GearBox bell housing leaking oil

The 4A, 4AB, 4AC, 4AD cars, including the SM 1500 Roadster and SMX
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Stephen
Posts: 164
Joined: Thu Feb 03, 2011 9:27 am
First Name: Stephen
Location: Victor Harbor, South Australia, Australia

GearBox bell housing leaking oil

Post by Stephen »

Hi Everyone .. when I restored the Singer 4 AD I reconditioned the motor but not the gearbox because it seemed OK .. just recently I have noticed a puddle of oil under the car and on closer examination it was found to be coming from the hole in the bell housing ..
My questions are .. is there a seal in the bell housing that would cause this or is it more likely to be motor related.
If there is a seal how hard is it to get to and has anyone had to do this seal before.
Is these a replacement number for the seal, if that is what it is
Regards
Stephen
bitsobrits
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Joined: Wed Jun 06, 2007 7:46 pm
First Name: Steve
Location: SW Iowa, USA

Re: GearBox bell housing leaking oil

Post by bitsobrits »

Stephen,

It's been awhile since I've had my gearbox out, but as I recall, the input shaft didn't have a seal, but a sort of reverse thread arrangement to return oil to the gearbox via a drain path in the front bearing retainer. I believe there is a paper gasket between the bearing retainer and gearbox, easy enough to make or replace with a gasket forming sealant.

In any case, removing the gearbox is pretty easy, once you remove the seats and front floorboards from the car. No need to remove the engine or bell housing, though of course you will need to support the rear of the engine.
Steve W
Singer 4ADT
Stephen
Posts: 164
Joined: Thu Feb 03, 2011 9:27 am
First Name: Stephen
Location: Victor Harbor, South Australia, Australia

Re: GearBox bell housing leaking oil

Post by Stephen »

Hi Steve .. thank you for the reply ..
What I have found is the the oil filter was leaking and I had a thought that when the car is moving it could be pushing the oil down to the bell housing and making me think it was leaking from there ? ( probably wishful thinking)
So have done is the easy task first ... degreased the motor so it is clean and I will see any oil leaks,.. Dropped the engine oil out and replaced the oil filter & O ring.
I will now tighten all bolts up around the bell housing to gearbox and take it for a drive and see what happens ..
If I have no leaks great, if I still have a leak from bell housing then I will take the gearbox out and investigate..
And yes I do recall a threaded oil sling type of arrangement now you mention it ..
Regards
Stephen
Stephen
Posts: 164
Joined: Thu Feb 03, 2011 9:27 am
First Name: Stephen
Location: Victor Harbor, South Australia, Australia

Re: GearBox bell housing leaking oil

Post by Stephen »

Finally I had a chance to get the Singer out for a decent run .. it was a combined run with our local Hillman club,.. Victor Harbor to Wellington around trip total of 148 miles ( 238 Klm) in 34 C heat with a hot north wind .. Singer went well with temperature going from the usual 140 F to 185 F due to heat on the trip there but back to 140 F on the way home with a head wind ..
But the bad news is the leak is still there so looks like gearbox out to find out why .. will have to wait as I have a 4 day singer run next week ..
If I find anything unusual that I think people should know I will submit but probably rear main seal ..
Regards
Stephen
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Mark Thompson
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First Name: Mark
Location: Nashville, TN

Re: GearBox bell housing leaking oil

Post by Mark Thompson »

When I rebuilt my 1952 4AD engine, I found that it didn't have a rear main seal. Instead it had a reverse thread (labrynth ?) arrangement that was designed to sling the oil back toward the engine.

Is there a way for you to differentiate whether the oil is coming from your engine or transmission? Viscosity difference? Use a colored oil, or dye the oil in one of them?

Mark Thompson
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kabu
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Location: Finland
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Re: GearBox bell housing leaking oil

Post by kabu »

Hi Stephen,

I also suspect that the oil might still be coning from the engine via the crankshaft rear end. As Mark said, there is only a reverse thread labyrinth seal there, as is common to most (british) cars of this era, and that construction is qiute prone to some leak. One fact that can increase this tendency is the temperature you have there down under and that might make the engine oil too thin. What viscosity oil do you have in the engine? You could also check that your engine breather tube is not blocked as that will increase the pressure in the crankcase and push oil out.

Of course the oil can also come from the gearbox. As said, the gearbox can be removed backwards without removing the engine from the car.

Regards,
Pekka
4ADT Roadster, 1954 --- http://www.guru-group.fi/kabu/singer
Stephen
Posts: 164
Joined: Thu Feb 03, 2011 9:27 am
First Name: Stephen
Location: Victor Harbor, South Australia, Australia

Re: GearBox bell housing leaking oil

Post by Stephen »

Hi Mark & Pekka thanks for the suggestions .. sorry for the delay in getting back to you, but our interstate Singer Club and our local singer club have been on a Border Bash for a week and have only just surfaced ..
OIL LEAK is still there but not as bad as some of the other Singer cars, so that made me feel a little better.
I still want to eliminate the leak, and have determined it is come from the engine, and not the gearbox,.. before I went away I put a heavy duty oil in the gearbox so I could differentiate.. definitely engine oil.
When I first put oil in the engine after the rebuild I put a heavy oil recommended for older cars in, but was told it should have a 20 w 50 in it so I changed the oil..
I think I will go back to the heavier oil, as per Pekkas suggestion, .. I found the engine leaks more on a long run on a hot day, so the oil may have lost some of it's viscosity .
Will be a week before I tackle the oil change as I am off to Bendigo Swap meet .. one of Australia's largest swap with over 2000 sellers.
Will let you know what happens ..
Regards
Stephenw
Stephen
Posts: 164
Joined: Thu Feb 03, 2011 9:27 am
First Name: Stephen
Location: Victor Harbor, South Australia, Australia

Re: GearBox bell housing leaking oil

Post by Stephen »

Hi Everyone .. not much of an update, my son has been undergoing tests and the prognosis is not good, so the Singer is on the back burner for quite a while,, but before this happened I did remove the breather as the previous owner had cut and welded it at right angles instead of the smooth bend that is on the original breathers, by doing that he restricted the air flow from the crankcase, but it looks liker I will not be trying it out for a while ..

If it still pushes oil out after the next run, I know that is not the problem and will add the heavier oil ..

Everyone have a safe, healthy and prosperous 2015 .

Stephen
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