The Ford Barn

Dave in MN · 01-29-2016, 05:03 PM

carquest one,
Unexpected leaks can be really tough to fix, I understand your frustration.
When I first started restoring these engines, I will admit to having taken a few off the engine stand after test running to chase an unexpected leak. Often the cause was not clear and seemed somewhat random. Careful study of the "path of oil" educated me pretty quickly.

My theory after reading the previous comments and thinking some more about it:
With the hole mid-point in the cap adding to the oil passing through the galley and drop pipe, I think you have a case of being right on the edge of too little capacity for oil drainage. Upon cold start, the resistance for the cold oil is less out the back of the engine than down the drain tube so the flow starts moving back. Once the oil is moving, the rear slinger can act like a pump if the slinger is slightly off center of rotation with the journal (not concentric) and once the cap is loaded to the rear of the slinger, it can only overflow. Once the oil is moving back, it has a tendency to continue in that direction. When warm, the drain system has the capacity to allow the warm (thinner) oil to move through galley passage and drain tube and not cause the start of the reverse flow. The solution if I am correct is to increase the galley passage diameter and install the 3/8" drain tube if it is not already done and plug that hole in the rear main cap that is allowing oil directly into the galley passage.
I have dealt with quite a few leaks when rebuilding and working on customer's engines. The cause of these leaks is often the result of a few small things adding towards failure. Increasing the drainage capacity and plugging the cap hole are easy to do without removing the engine. Try this modification/repair first....if I am correct, good. If I am wrong, sorry but it wasn't as much work as pulling the engine and tearing it down.

Good luck in your search for a fix.
Good Day!

My website:
www.durableperformance.net

Brian T · 01-29-2016, 05:55 PM

If I ever get around to rebuilding an engine for my future project I am convinced now to leave it Henrys way, I have never liked taking things back apart to re-fix things, if it drips a little like they did when new, then so be it.

carquest one · 01-30-2016, 04:28 PM

to dave in mn--thenk you for your input. Im sure you have better and more financially feasible things to do then typing. Im thinking too that the extra hole may be my issue. going to plug that. Debated drilling the hole in the galley bigger like the later caps, but thought it might reduce the ledge for the welch plug too much. Im anxious to try it. looks like iowa has a bullseye on it for this snowstorm so i have to wax my wifes snow shovel first ! to brian t - i agree, if henry thought the cap needed another hole he would have put it there thanks

Dave in MN · 01-30-2016, 06:20 PM

Increasing the galley passage and drain pipe from 5/16" to 3/8" is not difficult. I have attached a series of photos that shows the steps. I have a dedicated jig to hold the caps on my bridgeport and drill press so it only takes me about 10 minutes to complete the process.

Steps that match the photos below: (You can left click on the photos to enlarge)
1) Remove the 5/16" drain pipe and discard
2) Make a jig to hold the cap for drilling and tapping for the drain pipe
Note: Construct the jig prior to removing the pipe. When the cap is in the jig, the pipe must be plumb (vertical)
3) Cap being opened to 5/16" with a mill cutter for a 1/8" pipe thread
4) Cap in position for starting the tap
5) Finishing the tapping by hand to control depth
6) Removing the galley plug with punch through newly tapped hole
7) Note size difference of 5/16" galley compared to the 3/8"
8) 3/8" drill vs 5/16"
9) Opening view of the 5/16" cap opened to 3/8" and an original 3/8" cap

There is plenty of "ledge" behind the galley plug to hold it in place after drilling it to 3/8". I do this modification to every engine with the 5/16" galley and drain pipe.
Good Day!

Brian T · 01-30-2016, 07:05 PM

Quote:

Originally Posted by carquest one

im on a roll now. acts as if drain system plugged. its not.cold start leaks badly no matter how long it runs. restart in 2 minutes no leak no matter how long it runs.

Just a thought, not to insult your intelligence but it maybe due too an oil level problem, possibly wrong dipstick?, my thinking is once the valve chamber receives its oil, the level in the oil pan will drop and the leak stops, it's also possible the oil return pipe from the valve cover to the pan is partially plugged which would further lower the level in the pan.
The one time I topped off my oil level to the full mark I could not believe how badly it leaked at idle, 1/2 way between add and full and all was OK.
Seek an you will find.

carquest one · 02-01-2016, 09:19 PM

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dave in mn----thanks for your tips, i forwarded this to my favorite brother, favorite because he has a bridgeport mill . had put a 3/8 tube but only ran a 5/16 bit thru the galley. to brian t---no insult taken,never claimed to be intelligent and was never accused of it either. checked 3 dipsticks,read the same.tried low oil level,then thought maybe tube uncovered on cold start and blowby was the problem. tried high on stick ,no better. has low valve cover outlet and cleaned return tube. thanks,trying not to let it beat me.

01-29-2016, 05:03 PM	#21
Dave in MN Senior Member Join Date: May 2010 Location: Jordan, MN Posts: 1,416	Re: leaky rear main,what else is new carquest one, Unexpected leaks can be really tough to fix, I understand your frustration. When I first started restoring these engines, I will admit to having taken a few off the engine stand after test running to chase an unexpected leak. Often the cause was not clear and seemed somewhat random. Careful study of the "path of oil" educated me pretty quickly. My theory after reading the previous comments and thinking some more about it: With the hole mid-point in the cap adding to the oil passing through the galley and drop pipe, I think you have a case of being right on the edge of too little capacity for oil drainage. Upon cold start, the resistance for the cold oil is less out the back of the engine than down the drain tube so the flow starts moving back. Once the oil is moving, the rear slinger can act like a pump if the slinger is slightly off center of rotation with the journal (not concentric) and once the cap is loaded to the rear of the slinger, it can only overflow. Once the oil is moving back, it has a tendency to continue in that direction. When warm, the drain system has the capacity to allow the warm (thinner) oil to move through galley passage and drain tube and not cause the start of the reverse flow. The solution if I am correct is to increase the galley passage diameter and install the 3/8" drain tube if it is not already done and plug that hole in the rear main cap that is allowing oil directly into the galley passage. I have dealt with quite a few leaks when rebuilding and working on customer's engines. The cause of these leaks is often the result of a few small things adding towards failure. Increasing the drainage capacity and plugging the cap hole are easy to do without removing the engine. Try this modification/repair first....if I am correct, good. If I am wrong, sorry but it wasn't as much work as pulling the engine and tearing it down. Good luck in your search for a fix. Good Day! My website: www.durableperformance.net Last edited by Dave in MN; 01-29-2016 at 05:43 PM.

01-29-2016, 05:55 PM	#22
Brian T Senior Member Join Date: May 2010 Location: San Diego,Ca Posts: 1,377	Re: leaky rear main,what else is new If I ever get around to rebuilding an engine for my future project I am convinced now to leave it Henrys way, I have never liked taking things back apart to re-fix things, if it drips a little like they did when new, then so be it. __________________ Nothing can be made foolproof, ---- fools are ingenious bastards.

01-30-2016, 04:28 PM	#23
carquest one Junior Member Join Date: Jan 2016 Posts: 10	Re: leaky rear main,what else is new to dave in mn--thenk you for your input. Im sure you have better and more financially feasible things to do then typing. Im thinking too that the extra hole may be my issue. going to plug that. Debated drilling the hole in the galley bigger like the later caps, but thought it might reduce the ledge for the welch plug too much. Im anxious to try it. looks like iowa has a bullseye on it for this snowstorm so i have to wax my wifes snow shovel first ! to brian t - i agree, if henry thought the cap needed another hole he would have put it there thanks

02-01-2016, 09:19 PM	#26
carquest one Junior Member Join Date: Jan 2016 Posts: 10	Re: leaky rear main,what else is new Sponsored Links (Register now to hide all advertisements) dave in mn----thanks for your tips, i forwarded this to my favorite brother, favorite because he has a bridgeport mill . had put a 3/8 tube but only ran a 5/16 bit thru the galley. to brian t---no insult taken,never claimed to be intelligent and was never accused of it either. checked 3 dipsticks,read the same.tried low oil level,then thought maybe tube uncovered on cold start and blowby was the problem. tried high on stick ,no better. has low valve cover outlet and cleaned return tube. thanks,trying not to let it beat me.