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Hey guys I have some protopline heads with only 500kms on them. They seem to be getting oil into the intake tract somehow. I'm wondering if anyone has encountered this before. The intake valves are covered in oily carbon as is the piston tops and combustion chambers.
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Possible from PVC valve, if not baffled good enough.
Possible from bottom edge of the intake manifold, sucking from the lifter valley past the bottom of the gaskets..

If this is a fresh engine, also possible with that much oil is the second ring installed upside down. Second "compression" ring is actually the final oil scraper, it preps the cylinder wall with just the minimal amount of oil for the top ring to ride on and seal up.
Second ring upside down turns it into a mini oil pump, right up into the combustion chamber.
Reversion then carries to up into the intake ports.

That looks to me like a lot more oil than just a set of leaking valve stem seals.....that's a lot of oil showing in the chamber.
 

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Yeah the source is higher in the runner than the valve stems.

A common source especially where block machining like decking is mixed with aftermarket heads and intake is pulling oil and blow by gasses from the valley along the bottom of the intake gasket.

Another strong possibility is it’s sucking oil with the blow by through the crankcase venting system.

Bogie
 

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Yep, I'm sure that's where my 383 is losing oil too.
I knew I needed to put thread sealant on them, but since I have split guide plates, and had to do alot of loosening and retightening, the plan was to get everything adjusted, test it all out to make sure the guide plates are exactly where they need to be, tack weld the guide plate halves together, then pull out the intake rocker studs and seal them.
After dealing with other issues, I completely forgot about that plan...
I've been wondering what's been causing the oil loss, then awhile back I saw a post that mentioned the rocker studs again, and it all came back to me! :rolleyes:
 
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