63split63

Having trouble finding an oil leak on a 67 bb . Lower half of the fuel pump gets wet and oil blows back from there . Changed the fuel pump , same problem . Hooked up a smoke machine and got nothing . Fuel pump push rod plug is not leaking ,
Seems to only leak while driving , no leak while running on the lift .
Any suggestions are welcome .

Nowhere Man

Valve cover gaskets?

Bluestripe67

Look at the front timing cover and the crank seal. The damper/balancer could have a slight groove from age and normal ware. Those two coupled together make a wider gap, then you can have a leak. The gasket at the bottom of the timing cover as it mates to the oil pan gasket could be your problem. Dennis

DucatiDon

this

63split63

Thanks for the help. The engine is a fresh rebuild . If it was the pan gasket or timing cover seal I would have thought the smoke would have leaked out there .

Bluestripe67

Now that we know the critical info, "is a fresh rebuild" may make a difference. I would now look at the PVC system too make sure it is plumbed correctly. Did you follow the exact steps for the use of the smoke machine? Dennis

63split63

Thanks for the help. I had the smoke machine into the rocker cover for about 15 min and found a small leak out the back of the intake , then into the dipstick tube for about 10 min . I don't know what you mean by the exact steps for the use of the smoke machine , pretty straight forward process .

Bluestripe67

You should be pumping smoke into the engine via the dip stick tube. Close off the PCV, and the carb. Temporarily remove the oil fill cap, continue pumping smoke until it comes out of the oil fill tube, then close it off. Continue pumping and look for leaks. Dennis

cardo0

Cheap trick is clean the block/area and once dry cover affected area with white flour. Then take laps around the block to watch the leak as it progresses each lap.

Hope this helps.

63split63

Just wanted to update this issue . In the end the problem was the harmonic balancer seal . Although the balancer seal surface measured good and looked good we installed a sleeve and the problem went away .

Thanks for the help .

Bill

Bluestripe67