Valve seals

[Unkle Krusty]

I added a post to my thread valve springs. Has pics.
The complete gasket set I bought has two types of seals. 8 look like the original smaller seals. 8 will not work.
The seals that were removed were of two different types. Are folks using all the same type, or different seals for the exhaust and inlet. Rock Auto has Engine Tech S2888, fancy seal with a metal expanding ring. Are these too restrictive, or just right.
Do the seals need to fit snug over the extruding part of the head / valve guide. I assume that will prevent them from going up and down with the valve. 8 of the original do not fit snug. Maybe the valve springs held them in place.
I will be back on the job Friday and can study them a bit more.
Pics, are on my valve spring thread. Thank you UK. Learning more about these engines every day.

 

[pnora]

Commonly they had 8 full umbrella intake and 8 half umbrella exhaust. I used to install the full umbrella on all 16 in just about any small block or big block Mopar. You have to be careful on the seals that lock on to the guide as they are valve and guide size specific. What gasket set did you buy?

 

[Unkle Krusty]

I will be checking all the sizes on Friday. Valve stem is 3/8, and that is the listed size for tne S2888. Are you suggesting the non spring seals may be more desirable?

 

[pnora]

I will be checking all the sizes on Friday. Valve stem is 3/8, and that is the listed size for tne S2888. Are you suggesting the non spring seals may be more desirable?

Myself I normally did not use them. Like I said they are guide and stem size specific. So you need to measure. Plus some of them require the guides to be machined. With that being said I commonly used 16 of the same umbrella seals.

 

[Geoff 2]

You could NOT get a worse seal than the dumbrella seal. They go hard with heat, crack up. Use proper Viton seals which require machining the guides. The best ones have a garter spring aroud the v/stem which compensates for the seal wearing. The section that fits over the guide is metal clad, usually 0.500" or 0.530".

 

[dadsbee]

Okay, the OE's in my Superbird's 440 are now 55.5 years old. Checked them last year and they're still all in place and doing their job!

I had a couple in my 383 Bee that died by 2016 and replaced them all. Engine rebuilt in 1976.

 

[69Bee]

OE seals were nitril and are only good up to 250^F. Fel-Pro replacement seals are Polyacrylate and good up to 350^F. Modern positive seals can be silicone or viton which ate both good to 450^F, but need to have the guide OD cut to the proper od and height. Three normal guide OD seals are 0.065", 0.032", and 0.500". If you want to keep costs down, just use the short umbrellas on the exhaust and either the long umbrellas or the push on positive seals on the intakes and you will be fine.

 

[pnora]

Okay, the OE's in my Superbird's 440 are now 55.5 years old. Checked them last year and they're still all in place and doing their job!

I had a couple in my 383 Bee that died by 2016 and replaced them all. Engine rebuilt in 1976.

Same results here. Looks like dumber and dumber is educating on dumbrella seals. How dumb is that.

 

[69Bee]

And on the topic of positive valve seals, the stem to guide clearance must be to spec for them to work properly. The positive seal spring holds the seal lip to the valve, but if the clearance is too much, the guide will tip over and open up the top of the seal so oil can pour in. Put your finger in your shirt collar and pull a little. That is what happens to the seal with extreme guide clearance.

 

[Unkle Krusty]

Thank you for the input men. Measuring and decision on Friday. These short non fitting seals I got with the gasket git, do not fit my engine, according to RockAuto site.
The original seals are hard, but were doing their job. 1977 to 2024, and about 65,000 miles. I can compare them to the 8 umbrella seals I got in the gasket kit. I think this gasket kit has also been sitting a while. New seals of the umbrella type would seem to fix the problem, and they were attach to the head. The valves are 3/8, and I will check again on Friday.
March will be put it all back together month.