Templeswain

The other day I went in reverse pulling out of work, and didn't relize the engine died and went to put it in first to go forward while slightly traveling backward and kinda jump started it in first going backward.

The engine started a little because the tach jumped.

Is this just one really ultra brainless way to blow your motor or what?

Or could you actually start it that way and drive your *** end up the street like it was a fivespeed?

LOL stupid question. I say motor blows in first 20 feet.

Digi7ech

iTrader: (1)

? how would it blow the engine?

It's the equivalent of push starting a car just in reverse though. The tranny doesn't rotate the engine the other way or something like that.

NZConvertible

Jump-starting a motor in reverse is no different to doing it in 1st.

Templeswain

Uh, no.

I mean having it in first gear, Engine dies and you don't know it yet, let off clutch and then the tach jumps a little and engine wants to fire while its going backwards in first.

Digi7ech

iTrader: (1)

Hmmmm
"backwards in first." You need to clarify what your saying.

The car going in reverse then putting it in 1st will hurt the tranny not engine. Unless it over rev's the engine.

nathantheman

thats crazy man! you know though even if your tach moves it dosn't mean it started, it could have been turning over, but not running. and i'm gonna guess that with all the components necessary to run the car starting the engine the opposite way would be impossible

xfeastonarsex

iTrader: (5)

I think that he means the car was traveling backwards and he poped the clutch while it was in first gear going backwards.

eternalblinkerman

Odd thing is there was an article that said that a rotary could run bacwards. the only problem was that the oil pump wouldn't pump the other way and you had to swap the intake and exhaust ports.If you figure out how to fix that, you could have a reverse running rotary.
So if your car still had unspent fuel mixture that was left in the exhaust manifold, and your engine was turned backwards it could have drawn in the fuel rich exhaust and kicked itself over backwards. Only problem I could see is that it would treat your intake as an exhaust and backfire,(or something like that).

red_ricer

iTrader: (3)

nah it doesnt hurt the car i have had to pull start my rx7 before because it was flooded so bad that i even pulled the injector fuse and cranked it over then put the fuse in and didnt work so we had to pull start it and still works fine

1987RX7guy

iTrader: (3)

lol...

Clueless


He did not JUST bump start his car... he was rolling backwards in 1st gear, not reverse. To clarify even more.. his car was traveling in a reverse direction (tail lights first ) with his transmission in 1st gear.

Templeswain

Exactly

But lets be even more clear.

I was traveling about 1/2 MPH.

You know? When you, "pull" out of work.

Not "Schreeeeeech" out of work.

and the tach jumped "pulling" out..

Just like nathantheman said:


crazy man! you know though even if your tach moves it dosn't mean it started,


I'm not saying it started.

I'm trying to say that it seemed like it "wanted" to start.


...and engine wants to fire while its going backwards in first.

And I thought to myself (after realizing I basically popped the clutch in first going backwards.) That's ******* crazy.

Really.

On a piston driven engine I would assume that the firing order and the rotational direction of the starter has the "say" in which direction the engine turns upon combustion.

Same with the rotary I guess. The starter and CAS turn a certain Direction.

Now I'm going to go out on a limb here.

I'd assume if you had a backwards rotary, then the exhuast would be on top and the intake would be on the bottem?

DigitalSynthesis

Well, yes if you kept the irons the way they are. Of course, if you put the exhaust and intake on the LEFT it would mandate they run intake on the top exhaust on the bottom for a clock-wise (from the driver's seat) operation. But think about it: that's the same as (basically) swapping the front plate with the back plate (in mirror image) and just turning the whole block around again. Presto! "backwards" running rotary!

But if you meant keep the intake and exhaust on the right (driver perspective again), then yes to run 'backwards' you'd have to put the exhaust on the top and vice versa. its a simple matter of physics: the rotor "sucks in" one port and "blows out" the other depending on its direction of rotation, so its _physically_ direction dependent, unlike a generic piston engine which is not necessarily so (at least in concept). This is another unique feature of the rotary engine.

You are also correct in that in a piston engine the firing order is the main determinant in whether or not the engine can sustain ignited operation in a particular direction or not. The starter just turns in in that preset direction.

Scott 89t2

your engine would spin the other way. with some decent speed you'd most likly break some apex seals.

SureShot

A short reverse spin is no problem.
Yea, the oil pump sucks, the spark is off time, & you might have some unburned fuel in the exhaust (but not enough to dirty the IM.)