Where is the oil on my clutch disk coming from?

[wlivesey]

I have had ongoing tranny problems and now I am experiencing clutch slippage after driving my BT7 for ~1 hr. I think I have smelled oil also. So I pulled the tranny again and found what appears to be an oil contaminated clutch disk. It is black - not the normal brown color. In addition the pressure plate has an oily film. I have been told the oil is coming from a leaking oil pan or the main seal. My question is - is there a way that I can confirm this? I think I could handle the oil pan, but I think I need some direction on the main seal. How do I get to the main seal? Does any one know of any good instructions that I could follow?

Thanks
Bill L

 

[Randy Forbes]

There is no rear main seal, just a reverse scroll that's supposed to sling the oil back into the sump.

By the time the BJ7 came along, at least there was a rubber lip-type seal on the transmission input shaft, and yours may be due for replacement.

There is an aftermarket lip-type seal conversion available for the crankshaft, so that's an option. I'm certain that it contains instructions, and required templates for installation.

 

[Keoke]

Hi Bill, I think what you may be faced with is a leaking "Rear Main Bearing Seal." In the healey engine it is not simply a replaceable part. OTOH, there are several new designs from the aftermarket that can be added to the rear of the engine while the trans is out. This is not a complicated upgrade but requires you to remove and modifiy the rear engine plate to implement it. The instructions in the kits are quite complete and some suppliers will exchange modified engine plates with you.--Fwiw--Keoke- /bcforum/images/%%GRAEMLIN_URL%%/cowboy.gif

 

[Healey 100]

I don't have any experience with aftermarket rear seal kits, but Healeys were built from the beginning with no rear seal and most of them manage to keep their clutches dry.

The non-sealed original rear main bearing leaks some but not enough to foul the clutch. If yours is leaking badly enough to get to the clutch, you probably have worn main bearings and/or lots of blowby on your engine -- both of these factors greatly increase leakage through that rear bearing. Putting an aftermarket seal may slow the leak but the best way to solve this problem is to rebuild the engine.

Since your leak seems so severe and sudden, maybe the problem is coming from the transmission. I would try rule that out. There is no front seal on the tranny either, but it may be overfilled or maybe the clutch shaft cover is leaking.

Good luck!

 

[Keoke]

Well HLY 100, not really, the healey was built with a rear main seal. Incidentally, it is a very expensive design. However, after 40 years it has become worn, is virtually irreplaceable with out tremendous cost and leaks more than it was designed to. The current aftermarket rear seal mimicks the the more modern engine's design type. Properly installed they will STOP rear main oil leakage.---Keoke-AZ /bcforum/images/%%GRAEMLIN_URL%%/cowboy.gif

 

[Dave Russell]

Re: Where is the oil on my clutch disk coming fro

I have had ongoing tranny problems and now I am experiencing clutch slippage after driving my BT7 for ~1 hr. I think I have smelled oil also. So I pulled the tranny again and found what appears to be an oil contaminated clutch disk. It is black - not the normal brown color. In addition the pressure plate has an oily film. I have been told the oil is coming from a leaking oil pan or the main seal. My question is - is there a way that I can confirm this? I think I could handle the oil pan, but I think I need some direction on the main seal. How do I get to the main seal? Does any one know of any good instructions that I could follow?

Thanks
Bill L

Has the engine just recently been put back together & just started leaking?

In addition to the scroll type seal on the crankshaft, the rear main cap is sealed to the block on each side by round cork or felt seals. If these seals are not correctly installed & a good sealer used, oil will leak around the sides of the rear main cap. Some engine builders suggest omitting these seals & filling the cavities with hardening type sealer.

Also, the rear main cap does not always sit flush with the pan rails on the block but a little below flush. Many gasket sets have an "extra" small cork strip that is intended to be stacked on top of the pan gasket to give extra fill in this gap. If it is missing, there will be leakage between the bottom of the main cap & the pan. Sometimes the front main cap has a similar problem.

In any event, leakage from the rear of the engine should be deflected by the flywheel & thrown off before it ever gets to the clutch. The small drain hole, with cotter, below the flywheel lets the oil out, if the hole is not plugged. The engine can usually leak a lot without oil getting on the clutch.
D

 

[MarkA]

Re: Where is the oil on my clutch disk coming fro

The oil on the clutch is probably not comming from the engine. For engine oil to reach the clutch disc, it is either comming through the center of the flywheel or the bell housing is filling with oil. Both of these are highly unlikely. It is more probable that the leak is wicking down the trans input shaft to the clutch. Although after a very long time of engine oil moving around in the bell housing it will reach the clutch, a short term event like this is probably trans oil.

Don't you think?

Mark

 

[Patrick67BJ8]

Re: Where is the oil on my clutch disk coming fro

I agree with Mark. I overhauled several Healey engines back in the late 70's and did one engine that had a cracked rear main cap. Even with the crack there was no oil on the clutch.
I was working with a very good machine shop at the time and we also came up with a solution which saved the owner from having to buy another block. We built up the worn main bearing & cap and trued up the crank and then recut the main bearing area by align boring it.

 

[bob hughes]

Re: Where is the oil on my clutch disk coming fro

It has taken me 2 years to pluck up courage to attend to my clutch and I have just replaced it earlier this year - same problem, slippage once the engine was really warm. Whilst everything was apart, I replace the oil seal in the bell housing, to keep the gear box oil out, this should be done as a matter of course seeing that it really is a five minute job by comparison, I then fitted the rear oil seal modification onto the crank as well ( see one of my earlier topics for a tool to get the spring in ). I still have a slight drip from some where, and that needs investigating but I have travelled some 2000 miles so far this year, 1000 of it fast motoring for periods of over 1 hour and so far no reoccurance of the problem. Discussions with a friendly Healey mechanic this week end, revealed that they may not stop the problem completely, but they drastically reduce the leakage.

Bob

 

[MarkA]

Re: Where is the oil on my clutch disk coming fro

After I installed a rear main seal kit, I too still have a very small leak. After pulling the tranny and taking another look, it appears that the rear main cap is leaking. I should have replaced the cap seals when I had the pan and rear plate off. But a drop a day is a lot better than what it used to be! One day soon when I have a spare weekend, I will overhaul the engine and take car of that problem.

Mark

 

[Keoke]

Re: Where is the oil on my clutch disk coming fro

Hi Bob & Mark, what is not always stated regarding the installation of the rear seal kit is; the engine block and the rear main cap must line up perfectly to get an absolute seal at that interface. But I agree a small leak can be tolerated.---Fwiw--Keoke- AZ /bcforum/images/%%GRAEMLIN_URL%%/cowboy.gif

 

[bob hughes]

Re: Where is the oil on my clutch disk coming fro

Hi Keoke

It was stated in my kit, they suggested loosening the mains cap and tapping it over to line up, mine was good, with only a hint of a step and I doubt if I could have got it any better so that was it for me.

Bob

 

[wlivesey]

Re: Where is the oil on my clutch disk coming fro

When I get under the car and look up between the fly wheel and backplate (probably ~1 inch) I do not see any sign of oil. Do you think I am safe to assume the oil is not comming from the engine side. In addition, the trans shop has said there is a seal in te tranny that is shot and is probably the source of the oil.

 

[Dave Russell]

Re: Where is the oil on my clutch disk coming fro

Very likely, since unlike the earlier cars, the BT7 transmission DOES have a front seal.
D

 

[bob hughes]

Re: Where is the oil on my clutch disk coming fro

Wlivsey

That's an easy one then, joist hoick the seal out of the bell housing and replace it with new, make sure that you put the new one the right way around. I had to remove my bell housing from the gearbox as the clutch fork needed attention, so it was easy. Not sure if you can do it properly without removing it, as the first motion shaft will be in the way.

Bpb