear pretty fast.
--
Paul Hovnanian mailto:Pa...@Hovnanian.com
------------------------------------------------------------------
jim beam
Apr 30, 2012, 10:05:13 PM4/30/12
to
On 04/29/2012 02:05 PM, Steve W. wrote:
<clarity>
> Current vehicles use the crank/cam sensors to not only tell the ECM when
> to fire but also look for the power pulse and duration to determine IF
> the cylinder fired properly.
at both ends of the plug. systems that can monitor the voltage decay of
the coil can tell if the plug's not firing. this helps differentiate
between plug and injector faults.
--
nomina rutrum rutrum
<clarity>
> Current vehicles use the crank/cam sensors to not only tell the ECM when
> to fire but also look for the power pulse and duration to determine IF
> the cylinder fired properly.
the coil can tell if the plug's not firing. this helps differentiate
between plug and injector faults.
--
nomina rutrum rutrum
jim beam
Apr 30, 2012, 10:12:47 PM4/30/12
to
On 04/30/2012 07:04 PM, Paul Hovnanian P.E. wrote:
> hls wrote:
>
> [snip]
>
>> Since we dont know what your needs are, it is hard to comment further.
>
> I'm building a new ignition module for a 33 year old vehicle whose old
> module is getting a bit flaky (intermittent).
before you blame the module, just make sure it's not something like an
> hls wrote:
>
> [snip]
>
>> Since we dont know what your needs are, it is hard to comment further.
>
> I'm building a new ignition module for a 33 year old vehicle whose old
> module is getting a bit flaky (intermittent).
issue on the h.t. end. that's where the vast majority of ignition
reliability problems lie - hence the modern move to coil on plug systems.
>
> Its a 1979 Toyota Landcruiser with a reluctor pickup and solid state
> ignition. Replacement (original) parts can occasionally be found for $350.
> So I figured I'd build one.
>
> I've seen several DIY conversions for points systems, but since I've already
> got the pickup in the distributor, I'm one step ahead of those projects.
>
> If I can keep the existing system running, I can throw an oscilloscope on it
> to see what it does, but that's sort of iffy. And I don't like hooking my
> (non automotive) electronics gear up to ignition systems. The inductive
> kick (even on the primary) can blow the input stage out of some expensive
> gear pretty fast.
>
signal to drive an off-the-shelf "igniter" unit. the igniter takes care
of the coil current [and in some cases, dwell], so all you have to do
now is figure out how to trigger it. junkyards are full of suitable
candidates.
--
nomina rutrum rutrum
hls
May 1, 2012, 9:51:17 AM5/1/12
to
news:v4Sdnax9ONvi2QLS...@posted.isomediainc...
involved in the intermittency? Also assume the the spark advance is
mechanically generated?
You have a number of options and it should be a fun project.
> hls wrote:
>
> [snip]
>
>> Since we dont know what your needs are, it is hard to comment further.
>
> I'm building a new ignition module for a 33 year old vehicle whose old
> module is getting a bit flaky (intermittent).
>
> Its a 1979 Toyota Landcruiser with a reluctor pickup and solid state
> ignition. Replacement (original) parts can occasionally be found for $350.
> So I figured I'd build one.
>
> I've seen several DIY conversions for points systems, but since I've
> already
> got the pickup in the distributor, I'm one step ahead of those projects.
>
> If I can keep the existing system running, I can throw an oscilloscope on
> it
> to see what it does, but that's sort of iffy. And I don't like hooking my
> (non automotive) electronics gear up to ignition systems. The inductive
> kick (even on the primary) can blow the input stage out of some expensive
> gear pretty fast.
Understood. I assume that you are pretty sure the reluctor pickup is not
>
> [snip]
>
>> Since we dont know what your needs are, it is hard to comment further.
>
> I'm building a new ignition module for a 33 year old vehicle whose old
> module is getting a bit flaky (intermittent).
>
> Its a 1979 Toyota Landcruiser with a reluctor pickup and solid state
> ignition. Replacement (original) parts can occasionally be found for $350.
> So I figured I'd build one.
>
> I've seen several DIY conversions for points systems, but since I've
> already
> got the pickup in the distributor, I'm one step ahead of those projects.
>
> If I can keep the existing system running, I can throw an oscilloscope on
> it
> to see what it does, but that's sort of iffy. And I don't like hooking my
> (non automotive) electronics gear up to ignition systems. The inductive
> kick (even on the primary) can blow the input stage out of some expensive
> gear pretty fast.
involved in the intermittency? Also assume the the spark advance is
mechanically generated?
You have a number of options and it should be a fun project.
Scott Dorsey
May 1, 2012, 10:16:52 AM5/1/12
to
hls <h...@nospam.nix> wrote:
>"Paul Hovnanian P.E." <pa...@hovnanian.com> wrote in message
>news:v4Sdnax9ONvi2QLS...@posted.isomediainc...
>>
>"Paul Hovnanian P.E." <pa...@hovnanian.com> wrote in message
>news:v4Sdnax9ONvi2QLS...@posted.isomediainc...
>>
>> If I can keep the existing system running, I can throw an oscilloscope on
>> it
>> to see what it does, but that's sort of iffy. And I don't like hooking my
>> (non automotive) electronics gear up to ignition systems. The inductive
>> kick (even on the primary) can blow the input stage out of some expensive
>> gear pretty fast.
That's why we have 10X probes, to deal with that. Or get yourself a nice
>> it
>> to see what it does, but that's sort of iffy. And I don't like hooking my
>> (non automotive) electronics gear up to ignition systems. The inductive
>> kick (even on the primary) can blow the input stage out of some expensive
>> gear pretty fast.
reliable Tek 545. The probe will arc over before the nuvistor is damaged.
>You have a number of options and it should be a fun project.
discharge system like the Mark Ten or the like, and Brant's book has
details on various different designs (including some complete schematics
that can be used outright) as well as details on the stuff that should be
coming off the various different types of pickup.
I have a Mark Ten retrofit unit in my 2002 and it's been running fine for
the past 150,000 miles. I don't think I have replaced points in all that
time although I have had to adjust them. It doesn't care about how the actual
dwell is set; there's an internal RC network that sets the length of time
the SCR is kept conducting no matter how wide the input pulse is. So it
would not seem to be difficult to trigger it from a variable reluctance
pickup or a phototransistor.
jim beam
May 1, 2012, 10:25:08 AM5/1/12
to
the difference between inductive and capacitive ignition discharge is
really asking questions unrelated to the op's topic - that of dwell
angle management - you know, like "Dwell angle, electronic ignition"???
>
> You have a number of options and it should be a fun project.
drivel, you still go ahead and do it anyway.
--
nomina rutrum rutrum
jim beam
May 1, 2012, 10:48:27 AM5/1/12
to
On 05/01/2012 07:16 AM, Scott Dorsey wrote:
> hls<h...@nospam.nix> wrote:
>> "Paul Hovnanian P.E."<pa...@hovnanian.com> wrote in message
>> news:v4Sdnax9ONvi2QLS...@posted.isomediainc...
>>>
>>> If I can keep the existing system running, I can throw an oscilloscope on
>>> it
>>> to see what it does, but that's sort of iffy. And I don't like hooking my
>>> (non automotive) electronics gear up to ignition systems. The inductive
>>> kick (even on the primary) can blow the input stage out of some expensive
>>> gear pretty fast.
>
> That's why we have 10X probes, to deal with that. Or get yourself a nice
> reliable Tek 545. The probe will arc over before the nuvistor is damaged.
>
>> You have a number of options and it should be a fun project.
>
> If it were me, I would just go with a conventional analogue capacitive
> discharge system
but capacitive discharge is not "conventional" - inductive is.
> hls<h...@nospam.nix> wrote:
>> "Paul Hovnanian P.E."<pa...@hovnanian.com> wrote in message
>> news:v4Sdnax9ONvi2QLS...@posted.isomediainc...
>>>
>>> If I can keep the existing system running, I can throw an oscilloscope on
>>> it
>>> to see what it does, but that's sort of iffy. And I don't like hooking my
>>> (non automotive) electronics gear up to ignition systems. The inductive
>>> kick (even on the primary) can blow the input stage out of some expensive
>>> gear pretty fast.
>
> That's why we have 10X probes, to deal with that. Or get yourself a nice
> reliable Tek 545. The probe will arc over before the nuvistor is damaged.
>
>> You have a number of options and it should be a fun project.
>
> If it were me, I would just go with a conventional analogue capacitive
> discharge system
"electronic" != capacitive.
capacitive is a fad among after-market systems as some form of
differentiation, and people whose electronics knowledge has not
progressed since the 1970's. while it may offer benefits over kettering
ignition, it's inferior to inductive due to lower spark ignition
duration and energy delivery.
> like the Mark Ten or the like, and Brant's book has
> details on various different designs (including some complete schematics
> that can be used outright) as well as details on the stuff that should be
> coming off the various different types of pickup.
>
> I have a Mark Ten retrofit unit in my 2002 and it's been running fine for
> the past 150,000 miles. I don't think I have replaced points in all that
> time although I have had to adjust them.
> It doesn't care about how the actual
> dwell is set; there's an internal RC network that sets the length of time
> the SCR is kept conducting no matter how wide the input pulse is. So it
> would not seem to be difficult to trigger it from a variable reluctance
> pickup or a phototransistor.
state ignition"...
> --scott
--
nomina rutrum rutrum
hls
May 1, 2012, 11:01:58 AM5/1/12
to
"Scott Dorsey" <klu...@panix.com> wrote in message
news:jnor8k$c6a$1...@panix2.panix.com...
>> If it were me, I would just go with a conventional analogue capacitive
> discharge system like the Mark Ten or the like, and Brant's book has
> details on various different designs (including some complete schematics
> that can be used outright) as well as details on the stuff that should be
> coming off the various different types of pickup.
>
> I have a Mark Ten retrofit unit in my 2002 and it's been running fine for
> the past 150,000 miles. I don't think I have replaced points in all that
> time although I have had to adjust them. It doesn't care about how the
> actual
> dwell is set; there's an internal RC network that sets the length of time
> the SCR is kept conducting no matter how wide the input pulse is. So it
> would not seem to be difficult to trigger it from a variable reluctance
> pickup or a phototransistor.
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."
This would be one of the simpler options, Scott. There are so many ways
> discharge system like the Mark Ten or the like, and Brant's book has
> details on various different designs (including some complete schematics
> that can be used outright) as well as details on the stuff that should be
> coming off the various different types of pickup.
>
> I have a Mark Ten retrofit unit in my 2002 and it's been running fine for
> the past 150,000 miles. I don't think I have replaced points in all that
> time although I have had to adjust them. It doesn't care about how the
> actual
> dwell is set; there's an internal RC network that sets the length of time
> the SCR is kept conducting no matter how wide the input pulse is. So it
> would not seem to be difficult to trigger it from a variable reluctance
> pickup or a phototransistor.
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."
to go that are interesting, but probably dont improve the system so much.
The dwell should not make much difference, if any, on a system like the
one you describe. When points are used like this, there is usually a set
current range through the points which will help retard burning the points.
The first plug firing voltage spike is enough to ignite the gas/air charge
and
there is not much to be gained by allowing the circuit to have multiple
discharges. There has been a lot published about this, but many will
still not believe it.
Timing is a lot easier to deal with if you retain the distributor, but even
that is not necessary.
Scott Dorsey
May 1, 2012, 11:46:27 AM5/1/12
to
In article <jnot3p$770$1...@speranza.aioe.org>, jim beam <m...@privacy.net> wrote:
>>
>> I have a Mark Ten retrofit unit in my 2002 and it's been running fine for
>> the past 150,000 miles. I don't think I have replaced points in all that
>> time although I have had to adjust them.
>
>you have a 2002 vehicle with points????????????
BMW model 2002.
>>
>> I have a Mark Ten retrofit unit in my 2002 and it's been running fine for
>> the past 150,000 miles. I don't think I have replaced points in all that
>> time although I have had to adjust them.
>
>you have a 2002 vehicle with points????????????
>> It doesn't care about how the actual
>> dwell is set; there's an internal RC network that sets the length of time
>> the SCR is kept conducting no matter how wide the input pulse is. So it
>> would not seem to be difficult to trigger it from a variable reluctance
>> pickup or a phototransistor.
>
>but we already know that the vehicle has "reluctor pickup and solid
>state ignition"...
ignition modules.
AMuzi
May 1, 2012, 5:12:24 PM5/1/12
to
great car! The '74 not so much - quite a bit heavier.
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
Paul Hovnanian P.E.
May 1, 2012, 5:45:00 PM5/1/12
to
hls wrote:
>
> "Paul Hovnanian P.E." <pa...@hovnanian.com> wrote in message
> news:v4Sdnax9ONvi2QLS...@posted.isomediainc...
>> hls wrote:
>>
>> [snip]
>>
>>> Since we dont know what your needs are, it is hard to comment further.
>>
>> I'm building a new ignition module for a 33 year old vehicle whose old
>> module is getting a bit flaky (intermittent).
>>
>> Its a 1979 Toyota Landcruiser with a reluctor pickup and solid state
>> ignition. Replacement (original) parts can occasionally be found for
>> $350. So I figured I'd build one.
>>
>> I've seen several DIY conversions for points systems, but since I've
>> already
>> got the pickup in the distributor, I'm one step ahead of those projects.
>>
>> If I can keep the existing system running, I can throw an oscilloscope on
>> it
>> to see what it does, but that's sort of iffy. And I don't like hooking my
>> (non automotive) electronics gear up to ignition systems. The inductive
>> kick (even on the primary) can blow the input stage out of some expensive
>> gear pretty fast.
>
> Understood. I assume that you are pretty sure the reluctor pickup is not
> involved in the intermittency?
Pretty sure. The reluctor continuity is good (even during a failure
>
> "Paul Hovnanian P.E." <pa...@hovnanian.com> wrote in message
> news:v4Sdnax9ONvi2QLS...@posted.isomediainc...
>> hls wrote:
>>
>> [snip]
>>
>>> Since we dont know what your needs are, it is hard to comment further.
>>
>> I'm building a new ignition module for a 33 year old vehicle whose old
>> module is getting a bit flaky (intermittent).
>>
>> Its a 1979 Toyota Landcruiser with a reluctor pickup and solid state
>> ignition. Replacement (original) parts can occasionally be found for
>> $350. So I figured I'd build one.
>>
>> I've seen several DIY conversions for points systems, but since I've
>> already
>> got the pickup in the distributor, I'm one step ahead of those projects.
>>
>> If I can keep the existing system running, I can throw an oscilloscope on
>> it
>> to see what it does, but that's sort of iffy. And I don't like hooking my
>> (non automotive) electronics gear up to ignition systems. The inductive
>> kick (even on the primary) can blow the input stage out of some expensive
>> gear pretty fast.
>
> Understood. I assume that you are pretty sure the reluctor pickup is not
> involved in the intermittency?
condition) and it seems to be putting some AC signal out when cranking the
engine at these times.
>
> Also assume the the spark advance is
> mechanically generated?
> You have a number of options and it should be a fun project.
--
Paul Hovnanian mailto:Pa...@Hovnanian.com
------------------------------------------------------------------
Steve Austin
May 1, 2012, 6:29:43 PM5/1/12
to
hls
May 1, 2012, 6:56:51 PM5/1/12
to
> Pretty simple, actually. Once I figure out what the requirements are.
>
> --
> Paul Hovnanian mailto:Pa...@Hovnanian.com
I dont see that you have any extreme ignition requirements for this
>
> --
> Paul Hovnanian mailto:Pa...@Hovnanian.com
type of car. You could spend a ton of money and engineer a
sophisticated system, or you could take an aftermarket system and
adapt it. Performance will likely be about the same either way.
Scott Dorsey
May 1, 2012, 7:05:52 PM5/1/12
to
In article <jnpjjo$ndl$1...@dont-email.me>, AMuzi <a...@yellowjersey.org> wrote:
>
>I believe Scott has a BMX 2002, as did I. My '72 was one
>great car! The '74 not so much - quite a bit heavier.
It is, and even worse I have the Solex carbs. But it's still a fun car!
>
>I believe Scott has a BMX 2002, as did I. My '72 was one
>great car! The '74 not so much - quite a bit heavier.
Scott Dorsey
May 1, 2012, 7:07:14 PM5/1/12
to
Give that man the kewpie doll!
You should get the book, though, so you know what's inside the module. And
if you decided to build your own, you could steal their design.
You should get the book, though, so you know what's inside the module. And
if you decided to build your own, you could steal their design.
Kevin Bottorff
May 1, 2012, 7:17:59 PM5/1/12
to
"hls" <h...@nospam.nix> wrote in
news:lPWdneB1aZzT9z3S...@giganews.com:
or you could get Dr. Jacobs ign book and put any ign module you want on
it. chry is cheep and relighible. done many. KB
news:lPWdneB1aZzT9z3S...@giganews.com:
it. chry is cheep and relighible. done many. KB
Nate Nagel
May 1, 2012, 7:47:37 PM5/1/12
to
common to use HEI module in place of the "orange box," search online for
it, have thought about doing that myself. (have an "orange box"
ignition on my Studebaker; it works fine, but if it ever dies I will
probably use a HEI module.)
nate
--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
jim beam
May 1, 2012, 9:59:05 PM5/1/12
to
On 05/01/2012 04:05 PM, Scott Dorsey wrote:
> In article<jnpjjo$ndl$1...@dont-email.me>, AMuzi<a...@yellowjersey.org> wrote:
>>
>> I believe Scott has a BMX 2002, as did I. My '72 was one
>> great car! The '74 not so much - quite a bit heavier.
>
> It is, and even worse I have the Solex carbs. But it's still a fun car!
> --scott
>
can you not get webers for it? a couple of dcoe40's would pep it up nicely.
> In article<jnpjjo$ndl$1...@dont-email.me>, AMuzi<a...@yellowjersey.org> wrote:
>>
>> I believe Scott has a BMX 2002, as did I. My '72 was one
>> great car! The '74 not so much - quite a bit heavier.
>
> It is, and even worse I have the Solex carbs. But it's still a fun car!
> --scott
>
--
nomina rutrum rutrum
jim beam
May 1, 2012, 9:59:48 PM5/1/12
to
On 05/01/2012 08:46 AM, Scott Dorsey wrote:
> In article<jnot3p$770$1...@speranza.aioe.org>, jim beam<m...@privacy.net> wrote:
>>>
>>> I have a Mark Ten retrofit unit in my 2002 and it's been running fine for
>>> the past 150,000 miles. I don't think I have replaced points in all that
>>> time although I have had to adjust them.
>>
>> you have a 2002 vehicle with points????????????
>
> BMW model 2002.
ah, that makes more sense!
> In article<jnot3p$770$1...@speranza.aioe.org>, jim beam<m...@privacy.net> wrote:
>>>
>>> I have a Mark Ten retrofit unit in my 2002 and it's been running fine for
>>> the past 150,000 miles. I don't think I have replaced points in all that
>>> time although I have had to adjust them.
>>
>> you have a 2002 vehicle with points????????????
>
> BMW model 2002.
>
>>> It doesn't care about how the actual
>>> dwell is set; there's an internal RC network that sets the length of time
>>> the SCR is kept conducting no matter how wide the input pulse is. So it
>>> would not seem to be difficult to trigger it from a variable reluctance
>>> pickup or a phototransistor.
>>
>> but we already know that the vehicle has "reluctor pickup and solid
>> state ignition"...
>
> Right, so should be no problem to trigger any one of the third-party
> ignition modules.
an appropriate donor in the junkyard than going aftermarket. even some
of the new oem styles from napa are crazy cheap. it's certainly not
worth trying to build one from scratch unless you really have a
hankering for the science project aspect.
Kevin Bottorff
May 2, 2012, 9:45:13 AM5/2/12
to
Nate Nagel <njn...@roosters.net> wrote in
news:jnpsm...@news4.newsguy.com:
The only problem with the HEI is it is not as relighable KB
news:jnpsm...@news4.newsguy.com:
Scott Dorsey
May 2, 2012, 10:14:17 AM5/2/12
to
Kevin Bottorff <kb...@gmail.com> wrote:
>
> or you could get Dr. Jacobs ign book and put any ign module you want on
>it. chry is cheep and relighible. done many. KB
I don't know the book! Have you got a full citation?
>
> or you could get Dr. Jacobs ign book and put any ign module you want on
>it. chry is cheep and relighible. done many. KB
Nate Nagel
May 2, 2012, 10:14:35 AM5/2/12
to
failure. that said I knew there was an explanation somewhere of why the
HEI was technically better (although interchangeable) here is one
http://www.slantsix.org/forum/viewtopic.php?t=15779
Scott Dorsey
May 2, 2012, 10:16:23 AM5/2/12
to
In article <jnq4d8$91m$3...@speranza.aioe.org>, jim beam <m...@privacy.net> wrote:
>On 05/01/2012 04:05 PM, Scott Dorsey wrote:
>> In article<jnpjjo$ndl$1...@dont-email.me>, AMuzi<a...@yellowjersey.org> wrote:
>>>
>>> I believe Scott has a BMX 2002, as did I. My '72 was one
>>> great car! The '74 not so much - quite a bit heavier.
>>
>> It is, and even worse I have the Solex carbs. But it's still a fun car!
>
>On 05/01/2012 04:05 PM, Scott Dorsey wrote:
>> In article<jnpjjo$ndl$1...@dont-email.me>, AMuzi<a...@yellowjersey.org> wrote:
>>>
>>> I believe Scott has a BMX 2002, as did I. My '72 was one
>>> great car! The '74 not so much - quite a bit heavier.
>>
>> It is, and even worse I have the Solex carbs. But it's still a fun car!
>
>can you not get webers for it? a couple of dcoe40's would pep it up nicely.
It's on the list of things to do after I get the E28 fixed up. In the
meantime, I drive it to work a couple days a week and it's got 480,000 miles
on the odometer and still has the original head gasket.
Scott Dorsey
May 2, 2012, 10:18:25 AM5/2/12
to
In article <jnq4ej$91m$4...@speranza.aioe.org>, jim beam <m...@privacy.net> wrote:
>
>it's still much much cheaper to go with some other vehicle's module from
>an appropriate donor in the junkyard than going aftermarket. even some
>of the new oem styles from napa are crazy cheap. it's certainly not
>worth trying to build one from scratch unless you really have a
>hankering for the science project aspect.
I think the original poster has a hankering for the science project part,
>
>it's still much much cheaper to go with some other vehicle's module from
>an appropriate donor in the junkyard than going aftermarket. even some
>of the new oem styles from napa are crazy cheap. it's certainly not
>worth trying to build one from scratch unless you really have a
>hankering for the science project aspect.
and I understand that. What I don't understand is using a microcontroller
for something you can do with a small handful of discretes. I'll even donate
some SCRs from the junkbox.
hls
May 2, 2012, 11:19:58 AM5/2/12
to
"Nate Nagel" <njn...@roosters.net> wrote in message
news:jnrfg...@news7.newsguy.com...
>
> not sure if that's true, I've never had any kind of electronic ignition
> failure. that said I knew there was an explanation somewhere of why the
> HEI was technically better (although interchangeable) here is one
>
> http://www.slantsix.org/forum/viewtopic.php?t=15779
>
> nate
>
I've seen the GM HEI system fail a lot of times......more than anything else
> not sure if that's true, I've never had any kind of electronic ignition
> failure. that said I knew there was an explanation somewhere of why the
> HEI was technically better (although interchangeable) here is one
>
> http://www.slantsix.org/forum/viewtopic.php?t=15779
>
> nate
>
it
was shorting of the high energy coil inside the distributor.
I owned a 1997 Dodge van and never had a moments problem with it as far as
ignition.
As far as your link, the great punch line is how the HEI system gives better
(this, that and the other) because you have "a hotter, longer-duration spark
(for better ignition and more complete combustion) ".
First, you dont really need a hotter spark than it takes to ignite the
charge, and
the longer duration spark doesnt necessarily give better ignition nor
combustion,
according to a number of researchers.
There were some REALLY high energy systems that have been researched over
the years. Smokey Yunick worked with one that put relatively huge amounts
of energy into the spark....I believe he said it sounded like a pistol shot.
It never
went anywhere to speak of.
A British researcher published a complete and scholarly report on the
subject,
and he indicated that there was something to be gained, maybe, but he was
taking an elephant gun on a mouse hunt.
HEI is good enough, Kettering was good enough for most things, and CD was
also pretty good. You CAN overengineer a mousetrap.
Scott Dorsey
May 2, 2012, 1:00:56 PM5/2/12
to
hls <h...@nospam.nix> wrote:
>
>First, you dont really need a hotter spark than it takes to ignite the
>charge, and
>the longer duration spark doesnt necessarily give better ignition nor
>combustion,
>according to a number of researchers.
I think the issue is that if you have a carb and don't have good even
>
>First, you dont really need a hotter spark than it takes to ignite the
>charge, and
>the longer duration spark doesnt necessarily give better ignition nor
>combustion,
>according to a number of researchers.
fuel-air mixture going into the cylinders, the hotter spark can help.
However, with modern fuel injection systems it's become a complete non-issue.
>There were some REALLY high energy systems that have been researched over
>the years. Smokey Yunick worked with one that put relatively huge amounts
>of energy into the spark....I believe he said it sounded like a pistol shot.
>It never
>went anywhere to speak of.
Nate Nagel
May 2, 2012, 8:18:32 PM5/2/12
to
time I've ever been left at the side of the road by an ignition failure
was by a traditional Kettering system. Granted, it was probably poorly
maintained, and knowing what I know now, I probably could have been
going again with a nail file/matchbook cover/whatever, but neither the
Chrysler "orange box" or the HEI module have ever let me down.
I did have some VW coil packs replaced under warranty, now that I think
about it...
jim beam
May 2, 2012, 9:00:39 PM5/2/12
to
management becomes a breeze. current management becomes a breeze. rev
limiting [with multiple methods] becomes a breeze. and if you really
want to get into it, security becomes a breeze - rfid tag your ignition!
--
nomina rutrum rutrum
jim beam
May 2, 2012, 9:03:15 PM5/2/12
to
On 05/02/2012 07:16 AM, Scott Dorsey wrote:
original head gasket is impressive. if it ever has to come off, don't
let this happen:
<http://www.flickr.com/photos/38636024@N00/6904448039>
--
nomina rutrum rutrum
let this happen:
<http://www.flickr.com/photos/38636024@N00/6904448039>
--
nomina rutrum rutrum
jim beam
May 2, 2012, 9:18:46 PM5/2/12
to
On 05/02/2012 10:00 AM, Scott Dorsey wrote:
> hls<h...@nospam.nix> wrote:
>>
>> First, you dont really need a hotter spark than it takes to ignite the
>> charge, and
>> the longer duration spark doesnt necessarily give better ignition nor
>> combustion,
>> according to a number of researchers.
>
> I think the issue is that if you have a carb and don't have good even
> fuel-air mixture going into the cylinders, the hotter spark can help.
it's not heat, it's total energy. static electricity can create
> hls<h...@nospam.nix> wrote:
>>
>> First, you dont really need a hotter spark than it takes to ignite the
>> charge, and
>> the longer duration spark doesnt necessarily give better ignition nor
>> combustion,
>> according to a number of researchers.
>
> I think the issue is that if you have a carb and don't have good even
> fuel-air mixture going into the cylinders, the hotter spark can help.
millions of degrees in a spark on a very local basis. but it's not got
the energy to do stuff like weld steel. energy matters more than
temperature. a good fat energetic spark is what gets the job done.
"weaken" a spark by pulling off a plug lead and dissipating some of the
energy to atmosphere with a second spark gap and see for yourself.
> However, with modern fuel injection systems it's become a complete non-issue.
>
>> There were some REALLY high energy systems that have been researched over
>> the years. Smokey Yunick worked with one that put relatively huge amounts
>> of energy into the spark....I believe he said it sounded like a pistol shot.
>> It never
>> went anywhere to speak of.
>
> Smokey Yunick worked on a lot of craziness that never went anywhere....
> --scott
--
jim beam
May 2, 2012, 9:20:49 PM5/2/12
to
On 05/02/2012 08:19 AM, hls wrote:
>
> "Nate Nagel" <njn...@roosters.net> wrote in message
> news:jnrfg...@news7.newsguy.com...
>>
>> not sure if that's true, I've never had any kind of electronic
>> ignition failure. that said I knew there was an explanation somewhere
>> of why the HEI was technically better (although interchangeable) here
>> is one
>>
>> http://www.slantsix.org/forum/viewtopic.php?t=15779
>>
>> nate
>>
>
> I've seen the GM HEI system fail a lot of times......more than anything
> else it
> was shorting of the high energy coil inside the distributor.
>
> I owned a 1997 Dodge van and never had a moments problem with it as far as
> ignition.
>
> As far as your link, the great punch line is how the HEI system gives
> better
> (this, that and the other) because you have "a hotter, longer-duration
> spark
> (for better ignition and more complete combustion) ".
>
> First, you dont really need a hotter spark than it takes to ignite the
> charge, and
> the longer duration spark doesnt necessarily give better ignition nor
> combustion,
> according to a number of researchers.
cite your "sources" big guy.
>
> "Nate Nagel" <njn...@roosters.net> wrote in message
> news:jnrfg...@news7.newsguy.com...
>>
>> not sure if that's true, I've never had any kind of electronic
>> ignition failure. that said I knew there was an explanation somewhere
>> of why the HEI was technically better (although interchangeable) here
>> is one
>>
>> http://www.slantsix.org/forum/viewtopic.php?t=15779
>>
>> nate
>>
>
> I've seen the GM HEI system fail a lot of times......more than anything
> else it
> was shorting of the high energy coil inside the distributor.
>
> I owned a 1997 Dodge van and never had a moments problem with it as far as
> ignition.
>
> As far as your link, the great punch line is how the HEI system gives
> better
> (this, that and the other) because you have "a hotter, longer-duration
> spark
> (for better ignition and more complete combustion) ".
>
> First, you dont really need a hotter spark than it takes to ignite the
> charge, and
> the longer duration spark doesnt necessarily give better ignition nor
> combustion,
> according to a number of researchers.
>
> There were some REALLY high energy systems that have been researched over
> the years. Smokey Yunick worked with one that put relatively huge amounts
> of energy into the spark....I believe he said it sounded like a pistol
> shot. It never
> went anywhere to speak of.
giggles - no dyno data ever collected on that theory whatsoever.
>
> A British researcher published a complete and scholarly report on the
> subject,
> and he indicated that there was something to be gained, maybe, but he was
> taking an elephant gun on a mouse hunt.
[rhetorical]. one with dual plugs? [rhetorical] because if you ever
had, and you'd tested the magnetos mid flight, i.e. switched off one at
a time, you'd know just how ridiculous your statement was.
>
> HEI is good enough, Kettering was good enough for most things,
> and CD was
> also pretty good.
reason - it's fundamentally inappropriate for the job. but i can't see
you getting into the science of it.
> You CAN overengineer a mousetrap.
knowledge level.
--
nomina rutrum rutrum
Kevin Bottorff
May 3, 2012, 9:31:47 AM5/3/12
to
klu...@panix.com (Scott Dorsey) wrote in
news:jnrffp$hpt$1...@panix2.panix.com:
> Kevin Bottorff <kb...@gmail.com> wrote:
>>
>> or you could get Dr. Jacobs ign book and put any ign module you want
>> on
>>it. chry is cheep and relighible. done many. KB
>
> I don't know the book! Have you got a full citation?
> --scott
I will go look and get back with the full title. KB
news:jnrffp$hpt$1...@panix2.panix.com:
> Kevin Bottorff <kb...@gmail.com> wrote:
>>
>> or you could get Dr. Jacobs ign book and put any ign module you want
>> on
>>it. chry is cheep and relighible. done many. KB
>
> I don't know the book! Have you got a full citation?
> --scott
jim beam
May 3, 2012, 9:57:19 AM5/3/12
to
--
nomina rutrum rutrum
jim beam
May 3, 2012, 10:31:21 AM5/3/12
to
On 05/02/2012 07:14 AM, Scott Dorsey wrote:
> Kevin Bottorff<kb...@gmail.com> wrote:
>>
>> or you could get Dr. Jacobs ign book and put any ign module you want on
>> it. chry is cheep and relighible. done many. KB
>
> I don't know the book! Have you got a full citation?
> --scott
it's on amazon - just search for "jacobs ignition". the guy likes the
> Kevin Bottorff<kb...@gmail.com> wrote:
>>
>> or you could get Dr. Jacobs ign book and put any ign module you want on
>> it. chry is cheep and relighible. done many. KB
>
> I don't know the book! Have you got a full citation?
> --scott
sound of his own voice and simply can't resist glossing over the facts
from what i can see in the preview. you're better off with the bosch
automotive handbook. pages 379 and 570 of the current edition will
start you off.
--
nomina rutrum rutrum
AMuzi
May 3, 2012, 12:06:18 PM5/3/12
to
C. E. White
May 3, 2012, 12:06:11 PM5/3/12
to
news:jnsis...@news6.newsguy.com...
> True dat... but just my one completely anecdotal data point, the only time
> I've ever been left at the side of the road by an ignition failure was by
> a traditional Kettering system. Granted, it was probably poorly
> maintained, and knowing what I know now, I probably could have been going
> again with a nail file/matchbook cover/whatever, but neither the Chrysler
> "orange box" or the HEI module have ever let me down.
>
> I did have some VW coil packs replaced under warranty, now that I think
> about it...
>
> nate
Clearly you never had a Ford from the mid/late 70's or mid 80's or late
90's/early 00's. Ford seems to screw up an electronic ignition system about
every 10 years - first the aluminum box things on the firewalls, then the
modules inside the distributors and most recently coil packs on 5.4L V8s.
I've personally been lucky, one coil pack and I think the dealer screwed it
up when he changed the plugs, but my pareants had the aluminum case ignition
module fail on a '78 Ford and the internal distributor module fail on a 86
Ranger. Neither failure was expensive, or even particularly time consuming,
but they were annoying. Those potted aluminum ignition modules were so bad,
most car parts places just had them under the counter to hand out. Of course
by the mid 80's they got those bullet-proof, so they switched to a little
modules inside the distributor and it took another 5 years to get those
right, at which point they switched to something else. At least since about
2001, I think Ford has managed to avoid a new ignition module / coil pack
problem, but I suppose it has been 10 years, so maybe they'll screw up
something new this year or next. Of course comapred to the crap VW sells,
anything looks good. To be honest, most modern ignition systems are so good,
you are shocked when one fails. I've never actually been left on the side of
the road by an ignition failure (even back to old point type systems)
although in the old days, I did have performance conerns related to ignition
systems.
Ed
> True dat... but just my one completely anecdotal data point, the only time
> I've ever been left at the side of the road by an ignition failure was by
> a traditional Kettering system. Granted, it was probably poorly
> maintained, and knowing what I know now, I probably could have been going
> again with a nail file/matchbook cover/whatever, but neither the Chrysler
> "orange box" or the HEI module have ever let me down.
>
> I did have some VW coil packs replaced under warranty, now that I think
> about it...
>
> nate
90's/early 00's. Ford seems to screw up an electronic ignition system about
every 10 years - first the aluminum box things on the firewalls, then the
modules inside the distributors and most recently coil packs on 5.4L V8s.
I've personally been lucky, one coil pack and I think the dealer screwed it
up when he changed the plugs, but my pareants had the aluminum case ignition
module fail on a '78 Ford and the internal distributor module fail on a 86
Ranger. Neither failure was expensive, or even particularly time consuming,
but they were annoying. Those potted aluminum ignition modules were so bad,
most car parts places just had them under the counter to hand out. Of course
by the mid 80's they got those bullet-proof, so they switched to a little
modules inside the distributor and it took another 5 years to get those
right, at which point they switched to something else. At least since about
2001, I think Ford has managed to avoid a new ignition module / coil pack
problem, but I suppose it has been 10 years, so maybe they'll screw up
something new this year or next. Of course comapred to the crap VW sells,
anything looks good. To be honest, most modern ignition systems are so good,
you are shocked when one fails. I've never actually been left on the side of
the road by an ignition failure (even back to old point type systems)
although in the old days, I did have performance conerns related to ignition
systems.
Ed
Nate Nagel
May 3, 2012, 1:13:23 PM5/3/12
to
don't think I ever regularly drove any others. However, it seems that
I'm getting a new one because of some fleet management shift at work...
so we'll see. (fingers crossed.) Last company car it was the water
pump failing catastrophically... dunno what the typical Ford failures
are :)
C. E. White
May 3, 2012, 4:07:46 PM5/3/12
to
news:jnueb...@news6.newsguy.com...
VWs and Toyotas. My parents always bought Fords. I've been more diverse in
my purchases (name a major lower cost brand, and either I've had it or
someone close to me has - except nothing Korean). I've never had a truly
unreliable Ford, although I did have a 78 Fairmont that must have been
painted on a Saturday night by someone under the influence of something. The
Ford trucks we have had for our farm have always been reliable. The ignition
module in my Father 86 Ranger was about as bad as it got. My first wife had
a 89 Taurus wagon that went to hell after we got divorced, but then the
Toyota she drove before that was a smoking turd that was ready for the junk
yard at 60k miles (worst car ever!). For the most part cars are much much
better now than they were 30 years ago (or even 15). I sometimes get the bug
to buy an old Mustang or Camaro or even something British (TR-6 for
instance). But then I remember I lived through those once already and they
weren't that good. I loved the 280Z I had in 1975, but then I remember the
problems it had and I think I should just stick with newer stuff. I had a
1992 F150 with the 300 Six. I drove it for 14 years and the only expense
worth mentioning was a new fuel pump in year 14 (and even then the truck ran
fine, but the check valve in the pump leaked, so if it sat for a few days,
it would be slow to start). I actually prefer that 1992 truck to my 2009,
but then I made a mistake when I bought the 2009 and got one with too much
fluff. The truck is too nice for trashing on the farm (not that that stops
me).
Ed
> Hah... no, I've owned exactly one Ford ('93 pickup) in my life, and don't
> think I ever regularly drove any others. However, it seems that I'm
> getting a new one because of some fleet management shift at work... so
> we'll see. (fingers crossed.) Last company car it was the water pump
> failing catastrophically... dunno what the typical Ford failures are :)
Any brand of car you care to name has horror stories. Mine mostly involve
> think I ever regularly drove any others. However, it seems that I'm
> getting a new one because of some fleet management shift at work... so
> we'll see. (fingers crossed.) Last company car it was the water pump
> failing catastrophically... dunno what the typical Ford failures are :)
VWs and Toyotas. My parents always bought Fords. I've been more diverse in
my purchases (name a major lower cost brand, and either I've had it or
someone close to me has - except nothing Korean). I've never had a truly
unreliable Ford, although I did have a 78 Fairmont that must have been
painted on a Saturday night by someone under the influence of something. The
Ford trucks we have had for our farm have always been reliable. The ignition
module in my Father 86 Ranger was about as bad as it got. My first wife had
a 89 Taurus wagon that went to hell after we got divorced, but then the
Toyota she drove before that was a smoking turd that was ready for the junk
yard at 60k miles (worst car ever!). For the most part cars are much much
better now than they were 30 years ago (or even 15). I sometimes get the bug
to buy an old Mustang or Camaro or even something British (TR-6 for
instance). But then I remember I lived through those once already and they
weren't that good. I loved the 280Z I had in 1975, but then I remember the
problems it had and I think I should just stick with newer stuff. I had a
1992 F150 with the 300 Six. I drove it for 14 years and the only expense
worth mentioning was a new fuel pump in year 14 (and even then the truck ran
fine, but the check valve in the pump leaked, so if it sat for a few days,
it would be slow to start). I actually prefer that 1992 truck to my 2009,
but then I made a mistake when I bought the 2009 and got one with too much
fluff. The truck is too nice for trashing on the farm (not that that stops
me).
Ed
mike
May 3, 2012, 5:18:19 PM5/3/12
to
On 4/29/2012 10:51 AM, Paul Hovnanian P.E. wrote:
> Back when dwell angle meant anything (when we all had points in our ignition
> systems), 30% dwell meant that the points were closed and the coil
> conducting for 30% of the time. As RPM went up and down, the dwell stayed
> constant. Which meant the coil conducted for a longer period of time at low
> RPM than at high.
>
> I've got a project involving building a new electronic ignition module for a
> vehicle, and I've never looked into how electronic ignitions handle the
> dwell issue.
>
> Once a coil has 'charged up' so to speak (the DC current has risen to a
> steady state value given the coil's primary inductance), allowing it to
> conduct for a longer period of time until the points open buys you nothing.
> The stored energy in the coil is the same.
Inductance has no bearing on final current. It heads for infinity or until
you cut it loose. It's the RESISTANCE that limits the current.
And it's usually small enough that you can smoke the coil in short order.
That's why there's often a ballast resister in series wit the coil on a
point's system.
The spark timing depends on when the points open.
The energy in the coil depends on the current at the time that happens.
You could probably measure what you've got in the current system vs. RPM.
A CD ignition works differently. It charges a cap and dumps it into
the coil at spark time. I don't think dwell has much bearing on the system.
>
> Back in the days of points, it made more sense just to let the closed time
> track up and down inverse to the RPM. A simple cam will suffice. But now,
> its possible (and actually easier) to build a one-shot circuit that breaks
> the coil primary for a fixed period of time regardless of RPM. Of course,
> that lets the dwell angle go all over the place. But as long as the coil
> conducts for the requisite minimum amount of time, there should be no
> problem. In fact, such a system is a back door way of implementing a speed
> governor. Once the RPM goes so high that the fixed 'open' time exceeds the
> time needed between sparks, the engine effectively shuts down (the crank
> angle sensor keeps resetting the one-shot before it can time out and close
> the circuit).
>
> So, how do modern electronic systems work? Still constant dwell angle?
> Constant time? Granted, the ECU controlled ignition could easily be
> implement some sort of active coil current control. But that's going a bit
> overboard for my needs.
>
First task is to decide EXACTLY what's broke.
If you're unwilling to poke instrumentation under the hood, you've got
a significant handicap.
This is going to turn out like most projects. 99.9% trivial, and 0.1%
expensive development failures. You're out of your element and must learn
what the auto guys spent the last 100 years figuring out.
Make sure the hood is well out of the way when you're under there.
You don't want to rip a big gash in your head when you get shocked
and come flying out of there. Don't ask me how I know.
33 years might be old enough that you won't go to jail for tampering
with the ECU. Depends on where you live.
I feel your pain. $350 will buy a few rounds of golf or dinners out.
But what's the cost of being stranded on the mountain in a snow storm.
Or in a bad part of town at Midnight. Or missing your plane.
Before I jumped, I'd look into after-market CD ignition conversions
and see what's available. Might be easier to start with something
with a tested/reliable high voltage/current side and interface that to your
sensor on the low voltage/current side. Also, check the DEQ to see if
it's legal for your vehicle.
> Back when dwell angle meant anything (when we all had points in our ignition
> systems), 30% dwell meant that the points were closed and the coil
> conducting for 30% of the time. As RPM went up and down, the dwell stayed
> constant. Which meant the coil conducted for a longer period of time at low
> RPM than at high.
>
> I've got a project involving building a new electronic ignition module for a
> vehicle, and I've never looked into how electronic ignitions handle the
> dwell issue.
>
> Once a coil has 'charged up' so to speak (the DC current has risen to a
> steady state value given the coil's primary inductance), allowing it to
> conduct for a longer period of time until the points open buys you nothing.
> The stored energy in the coil is the same.
Inductance has no bearing on final current. It heads for infinity or until
you cut it loose. It's the RESISTANCE that limits the current.
And it's usually small enough that you can smoke the coil in short order.
That's why there's often a ballast resister in series wit the coil on a
point's system.
The spark timing depends on when the points open.
The energy in the coil depends on the current at the time that happens.
You could probably measure what you've got in the current system vs. RPM.
A CD ignition works differently. It charges a cap and dumps it into
the coil at spark time. I don't think dwell has much bearing on the system.
>
> Back in the days of points, it made more sense just to let the closed time
> track up and down inverse to the RPM. A simple cam will suffice. But now,
> its possible (and actually easier) to build a one-shot circuit that breaks
> the coil primary for a fixed period of time regardless of RPM. Of course,
> that lets the dwell angle go all over the place. But as long as the coil
> conducts for the requisite minimum amount of time, there should be no
> problem. In fact, such a system is a back door way of implementing a speed
> governor. Once the RPM goes so high that the fixed 'open' time exceeds the
> time needed between sparks, the engine effectively shuts down (the crank
> angle sensor keeps resetting the one-shot before it can time out and close
> the circuit).
>
> So, how do modern electronic systems work? Still constant dwell angle?
> Constant time? Granted, the ECU controlled ignition could easily be
> implement some sort of active coil current control. But that's going a bit
> overboard for my needs.
>
First task is to decide EXACTLY what's broke.
If you're unwilling to poke instrumentation under the hood, you've got
a significant handicap.
This is going to turn out like most projects. 99.9% trivial, and 0.1%
expensive development failures. You're out of your element and must learn
what the auto guys spent the last 100 years figuring out.
Make sure the hood is well out of the way when you're under there.
You don't want to rip a big gash in your head when you get shocked
and come flying out of there. Don't ask me how I know.
33 years might be old enough that you won't go to jail for tampering
with the ECU. Depends on where you live.
I feel your pain. $350 will buy a few rounds of golf or dinners out.
But what's the cost of being stranded on the mountain in a snow storm.
Or in a bad part of town at Midnight. Or missing your plane.
Before I jumped, I'd look into after-market CD ignition conversions
and see what's available. Might be easier to start with something
with a tested/reliable high voltage/current side and interface that to your
sensor on the low voltage/current side. Also, check the DEQ to see if
it's legal for your vehicle.
Kevin Bottorff
May 3, 2012, 6:34:30 PM5/3/12
to
AMuzi <a...@yellowjersey.org> wrote in news:jnuadn$rjt$1...@dont-email.me:
> http://www.alibris.com/booksearch?keyword=ignition+jacobs&mtype=B&hs.x=
> 0&hs.y=0&hs=Submit
THis is the exact one I have used for years to use any ign module on almost
any vehicle. KB
http://www.alibris.com/booksearch?qwork=-999797468&matches=1
&cm_sp=works*listing*title
> http://www.alibris.com/booksearch?keyword=ignition+jacobs&mtype=B&hs.x=
> 0&hs.y=0&hs=Submit
THis is the exact one I have used for years to use any ign module on almost
any vehicle. KB
http://www.alibris.com/booksearch?qwork=-999797468&matches=1
&cm_sp=works*listing*title
Kevin Bottorff
May 3, 2012, 6:36:47 PM5/3/12
to
jim beam <m...@privacy.net> wrote in news:jnu4rn$70u$1...@speranza.aioe.org:
since you know nothing about him of course your qualified to criticize him.
You just can`t stand not being a blowhard can you?? KB
You just can`t stand not being a blowhard can you?? KB
jim beam
May 3, 2012, 8:38:01 PM5/3/12
to
read it kev? or should i say, could you understand it kev? the
evidence says "no".
> You just can`t stand not being a blowhard can you?? KB
knowledge pool?
--
nomina rutrum rutrum
jim beam
May 3, 2012, 8:40:06 PM5/3/12
to
--
nomina rutrum rutrum
jim beam
May 3, 2012, 8:47:00 PM5/3/12
to
On 05/03/2012 02:18 PM, mike wrote:
> On 4/29/2012 10:51 AM, Paul Hovnanian P.E. wrote:
>> Back when dwell angle meant anything (when we all had points in our
>> ignition
>> systems), 30% dwell meant that the points were closed and the coil
>> conducting for 30% of the time. As RPM went up and down, the dwell stayed
>> constant. Which meant the coil conducted for a longer period of time
>> at low
>> RPM than at high.
>>
>> I've got a project involving building a new electronic ignition module
>> for a
>> vehicle, and I've never looked into how electronic ignitions handle the
>> dwell issue.
>>
>> Once a coil has 'charged up' so to speak (the DC current has risen to a
>> steady state value given the coil's primary inductance), allowing it to
>> conduct for a longer period of time until the points open buys you
>> nothing.
>> The stored energy in the coil is the same.
> Inductance has no bearing on final current.
inductance most /definitely/ has a bearing on current all the way up to
> On 4/29/2012 10:51 AM, Paul Hovnanian P.E. wrote:
>> Back when dwell angle meant anything (when we all had points in our
>> ignition
>> systems), 30% dwell meant that the points were closed and the coil
>> conducting for 30% of the time. As RPM went up and down, the dwell stayed
>> constant. Which meant the coil conducted for a longer period of time
>> at low
>> RPM than at high.
>>
>> I've got a project involving building a new electronic ignition module
>> for a
>> vehicle, and I've never looked into how electronic ignitions handle the
>> dwell issue.
>>
>> Once a coil has 'charged up' so to speak (the DC current has risen to a
>> steady state value given the coil's primary inductance), allowing it to
>> conduct for a longer period of time until the points open buys you
>> nothing.
>> The stored energy in the coil is the same.
> Inductance has no bearing on final current.
saturation. and inductance /definitely/ had a bearing on time to
saturation..
> It heads for infinity or until
> you cut it loose. It's the RESISTANCE that limits the current.
> And it's usually small enough that you can smoke the coil in short order.
> That's why there's often a ballast resister in series wit the coil on a
> point's system.
>
> The spark timing depends on when the points open.
> The energy in the coil depends on the current at the time that happens.
<http://en.wikipedia.org/wiki/Inductors#Stored_energy>
> You could probably measure what you've got in the current system vs. RPM.
>
> A CD ignition works differently. It charges a cap and dumps it into
> the coil at spark time. I don't think dwell has much bearing on the system.
except a few outdated aftermarket systems, and even those manufacturers
quietly offer inductive systems as well because they know the reality,
<snip>
>
> Before I jumped, I'd look into after-market CD ignition conversions
> and see what's available.
why? why? why? cdi doesn't work as well. and why do so many people
> Before I jumped, I'd look into after-market CD ignition conversions
> and see what's available.
think electronic ignitions are all capacitive???
and just use an inductive retrofit module. chances are the o.p. can
pick one up for a few bucks, and won't even have to change their coil.
cdi requires coil change, so that's even more expense on top of the
hundreds spent on aftermarket that won't work as well because it doesn't
deliver as much energy.
> Might be easier to start with something
> with a tested/reliable high voltage/current side and interface that to your
> sensor on the low voltage/current side. Also, check the DEQ to see if
> it's legal for your vehicle.
[inductive] components.
--
nomina rutrum rutrum
Scott Dorsey
Jun 8, 2012, 10:39:35 AM6/8/12
to
In article <jnu4rn$70u$1...@speranza.aioe.org>, jim beam <m...@privacy.net> wrote:
>On 05/02/2012 07:14 AM, Scott Dorsey wrote:
>> Kevin Bottorff<kb...@gmail.com> wrote:
>>>
>>> or you could get Dr. Jacobs ign book and put any ign module you want on
>>> it. chry is cheep and relighible. done many. KB
>
>On 05/02/2012 07:14 AM, Scott Dorsey wrote:
>> Kevin Bottorff<kb...@gmail.com> wrote:
>>>
>>> or you could get Dr. Jacobs ign book and put any ign module you want on
>>> it. chry is cheep and relighible. done many. KB
>
>it's on amazon - just search for "jacobs ignition". the guy likes the
>sound of his own voice and simply can't resist glossing over the facts
>from what i can see in the preview. you're better off with the bosch
>automotive handbook. pages 379 and 570 of the current edition will
>start you off.
Okay, I got "The Doctor's Step By Step Guide to Optimizing your Ignition"
>sound of his own voice and simply can't resist glossing over the facts
>from what i can see in the preview. you're better off with the bosch
>automotive handbook. pages 379 and 570 of the current edition will
>start you off.
which was $3 at thriftbooks.com.
It's not good but not bad. It does flog some of Jacobs' products, but less
than you'd expect for a book like this. It has some interesting and useful
stuff like his method for estimating horsepower on the road which is really
kind of ingenious.
It has a lot of advice in it that is good advice but is not backed up with
proper explanations of any sort. His basic electricity introduction is
misleading and doesn't include some of the stuff that is needed for some of
his later discussions. It also has some advice that seems a little suspicious
to me.
It has basically zero information about what is really going on inside
the box.
On the other hand, some of the empirical "I tried this and it worked and I
tried this and it didn't" could be very useful.
And, the discussion of reading sparkplugs (and how reading sparkplugs for
performance tuning is not really as useful as it used to be) is very very
good and makes a lot of points that people seem to ignore today.
So, I'd give it a 2/5. I'd give the TAB book by Brant a 2/5 also, but the
information in the Brant book is a lot more detailed about what goes on inside
the box. Either one is well worth $3 on thriftbooks.
Kevin Bottorff
Jun 8, 2012, 2:12:57 PM6/8/12
to
klu...@panix.com (Scott Dorsey) wrote in
news:jqt2r7$4g2$1...@panix2.panix.com:
Jocobs instructions. much cheeper than reinventing the wheel, unless you
want a elect project. KB
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