which way do engines spin?
*
direction? In particular which way dose a 4agze spin?
thanks
J Devereux
Peter McMillan
>This might be a stupid question but do all motors rotate the same
>direction? In particular which way dose a 4agze spin?
Not all. Almost everything spins clockwise when looking at the front
of the crank, but Fiat 850 and early Honda Civic spin anticlockwise.
Might be others too.
Cheers,
Peter! -=DUH#14=- (Y1)
"What does this button do? Oops .... flames. RUN!!"
To email me, change .com in my address to .au
Dion Mikkelsen
McMillan) wrote, with the use of a cucumber dipped in blackberry
sauce:
>* <q942...@mail.connect.usq.edu.au> wrote:
>
>>This might be a stupid question but do all motors rotate the same
>>direction? In particular which way dose a 4agze spin?
>
>Not all. Almost everything spins clockwise when looking at the front
>of the crank, but Fiat 850 and early Honda Civic spin anticlockwise.
>Might be others too.
<warning: badly thought out logic follows ...>
Dumb question time ... how does an engine really know which way it is
turning ? Okay, assuming it is started in that direction by the
starter motor then I suppose ...
But what if you roll started it in reverse - could you get the engine
to run 'backwards' ? I guess things like the water pump may not like
running backwards, but after giving it about 5 seconds thought, there
doesn't seem to be any real reason for it not to run backwards ?
After all, combustion just pushes cylinders up and down, the crank
converts that to rotational motion ... is there something in the crank
design ... or am I missing something obvious.
--
Dion! -=DUH#12=- (Y1)
"Don't flame me - I'm <insert excuse here>"
Julian Simmonds
Sometimes you could kick them over and you would be going backwards.
How does this effect the gearbox (in cars?) Could you imagine doing 100kph
(let alone 200kph) going backwards in 5th? hehe
- Julian
Peter McMillan
>But what if you roll started it in reverse - could you get the engine
>to run 'backwards' ? I guess things like the water pump may not like
>running backwards, but after giving it about 5 seconds thought, there
>doesn't seem to be any real reason for it not to run backwards ?
Good thinking, 99. Yes, an engine can run in the opposite direction.
In fact, the engine in my old motorkhana car (the one you've been for
a drive in) was originally an 850 engine, running counterclockwise. I
needed it to run clockwise, so it was simply a matter of getting the
right start motor, oil and water pumps, camshaft, and drive gears, and
hey presto - it's actually a really easy conversion when the engine
was designed to run in both directions from the factory.
Benjamin Marsh
: dmikk...@rocketmail.com (Dion Mikkelsen) wrote:
:
: >But what if you roll started it in reverse - could you get the engine
: >to run 'backwards' ? I guess things like the water pump may not like
: >running backwards, but after giving it about 5 seconds thought, there
: >doesn't seem to be any real reason for it not to run backwards ?
Sounds right but .. It is the gearbox that makes the car reverse not
the engine, ie, when you select reverse the engine doesn't start spinning
the other way BUT if you were in a forward gear rolling backward (or
reverse rolling forward) then I guess it is possible to get the engine
to run backward - EFI ones probably wouldn't though....
my brain hurts.
Ben
:
Don Quixote
Mikkelsen) wrote:
>Dumb question time ... how does an engine really know which way it is
>turning ? Okay, assuming it is started in that direction by the
>starter motor then I suppose ...
>
>But what if you roll started it in reverse - could you get the engine
>to run 'backwards' ? I guess things like the water pump may not like
>running backwards, but after giving it about 5 seconds thought, there
>doesn't seem to be any real reason for it not to run backwards ?
>
>After all, combustion just pushes cylinders up and down, the crank
>converts that to rotational motion ... is there something in the crank
>design ... or am I missing something obvious.
The Zeta, built in Australia by Lightburn in the 1960's, ran in either
direction. They had no separate reverse gear and which way they went
depended on which way the key was turned to start the engine ;
presumably it changed the spark timing as well as the starter
direction. I'm pretty sure they used a Messerschmitt 2-stroke twin so
the little Messerschmitt bubble cars (like in Heartbeat) were probably
the same.
Four strokes would need to reverse the camshaft direction to keep the
valve opening sequence correct.
John H
Peter McMillan
>Sounds right but .. It is the gearbox that makes the car reverse not
>the engine, ie, when you select reverse the engine doesn't start spinning
>the other way
The Fiat 850 engine I was talking about uses a gearbox that runs
counterclockwise to give forward movement. The gearbox I actually
wanted to use is designed to run clockwise - that's why I had to
reverse the direction of rotation of the engine.
BUT if you were in a forward gear rolling backward (or
>reverse rolling forward) then I guess it is possible to get the engine
>to run backward - EFI ones probably wouldn't though....
>my brain hurts.
>Ben
>:
Peter! -=DUH#14=- (Y1)
Terry Duell
> dmikk...@rocketmail.com (Dion Mikkelsen) wrote:
>
> >But what if you roll started it in reverse - could you get the engine
> >to run 'backwards' ? I guess things like the water pump may not like
> >running backwards, but after giving it about 5 seconds thought, there
> >doesn't seem to be any real reason for it not to run backwards ?
>
> Good thinking, 99. Yes, an engine can run in the opposite direction.
> In fact, the engine in my old motorkhana car (the one you've been for
> a drive in) was originally an 850 engine, running counterclockwise.
----------snip--------
Some engines have the piston pin off centre (ie not on the centerline of
the bore), in which case running in reverse rotation may prove somewhat
problematic!
Reverse engine direction will cause the thrust forces on helical gears
(eg distributor, oil pump drive) to also be in the opposite direction,
and there probably may not be any bearings/thrust faces/good lube etc to
make this a lasting mode of operation.
--
Terry Duell
Dion Mikkelsen
wrote, with the use of a cucumber dipped in blackberry sauce:
>Four strokes would need to reverse the camshaft direction to keep the
>valve opening sequence correct.
You mean that the cam direction would stay the same .. even though the
crank would be spinning the same way ... actually yeah that would make
sense wouldn't it - the cams would have to stay the same, just the
crank would be going the opposite direction ...
But on say a simple 2 valves per cylinder OHC engine, the engine would
still run, sort of wouldn't it ? Just very rough I guess ... although
then the timing would be off too ...
Hmmm, my brain hurts :-)
Maybe I should just let the Pulsar roll backwards down the driveway,
clutch start it and see .... (just kidding!).
--
Dion! -=DUH#12=- (Y1)
"If you chip your newsreader, you'll get a 10% increase in flaming."
Arnie
>Dumb question time ... how does an engine really know which way it is
>turning ? Okay, assuming it is started in that direction by the
>starter motor then I suppose ...
>
>to run 'backwards' ? I guess things like the water pump may not like
>running backwards, but after giving it about 5 seconds thought, there
>doesn't seem to be any real reason for it not to run backwards ?
>
>converts that to rotational motion ... is there something in the crank
>design ... or am I missing something obvious.
If you turn the engine backwards, it'll try to suck air in from the exhaust
and exhaust it out the inlet due to the reverse valve timing. And that won't
go as the fuel is not supplied from the exhaust side. Also, the timing
chain/belt won't be happy as the tensioner will be on the wrong side.
2 stroke engines can run backwards quite easily though. Hmmm, a Trabant
could go pretty fast in reverse! :)
Now that would be a pretty nasty stunt rewiring the starter to crank the
other way and the look on the poor German's face when he drops the clutch in
1st!
"Heil Shitler! Vot da Fark!"
Ah, that's another reason the rotary can't be classified a 2 stroke, it's
not reversible!
Arnie
Dion Mikkelsen
wrote, with the use of a cucumber dipped in blackberry sauce:
>Sounds right but .. It is the gearbox that makes the car reverse not
>the engine, ie, when you select reverse the engine doesn't start spinning
>the other way BUT if you were in a forward gear rolling backward (or
>reverse rolling forward) then I guess it is possible to get the engine
>to run backward
Yeah, that's what I was thinking. Roll starting it in reverse would
simply start the engine as per usual ;-)
Dion Mikkelsen
with the use of a cucumber dipped in blackberry sauce:
>If you turn the engine backwards, it'll try to suck air in from the exhaust
>and exhaust it out the inlet due to the reverse valve timing. And that won't
>go as the fuel is not supplied from the exhaust side.
Oh yeah, of course ... I should draw a diagram so it's all clear in my
head ... neglect my comment in the other post ...
>Also, the timing
>chain/belt won't be happy as the tensioner will be on the wrong side.
Yeah, they're all minor things, was just wondering if the sucker would
start. You know try it on a shitbox/company car/rental car ;-)
>2 stroke engines can run backwards quite easily though. Hmmm, a Trabant
>could go pretty fast in reverse! :)
>Now that would be a pretty nasty stunt rewiring the starter to crank the
>other way and the look on the poor German's face when he drops the clutch in
>1st!
>"Heil Shitler! Vot da Fark!"
ROTFL ! Next time you're in Germany ... ;-)
>Ah, that's another reason the rotary can't be classified a 2 stroke, it's
>not reversible!
Bah! A rotary's not a real motor anyway! <flameproof suit on> ;-)
Peter McMillan
>Reverse engine direction will cause the thrust forces on helical gears
>(eg distributor, oil pump drive) to also be in the opposite direction,
>and there probably may not be any bearings/thrust faces/good lube etc to
>make this a lasting mode of operation.
Unless you are using an engine that was designed to run in either
direction, with gearsets available for both directions of travel off
the shelf. Then, no problem!
By the way, the engine I was talking about in an earlier post has
since moved on from my hands, but is used regularly in a friend's
competition car still. Sees 8500 rpm regularly and never misses a
beat.
Cheers,
Greg Stewart
> <warning: badly thought out logic follows ...>
>
> turning ? Okay, assuming it is started in that direction by the
> starter motor then I suppose ...
>
> But what if you roll started it in reverse - could you get the engine
> to run 'backwards' ? I guess things like the water pump may not like
> running backwards, but after giving it about 5 seconds thought, there
> doesn't seem to be any real reason for it not to run backwards ?
>
> After all, combustion just pushes cylinders up and down, the crank
> converts that to rotational motion ... is there something in the crank
> design ... or am I missing something obvious.
>
I a 2 stroke engine, yes it is possible!!
but it just won't work on a 4 stroke!! lets see, open exhaust valve,
suck in, compress, spark, open intake valve and push cylinder contents
out!!! hmmmm, don't think so!!!
--
Greg Stewart
Correct Email address - gregjs 'at' ozemail 'dot' com 'dot' au
The Gardners
The closer it is, the more easier it is to run backwards.
I think.
Al Gardner
>Dumb question time ... how does an engine really know which way it is
>turning ? Okay, assuming it is started in that direction by the
>starter motor then I suppose ...
>
>But what if you roll started it in reverse - could you get the engine
>to run 'backwards' ? I guess things like the water pump may not like
>running backwards, but after giving it about 5 seconds thought, there
>doesn't seem to be any real reason for it not to run backwards ?
>
>After all, combustion just pushes cylinders up and down, the crank
>converts that to rotational motion ... is there something in the crank
>design ... or am I missing something obvious.
>
>
Forg
>
> This might be a stupid question but do all motors rotate the same
> direction?
Almost all the same; there are few exceptions, and I'm pretty sure
they're all really old (like a Toyota 700).
--
Forg! -DUH#6=- (Y1)
"Flamin' heck; another Volvo Driver!"
"...
Another Turnip Boy;
A Forg stuck in the road
..."
[Greenday]
Don Quixote
Mikkelsen) wrote:
>But on say a simple 2 valves per cylinder OHC engine, the engine would
>still run, sort of wouldn't it ? Just very rough I guess ... although
>then the timing would be off too ...
Many diesels will, after a fashion, but I'd guess that they'd carbon
up the inside of their air filters fairly quickly.
John H
Dave
few times, but it wouldn't run backwards.
Dion Mikkelsen wrote:
>
> On Fri, 14 May 1999 01:51:47 GMT, p.mcm...@mailbox.uq.edu.com (Peter
> McMillan) wrote, with the use of a cucumber dipped in blackberry
> sauce:
>
> >* <q942...@mail.connect.usq.edu.au> wrote:
> >
> >>This might be a stupid question but do all motors rotate the same
> >>direction? In particular which way dose a 4agze spin?
> >
> >Not all. Almost everything spins clockwise when looking at the front
> >of the crank, but Fiat 850 and early Honda Civic spin anticlockwise.
> >Might be others too.
>
> <warning: badly thought out logic follows ...>
>
> Dumb question time ... how does an engine really know which way it is
> turning ? Okay, assuming it is started in that direction by the
> starter motor then I suppose ...
>
> But what if you roll started it in reverse - could you get the engine
> to run 'backwards' ? I guess things like the water pump may not like
> running backwards, but after giving it about 5 seconds thought, there
> doesn't seem to be any real reason for it not to run backwards ?
>
> After all, combustion just pushes cylinders up and down, the crank
> converts that to rotational motion ... is there something in the crank
> design ... or am I missing something obvious.
>
> --
> Dion! -=DUH#12=- (Y1)
> "Don't flame me - I'm <insert excuse here>"
--
Dave
Dave
Julian Simmonds wrote:
>
> I think this happened in some old motorbikes (can't remember which ones)
> Sometimes you could kick them over and you would be going backwards.
>
> How does this effect the gearbox (in cars?) Could you imagine doing 100kph
> (let alone 200kph) going backwards in 5th? hehe
>
> - Julian
>
Peter McMillan
>All your ignition and valve timing would be wrong! I might splutter a
>few times, but it wouldn't run backwards.
..... unless you have the right parts, made for the job. Then it's a
snip.
Benjamin Marsh
If you fired up a turbo diesel backwards - would the turbo still
spool up and blow air in but through the exhaust?
Ben
Sunny
Simple two strokes can!
Try this,
Get a go cart (the real ones, two stroke without a clutch). Do a 180 so your
going backwards on the track and take your foot off the brake and hit the
throttle.
The cart will turn the engine backwards and restart!
Instant negative G's. Pretty f'ing sarey too.
Sunny...
Dion Mikkelsen wrote in message <373b86a2...@news.ozemail.com.au>...
Dave
direction, for highest efficiency. It will work the other way too, but
not well. Impeller designs are usually like this too.
--
Dave
Greg Stewart
Benjamin Marsh wrote:
> If you fired up a turbo diesel backwards - would the turbo still
> spool up and blow air in but through the exhaust?
>
> Ben
First try to get a diesel 4 stroke engine spinning backwards without
mods, then we will tackle the turbo question!!!
David Tyrrell
similar but unrelated occasions. They were all when doing some serious
off-roading. Basically the driver did not get up a steep incline, and the
vehicle rolled back a bit when the driver was trying to change gears. (I am
aware of correct gear selection, ground appreciation, etc. It was a
learning environment and the driver stuffed up.)
Because of the angle of the hill, and the fact that the driver did not get
on top of the situation quickly enough, when the driver got the vehicle into
gear it was already going backwards. When the clutch was released the
engine stalled and then reversed effectively at the same time.
The engine idled very roughly, and would not develop any revs or power, and
the air intake was emitting a strange grey smoke. It also sounded very
strange, which was to be expected. Clearly the turbo had nothing to do with
it.
The solution was to cut off the fuel to stop the engine, and then restart -
no problem.
I would NOT recommend anybody trying it.
However,
Greg Stewart <gjst...@bigpond.com> wrote in message
news:37411A8E...@bigpond.com...