Shims on the kickstart shaft.

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pierodn said:
But still I should like to clarify again that I never said and not hinted that i had paid the bearing (bronze ball bearing) as the Roller Bearing n.067110.
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Piero,

Yes, it was a simple misunderstanding which has been cleared up now, no need for you to be overly concerned about it. :)
 
Dear all,
I wanted to communicate the professionalism and kindness of Norton Andover.
Aware of the misunderstanding about my old order, Norton Andover offered me a new 067710 bearing free of charge to make up for the inconvenience.
I am very happy they understood my good faith and "rewarded" an enthusiastic novice.
Ciao.
Piero
 
Piero,
Glad to hear it. Once your command of the English language improves you will have the option of being blunt and rude as well as enthusiastic! (oh I hope that translates well :) )

I have been watching this thread with interest, because for some reason I am drawn to the debate over bearing choice. I am clearly in the roller bearing group having rebuilt a total of two (yes 2!) AMC gearboxes and using roller bearings and shims in both. Someday, perhaps I will put enough miles on both of them to figure out whether or not that choice mattered a whole lot. I like the idea of being able to measure the end float and then shim to desired amount. I want for my dogs to engage well and it is not as easy to determine this with a ball bearing. Judging by the number of stories of bearing races that have spun in the casing, I would doubt the ability of the bearing to "lock" the shaft in place. But we all have to pick a peg to hang our hats on. That just happens to be mine.

But I also note that legendary gearbox man, Mick Hemmings does not recommend a roller bearing. Hemmings also sells a preferred ball bearing that is the "racing" bearing according to his catalog. Some day I hope to have the opportunity to discuss this in person over a pint. But in the meantime, I will have to rely on this crowd to sort it out.

Russ
 
I sow the Hemmings DVD and he dont used a roller bearing but a ball (FAG 6203 Tb P63 i think) and he do not shim the kick shaft.
I will use this ball because i dont feel me able to shim a roller (FagNJ203E.M1.C3.).
If i could be able to misure the end play i could use a roller.
Thanks.
Ciao
Piero
 
I'm sure that the Hemmings bearing will treat you well. The first gearbox I did, I got an assortment of shims. Put some in and kept testing for end play, finally put one more .005 shim in that caused the shaft to rotate with a tiny bit of friction, so I took it back out and called it good. No caliper or dial gauge used. More or less measured by "feeler" gauge. Yes, I had to take the inner cover off about 4 or 5 times, but the process works.

Russ
 
I put the Hemmings ball layshaft bearing in with standard gaskets and it seems fine. I did no shimming. Works like it always did.

Dave
69S
 
Don't forget a roller has near twice the load rating that of a ball! Shimming takes about an extra 10 minutes. :mrgreen:
 
Foxy said:
Don't forget a roller has near twice the load rating that of a ball! Shimming takes about an extra 10 minutes. :mrgreen:
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All right, let's keep this going a little.

Foxy, you are correct, however the axial requirement of the layshaft is minimal compared to the load rating of a good ball bearing and a roller in this regard is overkill, not to mention to offer up axial load for unsupported linear motion is a bad trade.

I dislike the thought of rollers hitting up against the inner race lip and the kickshaft running up against the kickshaft bushing with shims being a bearing surface.

Using some sort of a thrust bearing at the kickshaft is one thing, if even possible, but what do you do about the rollers against the inner lip.

I say the layshaft needs to be supported linearly and operated as suggested by the manufacturer.
No heavy gear braking and no clutchless/power shifting. Clutch plates are cheap compares to gearbox parts and a lot easier to change.
 
G'day pvisserii, yes I understand what your saying and I agree to a point. Given that my 920 is going to put extra load on the small already problematic layshaft bearing, I've opted for the roller as the design has the highest load capacity and also NJ handles unidirectional thrust loads http://www.timken.com/EN-US/products/be ... fault.aspx so that hopefully covers concerns over thrust loading, unless abusive heavy footed gear changes which will destroy internals and cases.
Gearboxes/transmissions/ wheel bearings in many of my high hp tractors, trucks, harvesters etc etc run rollers. Although some of these are conical and adjustable via shims or castellated nut, regardless of what bearing is used roller or ball, end float should be reduced to bring into play maximum gear and bearing surface.
 
Yes, this is interesting. They say under light unidirectional thrust loads that are up to 10 percent of the radial load.

They also say "Lubrication can become critical when limiting thrust conditions are reached. Your Timken sales representative should be consulted for such applications. When thrust loads are very light, these bearings may be used in an opposed mounting to locate the shaft. In these cases, shaft endplay should be adjusted at the time of assembly."

This tells me that although it can take little thrust, it is not what it is designed to do. Take note that they say the opposing bearing could be use to help locate the shaft. Not an option for us.

That being said, I would say you have the ability to fine tune and understand your position in this regard. I am sure you will be fine in what ever you decide is proper for you.
 
Foxy said:
Don't forget a roller has near twice the load rating that of a ball! Shimming takes about an extra 10 minutes. :mrgreen:
Click to expand...
Well,
Could you teach me how do you shim and where do I get the shims?
Ciao
Piero
 
You assemble the gearbox cover then measure the end play :
Shims on the kickstart shaft.


and shim to obtain 0.15 to 0.25 mm end play

all this is very well detailled on old britts web site http://www.oldbritts.com/gearbox_a.html
 
A little too much is better than not enough.

Stay towards the higher number.

.15mm to .25mm (.006" to .010") seems tight to me. I would concider .30mm to .50mm (.012" to .020") a safer number.
As mentioned in Old Britts instruction, somethings loosen up when they get hot, and I also find that somethings get tight when they get hot.

So, if you shim to the tight side, .015mm, and the kickshaft starts to bind a little, there will be trouble.
 
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