4 speed narrowcase output shaft rollers

[bodge]

ive got what i believe to be a late 4 speed with individual roller bearing output shaft (engine number stamped on the 5 speed side) it doesnt take the 5 speed rollers as they are much too big,does anyone know the size and spec of the rollers i need?

[Eldert]

do you have a Mototrans engine ? they use a needle bearing .

a Timken B - 208

Eldert

[bodge]

hi eldert no its a late seemingly relativly rare,tho unfortunatly not valuable italian 4 speed with the dm prefix on the "wrong" side.

edit - just checked no its not the timken its a loose roller like in the 5 speed with an outer race pressed into the case but the size is smaller in both length and diameter.

[LaceyDucati]

Yes there was a late 4 speed model with a roller track similar to the 5 speed with loose rollers. There weren't many and the roller track is probably unobtainium. However I suspect the rollers are just standard rollers....maybe 6x6 rather than the 7x7 used in the 5 speed, don't have a parts book for that year/model to confirm. I may have a track somewhere to measure, but finding it may be an issue! They should be obtainable from any bearing factor.

Regards Nigel

[bodge]

hi nigel,thanks for the response ,measured with cheap digital calipers ive got

id of outer track 38.5
od of inner track 24.6
height of inner track i.e lenght available for roller 6.66 (this is most likely out due to access with calipers)

so a space of aprox 13.9 which doesnt seem to work with 6 or 7 mm rollers or am i missing something like the rollers are never actually opposite? there are actually 2 different roller 4 speed outputs listed in another thread on this subject but one of them doesnt look right to me ?

if i start just randomly looking for something to fit what sort of spec am i looking for in the roller material etc or are they all the same?

edit does this look possible hardness etc? https://www.northwestbearings.co.uk/loo ... %20inch%5D

would leave a tolerance of 0.2 but my measuring could be out

[George]

Hi Bodge digital calipers are not realy accurate enough for what you want to measure. I am assuming that you do not have the original rollers to measure. Rollers are not expensive and before spending on measuring equipment why not buy rollers of size you think is correct and try them. Simply bearings keep stock.
https://simplybearings.co.uk/shop/Loose ... se+Rollers
Good luck

[bodge]

sounds like a plan george. ive found a cheaper place that has 6.5x6.5 which is closer to my measurments so will give that a go,seem to be the same spec aisi 52100 steel will be less money to throw away if wrong size.

https://www.ballandrollerstore.com/loos ... 6-5mm#cart
anyone know if this is the right sort of spec?

[LaceyDucati]

Sounds most likely 7x7 rollers, but difficult to say with possibly vague measurements. The gear and track don't fit tight together, so the track being slightly short of 7mm (if it is) may not be an issue. However a clearance of 0.4mm (if it is) in the assembly is! These components are not very well toleranced and the track in the cases rarely round, so a bit of variation in clearance is common. Therefore anything from zero in places to 0.05mm + is kind of normal clearance in the assembly.

The material is Chromium steel....normal, generally available rollers.

Hope that helps.

Nigel

[bodge]

doh! just checked,they are indeed the std 5 speed rollers i had forgoten the last time i tried was with the wrong (5 speed gear) which is where i got the idea in my head that i needed smaller rollers.
thanks for the heads up nigel,i will be ordering another set of them off you soon for my actual 5 speed.