I have the suspicion i have a valve leakage in my motor. I drove my car for 100miles this weekend. And it lost power during the way. It started huffing puffing through the exhaust (also have exhaust leakage).

It started to run rich and richer. And idle was around 1200 to 1500 rpm.
When i came home i checked the valve clearences. And they where all a little bit to tight. 0.05mm.

So i adjusted them and did a cold compression test at 0% throttle and 100% throttle.
Zero and 100% throttle didn't made any diffrence. All the cylinders where at 220, 230 psi accept for cylinder number 3 it had between 205 and 215 psi.

I had no problems starting the engine cold or warm.

So compression whas good after changing the lash. After the valves redone it was a hard time getting the engine to run right. High idle and rich mixture.
After setting the engine up i let i t warp up and then drove it for a mile or so. It still fellt slow but not abnormally slow (running at 13 AFR).

It feels if the exhaust pulls back some air sometimes. I checked with a cloth and it pulled of my hand a little bit sometimes.


Could this incident burn a valve wich doesnt show up on a compression test?
Could the afr be the cause of being slow?
Is there anything left to check? to surely know a valve ain't causing problems.

 

Hi,

What engine do you have and what did you set the valve clearances to? also, did you set them when the engine was hot or cold?

a burnt out valve would show up in your compression test, your results seem very good.

 

i would have expected in between 155-180 psi -yours seems high

 

Not a thing wrong with any valves with that compression. Or indeed symptoms given.

But some clues as to history, has it ever run good, what car or engine is it etc etc would go a long way to helping.