can your dsm have bent valves and not show it

[miller97tsi]

i took my head off and did not see any bent valves. but when i look at the top of my pistons it had indications of the valves kissing the pistons on the exhaust side. is this possible also i had 60 psi on all for cylinders when i did a comp check. what can be going on

 

[donniekak]

I would bet the timing messed up before, bent the valves, and they just installed other used valves without even lapping them in. Usually bent valves give close to 0 compression numbers. Either way you probably need a valve job.

 

[miller97tsi]

see here is what i found. when i took the exhaust mani off and looked into the valve chamber there was oil residue on the valve itself is that normal? i am not sure and if that were the case would i be leaking air from a comnp test?

 

[GooeyGus]

Pour some water into the intake/exhaust ports on the head. If it leaks, your valves are more than likely bent or not sealing properly.

Even just a tiny tiny tiny bend will cause compression problems.

 

[b00stAdict]

Pour some water into the intake/exhaust ports on the head. If it leaks, your valves are more than likely bent or not sealing properly.

Even just a tiny tiny tiny bend will cause compression problems.

+1

turn the head to each side (intake/exhaust) so that if your looking down at it you can see in the ports, pour water in there doesn't matter how much even the littlest amount will work. if your valves are bent at all even the tiniest bends will show, water will leak past the valves, if no water leaks past and the ports hold all the water, that valve(s) is good.

 

[Fabian]

if you just your valves and lapped them you'd know even if they were VERY SLIGHTLY bent. I found 3 bent valves that way in my awd project's head. Or else I woulda never seen they were bent and would have put it all back together like that. It's really easy to just lap em too.

 

[miller97tsi]

now what do yall mean by lapped. and i will try the water idea when i get home tomorrow

 

[donniekak]

now what do yall mean by lapped. and i will try the water idea when i get home tomorrow

Take the springs and retainers out, get some lapping compound, and a lapping tool. Now sit there like a boyscout making a fire and spin them in.

 

[BogusSVO]

here you go..

http://www.dsmtuners.com/forums/articles-engine-fuel/341636-how-lap-valve.html

if the head has gooten hot/overheated and been warpped, it can crack the valves of the seat an cause a compression leak.

no.. you should not have alot of oil in the exh, the seals or guides are wore/bad

 

[miller97tsi]

ok one last question, if my exhaust valves put small indentations in the top of the pistons will that hurt anything? they are not real big but i have never seend this before, any suggestions?

 

[Calan]

ok one last question, if my exhaust valves put small indentations in the top of the pistons will that hurt anything? they are not real big but i have never seend this before, any suggestions?

Are you sure you aren't talking about the valve relief that is cut into the piston?

And...if you have bent valves, you'll most likely know it.

 

[BogusSVO]

depends on how hard the valves met pistons.... you can pinch ring lands when valves bend, and the rings get pincehd and not move like they should.