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Tuesday, August 30, 2016

The real oil leak problem - The stroker shovelhead drains.

Well I have been fighting weird oil leaks since I built it into a stroker, then melted the heads, and put the S&S topend on it. Good news is that I think I'm down to the root cause, but the bad news is that it will require a full teardown to include splitting cases.

With the S&S second top end, I forgot to transfer drill the lower cylinder spigots for the now lower drain holes. I even double checked the base gasket holes lined up with the holes in the cases. But I somehow managed to miss these instructions from the S&S big bore cylinder instructions. I knew the cases were fine, but I just didn't look at the cylinders.

Here's what the cross section should look like.

This is what I actually built. It's pretty amazing that the valve seals held back that much oil in the head and the only leaks were the engine crank and pushrod tubes.

I will be working with Daniel at Longbow Custom in Bartlesville, OK to rebuild this motor once again this winter. His strategy is to go ahead and drill the cases straight through like an Evo as shown below. The piston skirt should still get plenty of oil from the flywheels and crankcase.

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