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Old 09-28-2011, 03:27 AM   #1
John Pasinski
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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?
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Old 09-28-2011, 04:28 AM   #2
heeroyue2002
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Re: Suggestions RE: Oil Fouled Plugs

i used non foulers for a bit.
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Old 09-28-2011, 06:46 AM   #3
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Lightbulb Re: Suggestions RE: Oil Fouled Plugs

Quote:
Originally Posted by John Pasinski View Post
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.
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Old 09-28-2011, 06:58 AM   #4
bobs409
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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.
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Old 09-28-2011, 07:37 AM   #5
JimKshortstep4x4
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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
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Old 09-28-2011, 04:32 PM   #6
John Pasinski
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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.
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Old 09-28-2011, 06:16 PM   #7
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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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