ET: Engine (Twin) Installing ET92 Inner Roller Set on Mainshaft

[stu spalding]

a slide fit is allright as all inner races plus spacer are under high side load from the ESA springs.

Hi Vic, I'd like to think that they were locked in place by tightening crank nut PD7. Cheers, Stu.

 

[oexing]

Hi Stu, you are quite right, the ESA nut loads the sprocket steel bush and that on the inner ball bearing race. So the whole lot is tightened onto the crankweb. I did it differently as the original setup offers only part of that area that gets the ESA spring loads and wears the inner radiused bearing race plus the sprocket face. A second roller bearing could help here as you could do a top hat bush for positioning outer lip plus wide face for the sprocket loads - or so I hope with my idea . . .

Vic

 

[craig]

I am needing a refresh on the need or procedure for shimming ET92 on the timing side.
What is to be accomplished?


View attachment 45715

It would appear the goal of right side ET92 spacers/shims is to centralize the smaller roller timing side bearing ET94.
I am reading David Dunfey's Competition Comet book page 239.
David's book "Building a Competition Vincent Single Cylinder" is 475 large pages of excellent photos and tech.
ISBN 978-0-57893735-9

 

[chankly bore]

Centralizing the small roller is far less important than centralizing the connecting rods. "Richardson" again, folks. If you think on, as they say in Yorkshire, the ET92 bearings themselves originally didn't run central. Perhaps I'm just out of date here, sorry.

 

[timetraveller]

Chankly is right on this. One of the advantages of roller bearings is that there is some degree of sideways tolerance.

 

[craig]

Thanks, yes we have centralized the rod by shimming left drive side. The left side determines where the rod will centralize so ....................
now we are concerned with right side crank components - roller, scroll, roller, pinion.
Should the right side components be shimmed?
And if so, what is the goal?
Should there be shims in between crankshaft right side pieces for some reason?

 

[Bill Thomas]

Just checked a few good looking wheels,
They have a 50 thou raised bit on both Wheels, Drive side and Timing side
I have seen it where that have been almost flat , Due to spinning inner race,
So I would have thought you only need to shim T/side if it's less than 50 thou ridge ?.
Cheers Bill.

 

[timetraveller]

I have never seen shims on the timing side. The oil pump worm and the two roller bearings are not critical for horizontal alignment so unless there is something seriously wrong, givng, say, several tens of thou misalignment there is nothing to worry about.

 

[Bill Thomas]

Funny , It's another thing I have never bothered to check the size,
Always thought it was 30 thou,
Shocked to find it 50 thou !!,
Thinking if it was flush a gearbox shim would fix it, E 36 ?.
Just shows how good this Forum is !, To bring it to out Attention ?.

Also for me , I have ground mine off !, So that I can do a special boring job
On my wheels, So now I know what to make it up to, Thanks Craig .
Cheers Bill.

 

[craig]

I found that with the bearings ET92 , Scroll OP31 and bearing ET94 installed without a shim at ET92/flywheel, the ET94 roller is about 0.010" to the outside of exact center. So that seems acceptable being very close to running on center. This particular ET94 has about 0.103" running race on either side. Other older supplied ET94 have actually narrower rollers allowing even more running race.

So in this case no shims for ET92 required.