Oil on sparkplug threads, what's the culprit?

Fastime331 · Mar 24, 2004

I'm hoping that the oil on the plugs dosen't mean I have a serious problem.

Under full throttle blasts oil gets forced out the front and rear main seals though

I'm going to perform a compression check today, I'll let you know how it goes.

Anyone want to post their compression #'s?

MUSTHAVE302 · Mar 24, 2004

as far as oil getting forced out of the seals - are you sure you have adequate crankcase ventilation? If you have a couple breathers i would think that the extra pressure generated during full throttle would vent thru the breathers. Your PCV system may be too restrictive.

As far as oil on the plugs - sounds to me like rings might be letting some oil by. Does it smoke at all?

Fastime331 · Mar 24, 2004

No smoke from the exhaust at all...

My compression varied greatly fron 162-184 psi.

sublime29 · Mar 24, 2004

You might have valve covers leaking down to the spark plug.Then its working its way in the spark plug threads.Make sure you don't have a leak there.If you have a leak don't try to tighting them.It will make it worse.You need new gaskets.

Fastime331 · Mar 24, 2004

sublime29 said:
You might have valve covers leaking down to the spark plug.Then its working its way in the spark plug threads.Make sure you don't have a leak there.If you have a leak don't try to tighting them.It will make it worse.You need new gaskets.

Do you mean on the outside or inside of the valve cover? I can find any leaks on them at all. The whole engine is relatively new ie. 1 year @ 2500 miles. All gaskets are top of the line and new.

wisconsinboy · Mar 24, 2004

itd probly be the oil rings and you might not of torqued everything down right if you still got oil comin out the front and rear seals. just a thought

Fastime331 · Mar 24, 2004

wisconsinboy said:
itd probly be the oil rings and you might not of torqued everything down right if you still got oil comin out the front and rear seals. just a thought

Torqued down right?

I have ARP eveything and studded. Now as far as torque, beside the intake manifold lower gasket allowing some residual oil in from the valley (unlikely)

What about the PCV valve, If it is allowing oil to bypass how can this be stopped?

and

I don't think even a bad PCV valve would cause 6-8 oz. of oil to be purged from the front and rear main seal under a full on blast on the DYNO.

What is the max deviation for PSI between cylinders?

goldbomb79 · Mar 25, 2004

what's your oil pressure reading when this is happening? is it higher than normal or? also, have you taken the pcv screen out and changed it lately? j/w

Michael Yount · Mar 25, 2004

If you're forcing that much oil out on wot runs, it sounds like you have a crankcase ventilation problem. If the pcv system is not providing enough ventilation for the crankcase, the pressure that builds in the crankcase can force oil out of perfectly good, even brand new front and rear crank seals. Tell us more about your pcv system - is it stock? Valve new? Is the screen/oil trap under the valve new? If that screen is clogged up (as most are on higher mileage engines), it will block the flow of crankcase pressure/vapors to the pcv valve and cause pressure to build in the crankcase - forcing oil out where ever the weak link is; and often the weakest links are the crank end seals. What about the tube from your valve cover oil filler neck nipple to the throttle body - is that still functioning as well? It also vents crankcase pressure when you're under wot. You say all gaskets are new/low miles -- did you also replace the front and rear seals when you did the other work?

ashford · Mar 25, 2004

more than likely your rings didnt seat properly, i had a problem with squirting oil out my dipstick at wot. i ended up re-honing the cylinders and using new rings that took care of the problem. causes for this is your machinist used too fine or coarse of stones for the rings you got, always tell the machinist what kind of rings youll be using.

shawn13 · Mar 25, 2004

Warm yor car up and pull the oil fill cap off and see how much smoke comes when reving I did a 390 once with crome molly ring 2 cly. never sealed leared a good lesion on that one

Michael Yount · Mar 25, 2004

Clearly if the rings aren't seated properly you're gonna get lots of blowby - which could also be the source of the crankcase pressure. I guess I just assumed the rebuild was sound - bad assumption on my part perhaps.

Fastime331 · Mar 25, 2004

Michael Yount said:
If you're forcing that much oil out on wot runs, it sounds like you have a crankcase ventilation problem. If the pcv system is not providing enough ventilation for the crankcase, the pressure that builds in the crankcase can force oil out of perfectly good, even brand new front and rear crank seals. Tell us more about your pcv system - is it stock?

Yes the PCV system is dead stock.
Valve new?

Yes, new PCV valve

Is the screen/oil trap under the valve new?

No but I did clean it once before. Good Idea I'll check again.
If that screen is clogged up (as most are on higher mileage engines), it will block the flow of crankcase pressure/vapors to the pcv valve and cause pressure to build in the crankcase - forcing oil out where ever the weak link is; and often the weakest links are the crank end seals. What about the tube from your valve cover oil filler neck nipple to the throttle body - is that still functioning as well?

Yes I still have that installed. There is however more vaccum present on the valve cover side though than on the TB side. Is that the norm?

It also vents crankcase pressure when you're under wot. You say all gaskets are new/low miles -- did you also replace the front and rear seals when you did the other work?

Yes and then I re-replaced the rear main again because I thought it was somehow defective.

I did have a valve cover breather but that diddn't work either

Thanks for your help Mike, You have a wealth of helpful knowledge.

Fastime331 · Mar 25, 2004

shawn13 said:
Warm yor car up and pull the oil fill cap off and see how much smoke comes when reving I did a 390 once with crome molly ring 2 cly. never sealed leared a good lesion on that one

Good point I'll try that too

Fastime331 · Mar 25, 2004

Michael Yount said:
Clearly if the rings aren't seated properly you're gonna get lots of blowby - which could also be the source of the crankcase pressure. I guess I just assumed the rebuild was sound - bad assumption on my part perhaps.

I am worried about that as well, I let a local machinest do the work. He has built many engines but does not specialize in Fords.

Should have known better

Fastime331 · Mar 25, 2004

Can mal adjusted rockers cause this buy any stretch?

Michael Yount · Mar 25, 2004

Do you have adjustable rockers? Most of them on our engines aren't adjustable.

Fastime331 · Mar 25, 2004

Michael Yount said:
Do you have adjustable rockers? Most of them on our engines aren't adjustable.

Yea I've got Omega 7/16 stud mount adjustable rockers.

I'm taking it to a local Speed shop to have them perform a leakdown first and if that passes (which I doubt)

I was half tempted to buy an Autometer guage guage with a vaccum/boost guage to monitor when and why it creates the crankcase pressure. NOt sure if that would work...

What I did notice about this engine is that when I first got it running and began driving it around it would NOT stay cool. It was around @200-210 (even with a 180 deg. stat and 3 core radiator). I made sure the cooing system was free of air and everything.

My guess is that when he (the machinest) did the hone he either made it too rough and diddn't file fit the chrome moly rings correctly or a combination of either. He also ceramicoated the pistons but I'm not sure if that would cause the heat???

Maybe it is finally time that
I whipped out the plastic and bought a 331 stroker kit and have it assembled by a FORD SPECIALIST

Oil on sparkplug threads, what's the culprit?

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