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jayd_2 10-13-2012 12:56 PM

1989 SBC Valve Stem Seals
I've got a 1989 SBC with a one cylinder fouling the plug and using oil but does not smoke. The engine has been rebuilt and runs great, don't know how many miles are on it. It takes 800-1000 miles for the plug to foul and it uses at least a quart every 2000-3000 miles.

Is there a chance it's the valve stem seal(s)?

The parts stores list both the o-ring type and umbrella style. If it is the umbrella type should it have failed so soon? I know the old style o-ring seals are crap but the umbrella type work great. 10-13-2012 03:08 PM

89 uses the positive intake seal and plastic exhaust umbrella and O ring.

It is possible that the seals were not correctly installed or the valve guides were not properly checked/sized during the "rebuild".

jayd_2 10-14-2012 12:19 AM

I read another post on the forum that said use the positive on both valves. Should I do this or stick witrh the stock setup? 10-14-2012 08:40 AM

GM started using positive seals on the Vortec heads. Mostly for emissions benefit. Older heads need some lube on the exhaust. The intake seals will determine oil use the most tho. Vacuum on intake side, pressure on exhaust, most of the time.

Check for excessive valve/guide clearence when you change seal. Just try to wiggle valve sideways with no spring load/pressure on it. Should be no movement on a lubed stem.

jayd_2 10-14-2012 06:29 PM

Thanks for the info, I'll be sure to check the valves, hope it's just a bad seal.

techinspector1 10-14-2012 07:24 PM

It could also be a bad match between the intake manifold and the cylinder head, preventing a good seal at the gasket and allowing oily vapors from the crankcase to be pulled up into the cylinder through the gap.

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