SBC 355 Pressure Under Valve Covers???

[Ozie P]

Fresh rebuilt motor with less than 100 miles on it. My issue is this- what would be causing pressure under the valve covers? At idle there seems to be no pressure, but once rpms raise up the pressure increases and pushes oil past grommets and out the breather cap. Could a valve be staying open too long? I’m becoming concerned that the engine builder didn’t replace the rings....even though he’s a very reputable builder for race engines. Any opinions?


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[richard A lindner]

My guess would be oil pump relief valve. Had on pop out on a race engine and it blew the oil filter off

 

[Shorty81]

Do you have a PCV valve on your valve cover to vent to the carb?

 

[Rickf]

Do you have a PCV valve on your valve cover to vent to the carb?

That's what I was wondering. I think he has an air pressure issue.

 

[gotyourgoat]

You mentioned breathers, so I'm assuming no pvc. That could be part of your issue. Are the remaining vacuum lines routed correctly? Are there baffles in the valve covers or the grommets?

 

[73c20jim]

On my race car SBC 355, when I had individual lines from each valve cover going to the catch can I blew a lot of oil. But when I connected the two valve covers together and then into the catch can, not much oil. Go figure.

Just sayin'