The Ford Barn

Doctor's Ford · 09-09-2015, 10:54 PM

Now on my 4th attempt to fix large oil leak on the rear main. This is where I stand currently with the engine apart

1) Cut grooves in Babbitt in main cap replicating the original pattern (shown in prior post)
2) Today I measured crankshaft clearance. I could not locate plastigauge around here so used aluminum foil to estimate clearance and this is what I found:

It took 7 layers of aluminum until the crankshaft would not rotate easily. With 6 layers it felt correct. I used my micrometer and measure the stack of aluminum foil thickness several times and got between 0.0027 and 0.0039. There was a small play on the crank that could be felt by hand when trying to move it upwards.

Questions:

1) If this measurement is accurate, is this clearance large enough that can explain massive oil leak on the rear main? I understand 0.0015 is the ideal.

2) I have NO ACCESS TO PROS WHO CAN POUR NEW BABBITT, so I would like to fix using less conventional methods. For instance, can this be fixed by removing a couple of thousands inches from the main cap so the crank will fit correctly? I read many strongly oppose to this. Can you educate me why that is a problem?

Appreciate your input, thank you. Manuel

09-09-2015, 10:54 PM	#1
Doctor's Ford Senior Member Join Date: Jun 2011 Location: South Dakota Posts: 410	Model B Rear main oil leak: What to do next? Now on my 4th attempt to fix large oil leak on the rear main. This is where I stand currently with the engine apart 1) Cut grooves in Babbitt in main cap replicating the original pattern (shown in prior post) 2) Today I measured crankshaft clearance. I could not locate plastigauge around here so used aluminum foil to estimate clearance and this is what I found: It took 7 layers of aluminum until the crankshaft would not rotate easily. With 6 layers it felt correct. I used my micrometer and measure the stack of aluminum foil thickness several times and got between 0.0027 and 0.0039. There was a small play on the crank that could be felt by hand when trying to move it upwards. Questions: 1) If this measurement is accurate, is this clearance large enough that can explain massive oil leak on the rear main? I understand 0.0015 is the ideal. 2) I have NO ACCESS TO PROS WHO CAN POUR NEW BABBITT, so I would like to fix using less conventional methods. For instance, can this be fixed by removing a couple of thousands inches from the main cap so the crank will fit correctly? I read many strongly oppose to this. Can you educate me why that is a problem? Appreciate your input, thank you. Manuel