Question: Positive stop valve seals. . .clearance issues

[Bolisk]

Just removed my springs to find that my brand new positive stop (PC) valve seals were shreaded and causing smoke out the tail pipes. Long story short the top of the seals were shreaded away from the metal ring base. They look like they were cut when installed or via some other means.

I'm trying to determine how this happened. They look like they were cut when installed or via some other means. I figured it has to be one of the following:

1) Crap seals (just split when the engine started)
2) Install failure (install tool damaged them
3) Spring retainer bottoming out on them

Is it possible for the spring retainer to bottom out on them and cut them? How much clearance (between the top of the seal and the bottom of the retainer) should I have with stock hi-perf springs and retainers?

Also, can I use o-ring seals at the retainer if my new valves do not have the second lower groove for the o-rings?

-JR

 

[lars]

It's not likely that the spring retainer hit the seals - the springs will go into spring bind before the retainers can hit the tops of the valve guides. More likely, the umbrella seals, which are not positively attached to the valve guide bosses, are moving up and down with the valves and being shredded against the guide bosses and inner springs each time the valves open.

Lars

 

[Bolisk]

Ok, so final story on this one.

I agree with lars, I think the postitive stop seals were installed incorrectly. In other words, the machine shop (who shall remain nameless) attempted to install these (Manley 24045-8 - Manley Viton® Valve Stem Seals - Overview - SummitRacing.com) .530 sized postivie stop seals on my guides which were machined (a long time ago) to .570. When I inspected those seals. . .many of them were torn/ripped at install because they were hammered apon to get them to fit on the existing guide. When I pulled those seals off. . .they viton inside the metal sleave was all bunched up and squished up to the top and all jamped together. In several cases the tops were sperated from the base. . .and in others, the metal case was split from being over stressed. I removed them.

When I talked to the machine shop, they said that those seals were special ones that would fit on that sized guide. I called Manley, Felpro, and Edelbrock, and all of them had the same story. . .those seals come it two sizes to fit the same size guide O.D. .530 and .500.

I looked in vain for several days to try and find larger positive stop valve seals. I gave up and decided to go back to the o-rings. . .only to find that the new valves do not have the second groove for the o-rings. Thanks again. . .mr. machince shop. Then I decied to go with umbrella seals. . .only to find that no one makes an umbrella seal that will work with the hi-perf springs that have the damper coil in them. All the umbrella seals that I found. . .would not fit inside the spring.

Then at one autoparts stop, they showed me these fel-pro seals: Fel Pro SS72527 Fel-Pro Valve Stem Seals

These are viton (according to the fel pro packageing) even though both JEGS and Summit say they are rubber. Anyway, these positive stops seals have a spring retainer that can streatch arround the .570 guide. So I tried them and they went on without any issues and appear to be solidly connected to teh guide. My only concern is that these were slighly bigger in the OD over the other seals. . .and I was concerned with clearance betweent he OD of the seal and the ID of the spring (with damper).

After installing and checking it. . .these fel-pro seals do not touch the spring. . .but they are DAMN close. Got it all back together last night, and started her up.

ZERO exahust smoke!! Car runs perfect, and is not embarrasing.

If you are reading this thread. . .and have similar behavior. . .check the seals first, then play with the intake. Take my word for it.

Regards,
Bolisk

 

[navy2kcoupe]

Good for you, perseverance pays off!
Andy