how many rotations of crankshaft does it take to fire all cylinders of v8 engine
black_13
v8 engine
black_13
Steve W.
Depends on what type of engine.
2 stroke? 4 Stroke?
Assuming you mean an automotive V-8 as installed in a P/U
One cylinder fires every 120 degrees of crank rotation.
So taking a few liberties and assuming that each cylinder fires once
then stops
1- 120 degrees
2- 240 degrees
3- 360 degrees (1 full turn)
4- 480 degrees
5- 600 degrees
6- 720 degrees (2 full turns)
7- 840 degrees
8- 960 degrees (2.7 turns)
--
Steve W.
Nate Nagel
That seems wrong; assuming a 4-stroke, any given cylinder, assuming that
it fires at zero degrees, will fire again 720 degrees later. lessee...
1 - 0 degrees
8 - 90
4 - 180
3 - 270
6 - 360
5 - 450
7 - 540
2 - 630
1 - 720
yup, that's more like it (for everything but F*rds, anyway... don't ask
me what a F*rd firing order is, they number things weird)
So the short answer is, for pretty much any 4-stroke, "two revolutions"
but to be strictly accurate, all cylinders actually fire within
720-(720/(number of cylinders)) degrees. For a 2-stroke, it'd be "one
revolution" or, again, more strictly accurately, 360-(360/(number of
cylinders)) degrees.
nate
--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
Killer Kowalski
crankshaft degrees for any and all four stroke cycle engines!
aarcuda69062
<03f4ddcf-b757-49b0...@z41g2000yqz.googlegroups.com>,
black_13 <jjos...@gmail.com> wrote:
At the risk of NOT overcomplicating the answer...
Two.
hls
"aarcuda69062" <none...@sbcglobal.net> wrote in message
news:nonelson-C94E74...@news.eternal-september.org...
Unless you have a two stroke cycle engine. Aarcuda, dont you hate the
"yeah but"
and "what if" responses.:>)
Your answer was concise.
Tim Wescott
Steve W.
You know It seemed wrong while I was posting it but....
Bit of a bummed mood anyway. This past month has been a real BIT%^...
Lost my 9 year old puppy to kidney failure and internal bleeding, wifes
Blazer ate it's cat, then the radiator split a tank. Got it all together
and then one of my friends over in the sandbox was hit and killed.
Then just to make it interesting I get the flu, and this is after I got
both flu shots!!!!
I will be real happy when December gets here....
--
Steve W.
Steve W.
What about external combustion or one of the 8-6-4 type toys
--
Steve W.
Tim Wescott
ben91932
> Then just to make it interesting I get the flu, and this is after I got
> both flu shots!!!!
>
> I will be real happy when December gets here....
>
> --
> Steve W.
God speed Steve , you will be in tonights prayers.
aarcuda69062
"hls" <h...@nospam.nix> wrote:
Welp, if it were a 2 stroke, the answer would still apply. ;-)
> Your answer was concise.
Thanks.
cuh...@webtv.net
cuhulin
Thomas Tornblom
The number of cylinders is irrelevant. A four stroke engine fires all
cylinders in two revs, a two stroke engine in a single rev, no matter
how many cylinders it has.
Killer Kowalski
fred
Ouch. It never rains as they say . Here's to a very happy Christmas for
you and yours.
Tegger
3173.bay.webtv.net:
> Only one cylinder fires at a time.
> cuhulin
>
>
True, but all eight are connected to the same crankshaft.
This means that once the crankshaft goes through two complete revolutions,
all eight cylinders have performed one complete cycle of
suck/squeeze/bang/blow, even if the sequence didn't start with "suck".
--
Tegger
C. E. White
"black_13" <jjos...@gmail.com> wrote in message
news:03f4ddcf-b757-49b0...@z41g2000yqz.googlegroups.com...
Depends on what you mean. Assuming you start counting when the a
particular cyclinder fires, it will be 630 degrees before the other 7
have fired as well. In general, I think you would say two complete
revolutions are need to insure that you ahve fired all eight
cylinders.
0 degrees - first cylinder fires
90 degrees - second cylinder fires
180 degrees - third cylinder fires
270 degrees - fourth cylinder fires
360 degrees - fifth cylinder fires (1 complete revolution)
450 degrees - sixth cylinder fires
540 degrees - seventh cylinder fires
630 degrees - eight cylinder fires
720 degrees - first cylinder is going to fire again..... (2 complete
revolutions)
Ed
hls
"C. E. White" <cewh...@mindspring.com> wrote in message
news:hf0nka$f08$1...@news.eternal-september.org...
>
> "black_13" <jjos...@gmail.com> wrote in message
> news:03f4ddcf-b757-49b0...@z41g2000yqz.googlegroups.com...
>> how many rotations of crankshaft does it take to fire all cylinders of
>> v8 engine
>> black_13
>
> Depends on what you mean. Assuming you start counting when the a
> particular cyclinder fires, it will be 630 degrees before the other 7 have
> fired as well. In general, I think you would say two complete revolutions
> are need to insure that you ahve fired all eight cylinders.
You are speaking only for a 4 stroke cycle engine. On a 2 stroke cycle
engine, each piston fires on every revolution.
Killer Kowalski
"The number of cylinders is irrelevant. A four stroke engine fires all
cylinders in two revs, a two stroke engine in a single rev, no matter
how many cylinders it has."
from "Thomas Tornblom"
C. E. White
"Killer Kowalski" <killerk...@localnet.com> wrote in message
news:_cOdnVju85kp5onW...@posted.localnet...
> The best and most accurate and most concise response remains --
>
> "The number of cylinders is irrelevant. A four stroke engine fires
> all
> cylinders in two revs, a two stroke engine in a single rev, no
> matter
> how many cylinders it has."
>
> from "Thomas Tornblom"
How about a Wankel? They are four stroke.....
Ed
Steve N.
Yea, I guess that's technically true, depending on the definition of
"stroke". Here's a great animation from HowStuffWorks.
Make sure to click on the "cycle breakdown" button in the upper right to
clearly see each "stroke".
http://auto.howstuffworks.com/rotary-engine4.htm
cuh...@webtv.net
cuhulin
dsi1
A four stroke that has a power stroke for every rotation of the
crankshaft, two if it's a two rotor motor. Three power strokes for every
revolution of the rotor. Wow.
>
> Ed
>
>
cuh...@webtv.net
Six stroke one cylinder engine
Different strokes for different folks.
The guy said the exhaust blew the paint off of the ceiling.
cuhulin
Killer Kowalski
described as a four stroke cycle engine as nothing in its internals
completes a stroke. One properly refers to phases of the combustion
cycle when speaking in reference to a rotary combustion engine...
Killer Kowalski
under discussion...
A four stroke cycle Diesel still requires 720 degrees of crank rotation
to fire all cylinders... and, again, a two stroke cycle Diesel requires
only 360 degrees...
hls
<cuh...@webtv.net> wrote in message
news:15845-4B1...@storefull-3172.bay.webtv.net...
> Diesel engines don't need spark plugs.
> cuhulin
>
subject. And there
are four stroke cycle diesels as well as two stroke cycle diesels.
dsi1
> No, actually, the Wankel Rotary Combustion engine is not *accurately*
> described as a four stroke cycle engine as nothing in its internals
> completes a stroke. One properly refers to phases of the combustion
> cycle when speaking in reference to a rotary combustion engine...
The Wankel does have cycles of induction, compression, power, and
exhaust when doing it's thing - my guess is that's the reason a lot of
folks are fooled into believing it's a 4 stroke engine. Consider me guilty!
dsi1
> No, actually, the Wankel Rotary Combustion engine is not *accurately*
> described as a four stroke cycle engine as nothing in its internals
> completes a stroke. One properly refers to phases of the combustion
> cycle when speaking in reference to a rotary combustion engine...
The Wankel does have cycles of induction, compression, power, and
exhaust when doing it's thing - my guess is that's the reason a lot of
folks are fooled into believing it's a 4 stroke engine. Consider me guilty!
>
Killer Kowalski
the 'tech' portion of this newsgroup's name valid :)
C. E. White
> No, actually, the Wankel Rotary Combustion engine is not
> *accurately* described as a four stroke cycle engine as nothing in
> its internals completes a stroke. One properly refers to phases of
> the combustion cycle when speaking in reference to a rotary
> combustion engine...
Geez...get technical will you. Look at stroke definition 6a below (6 a
: one of a series of propelling beats or movements against a resisting
medium) or even definition 2 (2 : a single unbroken movement;). Why
can't I properly say a Wankel is a 4 stroke engine using one of these
definitions of stroke? For a piston engine stoke definition 9 seems
best (9 : the movement in either direction of a mechanical part (as a
piston) having a reciprocating motion; also : the distance of such
movement)
From http://www.merriam-webster.com/dictionary/stroke :
Main Entry: stroke
Function: noun
Etymology: Middle English; akin to Old English strican to stroke -
more at strike
Date: 13th century
1 : the act of striking; especially : a blow with a weapon or
implement
2 : a single unbroken movement; especially : one of a series of
repeated or to-and-fro movements
3 a : a controlled swing intended to hit a ball or shuttlecock; also :
a striking of the ball b : such a stroke charged to a player as a unit
of scoring in golf
4 a : a sudden action or process producing an impact <a stroke of
lightning> b : an unexpected result <a stroke of luck>
5 : sudden diminution or loss of consciousness, sensation, and
voluntary motion caused by rupture or obstruction (as by a clot) of a
blood vessel of the brain -called also apoplexy, brain attack,
cerebrovascular accident
6 a : one of a series of propelling beats or movements against a
resisting medium <a stroke of the oar> b : a rower who sets the pace
for a crew
7 a : a vigorous or energetic effort by which something is done,
produced, or accomplished <a stroke of genius> <a brilliant diplomatic
stroke> b : a delicate or clever touch in a narrative, description, or
construction
8 : heartbeat
9 : the movement in either direction of a mechanical part (as a
piston) having a reciprocating motion; also : the distance of such
movement
10 : the sound of a bell being struck <at the stroke of twelve>; also
: the specific time indicated by or as if by such a sound
11 [1stroke] : an act of stroking or caressing
12 a : a mark or dash made by a single movement of an implement b :
one of the lines of a letter of the alphabet
- at a stroke : all at once <spent her savings at a stroke>
dsi1
> :) no guilt associated... unless the guilt is mine for wishing to keep
> the 'tech' portion of this newsgroup's name valid :)
>
The Wankel does have a crankshaft so there's gotta be a stroke involved
somewhere and the engine does have a thingie up front with regular
timing marks. I can't call it a harmonic balancer cause the crank was a
short, hefty, piece of metal and probably didn't need one.
My RX-2 had 2 distributors, a really big 4-barrel carburetor and a small
oil pump that shot motor oil into the carb to keep the seals lubricated
- just like a 2 stroke. It was a small, high-revving engine that liked
to consume gas. :-)
Steve
> Steve W. wrote:
>> black_13 wrote:
>>> v8 engine
>>> black_13
>>
>>
>> 2 stroke? 4 Stroke?
>>
>>
>> Assuming you mean an automotive V-8 as installed in a P/U
>> One cylinder fires every 120 degrees of crank rotation.
>>
>> So taking a few liberties and assuming that each cylinder fires once
>> then stops
>>
>> 1- 120 degrees
>> 2- 240 degrees
>> 3- 360 degrees (1 full turn)
>> 4- 480 degrees
>> 5- 600 degrees
>> 6- 720 degrees (2 full turns)
>> 7- 840 degrees
>> 8- 960 degrees (2.7 turns)
>>
>
> That seems wrong;
Because it is ;-)
Assuming even firing and 4-stroke, you're right, its every 90 degrees.
IF its a Detroit 8V71 two-stroke, then its one every 45 degrees, which
is why Detroit Diesel 8v71s sound like they're turning 5000 RPM when
they're really only turning 2500
Killer Kowalski
mainshaft (please note the absence of crank throws implicit with that
distinction) Anyway, it certainly will have timing mark, as ignition
timing remains important even in the absence of pistons and cylinders!
Ignition must still be timed to occur at the proper point during the
compression phase. Anyway, the four phases of cannot be described as
strokes as no piston is involved so the whole conversion of heat energy
into work is called by the general term, Otto-cycle-process, *not* by
the term four-stroke cycle process! Clear yet?
Killer Kowalski
the Society of Automotive Engineers (SAE) terminology and definitions
must take precedence over the Merriam-Webster dictionary definitions...
My comments regarding the Wankel and its phases of Otto-cycle are in
agreement with SAE terminology.
Killer Kowalski
That is a whole-'nother topic.... :)
(exercise -- an even-firing 90-degree (as used here, refers to the
included angle between the banks) V-6... how can it exist? Hint: an even
firing V-6 *should be* a 60 degree engine...)
dsi1
> No no no! a Wankel *does not* have a crankshaft! It *does* have a
> mainshaft (please note the absence of crank throws implicit with that
> distinction) Anyway, it certainly will have timing mark, as ignition
> timing remains important even in the absence of pistons and cylinders!
> Ignition must still be timed to occur at the proper point during the
> compression phase. Anyway, the four phases of cannot be described as
> strokes as no piston is involved so the whole conversion of heat energy
> into work is called by the general term, Otto-cycle-process, *not* by
> the term four-stroke cycle process! Clear yet?
Well, why didn't you just say so in the first place? I think we can both
agree it's an Otto-cycle engine, in fact, that's why they call them
ottomobiles. Ha ha.
Wouldn't a crankshaft still be the correct term in a piston engine if
the connecting rod bearing were so big that they overlapped the main
journals? That's what a Wankel mainshaft looks like to me. After all,
the engine still relies on the offset of the shaft to create torque at
the output. What's the difference?
Killer Kowalski
will have to think a bit about it... You are aware, I trust, that the
rotor is geared to the mainshaft to ensure proper phasing... The ratio
is three turns of the mainshaft per one turn of the rotor... I will,
temporarily (until I find authoritative answer) postulate that the
motion involved is more complex than can allow it to be thought-of as a
simple crank... Does that make sense at all? I admit to it being
cumbersome wording...
dsi1
> Your analogy is interesting :) and your question is a new-one on me! I
> will have to think a bit about it... You are aware, I trust, that the
> rotor is geared to the mainshaft to ensure proper phasing... The ratio
> is three turns of the mainshaft per one turn of the rotor... I will,
> temporarily (until I find authoritative answer) postulate that the
> motion involved is more complex than can allow it to be thought-of as a
> simple crank... Does that make sense at all? I admit to it being
> cumbersome wording...
Yes, there is a stationary gear on the rotor housing that is the key to
the rotor's wonderfully eccentric movement. I once replaced the seals on
my motor with the help of a Mazda mechanic. After we had bolted the
engine together, we realized the we had put the mainshaft in the wrong
way. Ha ha. Not that big of a deal cause we took it apart and put it in
the right way in about 20 minutes. It's a wonderfully simple motor cause
there's nothing to time except the distributer. No valves, no timing
chain - oh boy. :-)
N8N
wrote:
> Steve, please, no! let us not delve into even versus odd-firing!!! :)
> That is a whole-'nother topic.... :)
>
> (exercise -- an even-firing 90-degree (as used here, refers to the
> included angle between the banks) V-6... how can it exist? Hint: an even
> firing V-6 *should be* a 60 degree engine...)
Ooh! Ooh! (raises hand) split crank pins!
nate
C. E. White
> The best reason, *within the scope of this newsgroup*, is the fact
> that the Society of Automotive Engineers (SAE) terminology and
> definitions must take precedence over the Merriam-Webster dictionary
> definitions... My comments regarding the Wankel and its phases of
> Otto-cycle are in agreement with SAE terminology.
See http://en.wikipedia.org/wiki/Distinction_without_a_difference
Steve Austin
> (exercise -- an even-firing 90-degree (as used here, refers to the
> included angle between the banks) V-6... how can it exist? Hint: an even
> firing V-6 *should be* a 60 degree engine...)
>
An even firing v6 should be a 120 degree engine
cuh...@webtv.net
the first to sell Wankel engine cars.There was at least one German
motorcycle with a Wankel engine.There have been advancements in Wankel
engine technology over the years.Do any auto companies build and sell
Wankel engine vehicles nowadays? Wankel engine model airplane engines
are available nowadays, I think so.
cuhulin
Nate Nagel
yes, the Mazda MX-8 still has a rotary engine. Not sure if there are
any others or not. Which is a shame because the RX-7 was so pretty and
the RX-8 has so much more power and looks like a SUV mated with a
Transformer.
nate
--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
Nate Nagel
> cuh...@webtv.net wrote:
>> Didn't Felix Wankel invent the Wankel engine? I think NSU (Germany) was
>> the first to sell Wankel engine cars.There was at least one German
>> motorcycle with a Wankel engine.There have been advancements in Wankel
>> engine technology over the years.Do any auto companies build and sell
>> Wankel engine vehicles nowadays? Wankel engine model airplane engines
>> are available nowadays, I think so.
>> cuhulin
>>
>
> yes, the Mazda MX-8 still has a rotary engine. Not sure if there are
> any others or not. Which is a shame because the RX-7 was so pretty and
> the RX-8 has so much more power and looks like a SUV mated with a
> Transformer.
>
> nate
>
Of course I meant RX-8. Don't know what I was thinking, or not.
cuh...@webtv.net
Swashplate Engines
There are many different kinds of engines.Some of them I have read about
many years ago.
cuhulin
Steve
> Steve, please, no! let us not delve into even versus odd-firing!!! :)
> That is a whole-'nother topic.... :)
Awww but its so FUN!! :-)
>
> (exercise -- an even-firing 90-degree (as used here, refers to the
> included angle between the banks) V-6... how can it exist? Hint: an even
> firing V-6 *should be* a 60 degree engine...)
Splayed journals on each throw of the crankshaft. The problem is that if
you splay the journals far enough to make it *truly* even firing, then
the crank is significantly weakened by the lack of metal overlapping
between the two adjacent journals. So most 90-degree v6 engines are a
compromise- they splay the cranks enough to bring it CLOSER to even
firing, but not so far as to make the splayed journals fail to overlap
and thus weaken the crank. I'd have to go look it up to be sure, but I
think the Chrysler 90-degree engines (the old 3.9 and the current 3.7)
have something like 128 and 112 degree intervals instead of perfectly
even 120-degree intervals. Thats decidedly better than the 90� and 150�
intervals of a non-splayed crank 90-degree v6 like the first Buick v6.
As you add more cylinders, odd-firing becomes less of a problem. The
Dodge Viper V10 doesn't even have splayed journals, its just got so many
cylinders that is very smooth feeling even with the inherent odd-firing
of a 10-cylinder 90-degree V engine. Gives it a really gnarly exhaust
note, though.
True or false: Even- or odd-firingness has nothing to do with engine
balance.