Quaife shelled gearbox quandary.

I'm in a position to have two projects one the go at the moment, they both have quaife shelled 4 speed gearboxes does anybody know if the standard rear engine/gearbox plates need adapting to accept these modified boxes? I have a '74 850 that I replaced the plates due to corrosion, the gearbox that I removed now doesn't fit? neither does the Mick Hemmings built gearbox I have from a 750. They are very different gearboxes looks wise but neither fits? I'm feeling a bit stupid at the moment?

I take it you mean the reinforced Quaife shell with the ribs down the back. Yes, they will go in the standard Commando rear engine plates, including Mk3. But it is a tight squeeze and you need a clear run at it without sprocket, drain plug, centre stand, oil pipes and anything else I haven't thought of in the way.

stanthomas said:

I take it you mean the reinforced Quaife shell with the ribs down the back. Yes, they will go in the standard Commando rear engine plates, including Mk3. But it is a tight squeeze and you need a clear run at it without sprocket, drain plug, centre stand, oil pipes and anything else I haven't thought of in the way.

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Thanks....Mmmmm that might be true of the older gearbox plates but the replacements from Andover Norton do not allow the gearbox to fit, the drive side aperture is quite small, I did get it to fit in an old set of plates in the end but I suspect they had been modified to fit in the past. I need to go through the process again with the second gearbox soon, this gearbox has been machined back in areas compared to the other box so I'm hoping for an easier assembly with that.

My engine plates are originals. Gearbox shell dates from 1980s. I have no experience with anything newer but AN's stuff does seem to accurately match original parts, even when it might better if it didn't.

I assume you're talking about the sleeve gear bearing housing not clearing the drive side opening. It is tight there. You could try offering up the shell the otherway round. Then you'll know whether it's ever going to go in. Maybe buzz off the paint and any burrs from the opening with an abrasive flap wheel.

If you're trying to put this gearbox into the cradle while it's in the frame in the ISO and bolted to the engine, even OEM gearbox assemblies couldn't do that. The cradle needed to be radiused slightly in the upper left corner of the cradle on the right side (timing side). Quaife shells are much more bulkier, so I doubt you could do the install in situ.

Deckard said:

If you're trying to put this gearbox into the cradle while it's in the frame in the ISO and bolted to the engine, even OEM gearbox assemblies couldn't do that. The cradle needed to be radiused slightly in the upper left corner of the cradle on the right side (timing side). Quaife shells are much more bulkier, so I doubt you could do the install in situ.

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It wouldn't even fit on the bench I won in the end by fitting the original gearbox plates that I had discarded due to excessive corrosion on the surface where the swing arm 'o' rings sealed against, I ended up fitting some self lubricating swing arm bushes that need no oil tight storage. The old plates had significant alterations to the aperture. Two builds on the go at the moment that I will use the new plates and a different gearbox but still with a Quaife case, but now I know what to modify!!!