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Drilling out oil passage on 1937 Cadillac engine

Started by Eric 21241, July 11, 2006, 10:29:03 PM

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Eric 21241

Greetings all,
I am in the proccess of rebuilding a 1937 Cadillac engine.
I was told there is a way to drill out the rear main oil passage to eleviate the leaky rear main slinger where the later engines had seals.
Anyone know about this?

Bruce Reynolds # 18992

Gday Eric,

Have a look at this. TARGET=_blank>

I found it by going to the "Search" and searching on "rear mail oil leak" and came up with all the threads that have previously covered the topic.

The Tassie devil(le),
60 CDV

bryson Talamini CLC 21505

Eric, I recently did this mod after reading all the posts etc etc. I did the following and now have a dry rear main seal area: cut off the bearing cap vertical oil drain tube at 45 degrees so that it is only 1" long to the tip. Then remove the little [about 3/4"] freeze plug [or drill a 1/4" hole in it] that is at the end of the horizontal oil drain passage through which the oil flows to the vertical tube. Thats it! This works because the tube is now well above the sump oil level and air can enter the spaces in the bearing cap to eliminate a vacuum. Fit new square section cork blocks to the bearing cap,and a good new oil pan gasket after ensuring that the oil pan flange is not distorted from the screw holes pulling through. Dry as a bone!
Bryson in Oz


Merry Christmas everyone:
  Sorry for brining up an old thread, but do these procedures (of cutting drain tube or drilling.....) apply to engines after 1937? I have a 1939 and 1947 flatheaded cars. I noticed that the 1939 has a little leak between two bolts attaching the bell housing, could this be a rear main bearing seal leak? Also I am rebuilding the 1947 flathead too. Regards to all.