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- - Suggestions RE: Oil Fouled Plugs (https://67-72chevytrucks.com/vboard/showthread.php?t=486579)

John Pasinski

09-28-2011 03:27 AM

Suggestions RE: Oil Fouled Plugs

I have a '72 402BB. On the passenger side bank the plugs continue to foul out & build up with what appears to be more like oil than carbon. The first plug (front) isn't too bad, but they get worse till the rear plugs are really caked up. I do have "colder" plugs to install, but if the left bank is fine, I don't think installing a colder range plug will remedy this. I think its a more serious issue. My question is; how do I determine if it's valves, valve seals, or rings?

heeroyue2002

09-28-2011 04:28 AM

Re: Suggestions RE: Oil Fouled Plugs

i used non foulers for a bit.

Autoblueprint

09-28-2011 06:46 AM

Re: Suggestions RE: Oil Fouled Plugs

Quote:

Originally Posted by John Pasinski (Post 4924124)

My question is; how do I determine if it's valves, valve seals, or rings?

You can do a cylinder leakage test ( the tool is available at Summit Racing # SUM-900010 $72.95 ) but in all probability it is the valve seals that are oil fouling your plugs, which is a common problem on high mileage engines.

The valve seals are an easy enough fix as their replacement can be done with the heads on if you have an air compressor that puts out 150 PSI and have a air hold ( WMR-W84003 $9.95 ) and head-on valve spring compressor ( SUM-906784 $44.95 ). These are Summit Racing part numbers / prices.

bobs409

09-28-2011 06:58 AM

Re: Suggestions RE: Oil Fouled Plugs

Could also be the intake gasket is allowing oil to be sucked in from the lifter galley into the intake ports.

JimKshortstep4x4

09-28-2011 07:37 AM

Re: Suggestions RE: Oil Fouled Plugs

As mentioned it is probaly valve seals but make sure the drains in the heads are not plugged causing a ponding of oil in the valve cover.

Jim

John Pasinski

09-28-2011 04:32 PM

Re: Suggestions RE: Oil Fouled Plugs

My apoligies guys. I neglected to mention I overhauled it about 4000 miles ago. So I don't think it's the valve seals or plugged oil returns.
I'm waiting for a borrowed compression tester to get here. I want to see if the cylinders are close to a "normal" reading. It's only (at this point) the left bank (passenger side). And the fouling gets worse from front to back.

Wrenchbender Ret

09-28-2011 06:16 PM

Re: Suggestions RE: Oil Fouled Plugs

If its an auto trans. Check the modulator. It can suck iol out of the trans. The vacuum usually feeds off the rear port in the intake.

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