oil fouled plugs

[john bach]

Hi gents. New to this forum and new to owning GT40 so please bear with me. I now own SPF GT40P2116. Having trouble starting and keeping it running. Backfires frequently thru exhaust. Pulled plugs, Motorcaft AGSP32C, all oil fouled equally, no white on porcelain. Plugs are all black, not dripping, no carbon buildup. Car has MSD6AL ignition, Roush 427, Holley 770cfm 4 bbl
with choke wired open. Replaced plugs with Autolite APP3924. NAPA parts store does not carry Motorcraft plugs and said Autolite plugs are cross referenced to replace Motorcraft. (by the way what is spark plug gap, old plugs were about .040 give or take), Cranked engine over with inductive timing lite and got a lite at each plug. Searched the net for trouble shooting MSD but got no satisfaction. Have no trouble shooting old timey points and condenser and Pertronix on other cars but am a total loss at this kind of problem. would welcome any suggestion or advice. [email protected]

 

[Mark R]

Sounds like a carb problem to me. Has it been running lately? Its been my experience, that Holley carbs HATE to sit around with ethanol in them.

 

[Ron R.]

+1 on the carb.

I'd guess you're running really rich, though can't really tell you where to start. I'm sure someone familiar with Holley carbs can get you going in the right direction.

One easy thing to check is fuel pressure. Some carbs can be really sensitive to too high of a pressue. Generally results in too much fuel to all cylinders (you said all plugs looked bad). If you're runing a regulator, you might want to look there.

 

[Mark R]

Here is some good info on tuning and trouble shooting a Holley carb....

Holley Tune, Part 1

 

[Jack]

A good hint that it's running very rich is you mentioned that the choke was wired open.
Fuel pressure check in order too.

 

[Rich Roy]

Check the float levels at both front and rear bowls by removing the flat brass screw on the side of the bowl with car on flat level ground. If gas rushes out or is not oosing out when you rock the car a little, then they are off. This will make it run rough and foul the plugs as described.

 

John
Change your intake gaskets.
The Felpro gaskets fall apart at the bottom with the Ethanol gas.
It starts sucking oil from the valley.
Use Cometic or Edelbrock gaskets.
I bet your oil consumption has also gone up.
Good luck
Dennis.

 

[Robert May Eng.]

John
Change your intake gaskets.
The Felpro gaskets fall apart at the bottom with the Ethanol gas.
It starts sucking oil from the valley.
Use Cometic or Edelbrock gaskets.
I bet your oil consumption has also gone up.
Good luck
Dennis.

Aside of the gaskets this point of sealing is often overlooked, heads get skimmed,blocks get decked and unless you know the history of all the parts you have inlet sealing can throw up all sorts of problems.

bob

 

[John Milmont]

Completely rule out the carb first. I was chasing down what might be the same issue on my car for many months when it just turned out that it was too rich.

 

[Steve Wood (PANAVIA)]

That 770 carb was a pile of junk- we take them off and put on something decent every chance we get, --in addition the felpro gaskets from that period dissolve as others have said.

Also I would send an oil sample off to black stone labs to see if you have heavy gasoline contamination in the oil, if so you might have washed out cylinders and that would be a reson for fouling .

 

[Trond]

Hi
Also check that all your plug wires are intact. Theese often are close to the headers and crack up due to the heat. Start the engine in the dark and check for sparks! You see any damaged wires imidiately.

regards
Trond