Ran my 7M for years, shes been good, friend drove it, forgot to tell him where the cooling fan was before we got to the track, it got hot momentarily. It ran absolutely fine that night after cooling, but showed signs of a pressurized crankcase (blowing out the valve cover breathers) much more than usual. It was not misfiring, still ran the same ET/trap even. Got it home, leaked it down, showed 60% leakage in cyl 1, 3, 6, all going to crankcase. The crankcase also tested positive for hydrocarbons with block leak tester. It had ARP headstuds and an HKS MLS. The headstuds 'seemed' inconsistently torqued when taking them off (I havent retorqued them in a while) So since cyl 3 doesnt have an oil drain passage, which was my prev assumption, could it be leaking from the bolt holes and pressurizing it that way? Perhaps a cracked head? I checked with a straight edge and it does look a bit warped, Ill know more when I get it to the machine shop just wanted to check with my peeps first, thanks
Is it possible (probable in this case) to have a BHG from CC to bolt hole passages
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Bolt holes are blind, and they go to the coolant jacket, iirc. Cracked pistons due to detonation from overheating perhaps?