New Engine Oil Problem


Oct 25, 2018
Just finished builing an engine for my 1966 Mustang. 1976 302 block with 1969 351W heads. Had the blocked bored .020" over, and decked from the original 8.229" deck height to the normal SBF 8.206" deck height. Keith Black hypereutectic 2.6 cc domed pistons, with Hastings plasma-moly rings. Heads were milled .003" to ensure flat, machined for screw-in studs, hardened exhaust seats, three-angle valve job, and new valve guides. New Manley Street Flo stainless steel valves, new TrickFlow viton valve seals. New Cometic MLS head gaskets & Felpro 1250 intake gaskets. Shelby Cobra aluminum intake manifold. Calculated static compression is 10.31:1. Port matched intake ports.

Started the engine and broke in the new mechanical flat tappet cam - 28 minutes between 2,500 and 3,000 RPM - with no problems. Let it cool down about an hour and re-adjusted the valves. Several days later took the car on a short (6 mile) test drive with no hard acceleration. It ran fine until I was pulling in the driveway, and the carburetor started flooding the engine and some oil smoke came out of the tailpipe for about 5 seconds before it died. I saw no smoke or vapor coming out of the oil cap/breather (the hood is off). I since fixed the carburetor. I pulled the plugs, and every one of them was wet with oil. I checked the PCV hose from the valve to the manifold and it was dry and clean (it's also brand new).

What would cause ALL eight plugs to be wet with oil? Intake gaskets? Valve seals? Rings?


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