Valve Stem Seals

[Dave Taylor]

Thought I'd replace these while the top end is apart. Old ones come off easily enough, but how are the new ones put on? They seem awfully tight and I'm afraid to tap them for fear of deforming them. Help!!

Thanks, Dave

[afterburn 549]

there should be a seal gard with them (looks like a very small straw) clear plastic,you slip over the valve, slide seal dwn and remove lil plastic tube ,go to next one and so on.

[Dave Taylor]

afterburn,
They didn't come with the straw-like plastic, but I made one that works great. Thanks for the information.
Dave

[ChrisBennet]

The guy who does my heads for me always "stakes" the seals so they don't come off.
-Chris

[hcoles]

Chris,
I understand that on 3.2 engines, maybe others, over time there have been different seals that were used or could have been used. One theory is that one or more types of seals used by the factory were too good...not allowing enough oil to the stems. Is there an agreed current best brand and type to be used on rebuilds? It is a bit late for me to ask this but it might help others.
-Henry

[cstreit]

Stakes them?! By denting the seal metal ring or the valve guide itself... Scary if you ask me... I've never seen one come off..

[ChrisBennet]

Originally posted by cstreit
Stakes them?! By denting the seal metal ring or the valve guide itself... Scary if you ask me... I've never seen one come off..

I'll try to dig out a head and look at how they were staked. My memory is a little fuzzy on the details.
-Chris

[john walker's workshop]

use the 964 seals. the 928 part # seals are very hard to install without killing a few. the installation tool is a 13mm deep socket, cleaned very well inside, and a short extension. they push on by hand nicely. i used to use the hard white ones, but they get brittle and come off sometimes. i've never staked them. i wonder how that is done? on occasion, mostly on 912s, a bit of super glue keeps them in place. some guide tops are machined differently than others and the seals may fit tighter/looser.

[cstreit]

Slighty OT in this thread but...

I used the white teflon ones recently and found that despite the popular opinion of them allowing more oil for better cooling of the valves, they actually dragged on the valve more and appeared to offer less oiling.

In addition this particular motor had a very high lift cam and the taller teflon ones were getting hit by the valve spring retainer... So we had to use the viton ones on top, and used no seal on the bottom... (race motor)

[ChrisBennet]

I looked at a head this morning and the metal part of the valve stem seal has an obvious punch/prick mark where my head guy staked them.

My head guy once told me that the teflon ones wear out the valves faster for the reason the Chris S. discovered.

-Chris

[cstreit]

...and yet I had always heard they leak MORE and allow MORE oil through...

Anyone know the truth of this?

[afterburn 549]

like all of it,they get old and brittle in time....like me

[Steve@Rennsport]

Teflon seals allow a bit more oil through than the Factory Viton ones,....

I like to use them on the exhaust valves on Turbos for bit more lubrication for those highly stressed components.