I know ... oil again ...

hazelhoff

hazelhoff

Senior Member
Guys,

I have read all the posts on rear main oil leaks. However, I have a rebuilt engine leaking about a teacup full of oil running idle. It leaks along the cotter pin. I lowered the oil level to 1/4 between full and Low. Doesn’t have an effect at all. The engine has babbitt bearings and original oil slinger.
Before I start undertaking anything dramatic, my question would be: “what may be expected from a Model A engine dripping oil ?” What is normal ?

Henk
 
Several other things can cause oils leaks that appear to come from the rear of the engine. Any leaks from the oil return pipe, valve cover gasket or oil pan gasket will run toward the rear of the engine and flow to the lowest spot before dripping off the cotter pin.

Check the rear of the engine between the block and flywheel housing to be sure that there is a gasket, and that it is not installed backwards.

If the leak is indeed coming from the rear main bearing, check the bearing cap to be sure that the oil return tube is not screwed in too far, or it will block oil from draining into the pan. Also remove the small plug next to the oil return tube and check that the passage is not blocked with sludge or Babbitt material. If this all checks OK, then the bearing clearance may be too great, and you will need to adjust by removing shims.

My rebuilt engine with 2000 miles on it leaks a few drops after a good drive.

Good luck - Jim
 
The oil pipe in the rear main bearing maybe missing, plugged, too short. That pipe returns oil into the oil in your engine oil pan. Also I keep the oil level above the add line to no more than 1/2.
 
My normal is when visiting friends it behaves and doesn't drip, but at home in the dead of night it will drip some
 
I am disappointed.
I hought that we were going to have another discussion about modern oil vs the old stuff.
 
I like the Chevron 15-40 oil similar to what you are using. What are the others using :~))))))))) Not trying to start anything.
Gerry Birch Bay WA
 
If it comes down to setting the clearance, I particularly make sure the rear is at and no more than .0015".
 
I wonder if Hazelhoff parks on a hill. My 30 town sedan will leak if I park with the front end going up hill. For instance, in my driveway.
Marty
 
I miss the oil strip down the center of the highway, The smell of oil vapor from a road draft tube.. the smell of exhaust from an engine with no emission controls..it was a common occurrence years ago, now the only time I sense it is from driving my A.
 
Assembled and adjusted correctly the rear main bearing drain back system works correctly. One thing on my engine different than most is the addition of a second road draft tube placed in the valve cover above the rear main bearing feed. This insures no crankcase pressure affecting the gravity feed, essentially pressurizing the bearing.
 
Thx for all the help. From what I understand my engine is loosing way too much oil at the rear main. All the other options I have already checked and it really is the main rear leaking !

Is it possible to remove the rear bearing cap with engine installed ? Meaning just removing the oil pan and the flywheel housing cover ?

Henk
 
Today I checked the breather cap, which is repo of course. Cap came being stuffed with steel-wool, just like the “brillo” pads you used to clean your cooking pan with ..., so I took the wool out.
Checked the breather pipe, which was thoroughly clean !
Believe it or not, the engine doesn’t leak half the amount it used to do before !! First ten minutes no leaking at all, then starting to drip. I ran it for about half an hour and there is a 5 inch puddle of oil on the cardboard.
Now the question is: is this acceptable or still too much ?
 
Nothing else ... leaks but the rear main ! I measure endplay being .004”. Is that excessive ? All other clearances are just fine ! Engine is stock and rebuilt. I really don’t know what to do about it, even having read all the posts on this subject.
 
Good Afternoon Hazelhoff...A few thoughts. Does your engine have a warranty of any kind? How many miles has the engine run since it was rebuilt? My experience has been that after a year or so and with the run of a 1000 miles or more, the rear main might sometimes needs to be snugged up. It can be done with the engine in the car, with the pan and dust cover off. It should be done by someone with experience with Model
A's or at least cars of that time period. It might need one shim removed...it might also be leaking around the bolts that hold the rear main in place...permatex or some other material can usually stop the leak if that is the problem...Ernie in Arizona
 
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