SteveG75

Well, here is the situation.

Edelbrock RPM heads, 11/32" valve stems, valve guide machined to .530 inches.

When I went to the roller cam, the machine shop installed the Crane Teflon seals that came with the cam kit (PN 99820-16). Several of those seals did not stay down on the guides, causing an oil burn problem.


So, I replaced them with the original Edlebrock part (#9725) which are postive control seals, but made of Viton vice teflon. Worked for a while and now some of these are refusing to stay down on the guide.


Went to NAPA, bought a set of Perfect Circle VS-2. These barely fit over the stem but are too big at the guide so won't stay in place.

Does anyone know of a good postive control valve seal that will stay in place? This is starting to get frustrating. Heck, I can swap all 16 in about 4 hours but don't want to keep doing the job. The only thing I can think of with the Edelbrock seals is put a little crush on the lower ring so there is more tension on the guide part.

I just want to stop burning oil.

Edit: Starting to wonder if I should try seals with a .500" guide diameter???

page62

I'm gonna try a wild and uneducated guess here...you're probably treating the symptoms as opposed to curing the problem. Now for the guess: too much space between the valves and valve guides?

SteveG75

Maybe, but why would the seals be pulled off the guides and ride up on the stems. They are not staying down on the guides.

page62

My knowledge is limited, but most seals -- like umbrella seals -- do ride up on the valve stems. I guess the positive lock seals are intended to stay on the guides, but I imagine that with all that valve action, they have a hard time doing so! Seems to me it's like holding onto a flagpole in the middle of a tornado...

Do you also have o-ring seals on the valve stems?

SteveG75

No, my valve stems only have one groove (for the valve stem locks).

page62

Hmmm...well, at least I've done my best to help keep this post alive (while people were busy looking at soon-to-be-locked threads).

Perhaps someone with some REAL knowledge (not I) will chime in with some useful advice!

stingr69

Umbrella seals. They are made to ride up and down on the stem rather than stay attached to the guides. Make sure you have enough clearance inside the spring for them.

I have had the same issues as you when running the teflon seals so I do not like them anymore.

-Mark.

GTR1999

Steve I wish I had an answer for you. Did you try contacting Edelbrock to see what they say? FYI My WP S/R Torqueres and Sportsman 2's came with umbrella seals. I also have an oil usage issue but in my case I haven't done a leak down test yet-may be old rings with new heads=blown ring?
Please keep me informed on what you find out, I thought you solved it with those other seals a month or so ago.
Gary

SteveG75

Gary,

New rings, older heads. Umbrella seals aren't an option due to the dual valve springs that came with the cam. Plus, don't they need another groove in the valves for the O-ring? My valves only have one groove for the locks.

Yeah, I thought I had it solved as well. Got some more seals on order from Summit.

Hey, it gives me something to do while the snow is on the ground.

mvftw

Should use umbrella seals on a stock L82? This is my springtime project...

SmokedTires

AFR told me that they found that some people have experienced oil burning with teflon seals. I will be pulling my heads to replace the seals as soon as we're up into at least the 30's around here

Fevre

Is there a grove on the valve guide to hold the seals?

SteveG75

No. I presume that the lower spring on the seal is supposed to exert enough tension to keep the seal from moving.

I just ordered some Trick Flow replacement seals from Summit. They are for 11/32" valve stems and fit a .500 guide. Also made of Viton. The shop may have machined too much off the guide. I figure that the seals should slide fairly eaily on the stems and have to be forced down over the guides.

Good news is that this is only costing me about $20 for parts and 4 hours of my own labor each time. Good thing I am not paying a mechanic.

zwede

A few random thoughts:

1. Did you coat the stems with oil before assembly?

2. Check the guide where the seal goes. Make sure it is not concave (smaller at the top).

3. What is the diameter of the inner spring? Is is properly centered to the guide? Could the spring contact the seal and pull it off?

Tom454

Check the machined area of the guide with a micrometer.... see if it really is .530.

Positive lock valve seals are supposed to stay pressed onto the guide/head... not ride up & down.

If the machine work is sloppy.... too large, too small, cone shaped etc. they won't stay put.

Anyone can buy the valve guide cutter and Bubba it up.

73bbc

How hard was it to press the seals in place? It should be about impossible to press them in place with your finger without using a sleeve and something to tap them in place.
If it was easy to press the seal in place, the guide may have been cut too small, as you suspect.

Also, if the top edge of the guide wasn't chamfered it leaves a sharp edge that actually cuts the inside diameter of the seal away as the seal is pressed on, creating a loose fit. Bubba at work again...

SteveG75

Exactly the issue. The shop may have had trouble installing the teflons are cut the guides too much. I hope that the Viton seals with a .500 guide ID will fit much tighter. I figure if they cut it down to .510 or so, the Viton will have enough play to fit over it.