valve stem seal for street use LA (opinions?)

[DaveBonds]

Looking at seals for a stock 3/8 stem, stock springs, etc.

I'm debating on positive lock on all 16, material type and design types, etc. I don't have uncommon spring clearance issues or anything special in the valvetrain that would restrict.

I've had a set of stock rubber positive lock/ umbrella combinations on the engine that I'm driving with good results since they've been installed, but that's not saying much, because they've only been in for about 6 months.

This set is going on a different set of stock heads that will be used for the street. I'm looking for longivity, as replacing them on an assembled engine is a day's work and a night's back ache.

What do you think?

 

[SGBARRACUDA]

On a street engine the OEM umbrellas are hard to beat nd really only cause problems when they become old and brittle from years of use. Hell when I replace them with the engine in the car or on a set of race heads, I only use them on the intakes and not the exhausts.

 

[moper]

I persoanlly like the positive-type seals. With the cam designers going with lobes that require heavier springs it jsut makes sense to me to prepare for them even if "right now" you have no plans to make use of them. It's no extra if you're have the guides done anyway. I use Viton and have had gereat results. If you decide not to cut the guides - the factory had a rubber version of a positive seal - meaning it grabs the guide top too and doesn;t move with the valve - for the intake valves on later 318s and 360s. They come in most gasket sets now.

 

[66fs]

The best long term is factory Viton positive seal, but you can only use them on single valve springs. They fit tight on the factory guide. I use "short umbrellas on the exhaust. If dual springs, like Moper said.

 

[DaveBonds]

Thanks for the ideas!

I was leaning toward a basic lock set. The guides aren't cut, so I'll likely just go back to a simple, factory set with umbrella seals and locks that pop on to the tops of the guides, like the ones I had installed on the other set of heads.

I have a nice camshaft with new double springs and matching lifters that came with the set from Hughes, but it's for another engine. If I ever go with new springs on these heads, I'll be checking each piston at TDC with some rope through the spark plug hole, just to keep the valve from getting bent when I break the locks loose to install the new springs, at which point I'll have all access to the seal. I'd only be saving myself a tiny amount of work there.

Thanks again!

 

[moper]

Actually - you're preventing the possibility of running dual springs by not cutting the guides now. But - I have a question... What are you calling "dual springs"?
There are sinlge round-wire springs - as in stock...
There are single round-wire with a flat wound dampener - as in a performance replacement single spring (Comp 901-16, etc)...
And there are dual spring asemblies that consist of the single with dampener and an inner round wire spring.
The dual springs need the small guides and seals. The single and single with dampener can run factory umbrella type seals.

 

[66fs]

"There are single round-wire with a flat wound dampener - as in a performance replacement single spring (Comp 901-16, etc)... "


and factory 340, 383, 440 HP, and Hemi

 

[moper]

I'm fairly certain he's working on a 318. But you're right - the perforamnce engines came with them.

 

[DaveBonds]

Actually - you're preventing the possibility of running dual springs by not cutting the guides now. But - I have a question... What are you calling "dual springs"?
There are sinlge round-wire springs - as in stock...
There are single round-wire with a flat wound dampener - as in a performance replacement single spring (Comp 901-16, etc)...
And there are dual spring asemblies that consist of the single with dampener and an inner round wire spring.
The dual springs need the small guides and seals. The single and single with dampener can run factory umbrella type seals.

Sure, any of them. Basically, anything that would require a different seal, I suppose is all I was getting at. I guess a beehive spring would also qualify for a tight guide seal.

They would be in the way, you are correct, but it's not going to stop me from pulling them and pitching them for a $20 set, if I go through the trouble of tearing it all apart up top and going TDC, on all eight cylinders to do a swap again at some point. I suppose if it came down to it, I'd just pull the seal with everything else off, but I'm not likely going a higher performance route.

This car is a driver, so I don't really see any huge combo of cam/ parts going on this engine later down the road. I have a few 360 engines that I may build for something else, later. I almost just started assembling the one I have finished with a hughes HEH1019AL and round/flat combo springs to match, but I'd just be throwing my money down the filler neck at the gas stations I hit more frequently.

I guess my question would be surrounding longivity, alone. Basically, I'd like to put something into this engine that will last as long as the rest of it and if I have to replace something big, I'll likely swap it all out for displacement.

 

[moper]

I'm not really up on beehives and factory heads. My impression is they would need the positive seals.
What I meant is in order to run Teflon or Viton positive seals- the ones taht clamp onto the tops of the guides - you have to machine the guide doen in hieght and diameter. So you can eitehr do it while the heads are on the bench (my preference because any seal will work at that point) or you can wait, run the umbrella or that rubber sort-of-positive type now, and then pull the heads to have them cut later. Cutting the guides is not an "on the car" operation. that's what I meant. Sorry if I didn't present it well.