MYSTERY OIL CONSUMPTION
Sometimes we get engines in the shop that have unexplained oil consumption. The rings, valve guides and seals all appear to be just fine. Valve guide replacement, spring cup modifications, heavy porting and machining rocker arm bosses are just some of operations that can cause oil to leak into the intake ports, once an engine is running and pulling vacuum. To identify a problem area we first get the head clean and dry. Next, using your vacuum tester, pull vacuum through the intake ports while applying a colored liquid or dye on the valve cover side of the head. If it shows up in the port side then you can usually see the problem area.

Dave Matton
D and D Auto Machine
Bloomington, MN
October, 2016