pushing oil past the sparkplug

[ron 1995 r]

Does anyone have any issues with the Gt40 iron heads and oil pushing past the spark plug threads?

Anyone know what causes it?

My engine has 15000 miles on it.

Ron.

[rheacerdave]

Um.
I've raced with the same set of GT40 heads on the A/Sedan car for 12 years and I don't ever remember there being an oil journal to the spark plugs. :eek:
Rings or valve seats.
Doesn't sound like much mileage for rings, though.
Solid or hydralic lifters?
Not enough gap with solid lifters lets stuff by. Valves won't seat completely. Could be a stuck hydralic lifter.

[waynenorcross]

Make sure you have the correct plugs. The GT40 iron were different from standard 5.0L plugs. I don't know what the difference was, maybe just length.

Other thought we be that the oil is actually coming down from the valve cover gasket and just collecting in the spark plug well. Is there oil in all the plug wells?
Wayne

[rheacerdave]

I think you are right, the only difference I can find is reach and of course type of electrode and heat ranges of course. All should be 14 mm.
Ron you didn't say if this was with older plugs or some you just put in.
Dave

[SoCal94]

Is this specifically on the rearmost plugs? (In particular the passenger side?)

Every windsor powered Ford I've ever owned has somehow gotten oil around the back plug on the passenger side (#4), and sometimes the one in front of that too (#3).

The threads may allow some oil gunk to get by - they are not tapered or anything, and the sealing surface is on the outside anyway, so the plugs can allow a little stuff to pass over time if they're not snugged down.

You can reduce this by using a little anti-seize on the threads of the plug. I do that on my '94 primarily because I'm putting a steel plug into an aluminum head (I switched to TFS heads early on), but the anti-seize would help seal the cylinder a little better even with steel on steel (and prevent the plug rusting in place if the car sits a lot).

SoCal94

[tomshep]

Sounds like a valve cover gasket.

Tom

[SoCal94]

Yeah, that could do it too. If the valve cover gasket is gone, usually there is enough leakage to cause oil to seep down to the headers and burn off (smelly, dirty, etc). Do you have that problem?

SoCal94
PS - how ya doin, Tom?