75 HP Bristol engine.

[Geoff Dowdle]

John,
Standard Engines available for 400's (from 1946 to 1951)were as follows
85 Single Solex STD Cam 75bhp
85A 3 SU STD Cam 80 bhp
85B 3 SU Sports Cam 85bhp
85C 3 Solex STD Cam 85bhp
85AC 3 Solex STD Cam 85bhp
( Note the 85AC engine is possibly a 85A upgraded to 85C spec with
change of carbs
from 3 SU to 3 Solex. I have never seen reference to this 85AC designation
in any BAC produced
manual , handbook, partsbook, etc . The only reference I have seen is in the
BOC Register .
Does any one have a 400 with a 85AC engine fitted who can confirm the
stampings on the bulkhead plate ,
rocker cover plate and engine/head stampings.)

There were at least two 400's fitted with a FNS engine from new ,
number FNS1/5 for the Aldingtons of AFN Ltd.
Prototype #2 (Regn# NHX115) which I understand was destroyed in a rally
accident . This engine was then fitted to a
new car Chassis 600 , but it is not currently with that chassis . Does
anyone know of it's current location?

Chassis 500 was ordered by W.H. Lowe on Melbourne , Australia in 1948
with a Special Sports engine ,
with designation 85BS/1592 . It is possibly a FNS type engine stamped as
a BS (Bristol Sports) engine .
I have not seen the car or engine for many years but believe it has a
counter balance 2 in main crank, sports cam ,
higher compression, 3 Solex carbs ,STD 85 sump and possibly larger valves
with about 120bhp(similar spec to the FNS engine 126bhp at 5500 rpm).
This engine predates most of the other BS engines by a few years and is
unusual that it has 2in main journals .
Although in the" Bristol 2 Litre Sports Manual" there is reference to
BS1/SC & BS1A/SC engine types which have 2in main cranks .
(SC for Small crank ) and other specs similar to the BS1 and BS1A type
engines that were fitted to Cooper Bristols , Tojerio's, etc in the early
1950's.

As for the 400/75 designation , it is a bit of a mystery . It could have
been a mistake by a BAC staff member stamping the rocker cover 75 instead of
85
or another special order engine .
Geoff D