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MG MGB Technical - REAR ENGINE LEAK

I have an 18 v engine that was rebuilt 4 thousand miles ago. It have a leak at the rear seal of the engine. The crank had a grove in it so I had a speedy sleve put on. It still leaves a nice puddle of oil after a run. What to you suggest. My mechanic said pull the crank out and weld more on it and re grind and re nitrite it. What went wrong with putting on the new sleeve and would another on work better if we did something different. We used locktight on the sleeve. Someone suggested using JB weld instead. Any thoughts on what to do.
JEFF BECKER

What Loctite did you use, it should have been the shaft and bearing loctite. Given how tight the sleeve fits you want to use an anarobic sealer as it cures in the absence of air.
John H

Remember to keep an open mind on where the leak is coming from. All the oil that leaks from our Little British darlings ends up at the bottom rear of the motor.
If you are convinced that it is a rear engine seal problem, rule out crankcase pressure then check the archives for discussion of a "Sherpa" rear seal.
I've got a front tranny seal problem myself and find that the carpet sample squares do a FINE job of keeping the oil drips off my friends driveway.
Rick

The machine shop has told me I have two choices...remove the engine and put on a new speedi sleeve or remove the crank and weld material on it and regrind it then refit it with a new seal. Just putting on a new speedi sleeve would be the cheapest and easy to do. Has anyone put on material and then grind it off to a smooth searface. The main question is why did the sleeve fail or the seal fail.
JEFF BECKER

I NEVER use speedi sleeves or weld to cranks - just grind enough off the surface to remove the groove - usually about 5 thou. This makes absolutely no difference to the seals ability to seal.

Are you sure that you haven't got excess crankcase pressure forcing the oil out past the seal?

Use LUF10001 the black viton seal, not the red one.
Chris at Octarine Services

Chris, I have this engine in a MGA, I am using the tappet covers from a MGA which should allow the pressure to get out. I also have a Judson Supercharger with a cap which also vents. Any other ideas?
JEFF BECKER

You might try fitting the front tappet cover from an MGB and use positive crankcase ventilation to reduce the pressure in the crankcase and keep the oil in tht way - saves pulling the engine if it works!
Chris at Octarine Services

I agree with Chris, you need to be sucking the pressure from the crankcase. When I built the engine I replaced the closed circuit system on my GT with a neat little K&N filter on the pipe coming out of the front tappet cover - then lost all of the oil - put it back to standard straight away and it worked fine. A friend told me he had the same problem with a midget so I phoned the supplier (MGOC) and they told me that always happens... when I asked why they sell the filters in that case, they told me 'because people want to buy them'!

Neil
Neil Lock

How does the front tappet cover work. Does it have a small tube that goes to the carb filter to suck the fumes. My valve cover does not have one as I have a Judson Supercharger valve cover.
JEFF BECKER

Jeff,

Yes and no. There's a short piece of pipe on the front tappet cover, then a Y-piece, then two pieces of pipe going to a fixed pipe on each carburettor on the upstream side of the throttle.

Neil
Neil Lock

Jeff, WERE DID YOU GET THE REAR SEAL!!!!!!! We were rebuilding B motors for 15 years & we had some problems with the MOSS rear seals! Went to the gayco seal from Eangle imports 1 800 253 4080 (Zack) & changed all rear seals in 14 motors we had built, in stock & have not had a leak yet. There is nothing wrong with the speedy sleave, we use a lot of them. My motor man that built my motors was building motors at the end of WW 2 till the day he died 2 years ago & he used a LOT of the S.S. With no problems. Look at the seal!
Glenn Towery

Glenn, when you changed the seals, did the crank still have a groove in it from the old seal, or did you turn the crank smooth, or did they have speedi sleeves.
JEFF BECKER

If there is a small bit of a grove, we would leave it alone. you have the sleave on & I am sure that is not the problem, (if inst. right) Were did the rear seal come from? What color was it (oarange?) that might be the moss one. I made a lot of ph. calls to other shops to find that the moss seals were the problem 6 to 8 years ago.
Glenn Towery

I am not sure of the color as I had a machine shop do the engine work and putting it together. It sounds like I might be able to just remove the engine and replace the seal and not touch the crank. I presume all I have to do is remove the flywheel and remove the rear engine plate, replace the seal and a new rear gasket and reinstall. How close am I ?
JEFF BECKER

Before you take the engine out, check that the oil is actually coming out of the jiggle pin at the bottom of the clutch housing.
If it isn't, then it is not the crank seal.
If it is, it may also be the gearbox input shaft seal.
If it is coming out of the back of the engine and running down the outside of the backplate, it could be sump rear seal, or backplate gasket.

Anyway,

Pull the engine if you must.
Remove the pivot pin from the clutch arm (Remove release bearing by turning the spring clips over the ears on the bearing around) and pull the clutch arm out. Change the pivot bush if worn. Clean the gearbox inside the bell housing, and remove the plate covering the shafts that has the clutch pivot on. It will come off easily, if you undo all the bolts, (not miss one out like I did!) Change the oil seal in this cover, and refit with a new gasket.

Reassemble clutch release.

Goto engine.
Remove the clutch.
Check for wear against a new assembly. They look pretty much worn out when brand new BTW.
Remove flywheel bolts.(There is a big tab washer that secures all the bolts)
Mark one dowel,and the flywheel so it goes back on the same way.
Pull flywheel (Don't drop it on fingers or toes!)
Check if pilot sleeve falls out. If it does, and looks worn, change it.
Knock back tabs on seal retainer, remove retainer.
You could remove the seal now, but easier to
Remove all backplate bolts, and remove backplate with seal.
Now look for a wear groove in the crank. If there is a deep groove that your nail will catch in, speedi sleeve or machine the crank

Fit new seal (You can get seals with different lips that are supposed to be better)
Fit new backplate gasket.
Refit backplate, refit seal retainer, bend tabs over to secure bolts.
Refit flywheel, use a new circular tabwasher. Use waterpump pliers to squeeze tabs onto bolt heads.
Refit clutch, using an alignment tool, or you will never get the gearbox back on.
Replace engine.


Alternative, put a littertray on top of the oilstain, and always park in the same place!
Martin Layton

You may want to determine where the oil is coming from as mentioned in other posts. I had this problem so I bought a bottle of engine dye at Napa, and after driving the car for about 50 miles used a small black light my son had got with a kid's game and I could see where the oil was coming from and also that it was coming from the engine for sure, although some could have been the trans too. The light shows the streaks of oil and where it's coming from. Mine was tappet covers, oil pan you name it. Anyway, if you used the dye and don't want to buy a black light (Eastwood sell them) maybe you could take the car to a shop with a good black light and see where the leak is.
Also, if you see no dye in the oil puddle, then it's the trans. Good luck.
Sam Sullivan

My trans oil is red and that black stuff is oil on the floor. I will recheck the valve cover to see if it is leaking. The engine has only 5,000 since it was rebuilt 3 years ago.
JEFF BECKER

This thread was discussed between 14/12/2006 and 23/12/2006

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