[Ashley James]

Dorien
Please have a look at the technical section of www.jel450.com for all
this information supplied by Geoff Dowdle who has done so much to help
preserve these cars.

The main specialist engine machine shop for Bristols in the UK is
Hurley Engineering Services Ltd and it's well equipped with the best
modern equipment and Paul is the nicest man on the planet. His details
are also on the website.

The 85 engine had a lighter crankshaft with non detachable
counterbalance weights with the result that when used for racing in
the Frazer Nash Cars, it kept running its centre main bearings,
overheating the oil and self destructing. It's fine for road use if
the revs are kept down. The 100 series had a bigger heavier crank
that overcame this as well as bigger valves and differently jetted
carburettors and eventually a higher compression.

Several different camshafts were used and this may have as much to do
with trying to make them last as develop more power. All Brit
manufacturers were in difficulty with cam wear at that time.

I also get the impression that the jump in power from 85 to 100 HP was
as much to do as sorting out the carburettor jetting as anything
because mine was correctly jetted according to the manual and ran very
badly until I'd made it a slight variation on a 405, again with
Geoff's help.

I'm afraid that I have yet to give the back axle to Norman because
since I'v swapped the 85C gearbox for a Close Ratio one, the noise I
attributed to the axle has gone. Early reports of the car appear to
suggest that the gearboxes were noisy. I'll still get it done before
France in June though.

Ash