Date: Thu, 15 Aug 1996 20:42:26 -0400
From: Gary Slabaugh
Skip Schloss
In a message dated 96-08-15 10:27:05 EDT, you write:
>The "middle ground" is higher quality aluminium rods, made by Dave
>Nourish in England, I'm told. Again, this expenditure is possibly
>"overkill" for a street engine, although a person will have expended
>plenty of moneys on his stock rods giving them the treatment described
>above, and the Nourish rods might just be an affordable alternative
in
>light of said expenditure.
I have a Nourish catalogue and he does not list conrods for Norton, only for Triumph.
I spoke to Les Emery of Fair Spares several months ago concerning high performance conrods for Nortons and his advise was to never use 850 rods. He said the only rod failures he had ever heard of (not related to oil starvation to the big ends) were the 850 variety. He said the factory changed the alloy in a cost cutting move. Can any metallurgists on the list confirm this? My workshop manual for both 750/850 lists the different rod material designations BS.L83 or 2L65 or L77. It does not state what specification goes with what conrod.
All this got me to thinking, and I realised I had only heard of two instances over the years of conrods just breaking for no apparent reason and they were indeed 850s. Do any INOA members remember Pete Kogut blowing up his 750 racer last year due to rod failure?
I'm pretty sure he is using an 850 sleeved down to 750. I think he originally started using this motor because of problems with breaking cylinder flanges on his 750. It would be interesting to find out if he was still using the 850 rods.
Gary