Okay, something weird is going on in my engine bay. My car has always dieseled (sp) a little. No amount of carb tuning or timing adjustment has changed it, just a short 1 or 2 seconds of running after the key is off, then it shuts off.

Today I had a problem where I had to dive under a valve cover and adjust my rockers. After I was done, I turned the motor over real quick to make sure everything was lined up OK, and when it shut off, I noticed that the #3 exhaust valve was was opened in relatively the same way it had been before I turned it over.

So, because I am **** and annoying, I turned it over a second time to move that valve in a different position. It shut off with that same valve open.

Now I'm getting interested, so I take out a set of calipers and measure the height of the open valve. I turned the car over and shut it off another dozen or so times, including a ten minute run to recharge the battery, and every time it shut down with the valve in the same position. The creepy part is that the vavle was within 0.10" height from the first measurement every time. What is going on here? Is my car running on so that it can reach a comfortable position to rest in or what?

 

It is common for an engine to always stop at the same "clock" rotation. Have you ever noticed some flywheels with a wear spot localized to one spot. It's because the engine likes to come to rest there dictated by compression. Even more common in four cylinders. V8 usually have four spots, 4 cyl usually have two.

 

isnt that bad for the valves? i mean, to have the same set of valves resting open all the time would eventually put some extra wear on the springs, wouldnt it?

 

No. Compressed or uncompressed doesn't matter.

 

Correct. Stock springs are pretty much crap either way.