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MG MGA - spigot bushing on 5 Speed conversion

Hello,
I'm installing the extended spigot bushing into the rear of the crankshaft for the five speed conversion. After driving it in what seems like as far as it will go, the shoulder of the new extended spigot does not go in far enough to "flush up" to the rear of the crankshaft. It appears to be about 5mm from touching the rear of the crankshaft. Has anyone had experience with this?

Another concern with this is the distance from the face of the flywheel to the back of the the spigot bushing is just at 7mm not allowing much distance from the front of the clutch plate to the rear end of the spigot bushing. When the clutch plate is put up to the flywheel, it seems with little wear the clutch plate will come into contact with the extended spigot bushing.
Do I have the extended spigot bushing in far enough?
I would be calling the supplier,but on the weekend and at this hour..no chance.

Ray
Ray Ammeter

I got the ruler out again. I installed the bell housing and measured from the rear surface to the backside of the spigot bushing. It came out 5 5/8 inches. Then I measured from the front of the transmission where the bell housing bolts to, to the forward end of the splines on the input shaft. That distance was little over 5 5/8 inch.
I needed to drive the spigot bushing in some more, so out came the bigger hammer. I applied more solid blows and now I get a solid 10 mm from the flywheel surface to the rear of the spigot bushing. Still not fully flush to the back of the crankshaft.
Ray Ammeter

With that much driving force you likely crushed the bushing a little to have smaller ID. You should at least try the input shaft or clutch alignment tool in the bushing to check the fit. It is not nice to have the car completely reassembled, and then find the clutch does not release because of a tight spigot bushing.

If the bushing ID is now too small you may need to ream it or burnish it to restore the proper ID. The standard bushing is 0.625" ID, and the standard shaft spigot is 0.623" OD. If it needs to be reamed, use a standard 5/8" reamer (same as for rocker arm bushings).
Barney Gaylord

Ray, when I installed my 5 speed last year, the spigot extension snugged into position with a few taps with a rubber mallet. You shouldn't have to use undo force to seat the extension. Sounds like something isn't right if you had to whack it with the BFH. Definitely take Barneys advice and be sure the shaft doesn't bind in the bushing.


Andy Bounsall

Ray, my previous post was a bit misleading. After thinking about it a bit, I better remember installing that bushung extension. To seat it, I placed a block of wood over it and stuck the wood block with a few sharp blows of a 4 pound hammer. In any case, the exentsion did slide all the way in and snug up without having to use a lot of force.

If memory serves me, the ribbed part of the extension that slides into the crankshaft orifice is steel. The new bronze spigot bushing, which is a smaller diameter than the original, is only located in the outer end of the extension. So I don't think you would've crushed the new bushing as Barney suggested.

I think one of the installation steps has you check that the input shaft doesn't bind in the bushing. If not, good idea to check it anyway!

If the extension is not sliding all the way in for you without having to wail on it with a BFH, you might want to extract it (thread the the two supplied bolts into the holes in the extension) and check if there is something still in the crankshaft hole that it's catching on. Stupid question, but you did remove the old spigot bushing, right?
Andy Bounsall

Thanks for the comments.
Barney I lifted the transmission and inserted the input shaft into the spigot bushing. It went in. I would add, if the alignment is not correct, it would not go in. I was going today to purchase an alignment tool.

Andy thanks for the picture. Your spigot bushing looks indentical to mine. At this point its hard to measure the gap between the spigot bushing and the crankshaft. I took a piece of printer paper and doubled it,..then made a sharp bend and the end. IT will slip between the bushing and the crankshsft. SO not fully flush to the crankshaft.
Andy if you still have your engine apart. Can you measure the distance from the flywheel surface to the rear face of the pilot bushing. Mine measured just over 10mm.

thanks again
Ray Ammeter

One thing I forgot to think of, was how many times the flywheel has been resurfaced. This would make the distance from the flywheel face and the bushing different for every flywheel.
Ray Ammeter

Sorry Ray, I did the 5 speed installation about a year ago so I'm afraid I can't take that measurement for you.
Andy Bounsall

This thread was discussed on 27/01/2008

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