Oil pan tube

[oriondal]

I recently replaced my timing gear and in the process cleaned the oil pan. In the bottom of the pan I found a copper tube, about 3 inches long that appears to have broken off the back of the oil sump. It's not part of the oil pump, but looks like it might have been a pickup of some kind.
What is this tube?

[George Miller]

Originally Posted by oriondal

I recently replaced my timing gear and in the process cleaned the oil pan. In the bottom of the pan I found a copper tube, about 3 inches long that appears to have broken off the back of the oil sump. It's not part of the oil pump, but looks like it might have been a pickup of some kind.
What is this tube?

It probable is the drain tube out of the rear main. Depending on the year they were 1/4 for early fords and 5/16 dia for the later ones. Originals were steel.

[Joe K]

Inquiring minds want to know.

Have you noticed any increase in the oil leaking out the rear main?

Mind you this is for informational sake. An unbiased answer is requested.

Joe K

[Russell in Tulsa]

I agree with George miller, if the pan is still off check the rear main cap and you will probably find a hole that the tube fell out of.

[James Rogers]

George is correct that it is the tube from the rear main. Your engine will probably leak a lot from the rear when you park it and this is why. George missed the size though, the early tube is 5/16" and the later is 3/8".

[Bob C]

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Does it look like this?

Bob

[Brian T]

The drainage tube was missing in my engine, it had not been reinstalled by the last person in there, some believe the rear main will drain better without it, this is apparently utter BS the engine leaked like a sieve when driving and would fill up a rear main janitor in no time regardless of a reasonably good rear main and minor blowby.

What with the crankshaft windage and crankcase pressure the tube will shield the hole from these effects, and being submerged below the surface of the oil there I also a slight negative pressure in the tube caused by the oil flowing past it to the oil pump, apparently that why they only dribble after shut down

[oriondal]

Originally Posted by Bob C

Does it look like this?

Bob

It looks very much like that except that it appears to be copper and was brazed on instead of threaded. It doesn't seem to leak at all when parked, but has been when driving. I've been thinking the leak was from the rope gasket around the crankshaft which I replaced when I changed the timing gear. The pan is back on so I guess I'll need to remove it and try to reattach the tube.

[Joe K]

What with the crankshaft windage and crankcase pressure the tube will shield the hole from these effects, and being submerged below the surface of the oil there I also a slight negative pressure in the tube caused by the oil flowing past it to the oil pump, apparently that why they only dribble after shut down

Thank you. That is the first cogent reason I have heard that the tube - or it's absence - should make any difference.

There is a fair amount of windage in the crankcase. One has only to take the cap off while the engine is running to confirm this.

I may have been lucky (it has happened) that mine never leaked even minus the tube.

And it will be interesting to hear your comparison when your tube is restored.

Joe K

[Bob C]

I would not reuse that tube, it should be threaded and then
tack welded to the main bearing cap.

Bob

[Brian T]

Before installing my missing tube, there was a few things I had learnt here on the Barn, was to make sure the tube did not thread to far up into the bearing cap, I carefully cleaned the threads as at sometime it had been tack welded, (pipe tap, cant remember the size)
I measured the depth of the hole, it was obvious it wasn't going to bottom out when refitted, in addition I filed a small vee grove facing rearward to allow a little more drainage, added a little JB weld to the threads to lock it in place.
After a 5 mile road test I was happy not seeing the trail of oil where I had been.

[oriondal]

The engine does leak oil like a sieve when running. At speed it coats the everything under the cowl, but at idle or shut down, I don't notice any more leaking so it sounds like the tube is the culprit? Now that I've learned what to look for, I see the tube is threaded and was tack welded. I don't know how, but I might have knocked it off when I removed the pan, as it wasn't leaking at all before.I've ordered a new tube and will install it as soon as I get the chance.

[Fred K-OR]

If the hole were it screws in the rear main bearing cap is mess up you may need to weld it like mentioned above or you may need to get another rear main bearing cap. Yes it is easy to knock it off when you take the pan off when you are not expecting something like this.

[George Miller]

Originally Posted by oriondal

The engine does leak oil like a sieve when running. At speed it coats the everything under the cowl, but at idle or shut down, I don't notice any more leaking so it sounds like the tube is the culprit? Now that I've learned what to look for, I see the tube is threaded and was tack welded. I don't know how, but I might have knocked it off when I removed the pan, as it wasn't leaking at all before.I've ordered a new tube and will install it as soon as I get the chance.

You still might have a leak at the rope seal. How did you install it. They do not leak if done right. But a lot of people have trouble with them. I grew up working one rope seals front and back. Most all the older cars had rope seals. Buick was one of the last to stop using them.

[James Rogers]

Originally Posted by Brian T

Before installing my missing tube, there was a few things I had learnt here on the Barn, was to make sure the tube did not thread to far up into the bearing cap, I carefully cleaned the threads as at sometime it had been tack welded, (pipe tap, cant remember the size)
I measured the depth of the hole, it was obvious it wasn't going to bottom out when refitted, in addition I filed a small vee grove facing rearward to allow a little more drainage, added a little JB weld to the threads to lock it in place.
After a 5 mile road test I was happy not seeing the trail of oil where I had been.

It is a standard us tap and the thread is a 3/8-32. An unusual size thread but very available.
This is for the large tube. I believe the small tube is the same thread but at 5/16-32.

[oriondal]

Thanks all, I hope to get at it next week and will post the results.
This was my first experience with a rope seal, and I just pressed it in place and trimmed to a fit similar to the one I removed. Probably would have been better off leaving the old one in as it seemed to be doing the job. In the end, I'll I guess I'll wind up learning how to do it properly which is what I'm looking for.