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MG MGB Technical - spigot Bearing Seized?

I have just replaced the crank in a BGT. My engine man made & fitted a new spigot bush which was free on the centring tool which in turn was .001" bigger in dia. Engine went in very easily.

After starting the engine, the car would not go into gear and it looks as though the new spigot bush may have seized.

Its a brass bush and was lubricated with CV joint grease. The centring tool was a very good, if free fit, and caused an airlock once it was inserted and a loud "pop" when pulled out.

Has anyone had a similar experience?

If it has seized, how do we get the engine and gearbox apart?
Richard Tinkler

Richard,
The spigot bearing be sintered bronze, and soaked in engine oil before fitting.

David
David Overington

Richard,

David is correct, in fact it is soaked in engine oil over night! The sintered bronze is porus enough to absorb engine oil.

The engine and gearbox should come apart regardless of the condition of the spigot bearing. It will either release at the crank, or the front input shaft, but either way it should be soft enough to allow the two units to separate, perhaps with some force.

warmly,
dave
Dave Braun

Richard, I have come accross this problem before. Loosen all the transmission to engine bolts 1 turn. then place a jack under the transmission and apply a little pressure. Start the engine and try shifting the transmission. If it still resists apply some more pressure to the jack and try again. I think you are experiencing an engine to transmission misalighnment, be it ever so slight, that allows the trans input shaft to drag on the spigot bearing and turning the shaft all the time. Ray
RAY

I think Ray is on to something. I had to do some jiggling when mating my 3 synchro to my engine. After the first time I mated them I turned the engine by hand with a wrench. I could feel a drag on every revolution. After realigning per Ray all was smooth and no problems after 50k miles.

Yes, you should have soaked it in oil but I don't think that would lead to seizure like you describe. Too bad the plate and bell housing didn't use tapered pins at the factory.
Robert McCoy

Just try putting into gear, clutch down, and cranking it. Failing that tow it in 1st gear repeatedly operating and releasing the clutch pedal, i.e. treat it like a stuck clutch.
Paul Hunt 2

After a lot of grief, we have finally got theengine apart. Had to take the clutch off by turning each clutch bolt a half turn at a time with a thin spanner.

Spigot bush was completely seized to the spigot and wouldn't pull through the clutch.

All round a bitch of a job.

I don't understand why it seized as it was definitely in clearance. Maybe brass & CV grease was wrong.
Richard Tinkler

The bush is a tight fit in the crank. After you press it in, you need to ream it out to clear the input shaft.
Mine seemed to shrink about 0.2mm smaller than the shaft O.D.

I would have thought that a brass bush and C.V. grease would be o.k. as long as there are lubricant grooves inside the bush.

A new sintered one is only a few pounds, you might be lucky and it doesn't need reaming after fittment...
Martin Layton

Here is a photo of the offending bush.

Richard Tinkler

I've always understood that the use of sintered bronze for spigot bushes was standard practice, due to the wicking properties of the saturated bush.
The pores in the sintered bronze set up a circulation system for the oil while the shaft is rotating.

The only variation I have ever seen was the use of a ball bearing in a Toyota engine.
Does your engine man always use brass for this or was it what came to hand? I would be having a word to him as to who covers the labour cost of pulling the clutch out again!

David
David Overington

Richard,
Please see my post on the General forum regarding multiple posts of the same subject - we seem to have two groups of people replying to your problem, which could get a bit confusing.

David
David Overington

This thread was discussed between 18/04/2008 and 20/04/2008

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