crankshafts
 

I recall reading some while ago that there were developed for racing Bristols
some crankshafts which were polished all over and which had bolt on counterweights.

I read also that there were doubts about the counterweights and the prospect of failure.

Can any kind person remind me where I might have seen this information, and whether there were actual failures or just some anxiety?

Regards, Bill

crankshafts
 

Bill, the majority of 100 series type engines had bolt on counter weights
except the Arnolt BS engine .

The crank in your D2 is a replacement bought from BCL by Mort Shearer in the
late 70's . From memory it is a LeMans type crank that it polished all over
possibly ex a 450 , I have not heard that they had problems with these
cranks but only the small nose cranks probably with the rubber dampner.
I'll happily swap it for a new D2 Velasco crank that I have.
Regards
Geoff D

cranks
 

I had a bolt on crankshaft in an Arnolt that I raced. The crankshaft bent spun a bearing and damaged the block. The block can be line bored and fitted with new bearings, but I am not a fan of the Bristol crank. The dampner weight on one end and flywheel on the other move stress to the middle. If the engine is used at 5k plus rpm, I think you can expect damage.