Needle thrust bearing for primary gear

[65MK1S]

Anybody had any luck replacing the primary gear steel bushing with needle or ball thrust bearings?????

[Spider]

Dave Rosenthal did one on Needles a few years back. I don't have any photos or many details. I had a good look at it in his workshop and we did have a long chat about it. While the Gear was supported on NR Bearings, I can't recall how he did the thrusts. I recall there was an Oil Seal on it too, I think on the nose of it.

Doing a bearing conversion on these is one item on my 'to do' list at some point since there are no proper back end / top hat bushes available for these.

[65MK1S]

Thanks Spider, I've seen it before and was tempted to do it but
because I'm old and lazy I was hoping somebody else had already
accomplished it and done all the hard work. There's a couple of ways
to go with either roller with race or needle with race, the housing just
needs to be milled correctly to get the right clearance and use the one
that will be most durable and long lasting. Also would have to make sure
it was properly lubricated. You wouldn't want to put it together and
have it run for ten minutes and disintegrate

[bwaminispeed]

Remember, that, it is locked to the crank all the time (doesn't spin relative to the crank), and, only "runs" when the clutch is depressed.....

[mk1]

I always thought this was a brilliant conversion, not sure why it never made it into production.



The set of drop gears depicted to the left came from a guy who worked during the 1960's at Morris Engine Experimental, Coventry.

As you are no doubt aware, BMC were having problems with the "small" idler, fretting and chewing up the casing. Then failure! This was a possible answer to the problem. They look like they were manufactured for BMC by Jack Knight, as the numbering system seems similar. However, both the first motion gear, and Primary gear are totally unique. They have completely different off-sets to a "normal" straight cut set. I am not sure if they ever found there way into a race engine? But they have clearly been run at some point?