New Day, New Dilemma

bmwillia

bmwillia

Senior Member
As some of you know, I have been fighting several issues with my 35 Flatty. Timing, bent valve, running rich, etc...

I finally got the motor running decent, not perfect but good enough for a little while.

Anyway. Went for a about 30-40 mile drive Saturday morning. Car ran good. I pushed it hard a few times out on the highway during the drive, came home and parked it in the garage.

Couple hours later I went out to the shop to get some tools to hang a shelf for my wife and noticed a big pool of oil on the floor. I normally see anything from a quarter size to softball sized pool but that usually happens over night. this was at least a quart of oil on the ground and there was a steady drip coming off the cotter pin in the oil pan.

I am thinking my rear main seal just completely failed. Is there anything else it could be?

Is the only remedy to pull the engine and open it up?
 
Not a regular main seal. Think it's zinc or aluminum labrynthe casting. Might've cracked. Or perhaps too much oil in the crankcase? Or pan seal around rear main slipped out? Or parked with front end high?
 
Wasn't too much oil I checked before the drive and it was 1/4 - 1/2 inch below the full mark, and it was parked level.
 
I would check the oil level in the engine. The first generation flathead V-8s did not use a rear oil seal, there is a collar on the crankshaft that slings the oil out and it is collected by the rear main cap and drained back into the oil pan. If the level of fluid in the pan is too high in the crankcase it will leak out the rear main into the clutch/flywheel area where the cotter pin resides.

Sorry, too slow, I see Jack already provided this information.
 
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I appreciate the input Zeke and Jack. I have over 1,000 miles on the engine so far and this is the first time this has happened. I have been going by the marking on the dip stick to maintaining oil level the entire time with no issues.
 
Unless it has been converted. Also, lack of proper ventilation can blow oil out of the rear seal area.
 
bmwillia said:
I appreciate the input Zeke and Jack. I have over 1,000 miles on the engine so far and this is the first time this has happened. I have been going by the marking on the dip stick to maintaining oil level the entire time with no issues.
Click to expand...

How did you mark the dipstick? How many qt of oil?
 
Using the original markings on the dipstick.

its around 4qts to the full mark.

How do I check for proper ventilation?
 
Possibly from running it hard. My stock 36 with great engine will blow all the oil out the rear main if a run it wide open for any length of time.
 
To check vent, look inside the oil fill pipe for any obstruction. Clean the oil fill cap make sure the screen or filter element in the cap is clear. Then the oil pan vent is the triangular shaped metal can on the front right of the oil pan has a slot on one side. The slot is nearly as tall as the vent can. You should be able to insert a wire into the slot and make sure the can is it is open. Make sure the oil pan gasket is not blocking the vent hole in the block. That is about the best you can do without taking parts off the engine.
 
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