I've started the process of replacing my valve seals, but I am currently stuck. I've got the valve spring off, but where is the old seal and where does the new one go? I found the small "o" ring seal, but where does the big one go?

From looking at it, it almost appears I don't have a seal like that, and all I would need to do is slide that big white seal over the valve stem, but how could I not have one? I've looked inside the valve spring and the old one aint in there either.

Yes, the vice grips are on gently, and I am using an air compressor, but since I'm at a standstill, I decided to use the vicegrips for now.

 

how many have you done, it apears that the seal just slips over the valve stem then slips down on the guide.

 

This is the first one, it's also the exhaust valve, and I deffinatly agree with you, it appears that the seal mearly slides over the stem and all the way down, but if that's the case, where the hell is the old one? I'm just trying to double check, I don't want to screw anything up.

 

It doesn't have one because it likely disintegrated and was flushed out with the oil splash. If you've never done the valve seals and everything on the head is original, that is more than likely what happened.

The umbrella seal slips over the valve stem and gets pushed down all the way onto the valve stem boss. The o-ring is on the valve stem itself, on the second ring down from the top. The first ring is for the keepers.

 

I am looking to do the valve seals in my GTA 5.7 TPI soon as well... the umbrella seals just slip over the guide and actually stay there??? Umbrella seals have always baffled me on how they can stay put.

May I ask how much the umbrella seals were for you?

 

Is it actually possible to replace the valve seals (with the engine in car) without applying air or sticking rope through the spark plug holes? I heard you can just rotate the crank until each cylinder its at TDC. Let me know your thoughts.

 

It might be difficult to get the keepers unstuck from the retainers that way. The amount of work involved to retrieve a dropped valve makes it not worth taking the chance, I'd think.

 

Some engines didn't get a seal on the exhaust, other then the O-ring. For that matter GM didn't always put a seal (other then the O-ring) on the intakes either.

The umbrella seal will ride on the valve stem and move with it. It is enough to keep heavy splashes of oil out of the guide.

The intake side being subject to vacuum gets the positive seal. This style gets pushed down over the guide and stays put. There should be a little plastic tube that gets placed over the stem first, then the seal can be pushed on. The tube is just a tool and prevents the seal from being sliced by the sharp endge of the valve stem.

I still use the O-rings even with the other seals in place.

A long nose pliers with two heavy rubber bands around the handle makes a nifty tool for holding the valve stem.

RBob.

 

Wow.. finally some solid advice.. thanks rob. I went to a machinist here in town, and he cleared everything up concerning umbrella seals and positive type seals. He said go with positive tpe seals for intake and exhaust. I'll do them when I have the money. he also said a screwdriver which has been bent, will aid in keeping the valve shut while trying to install the spring again. Piston at TDC of course.