Model A Oil Pan on Model B engine
 

Hello.. I had an oil leak on the front of my Model A engine oil pan that resulted from my crank pulley coming loose last year. It tore up the inside of the front pan where the seal goes, and I finally decided to change the pan. So I got a pan from a friend who rebuilds model an engines for a living, cleaned it up, straightened the flanges and put it on. The oil leak at the front stopped but now it’s leaking pretty bad in the back.

My old pan didn’t leak in the back, so it got me thinking. I am using the same brand of oil pan gasket, same engine block, same rear main cap, same weight oil, same snap in tray, and same oil pan bolts, so the difference seems like it’s related to the replacement oil pan.

I have a Model B engine in my garage with a Model A oil pan on it. I thought the rear cap on a B engine was bigger because the journal was bigger, and the oil pan gasket sets do have 2 different seals. So when someone puts a A oil pan on a B, do they just grind out some metal on the back of the pan to accommodate the bigger main cap?

That’s what it is starting to feel like to me.

Re: Model A Oil Pan on Model B engine
 

A bit more info.. starting with a clean oil pan, in 10 minutes at idle I have a stream of oil coming from the rear of the oil pan all the way to the center of the oil pan, and then it drips to the floor….

Re: Model A Oil Pan on Model B engine
 

get a model b pan---in my 60+ years of fooling around with model A's I have never run across an A pan on a B

Re: Model A Oil Pan on Model B engine
 

Now you have :)

Re: Model A Oil Pan on Model B engine
 

If that's an A pan someone did a very good job of putting the dimples in the side of the pan. Could be a GAZ pan, I have one like that.

Re: Model A Oil Pan on Model B engine
 

I put an "A" pan on a "B" engine, the only difference is the larger rear main cap. I had to enlarge the semicircle to fit the cork gasket on the main cap. It's a little tricky but it came out fine, you have to figure how deep to to make the pan lip press into the cork. Also I used the stock rod nuts which hit the pan sides so just did little metal bumping to the area affected (this was 30 years ago before I knew about smaller rod nuts).

Re: Model A Oil Pan on Model B engine
 

So if you put that modified pan on a A engine, would you expect it to leak out the rear of the oil pan?

Re: Model A Oil Pan on Model B engine
 

For sure!

Re: Model A Oil Pan on Model B engine
 

Most definetly, there would be a 1/2" gap between the main cap & the pan! You would need another UNMODIFIED A pan.

Re: Model A Oil Pan on Model B engine
 

I believe the oil tray for the rod dippers sits lower in a model B Pan if i am recalling correctly----not positive

Re: Model A Oil Pan on Model B engine
 

The A pan can be used on a B engine by carefully enlarging the rear to fit the B rear main cap. Use ARP 12 point nuts on the rods in order to have clearance between the rods and the side of the pan, otherwise you will have to dimple the A pan so it looks like the sides of the B pan. These nuts do not take cotter pins, they are not needed anyway.