Dumb Engine Question

[Davis SC]

How many different spots (as on the ring gear) do the following engines stop? Straight 4, straight 6, V6, V8 ?
 

[RickieBlue]

An engine will always stop coming up on compression...a 4cylinder 2 spots as it fires every 180° an 8 cylinder 4 spots..every 90° and so on.................
 

[Janicholson]

2, 3, a variety with different V angles and offset rod journals usually 3, and 4 Jim
 

[ShadetreeRet]

I don't know if the number of cylinders makes that much difference or not, but I have seen a number of engines that had the flywheel ring gear badly worn in one spot. And I have heard it said that most engines stop in one spot, but have never researched it. Maybe there is an engineer or physics professor lurking out there somewhere who will be able to enlighten us.
 

[teddy52food]

Rickie is right.
 

[Davis SC]

Thanks, Maybe my question was not so dumb after all..
 

[PJH]

The starter ring gear on my 2 cylinder JD was worn out in one spot. Would it be safe to assume that a four cylinder would stop in two places, a six in three, and an eight in four?

This is a question, not an answer. . .
 

[ericlb]

i dont know on 4 or 6 cylinder engines but a good old v-8 will always stop on 1 of 4 different spots, i studied that one time back in high school, but that was 45 years ago, and i dont remember all of it but it seems like it had to do with a combination of compression, rotating mass, and rpm, when the key is switched off, with the engine at idle, depending on the instant the key was turned off the engine would always coast to a stop in 1 of 4 places, as i said we didnt do 4 or 6 cylinder engines back then
 

[Vernon in Ks]

neet topic, but what about the 3 and 5 cylinder engines?
 

[teddy52food]

You are right. It stops because of compression & will rock back & forth because of it.
 

[B-maniac]

I assume you mean "hypothetical" stop spots as apposed to actual tooth count. Actual tooth count will vary with the rock of reciprocating mass at actual stop. Hypothetical? the last guy got it right...4cyl IL=2 etc.
 

[Davis SC]

Yes, just the general area of the ring gear..