Valve Seals

[RyAn007]

Could valve seals cause a compression of 70 on one cylinder? I removed the headgasket and it actually doesnt look bad at all, but maybe im missing something very small, but either way im wondering if i should take the head apart and check for a bad seal?

 

[94_eclipse]

Im guessing that you mean the valve seat? Valve seals have no effect on compression, they just keep the oil from going down to the valve. But if you are low on compression it could mean two things, one- bad rings, two- bad valve seats. Im going to guess a bad valve seat on atlest one valve.

A way you could check is by an old farmers method. Take out the spark plug and squirt a couple squirts of oil from an oil can into the cyl. The oil will cover the rings on your pistion making a tempary seal. If your compression goes up its your rings, if not its your valve. Some people dont use this method because on dished pistons it will always increase your compression. But your pistons are not realy dished. So give it a shot.

Oh wait my fault. I missread your post, you have the head off. Right? If so you can still check to see if your valve is bad, Squirt some PB blaster into the port holes of your valves. Let your head sit over night (make sure its sitting on a table just as it would sit in the car) if the PB blaster leaked through the valve seat then there is your problem.

 

[RyAn007]

So i should remove the cams fron the head, and just spray some pb blaster, and what do you mean porthole??

 

[94_eclipse]

Right in your intake and your exhaust ports, basicly the back side of the valve you want to fill with PB. You will have to take your intake manifold off to get to the intake ports.

 

[RyAn007]

Alright i see what you mean, the head is already completely off and separated, so that will be no problem i will try that, what would i do to fix this problem?

 

[94_eclipse]

Well you could use valve grinding compound and reseat the valve that way. But i sugest getting all new valves since you have it all apart. Either way you will want to reseat the valves, new or old.


I said valve grinding compound, others call it lapping compound... didnt mean to confuse you.

 

[jrohner]

Bring you head to a machine shop and have them check it over and have a valve job done. You can get some really nice SS valves on ebay for under 100 bucks for all 16, and they are way better than NAPA ones that are 10 bucks each.