Cracked Weld On Rear Main Oil Drain
 

Hi everyone.. My model a was leaking a bit of oil out of the rear pan gasket so I dropped the pan and replaced the seals. I didn’t do it right and need to redo it, as it leaks more now than before.. When my engine was rebuilt with insert bearings, they tig welded the rear main oil drain pipe to the cap. The pipe is loose in the cap, and you can feel the pipe wiggle when you touch it.

If this pipe is loose in the rear cap, would that cause oil to leak out the back of the engine? The end of the pipe is in oil, but if the pipe is loose, it seems like this would be a problem.

Re: Cracked Weld On Rear Main Oil Drain
 

Yes, I think it would cause a leak

Re: Cracked Weld On Rear Main Oil Drain
 

The rear main bearing is set to a clearance, there is no positive seal at the rear main bearing cap. When that clearance is exceeded the ability of the drain to handle the oil flow is compromised, and your rear main bearing will leak.

Re: Cracked Weld On Rear Main Oil Drain
 

I agree with that.. my question is.. if the oil drain tube is loose at the rear main bearing cap, Will that cause more oil to leak out the back?

Re: Cracked Weld On Rear Main Oil Drain
 

No, as long as it in place it shouldnt

Re: Cracked Weld On Rear Main Oil Drain
 

Are you sure it’s open? ie: not partially plugged with weld, or too far into the cap.
Are the oil reliefs in the bearing correct. They shouldn’t go the outside edge. Also what is your clearance? The shims go up against the journal. And lastly, how much fore and aft play do you have in the crank. You can have someone step on the clutch, while you watch the crank pulley.

Re: Cracked Weld On Rear Main Oil Drain
 

Welding steel tube to cast iron cap = bad idea.
Originally they were threaded in. If the threads are stripped you could braze it in.
Since your engine is inserted you don't need to worry about melting the babbit out when you fix it.

Re: Cracked Weld On Rear Main Oil Drain
 

All good points.. I have to pull the pan once more to fix my oil leak, so I will check all your recommendations I will also pull the rear main cap to fix this, and check the clearance. Also need to check the lateral movement in the crank.. hand.t considered that.

Do inserted engines use shims for clearance? Guess I assumed they didn’t but could be wrong.

Re: Cracked Weld On Rear Main Oil Drain
 

No shims in an inserted engine