maybe its just because ive never worked on any of these 60 degree engines, but i thought all the valves had valve seals. why is it only the intake valves have seals on them?

 

don't know about your engine but i've never saw an engine with seals only on the intakes. actually i'd think if only one had seals it'd be the exhaust.

 

nope, these seals are on the intake valves only. that is really odd to me. anyone else know anything?

 

Valve guide seals....

 

sorry, you got me. thanks. valve GUIDE seals are only on the intake GUIDES

 

hi there............
they have whats usually called perfect circle seals on the intakes, then they have the old style seals on the exhaust.....it looks like an o ring and it goes in the groove on the valve just below where the keepers go that hold the retainer on the spring.........the reason they do that is they don't want any oil getting into the cylinder through the intake cause it can foul the plug, if any gets into the exhaust it just burns up. if you take the spring off the o ring style is usually very hard after 50 or 60 thousand miles and it just falls apart, so you might miss it....
Joe

 

but i didnt see a thing on any of the exhaust valve guides or valves. is it at all possible for the exhaust to not have any seals at all on the guides?

 

hey..
there very small o rings..........when they fall apart they look like pieces of carbon.anything is possible........but in all my years of taking apart gm engines i've never seen any valves without them.......on the 3.4 i'm doing now...they were even on the intakes......above the perfect circle seals.........
Joe

 

Yes the GM 2.8 v6 has positive style seals on the intake valves and rubber o-ring seals on all the stem tips. I run positive seals on all my valves as well as o ring seals on all the valves. I like my wide band oxygen sensor to get the best readings possible and I dont like excess oil in the cc or head.

I ran dupont intake seals and gm exhaust seals both the positve style+orings on all.

Please note the following! The dupont are blue, gm black. The o-ring seals are installed after the springs are compressed and are in the picture for referance only!

 

yoooo..........
great picture...........now why didn't i think of that.........i have a head apart also....must be the old age.......

 

Yep... I ran Fel Pro Viton seals on my 3.1. You want the little O ring seals on all the valves, and the guide seals at least on teh intake guides.

 

thats what i needed to hear. i found a bunch of o-rings i didnt know where they went. so all the valves get the orings and the intakes get the guide seals. thanks guys!!!!

 

you can run just the pc style seal on both the intake and exhaust when you do this the o rings is not necessary. when you do it ths way you can get rid of the oil shedder on the exhaust spring and get rid of some valvetrain weight for higher revs.

 

Thanks for the pic, 614! Is there a reason you went with Dupont instead of GM for the intake valves? Got any part #'s for us?

 

Title:
No more plain rubber

"Just as important as the design of a seal is the material thereof. Ordinary nitrile rubber was used for decades it's cheap, easy to mold, and has sufficient life as long as it doesn't have to endure temperatures of over 200250 degrees F. Wait a minute, where are you going to find such a cool environment inside today's hot running engines? Nowhere, so nitrile is seriously obsolete. Unfortunately, some off-brand manufacturers supply it for late model applications even though it just won't last.

The next step up is polyacrylate (or "P.A.," as they call it in the gasket trade), which can take 350 deg. F. Silicone has the highest temp resistance (480 deg. F.), but it's not very tough. The ultimate is Viton, DuPont's name for a very hightech (and expensive) fluorocarbon material that's practically bulletproof, is impervious to just about any chemical, and can withstand 450 deg. F. for a long, long time. As the previously quoted tech advisor told me, "Almost all late model valve seals are positive and made of Viton, which may be any of several colors. They may have annular grooves on intakes to provide oil control, and sometimes spiral grooves on exhausts to give the guide a metered amount of lubrication."

If you're wondering why all the auto-makers didn't go to Viton years ago, the answer is cost. How much of a difference can there be in the prices of some little rubber parts? A lot. If you assign nitrile a cost factor of one, then polyacrylate would be two, silicone five, and Viton 20! That big a difference made some import makers come up with seals that are more metal than expensive fluorocarbon. About this the gasket engineer said, "The all-Viton type of positive seal common on domestic engines can deflect and expand enough to accommodate an oversize stem. But the kind that's often found on imports with the metal shell and just a small sealing element can't expand as much, so you could get into trouble with an oversize stem."

All those synthetic rubbers look and feel the same, so the only way to be sure of getting the right stuff for the application is to buy O.E. or brand name aftermarket. But there's a further caution: I've heard reports that even O.E. may not be what you expect some Japanese car companies have specified lower quality parts for the replacement market than for the assembly line. While that's not common, it's enough to bias my purchasing decisions toward quality aftermarket brands. Wherever the labor-to-parts ratio is about a million to one, it's downright foolish to use anything but the best.

I'll conclude with a couple of miscellaneous points. One, you may balk at the price of those seals that have the metal valve spring seat and stem seal in combination. But this is no place to scrimp. And, two, always use a plastic installation tip to prevent the keeper grooves from tearing up the new seal. " - Bob Freudenberger ~ http://www.autosite.com


Viton
P/N Fel Pro SS72530 17.88 for 6 from parts america
more expensive than
polyacrylate? (OEM replacement)
P/N Sealed Power MV1888 13.22 for 6 from parts america

I should have used viton on the exhaust as well but I didnt