New to this list, I'm a 356 guy, needs help with a 2.2 911

No#6 cyl fills with oil if the car sits for a week or so. Daily driving it is fine, good power no smoke, but park it for a week or two, oil drops form on the #6 exhaust studs, and it smokes like a fiat for 2-3 minutes, Then it clears up and runs fine.

It did this for a few months last year, compression and leak down were OK. But tons of smoke. So we pulled and rebuilt the motor, with new PC, rebuilt the heads, went together fine, good compression, leak down etc back to the Rabbit it was built to be.

Let it sit for a week, pull the #6 plug crank it and it sprays oil out the plug hole, expels probably close to an Oz. Oil is clean like the tank. The other cylinders are dry.

Somehow, oil is gravity draining from the oil tank and ending up pooling in #6 Cyl. It's almost like the stuck carb float filling a cylinder with gas, but I have not gotten a hydraulic lock.

Anyone seen this before. Please email me

 

http://www.rothsport.com/Products/En...eck-Valves.htm

 

Not uncommon at all,.......

We use the Rothsport Check valve (patterned after the factory GT-3 one) to fix this problem.

 

Steve
Thanks, do you know what the entry path into the cylinder is? I figured it was a check valve leaking down, I just can't get my head around how the oil gets through the head.
Thanks again
John

 

John,

Fluids seek their own level (physics).

When the car sits for awhile, oil can flow from the tank back through the bottom hose, through the pump, filling the case up until the level is the same between the engine and tank. The looser the pump's internal clearances, faster this can happen.

 

How does it enter the combustion chamber??

Thanks
Johm

 

High oil levels in the case leave the lower parts of the cylinders, pistons & rings immersed in oil, resulting in a big cloud of smoke on start up.

 

What Steve says is quite true. What is not accounted for is the fact it's only happening in one cylinder.
Obviously something else is going on here. It is possible that despite the leakdown being OK there
is either a score on the bottom of the cylinder, the cylinder is out of round,a defective or unseated ring,
or another cause preventing the rings from rotating and the gaps are all towards the bottom
causing the oil to get by. I would ask whos P+C set it is.
Anther possibility is a bad exhaust valve seal-also under the oil level after sitting long enough.