The valve seals on my '79 have been leaking for the last year or so and I finally decided to do something about it. Wasn't sure of the guide diameter so I pulled a spring today and this is what I found:




If you look closely you will see the metal spring that keeps the seal tight on the guide is broken. I checked some of the others and found at least one more that is broken.

What would cause this? Also who makes the best valve seal?

 

My preference is a Viton® umbrella valve seal. (Comp Cams, Manley, Lunati, Sealed Power or Fel Pro) I always use them on both the intake and exhaust and have never had any issues.

COMP Cams 518-8
11/32" (valve stem) X .530" (valve guide)

(1979 standard SBC)

http://www.jegs.com/i/COMP-Cams/249/518-8/10002/-1

Is that a SBC or BB? Or is it just the picture that makes the valve look canted?

Good luck... GUSTO

 

Look at the pushrods, it sure looks canted to me.

 

SBC. Trick Flow heads.

 

Thanks...

You may need to mic the valve stems to see if they are the same as the originals. Many vendors sell seals for various stems and guides as well.

GUSTO

 

improper install, or just plain cheap seals...Viton are good, I always use Fel pro personally...and I never use any seals that come in a cheap rebuild kit...

 

not tight enough fit on the guide. the seal moved with the valve movement and the inter spring caught the metal band

 

Good theory, but the seal was so tight on the guide I had to pry it off to mike the guide, and I don't have inner springs. Something else going on here.

Showed the pic to the guy who did the rebuild on the heads. He didn't seem surprised. Didn't have an explanation, but said he's seen it before and he's using a different valve seal now.

 

"You may need to mic the valve stems to see if they are the same as the originals." Since the heads are non-stock you need to check diameters of both the guides and valve stems. My aftermarket BB aluminum heads on my 68 convert came with non-stock valves, so the Trickflow heads may have done the same thing.