Dear Heavyweighters,
I have a lightweight which uses a conrod very similar, but shorter and unbushed at the small end.
To recover damaged small ends I propose enlarging the conrod hole to take bush D12/159 or T2160 as used on Dominator with 11/16 ins gudgeon pin. Same as Lightweight.
Can anyone tell me the bore of the hole in the small end of a 500/600 dominator before the bush is driven in. I want to achieve the same interference fit as Dominator so that the bush stays in place.
The Lightweight has an oil hole drilled down from the top of the conrod for gudgeon pin lubrication. I'm assuming the Dominator conrod has the same feature, drilled through the bush too.
Thank you,
Peter
Hi Richard, I have just…
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Small end hole in conrod
Hi Dick,
This a great reply and gives me all the information I need to go ahead with my conrod bush repair using the standard Dominator part.
I'll ream the bush after fitting to suit the gudgeon pin. It's quite surprising how the pressure on a thin walled bush can shrink the I.D. Being sure to keep the reamer true and square.
Thank you
Peter
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Hi Richard,
I have just pushed the bush out of a spare 600cc con rod and the dimensions are as follows:-
Bore 0.8085”- 0.809” diameter with temperature at about 15 Deg C
Bush o/d 0.8125” diameter mean, it was slightly elliptical so this is the average of several measurements
There is a 0.4mm wide longitudinal oil way through the bush bore and oil hole. This is 0.018” deep.
If you are concerned about the bush rotating you could always turn a similar sized external groove around the circumference of the bush which will guarantee lubrication.
The only problem you have is deciding the manufacturing tolerances to be able to ream out the little end to fit the bush. If the new bush is plus or minus on mine adjust the bore accordingly. That should give you the same interference and you will be reaming to suit the pins anyway.
I will be replying to your e-mail this evening.
Regards
Dick