mk1-forum.net

OzOAP wrote: ↑Tue Dec 29, 2020 9:39 pm

Gary Schulz wrote: ↑Tue Dec 29, 2020 7:17 pm I too am a bit confused on why one would use needle bearings on that shaft. Doesn't that shaft go up an down as well as rotate? Isn't a bronze bush ideal for this combination of motions?

Fully aware on needle rollers/rotating shafts.
That is such a low load area that there is no problem, as has be proven over last 20 years and the amount of kits sold.

Can't argue with that. While it's not a modification I've done, as Oz has said, it's such a low load, I can well see this work quite OK. The shaft will slide quite OK through the Bearings, even with a little load on them.

In the words of Inspector Cleuso ...’the case is sol-ved!!
Thanks for all of your helpful replies folks.
Managed to lay hands on a coarse M16 tap and welded a bolt to my slide hammer. Jobs a good’un
Cheers

Exminiman wrote: ↑Tue Dec 29, 2020 9:53 pm

Gary Schulz wrote: ↑Tue Dec 29, 2020 7:17 pm Doesn't that shaft go up an down as well as rotate?

Is the shaft a loose fit in the bearing ?

The shaft is 0.005 smaller than the ID of bearing.
The main advantage of this kit is the seal top and bottom.
I have also shortened new bronze bushes by 3mm and just fitted seals.

I try ideas on my car or customers race/rally cars, (with their blessing), before I sell parts. Have been fitting/selling this kit for 20 years and will continue to until the theory experts/forum engineers convince me it doesn't work.

Just manage to make my own tools to remove and install the remote housing bushes, handy and easy!
M16 nuts welded to the nut used on slide hammer, and a long thread rod with nut welded at one end and flat washers plus nut to pull bushes in.

Al

I have come into this thread a bit late, especially in relation to the needle roller bearing idea. From the pure practical side of life, I can see the theory. But in practice, life is slightly different. True, the shaft only ever rotates through 8 degrees throughout its life. So far, so good, even though there is no real side load by the shaft on the needle rollers. But the fact remains that a FULL CONTACT area between the non (or marginally)-rotating shaft is better than a PARTIAL CONTACT area exerted on it by the needle rollers which are effectively redundant as rollers as Spider and others have alluded to in as many words.

The problem lies in the fact that the shaft is sliding up and down, up and down, through the needles EVERY time you change gear. Think about it..... Every time you change gear the shaft is sliding along 8 hardened steel needle roller contact points, causing wear along the same 8 contact points time after time after time.

If you use bushes, then there is equal wear around the whole of the circumference of the shaft because there is FULL contact, up and down time after time after time (as Cindy Lauper said.....)

Maybe a better idea would be a combination of part needle and part standard. If I was back in the development classroom, I'd be looking at shortening the bronze bushes slightly to accommodate the upper and lower oil seal. In my experience, it is the shit and grit on the shaft that causes the wear on the bushes and shaft. Keep the shite out with the oil seals and that's the end of the problem.

In case you think that the up and down movement of the shaft within a caged needle roller bearing is a bit of 'it'll never happen....' scenario, you better believe me, it did happen and only an early redesign saved the day. Larger diameter, longer and faster throw, but the same principle