bent valve

Sizzle · Sizzle's Garage

Anybody out there been through the 'poorly seating valve' issue? My car is making some noise under load from the middle cylinder on the left bank. I'm thinking its a bent valve. Compression and leakdown tests confirm some sort of issue back there. Would this sound / test any different than a poorly fitting cylinder / head junction?

thanks -

johnsjmc · 08-11-2005, 12:46 PM

I would be more inclined to suspect a pulled or broken head stud unless you know you over reved and can pin point when and how the valve might have bent.

Jeff Alton · 08-11-2005, 01:30 PM

Well, if you do a leakdown and the leaking air is comming out the exhuast or intake you most surely have a valve issue of some kind. A leaking cylinder to head seal will have the air pass out through it and you could hear it with a rubber hose up to your ear or a stethoscope. If it leaking due to a broken head stud, you will probably see some oil and combustion gas stains on the joint on the botton of the engine.

Cheers, Jeff

Sizzle · Sizzle's Garage

Great logic on the 'listen for the air' routine -- Mr. Walker will be under the car on Monday -- cross my fingers and hope for the best. Thanks.

Jeff Alton · 08-11-2005, 01:49 PM

The car will be in good hands then. What year and motor is it?

Jeff

Sizzle · Sizzle's Garage

Its a 1984 3.2. Another interesting clue in the tale of this car -- it will pass emissions with the injector pulled on that bad head...I'm thinking that a snapped stud would still enable pretty complete combustion within that cylinder and that a tweaked valve will let more HC blow by. This is my hope - i don't want a snapped stud. Mr. Walker said that the 'powder coated' dilivar studs in play in the 3.2 motors are very sturdy and don't get that corrosion-instigated crack going on.

Jeff Alton · 08-11-2005, 03:10 PM

The "injector pull" is a good trick to pass emission testing, works well. Good luck, keep us posted as to what the problem is.

Cheers, Jeff

Sizzle · Sizzle's Garage

No pulled studs! JW gave it a once over and snugged down all my head nuts and its running much better, especially when giving it a footfull of throttle. Yeah, I have something amiss up high in the #5, but its not way out of whack at this point. Top end rebuild in my future (when funds will support such undertaking). In the meantime, I'm just enjoying my $10k '84 immensely!