Rotax Temps
F. Feeney
I'm just getting in the air this season with a CGS Hawk with a Rotax 503,
DCDI engine on it. The plane came to me already equipped with an
electronic EIS system to measure the CHT and EGT on both cylinders.
During the brief time I flew it before the end of the season last year, I
noted that the temps on the two cylinders seemed a bit wide apart. I was
busy learning to fly it, so I didn't spend a lot of time recording the
actual temps in flight, but just noted that they weren't the same.
Checking the Rotax manual gives limits of something like 30 degrees
between CHT's and 50 for EGT's for spread. I'm right at that or somewhat
above that I believe. So what does that mean?
The engine runs steady and strong. It's got 180 hours on it and was just
decarboned and reassembled by a rotax service center, and it looks like
it's doing the same thing this season from my brief first flight last
night.
Temps are fine, a little on the cool side probably. I don't think the EGT
broke 1000 last night on four circuits around the pattern. CHT was in the
low 300's range. Fan belt tension is fine, checked again when the engine
was reassembled. Carbs are stock Bing 36's with factory jetting. Field
elevation is 1020'. Aircleaner's recently washed and re-oiled.
Tonight I plan to go cruise around a bit weather permitting, and I'll
take note of the temps at various points in the flight and write them
down.
I thought at first, maybe the senders were out of calibration and not
matching up, but when the engine is cold, both cylinders give the same
CHT and EGT readings, so they match up at least at the cool end of the
range.
I guess my question is, what is this difference telling me? is it
something to be concerned about? Do most engines run within the rotax
guidelines, or is it not unusual to have a larger spread? I can
understand the CHT's being different with the hotter cylinder in the
rear, but why the difference in the EGT's - that would imply different
mixture to me. But I'm new to all this two stroke jazz. Should I be doing
anything about it? Or am I just being a nervous nellie?
Thanks in advance
Kevin
Mark Smith
First, don't oil the aircleaner, it oils itself pretty good without
help.
and switching the wires at the gauge will tell some interesting things
about the wiring in the plane, etc
the unit itself may be out of calibration but rather unlikely,,,,,,,,
--
Mark Smith
Tri-State Kite Sales http://www.trikite.com
1121 N Locust St
Mt Vernon, IN 47620 mailto:ma...@trikite.com
1-812-838-6351
Can someone please convince me that MicroSoft isn't cheating on their
simple game of MineSweeper?
It seems that with a rather low 'best score', I never guess correctly
when the odss are clearly in my favor to guess correctly once in awhile.
F. Feeney
writes:
>
>First, don't oil the aircleaner, it oils itself pretty good without
>help.
>
Ummm, it's a pair of K&N cone styles, and the folks at the club say "When
you can't see red on the paper, time to clean and re-oil", and the K&N
docs say do it about every 10 hours. Maybe we're talking different kinds
of aircleaners?
>and switching the wires at the gauge will tell some interesting things
>about the wiring in the plane, etc
Yeah, I'm planning on doing some rewiring, but based on them matching at
cold temp, I don't think they are too likely to be very messed up.
>
>the unit itself may be out of calibration but rather unlikely,,,,,,,,
Another reason I checked them to see if they matched at cold temp. I may
drag out the millivolt meter and see what the senders are putting out
after shut down while things are still warmish.
But, assuming the senders and instrumentation are right - then what? Do I
have a problem, or just an unusual engine?
Thanks
Kevin
>--
>
>
Scrappman
a cowl. Seen a much wider band on a few liquids. As long as there not to
high, keep an eye on them, not that ya relax a little while flying.
Scrappman
Mark Smith
I don't use the pair of cleaners on a dual carb engine, I rather like
the dual element ones that stabnilize the carbs better.
also, KnN sys a lot of things but do they fly anything ?
I doubt it.
unless you fly through dust storms or hover over a ball diamond,,,
dale
out of synchonization at cruise throttle. Once adjusted there is about
10-15' difference.
Dale
Scrappman wrote in message <3B3A6AA8...@rconnect.com>...
F. Feeney
In article <3B3A6AA8...@rconnect.com> Scrappman, rap...@rconnect.com
writes:
> Doesn't sound that far off. If there both out in the open air, or
half in
>a cowl. Seen a much wider band on a few liquids. As long as there not to
>high, keep an eye on them, not that ya relax a little while flying.
> Scrappman
>
Well spending most of my time in the pattern right now, so it's a little
busy to be watching guages a lot. When the weather gets less hazy and i
can wander off a bit I'll get a chance to check them out in cruise a bit
more. Last night in climb I popped it into dual cylinder disply mode and
the EGT was 991 over 939. CHT's were about 35 degrees apart, in the low
300's.
The engine has a fan, so it's not a free air version, with the rotax cowl
that is part of that - directs the air over both cylinders and then out
vents near the plugs. The hawk is a pusher design, so you need the fan
and cowl I guess.
Kevin
F. Feeney
writes:
>I don't use the pair of cleaners on a dual carb engine, I rather like
>the dual element ones that stabnilize the carbs better.
That's a good point, I bet there's less chance of one coming loose and
they probably do keep things from wobbling about as much - maybe less
wear on the boots that way too. When the time comes to put a new one on,
I may go that route. This one came to me working this way and until I
learn a bit more about it all, I'm not going to mess with success. But
hanging out here listening to the discussions or getting pointers like
this is how I'll learn.
>
>also, KnN sys a lot of things but do they fly anything ?
I don't know. Probably a lot less dust up in the air than for most ground
vehicles. But they do say that the paper element doesn't provide the
filtration, it's the oil that it carries that does the actual filtering.
So for now, I'll do what they say, and learn as much as I can so I can
make my own decisions in the future.
>
>I doubt it.
>
>unless you fly through dust storms or hover over a ball diamond,,,
True, and several folks around don't run any air filters at all. I just
don't want to mess too much with a working configuration till I know more
about what I'm doing, that's all.
Kevin
>--
F. Feeney
In article <3b3a...@news.tisd.net> dale, wzy...@tisd.net writes:
>I had some difference in the EGT on my 503 and I found it to be the carbs
>out of synchonization at cruise throttle. Once adjusted there is about
>10-15' difference.
>Dale
How did you check the carb synch. Mine were checked a little while ago by
just watching the slides go up to make sure they clear the edge of the
throat at the same time. I used to use carb stix on the motorcycles years
ago, not sure how I'd do that on the rotax. Not sure I wanna be anywhere
near that turning prop while measuring either!
How do you synch your carbs? Last night the difference between the EGT's
was about 52 degrees (991-939).
Kevin
Russell
>I don't know. Probably a lot less dust up in the air than for most ground
>vehicles. But they do say that the paper element doesn't provide the
>filtration, it's the oil that it carries that does the actual filtering.
>So for now, I'll do what they say, and learn as much as I can so I can
>make my own decisions in the future.
because the engine will do the job for you. Two strokes especially,
spit back through the carbs at certain rev ranges and on a premix this
fuel that spits back out the carbs contains oil. I know my Cyuna
usually has tends to have a drip of oil hanging off the bottom of the
air cleaners even though I've never oiled them. Anyone know if oil
injected motors do the same thing? Or is the oil injected too far
into the inlet system to get back out through the carb throat?
Cheers
Russell
Mark Smith
Good point about the injected versus the non injected,,,,,,
but the oil is dribbled in the omtake manifold, not really injected at
all.
,,,,,,and the location is just outside the rotary valve so any spitback
would likely have the same oil ratio as the non injected.
the cuyunas were famour for filling the inverted plugs with oil inside
the engine on the wuicks, and the drip of oil off the filter corner is a
good indication that the filter is oil clogged and the engine is running
rich,,,,,,,,,,
dale
First swap the EGT probes or wiring to make sure you don't have a probe
reading higher than the other.
Check the needles and make sure both are set on the same notch. While in the
carb, check all the jet numbers to be sure they are all the same. Check the
float level. Mark has a point about the filters being too oily and causing
that cylinder to run a little rich.
Your temps are very clost to mine, about 300' CHT and 1000' EGT. Don't ever
let the CHT get over 400', the 503 will seize about 425' even though the
manual says "max CHT is 480", that is not true in the real world.
Synchronizing the carbs at open throttle is done that way, making sure both
slides clear the bore at the same time. If one carb is opening more than the
other it would be a little richer than the other, thus the temp would be
lower. You could mess with the cable adjustment on top of the carb making
the lower temp carb run a little leaner by lengthening the cable.
The 2 cycles are a new ball game and guys like Mark and Scrappman have
messed with them a long time and seen all the little tricks.
Dale
F. Feeney wrote in message <9hfkbk$fkc$3...@news01.cit.cornell.edu>...
F. Feeney
>Fenney,
>First swap the EGT probes or wiring to make sure you don't have a probe
>reading higher than the other.
Yeah, that's a project for the next rainy day. I can swap the CHT probes
easy, the EGT's are a little harder to do, so I'll probably swap the
wiring on those.
>
>Check the needles and make sure both are set on the same notch. While in
the
>carb, check all the jet numbers to be sure they are all the same.
Will do, I'm not real familiar with taking the carbs apart, so may want
to wait till I have a local expert on hand. I hate that "sproing" and
parts go flying thing that happens when I sometimes investigate new
mechanical devices. :-)
Check the
>float level.
Not sure how to do that.
Mark has a point about the filters being too oily and causing
>that cylinder to run a little rich.
I don't think that's the problem here. Both filters were cleaned and
oiled together and equally well. But the difference in temps was aparent
last fall too, when the filters were dry. There doesn't seem to be any
significant change since I've cleaned and oiled them. Temps are about
where they were, and peak RPM also.
>
>Your temps are very clost to mine, about 300' CHT and 1000' EGT. Don't
ever
>let the CHT get over 400', the 503 will seize about 425' even though the
>manual says "max CHT is 480", that is not true in the real world.
Wow, that's good to know. I was going to set the EIS limits at 425.
>
>Synchronizing the carbs at open throttle is done that way, making sure
both
>slides clear the bore at the same time. If one carb is opening more than
the
>other it would be a little richer than the other, thus the temp would be
>lower. You could mess with the cable adjustment on top of the carb making
>the lower temp carb run a little leaner by lengthening the cable.
Yeah, that's the same as motorcycles. The mechanic who checked it over
when I bought it checked that (and the needles and clips and the rest now
that I think about it) and it's only had about 7 hours on it since then.
But I'll double check it.
>
>The 2 cycles are a new ball game and guys like Mark and Scrappman have
>messed with them a long time and seen all the little tricks.
Indeed, I've noted that while lurking on the list which I why I came here
with my questions. I've already had several good pointers and some other
things to think about pointed out, like filter choices.
I guess one part of the question I haven't seen comment on is, why is the
difference in temps a problem? Thermal stress across the engine? One
cylinder working harder than the other and that causing stress or wear?
I've operated multicylinder motorcycle engines for years, and other than
balancing the carbs, which a lot of folks never bother to do, I've never
heard any real concern about temps or imbalances of other kinds between
cylinders - why is Rotax worried enough to specify max temperature
differences? Granted an engine failure airborne is much more critical
than if a motorcycle quits and you roll to a stop on the side of the
road. But I guess I don't see why one cylinder running richer than
another is a problem, unless you exceed the temp limits.
Thanks for all the good avice.
kevin
>
>Dale
>
>
dale
Back to the EIS and setting the parameters for alarms on CHT and EGT. Built
a show quality Kolb Firestar II, reading the manual and noting the 480' max
CHT, I set 440' which would give me 40' to do something before I reached the
max temp. Well with 2 hours on it and climbing slightly near the pattern for
the airport at 500', it seized. I did good, thinking I could glide to a
clearing on the airport property, I got the nose down and flew the plane,
but unfortunately it glided like a rock and it became quickly obvious I
would not make the clearing. I held it at the tops of the mesquite trees and
just stalled it in the trees. Not a lot of structural damage other than nose
cone but 13 holes in wings and tail fabric. Rotax? Engine seizures are not
covered under warranty, period. All 7 service centers told me that a 503
will not go to 480' and a couple even argued with me about the figure in the
manual. The alarm light never went off so it seized before it hit 440'. It
certainly left a bad taste in my mouth for Rotax. It has since gone 335
hours with nary a problem. There was something wrong or trash in the carbs,
but we never found any trash or incorrect assembly, but after going through
them seperately the temps came down.
I don't know if the difference in temps is so critical, but it stands to
reason you want both cylinders performing the same. EGT's pretty much
indicate the fuel mixture and change very quickly. CHT's indicate the
cooling whether by the fan or the fuel and don't change so fast.
If the fan belt were loose the EGT's would be normal, but the CHT's would be
high. On the other hand the fan could be cooling well and the EGT's go up
very high and it would take a little while for the CHT's to get really high.
I think mine run about 15' apart almost all the time. I don't see it as a
problem and haven't tried to get it out, but I think if I adjusted the slide
cables on the carb tops I could even it out. First I would swap the wires or
probes to see if it was the probes or not.
Just some thoughts.
Dale
Mark Smith
I now of nobody that would encourage operation at 480 degrees on a CHT
for any Rotax product.
The manual is wrong !!
I'll bet a call to the company would get another engine.
The 480 supposedly is the temperature at the base of the plug, not where
we actually measure temps at the upper end of the threads.
Very poor engineering, literature, etc,,,,,,,,,,,,
On the other hand, any of us with Rotax experience would suggest a
warning set point of 350 degrees for the CHT.
TN65X57
any run-in period when it seized?
LouisB
Curious minds always seek details.
dale
I had done the break-in by the book and kept a log of the temps for every
minute. It got to 420' on the max throttle run, but I made it through the
entire break-in.
There was something in the carbs. Ronnie Smith repaired the engine and
pulled #1 carb apart but found no trash nor anything amiss. Back at home the
#2 cylinder was running about 50' hotter than the #1 on the next break-in. I
pulled the #2 carb off went through it and found nothing. Put it back now
the temps were both together and I have never seen high temps again, 335
hours and 3 years.
Rotax would not even talk about it. I had never seen any written info on the
max temps until I read Mike Stratmans stuff in the CPS catalog. This of
course was after my incident. Rotax did tell me that the 480' was under lab
conditions and would be lower in the real world. Still no recourse from
them. Rotax is putting lives and planes in danger with this incorrect info,
they know it, but it has not changed in 3 years.
TN65X57 wrote in message <20010630082456...@ng-xc1.aol.com>...
RButler215
What engine did you put 115 hours on with one set of plugs? I hope not a Rotax
and if so I would not blame Rotax for your problems.
Mark Smith
I ran a plugs up 618 for 150 hours on the same plugs,,,,,,,,,,
what is the problem ?
dale
I am with Mark, you will not find ANYWHERE a better built and better cared
for Kolb Firestar than mine. I have 335 hours on it and put about 115 hours
on the same plugs on the 503 in the last year. The plugs were checked twice
during the last year, the color was good, they looked good, I checked the
gap and kept running them. I have oil injection and you can barely discern a
mag drop on run up. So like Mark, what is the problem?
I think Rotax has the best stuff on the market, had I only known or read
somewhere that a 503 will not endure CHT's over 420' I can assure you I
would have landed out before I let it get to 380'. The 2 cycle is a
different beast and you need to bone up on everything you can about it.
Rotax is wrong to leave the 480' figure in their manual. They have moved
stuff out of the US to Jamaica or somewhere to stave off the lawsuits. I
never even considered sueing them, it would have been nice had they
corrected the error in the manual.
Dale
Mark Smith wrote in message <3B3E40...@trikite.com>...
Mark Smith
Th situation described above of the engine seizing will not be predicted
on any gauge, either CHT or EGT.
Nothing measures piston toe cylinder wall temperature differenvce with
the different expansion ratios figured in on top.
New engines produce more heat than older ones due to less friction
beteween the piston and cylinder.
,and while the CGT does read head temps, this is not a good prediction
of seizure.
,,,,and while a rising CHT reading in an older and higher hour engine is
an indication that something is changing, it is obvious that a new
engine isn't going to run WOT for long periods of yime without possible
seizures occurring.
Seizures during the breakin period are not all that uncommon,,,,,,,,,,,
jon eiserling
started) and was going to follow the standard break-in routine. I have
"notched" the carb slide and increased idle jet size by 1 but other than
an airscrew cdi conversion it is stock. I'm aware the crank seals are
old but testing shows no leaks. I sure don't want to "seize" it! I have
single cht/egt, with cht on pto plug and egt probe 3.90" from piston
skirt. It's "plugs down", fan cooled, and on an MX with a 32X52 Tenn.
prop. Assuming the gauges are accurate what should the max temps be
during a static break-in? Thanks...
Jon
Ed Snyder
> RButler215 wrote:
> >
> > Dale
> > What engine did you put 115 hours on with one set of plugs? I hope not a Rotax
> > and if so I would not blame Rotax for your problems.
>
> I ran a plugs up 618 for 150 hours on the same plugs,,,,,,,,,,
>
> what is the problem ?
As a Kawasaki Motors dealer for a number of years I learned at one training seminar,
“that it is not the number of hours on a spark plug that is important, but the
condition of the spark plug when checked”. While hours of use on a plug is
indicative of the plugs condition it is not the sole factor. Plugs ware out for a
number of reasons. One of the main things to check is the center electrode. If the
electrode has sharp edges totally around it then it then the plug is good. A
rounded center electrode indicates the plug is used up. The same for the tip
electrode. The plug can continue to function for a long time, however it takes
considerable more kilovolts “KV” to get the spark to jump and while it does jump, it
is late in the fire cycle. The phenomenon is that for some reason the spark travels
best from the edges. No sharp edges, it appears to be looking for a place to go?
Javier Susaeta
Blazer S-10. The manual says that they have to be changed every 100000 miles
(!). The car has now a bit more (185000 km) and I don't feel any spark plug
underperformance. How things have changed... For cars, at least.
Regards
Javier
"Ed Snyder" <pwrs...@ix.netcom.com> escribió en el mensaje
news:3B3EC958...@ix.netcom.com...
Mark Smith
>
> I'm about to do the "break-in" on a new 377 (15 years old but never
> started) and was going to follow the standard break-in routine. I have
> "notched" the carb slide and increased idle jet size by 1 but other than
> an airscrew cdi conversion it is stock. I'm aware the crank seals are
> old but testing shows no leaks. I sure don't want to "seize" it! I have
> single cht/egt, with cht on pto plug and egt probe 3.90" from piston
> skirt. It's "plugs down", fan cooled, and on an MX with a 32X52 Tenn.
> prop. Assuming the gauges are accurate what should the max temps be
> during a static break-in? Thanks...
First off, replacing fifteen year old seals would be a good idea. total
cost if you do the work would be 50 bucks for the seals and new gaskets.
next, the 377 is almost bulletproof when it comes to operation until the
rings stick, and then it seizes just like the bigger engines.
It has the smaller fan, and shrounds than the 503, but also has smaller
power, and larger fin area than the souped up same size version, the
447.
you will probably get away with the standard rotax breakin with this
engine
you should reverse the prop for a 52-32 though !!!
Ed Snyder
factors when comparing the two types of engines: Four cycle engines fire the
plug only once during the four cycles. Four cycle auto engines run at much
lower rpms, fewer firing cycles. The two cycle plug is working extremely hard
when compared to the four cycle auto engine. New modern auto engines have high
energy ignition systems where the spark burn time very short. Less burn time to
eat up the electrode so they last longer than they did years ago. I would guess
that there are other factors I am not aware of. One of the Rans factory planes
was visiting my dealership awhile back. Their 912 engine was not running worth
a shit when they arrived. We checked all kinds things and could not find
anything wrong. So we changed the plugs. It fixed the problem instantly. When
comparing the old plugs to new we could not see much different. The old plugs
looked fine. So go figure.
Ed
Ray Leonard
<pwrs...@ix.netcom.com> wrote:
>Good question. First, I am far from an authority in this subject. Some of the
>factors when comparing the two types of engines: Four cycle engines fire the
>plug only once during the four cycles. Four cycle auto engines run at much
>lower rpms, fewer firing cycles. The two cycle plug is working extremely hard
>when compared to the four cycle auto engine. New modern auto engines have high
>energy ignition systems where the spark burn time very short. Less burn time to
>eat up the electrode so they last longer than they did years ago. I would guess
>that there are other factors I am not aware of. One of the Rans factory planes
>was visiting my dealership awhile back. Their 912 engine was not running worth
>a shit when they arrived. We checked all kinds things and could not find
>anything wrong. So we changed the plugs. It fixed the problem instantly. When
>comparing the old plugs to new we could not see much different. The old plugs
>looked fine. So go figure.
>
>Ed
>
Bet they were using 100LL
Ray
F. Feeney
>>
>> Kevin,
>> Back to the EIS and setting the parameters for alarms on CHT and EGT.
Built
>> a show quality Kolb Firestar II, reading the manual and noting the
480' max
>> CHT, I set 440' which would give me 40' to do something before I
reached the
>> max temp.
From reading the users manual, which those of us new to this tend to take
as a Bible vs what we hear around - being from the horses mouth as it
were, that's about what I was planning to do, set it to 425-450 or so.
But now I'll set it much lower.
Well with 2 hours on it and climbing slightly near the pattern for
>> the airport at 500', it seized. I did good, thinking I could glide to a
>> clearing on the airport property, I got the nose down and flew the
plane,
>> but unfortunately it glided like a rock and it became quickly obvious I
>> would not make the clearing. I held it at the tops of the mesquite
trees and
>> just stalled it in the trees. Not a lot of structural damage other
than nose
>> cone but 13 holes in wings and tail fabric.
Ouch! At least you did good and walked away it sounds like.
Rotax? Engine seizures are not
>> covered under warranty, period. All 7 service centers told me that a
503
>> will not go to 480' and a couple even argued with me about the figure
in the
>> manual. The alarm light never went off so it seized before it hit
440'. It
>> certainly left a bad taste in my mouth for Rotax. It has since gone 335
>> hours with nary a problem. There was something wrong or trash in the
carbs,
>> but we never found any trash or incorrect assembly, but after going
through
>> them seperately the temps came down.
Don't you hate mysteries like that.
>>
>> I don't know if the difference in temps is so critical, but it stands
to
>> reason you want both cylinders performing the same.
I agree, just wondering why they seem so concerned about it.
I was once on a long motorcycle trip (NY, AK, CA, NY) and one afternoon
on the last leg of the trip back to Rochester NY, the bike seemed to
require a bit more throttle to pass than I thought was normal. I pulled
over and the idle was a bit low, so I started pulling plug wires (GS750).
Two of them didn't make any difference. Turned out one set of points had
broken, and I had been riding for hours at highway speeds on 2 of the 4
cylinders. Didn't seem to hurt the engine. I sold it with over 60,000
miles on it, and it was up over 100,000 when I lost track of it.
Obviously that engine wasn't working nearly as hard as a little two
cylinder two stroke. But two cylinders not firing is a lot more out of
balance than a few degrees on the CHT too.
EGT's pretty much
>> indicate the fuel mixture and change very quickly. CHT's indicate the
>> cooling whether by the fan or the fuel and don't change so fast.
>> If the fan belt were loose the EGT's would be normal, but the CHT's
would be
>> high. On the other hand the fan could be cooling well and the EGT's go
up
>> very high and it would take a little while for the CHT's to get really
high.
>> I think mine run about 15' apart almost all the time. I don't see it
as a
>> problem and haven't tried to get it out, but I think if I adjusted the
slide
>> cables on the carb tops I could even it out. First I would swap the
wires or
>> probes to see if it was the probes or not.
>> Just some thoughts.
Thanks Dale. I did get a chance to look over the temps at cruise the
other night and they do seem to stabilise closer to each other than they
were in the pattern. I'm going to take up a clipboard tonight and try to
record them at various points in the flight so I have more hard data.
>> Dale
Mark said>>>
>
>I now of nobody that would encourage operation at 480 degrees on a CHT
>for any Rotax product.
>
>The manual is wrong !!
>
That's good to know Mark. Until this discussion, I'd have assumed the
manual was correct - after all if anyone should know it would be rotax
you figure - and might have ignored a potential problem.
>I'll bet a call to the company would get another engine.
>
>The 480 supposedly is the temperature at the base of the plug, not where
>we actually measure temps at the upper end of the threads.
Yup.
>
>Very poor engineering, literature, etc,,,,,,,,,,,,
>
I think the engineering is ok, most of the engines run fine. But the
literature and support looks like it could use some tweaking. I wonder
what else in the manual is wrong. Is the max EGT really 1200?
>On the other hand, any of us with Rotax experience would suggest a
>warning set point of 350 degrees for the CHT.
That's what I'm looking for, the voices of experience. I'll check tonight
that it's set at 350 or so.
Thanks to everyone involved in this discussion. It's been very helpful.
Kevin
Mark Smith
,,,,,,,,,,,
> Thanks to everyone involved in this discussion. It's been very helpful.
>
> Kevin
I have found the Rotax manual, and their warrantee to be about as useful
as their toolkit !!
Kevin McCue
out. Per "Click and Clack" the car guys, You may find that the plugs have
become one with the head if you do ever try to get them out. They recommend
at least pull and lube occassionally!
"Javier Susaeta" <j.su...@bitmailer.net> wrote in message
news:9hmojd$ec54d$1...@ID-90320.news.dfncis.de...
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dale
I think my limits on the EIS are set at 350' and 1130'. I've only had the
350 exceeded one day climbing out and not paying attention. I will exceed
the 1130 in a midrange area 4100 rpm to about 4600 rpm.
I can't say enough good things for the EIS, it has worked flawlessly so far.
Dale
Paul Westcott
plug firing frequency, but on several modern auto engines the plug
fires each time the piston goes over the top, just like a two cycle.
The 1989 Olds Quad Four does this, one of the spark plug firings is
into the exhaust stroke to it doesn't accomplish anything, but it
allows for electronic control of the ignition system and elimination
of the distributor. Instead a sensor reads the crankshaft position
and fires the appropriate plug, since this doesn't provide the 2:1
gear down of a distributor, the plug fires each time.
Paul Westcott
On Sun, 01 Jul 2001 10:31:37 -0700, Ed Snyder <pwrs...@ix.netcom.com>
wrote:
>Good question. First, I am far from an authority in this subject. Some of the
Pieter Litchfield
.......Their 912 engine was not running worth
> >a shit when they arrived. We checked all kinds things and could not find
> >anything wrong. So we changed the plugs. It fixed the problem
instantly. When
> >comparing the old plugs to new we could not see much different. The old
plugs
> >looked fine. So go figure.
> >
>
I have run a large number of high performance two and four cycyle engines.
It's not too unusual to encounter a plug that looks fine but works poorly.
Often a plug gap adjusted with the wrong tool (like prying the electrodes
apart with a screwdriver) can result in a hairline fracture of the center
insulator. This gives the spark a path to ground, and poor performance
results. It will become visually obvious after a while, but at first its
almost invisible. Other possibilities are a particle of carbon stuck
between the center insulator and the shell, and rounded electrodes (as
mentioned in a prior post),
David Brodbeck
Javier Susaeta wrote:
>
> I know it's a four-stroke, but I have never changed the spark plugs in my
> Blazer S-10. The manual says that they have to be changed every 100000 miles
> (!). The car has now a bit more (185000 km) and I don't feel any spark plug
> underperformance. How things have changed... For cars, at least.
Platinum plugs. They're good for a lot longer than the standard ones.
Only problem is that when the same plugs have been in the head for
100,000 miles without being touched, they're darn hard to get out when
you *do* have to change them. It's pretty common to strip the threads
on the plug hole and have to pull the head to put in a helicoil.
JUSTJEFFMC
the fuselage. My EIS shows about 30 deg difference between the CHT on 2
Cylinders (195 / 225). My EGTs are about 50-80 difference 1095 / 1025. My
Coolant temp however is running around 180. OAT around 80 degrees. I think
the chute is directing the air flow away from the radiators (Rotax radiators
mounted on the engine).
Mark Smith
The chute can't help the radiators, they don't work well alone.
I suggest a smaller radiator in series mounted somewhere out of the way
possibly.
,,,,,,,,and 180 is TOO hot
lucien stavenhagen
>
> First off, replacing fifteen year old seals would be a good idea. total
> cost if you do the work would be 50 bucks for the seals and new gaskets.
>
> next, the 377 is almost bulletproof when it comes to operation until the
> rings stick, and then it seizes just like the bigger engines.
>
> It has the smaller fan, and shrounds than the 503, but also has smaller
> power, and larger fin area than the souped up same size version, the
> 447.
>
> you will probably get away with the standard rotax breakin with this
> engine
Hey Mark,
Do you have a different breakin procedure that you use other than the
one in the manual? When I did the breakin of the 503 on CA IV, I did
it by that chart. Even with a 190 main jet, the CHT got up to 350
indicated during the final 3 minute WOT run. I went back to idle for a
minute after 2 minutes to let it cool down, than ran it wide open for
the final minute (that motor still runs ok, so guess it broke in
properly)
I'm fixing to replace the 447 on my trike and never ran one of those
in. I worry about the 447 overheating during the breakin moreso than
the 503. Do you have a preferable way that you suggest?
Thanks,
LS
Mark Smith
the rotax breakin requires some pretty high RPMs and times pretty soon
for a new engine.
i know they want to 'cya' theirs in this case, but ruining a good engine
doesn't appeal to me much, especially since I do a couple engines a week
and can't afford to have repeats requiring new pistons and such.
I use a half hour of the rotax chart and then go to flying the plane for
the balance.
tied to a stick, temps will be higher, and the prop will turn harder,
both leading to excessive loads from what will be seen in flight.
while I don NOT recommend crowhops for students or self training, I do
them to breakin the last half of the recommended hour,,,,,,,,,
also BTW, this allows me to adjust the brakes side to side, the idle,
the steering for straight ahead, etc.
and I seem to give a better walkaround when I have been off the ground a
foot or two and am preparing to go a couple hundred.
this particulary applies to the 'souped' up 447,,,,,,,,,,
ls
I think I'll use your procedure on the 447. When I ran in the 503, I
remember thinking that 2 and 3 minutes of wide open throttle on the ground
was awful hard work for a 2-stroke motor with only about an hour on it and
it did get pretty warm. But I know the 447 runs hot and I'm afraid I'll
burn the sucker up right at the end of the chart....
What you recommend in the flying part as far as how much wide open, how much
putting around, etc.? I can do crow hops, we got 4000' of runway....
LS
AC fun racer.
Mark Smith
my runway is 1600 or so and it works for me.
I pretty much do the rotax breakin as far as the rpms and the times are
concerned.
I just keep a good eye on the egt, cht, etc and backup several steps if
they approach my own personnal limits for high values,,,,,,,
I also keep the other eye on the approaching end of the runway, as I do
NOT want to do a go around on a new motor.
this may force flight with high gauge readings, say 'bad'
TN65X57
Are you concerned that they will get a little too brave on one of the hops and
"fly".
First UL I ever saw, way back when there was no instruction (kinda like it
still is in the Nashville area) a guy brought one to the airfield, assembled
the wings and started taxiing up and down one of the side ramps. As he gained
the feel he got faster and faster until he was 2-3 feet off the ground.
Finally oin one of these passes he would get squirelly and taxi around again
for awhile gaining speed as time marched on.
By mid afternoon he got up about 20-30 feet, it got real squirelly with him and
he went back to taxiing.
I left before he flew off into the sunset.
One of the 79 year olds in the local club and one of the young guys are trying
the self taught method.
Both have repaired at least 1 plane and are still not in airworthy/airborne!
LouisB
Looks like a perfect spot to be a BFI, but then I can't even get any
instruction to go that route.
Rick Pitcher
Yeah, 180 is a little too high. Those little radiators that Rotax
charges so much for just don't quite do the job sometimes.
I followed Mark's advice and added another radiator from a Honda
motorcycle, $50 at a motorcycle salvage shop. I removed the lower
cross-over hose and plumbed the new rad into the circuit as shown here:
http://www.qnet.com/~rpitcher/newrad.jpg
Now it runs around 155-165 degrees instead of 175-180 like it did before
:)
Rick P.