SBC valve stem seals

[EMSjunkie]

Looks like I need to replace mine.

what do y'all use :?:

o-ring type or umbrella type :?

I'm gonna change/replace them while the engine is still in the car.
I have the air chuck adapter thingy that screws into the spark plug hole, and I built a crude, but effective, lever to release the keepers.

I have heard pros and cons to both type of seals.

lemme know what y'all are running.

Thanks

Vance

[Dave]

Looks like I need to replace mine.

what do y'all use :?:

o-ring type or umbrella type :?

I'm gonna change/replace them while the engine is still in the car.
I have the air chuck adapter thingy that screws into the spark plug hole, and I built a crude, but effective, lever to release the keepers.

I have heard pros and cons to both type of seals.

lemme know what y'all are running.

Thanks

Vance

Used the stock stuff for years Vance.. If you really got a lot of oil from the overhead then its a guide problem > Was that a used engine or new rebuilt or crate?
The  air chuck in the plug hole works fine.. Someone stole mine when they got the rest of the tools..
A simple bent bar to go over the rocker  stud and cleared for the keepers to come out and rapped with a hammer while air is applyed to the cylinder works great (bastards stole that too) ....... That will give me sumpin to do ill make another    
Dave
Oh ya they got my home made spark plug air thingy too. knock the porcelin outta a plug and i just brazed an air fitting in to it....        Rock on DUDE

[EMSjunkie]

new rebuild.
not alot of oil, but wanna stop a problem before it gets too big.

was in my sprinter during the BIG accident. :oops:

had about 3 heat races and a couple mains on it before I went for a tumble

could be guides tho.......dunno if the machine shop replaced the guides or not :?

Vance

[GPster]

I was told of a trick that a guy used to change valve seals on boat motors where there wasn't air handy. He used clothes line rope. He put the cylinder down near the bottom of the stroke , fed a bunch of clothes line into the cylinder and cranked the crank until it wouldn't go any more because the rope was compressed/knotted-up in the cylinder. It seemed to be enough to hold the valves against the valve seat to do the trick compressing the valve spring and removing the valve keepers. Sounds like it would work and he used it on a lot of boats at private docks. GPster

[UGLY OLDS]

I use umbrellas....Careful though if you have bronze guides..The umbrellas sometimes keep out too MUCH oil.....  Make sure the cylinder is at TDC when you air charge it.  

[Mac]

I did stem seals on my son's Acura last year with the homemade airchuck trick. I had done it a time or 2 in the past succesfully. This time I had the air hooked up: hissing away, got the keepers off and watched in horror as the valve slid down and out of sight in the guide. I forgot to put the car in gear or otherwise lock the crank and without noticing it the air pushed the piston to BDC. :oops:
I took the exhaust mani. off and with a lot of stress and patience I was able to turn the crank a little at a time and working through the exhaust port using long needlenose I got the stem started back up the guide.

Please, lock the crank!

[Bruce Dorsi]

My preference is for positive-type valve seals!  .....These are the type that are snug on the o.d. of the guide, and "wipe" the valve stem as it moves up & down.

This style of seal is standard on many of the hi-perf ZZ crate motors, as well as on Edelbrock SBC heads, and they are also installed on many OEM GM applications.

I saw one case (a '32 coupe) where the rear of the engine was tilted down enough that the last guide (exhaust) on each bank was submerged in oil.  .....The umbrella type seals acted as miniature pumps, and actually forced oil down the guides.

Some guys use Ford umbrella seals on SBC's, and I think they are better than Chevy umbrellas, but not as good as the positive-type seals.

Some folks will say NOT to install the positive-type seals on the exhaust valves, for fear of starving the guides.  .......GM uses 16 seals on the ZZ4 crate motors, so obviously they think differently!

By all means, please avoid the use of all-teflon seals.  .....They're OK on a race engine, but they don't do well on a street engine.

The positive-type seals that you should use are black or blue, and are usually made of Viton.  ....They may, or may not, have a teflon wiper ring where the seal contacts the valve stem.

[EMSjunkie]

Thanks for the replies guys, I appreciate it.  

gonna pull the covers off this weekend and have a look.
I think I'm gonna go with the positive seal type the Bruce was talking about.

Vance