okay i was reading somewhere and they said to check for a burnt exhaust valve is that to put a peice of paper by the muffler and if it sucks the muffler in than u have a burnt exhaust valve..


how is that so..


when the intake is open and piston down i know it create vaccum and it sucks in air... wouldn't having a burnt valve kinda wouldn't the air escape thru the chipped exhaust valve and out thru the exhaust. low compression thus it trying to suck in air. explain thanks..

 

bump..........

 

When the intake valve is open & the piston is moving down in the intake stroke, there's a strong vacuum because the throttle is closed. It sucks exhaust back in thru the cracked valve.

I thought that test would work better on a lawnmower engine where there isn't 3 other cylinders all doing their thing at the same time...

 

Throw away that piece of paper and go get a cylinder leak down tester. LOL

 

true.. but if car isn't idle u wouldn't be able to tell.. the air going in while throttle is open.. its mostly like gonna try to push air out thru that cracked valve..