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Q: blow by around pcv and around oil breather cap.

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I have a 1983 5.0 convertable H.O 302 with 289 heads and chevy valves erson roller rockers re-grind cam a little one no big jump in cam. i did not rebuild the motor. New high volume oil pump. I am gettig blow by around my pcv valve and my oil breather/fill cap.I know my valves are out of adjustment can this cause blow by. Is the alternative possible cause bad rings? is there other reasons for blow by such as vaccume leaks or timing or anything besides rebuilding it
My car has a manual transmission.

A: Hi there. Engine blow-by is the result of c...

Hi there. Engine blow-by is the result of combustion gasses getting past the piston and/or piston compression rings, this builds crankcase pressure. The PCV (positive crankcase ventilation) valve system is designed to remove the pressure and recirculate the gasses back into the intake manifold. When the blow-by overcomes the PCV system, evidence will be seen at the PCV, oil cap, and KV breather filter. Excessive blow-by generally is an indication of worn cylinder walls and/or piston rings. The modifications to the upper engine and improperly adjusted valves are probably enhancing the blow-by. I recommend having your vehicle’s engine blow-by be diagnosed and repaired by a certified technician, such as one from YourMechanic.

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