Proper installation of Valve Seals

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wardriver

wardriver

10 Year 15 Year
Joined
Mar 29, 2010
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Location
Lynchburg, VA
I'm currently chasing down a few issues in my engine. The engine shows signs of being rebuilt in the past but is smoking. I've pulled the head to check the cylinders, clean carbon deposits, etc.

I've got the head and the block all cleaned up and I'm trying to correctly replace the valve seals.

I have two sets - FeelPro and Sealed Power. They both look like identical. Metal bell shaped lower, rubber upper with metal spring.


The previous seals were the umbrella style as well. The old seals were no longer attached to the metal umbrella. They were on the valve

When I drive either brand all the way down like the old ones - they are driven off the metal housing.

If I do not drive them all the way down - but snug them up with a few wacks on a socket and a 3lb hammer the seals stay attached.

So which is correct? Drive them down and off the metal umbrella to move on the valve stem or snug them up and keep them attached?
 
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Old seal:
image-2045665652.webp
 
New seal snugged up but not driven all the way down...
image-3863660588.webp
 
i just got my fel-pros in the mail yesterday and am hoping to replace at least #2's seals next week. a handful of guys here said they worked great. keep us posted when you figure it out.
 
kruisinkid said:
i just got my fel-pros in the mail yesterday and am hoping to replace at least #2's seals next week.
Click to expand...

If you are not removing the head make sure you use compressed air and not the rope trick that some guys talk about on here. I tried it and the rope tied itself in a knot.

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wardriver said:
If you are not removing the head make sure you use compressed air and not the rope trick that some guys talk about on here. I tried it and the rope tied itself in a knot.

Click to expand...


I would still like to know how the hell you did that <...
 
That makes two of us.
 
i have a strong feeling that the rope you used is like plastic braided anchor rope. all that rope wants to do is twist horribly no matter what. i have spools of 1/4" cotton sash that has no twist to it. should be fine.
 
Those are positive type valve seals, not umbrellas. Umbrella seals are the old style things that were one piece rubber and look like those rubber things that accountants wear on one finger to make page turning easier. Anyway, you don't want to drive the positive type seals on too hard or they come apart. I use a length of tubing that just barely fits over the top part of the seal and stops on the flared bottom edge. Then, using a really small hammer I tap the seal onto the valve guide until I feel it lightly bottom. Drive it straight, not allowing it to co*k sideways. You're done. You do not drive the seal all the way down on the guide, just until it feels like it bottomed inside the seal housing. Be sure to use some moly lube on the valve stem when inserting the valve. The kits come with a small clear plastic tube to protect the seal when you install the valve, but I don't use it. I hold my finger over the outside of the valve seal and create a plug. Then when I insert the end of the valve stem from the other side of the head, it creates a pressure bubble in the seal and the finger keeps the seal from tearing as you gently push the stem through. I doubt that anyone else does it that way, but it has always worked for me and I have assembled probably 20 engines doing it that way. Everything is supposed to stay attached to the seal. If the top rubber (Viton) part comes loose from the metal base, throw the seal away and get a new one.
 
Thanks Doug - that is what I was hoping to hear.

Now to just get the head painted and the engine buttoned back up.
 
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