75 HP Bristol engine.

[johnelfixit]

Well, my 400 instruction manual suggests that the "touring engine"
produced 75 bhp at 4500rpm and was equipped with a single dual port solex
carburetter, whilst the sports engine (with special camshaft) produced 85
bhp and had three downdraught SU`s. This sports engine is usually referred
to as the 85A. The engine and was then fitted with three Solex carbs,
became the 85C and was used in the 401. The single Solex was fitted to a
special manifold connected to the water circulation system.

John P

[brianjgkidd]

> I had an early Bristol 400 - still in existence, but not with me, unfortunately.

The Bristol Parts list (I still have it) which came with the car shows a SINGLE
Solex twin choke carburettor with a separate induction manifold. It also shows
three SU carburettors, attached directly to the head, to make it an 85A engine,
but with a catalogued power of 80 bhp.

My engine was subsequently fitted with three Solex carburettors to turn it into a
85AC engine, with a catalogued power of 85 bhp.

I'm sure an engine fitted with a single Solex would have given less than 80 bhp,
and Setwright's book refers to early 400 car engines giving 75 bhp. But how many
of these were sold, I don't know.


Best wishes,

Brian Kidd> > > > >

[Geoff Dowdle]

Lewis and others,
It is interesting that this engine is marked 400/75

The 400- 403 Workshop Manual states "Type 85 engine is 75BHP at 4200rpm
fitted with single Solex30 AAPI

85A is 80BHP at 4200 three SU - D2

85C is 85BHP at 4500 three 32 BI

You all would have known this , but there is no mention of a type 75 engine
( it could have been a special engine producing less than 75 BHP )

Of the First series 400's delivered to Australia the BOCA has record of
eight 85 series engines , most have been converted by fitting 3 SU's or 3
Solex
Lewis your 75 series engine is the only one of it's type that I have heard
off . I can only assume it produced lower bhp by lower compression or change
of
camshaft although there is no mention of those parts in the 400 Parts Book .

If you look at Ashley's website www.jel450.com there is a Register I
compiled of all known 400's .
Engine 400/75 #1065 was originally fitted to a first series chassis # 530
which is Car# 266 ( one can assume the 166th type 400 of approx 420
produced ) ,
although the engine I assume was the 65th produced & unlikely to be a
development engine.
Chassis 530 is currently owned by Nick Wood in Perth , W.Australia it would
be interesting to find out what was stamped on the bulkhead ID plate.
BAC did not assemble type 400's , chassis # , engine # or Car # in any
order , its a real jumble , unlike later models .
I believe that the standard Filton bodied 400's were produced in Car#
sequence and Chassis and Engines were just selected from a stock at random.

The Blocks of the early engines were different to later 400 engines . At the
rear of the block there is a screw in welsh plug rather than a bolt on alloy
plate ,
Lewis does you engine have this feature ?
What engine number is stamped on the block near the starter motor mounting
? Does it have a prefix ?

We can all have our theories , but as time passes facts & knowledge pass
with men that produced the cars.
All the inaccuracies printed in the past by so called experts are reprinted
and eventually become fact.

Regards
Geoff Dowdle

[Geoff Dowdle]

John,
The sports engine you refer to is a 85B having Sports Cam & 3 SU Carbs
producing 85 bhp

85 , 85A & 85C (or 85AC) all had the same touring cam but different carbs ,
Geoff D

[johnelfixit]

Geoff,
You could well be right, however my workshop manual for the 85A engine and
gearbox clearly shows an engine with three SU`s and quotes 80 BHP at 4200
rpm. The instruction manual (the book supplied with the car) quotes power
output figures at 4500 rpm which are 5 BHP higher. Early marketing speak??

John P

[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

[Lewis]

Thank you all for the interesting speculation and forgive me for not responding more promptly. We have been shepherding the youngest son through Year 12 exams and, frankly, mounting a takeover for BHP would be easier. His school days over, he will be concentrating on the pursuit of young women and booze.

I bought this engine from Graeme Lowe of Mornington (?), Victoria. It was the usual heap of boxes filled with almost unrecognizable bits of metal. There were no carburetors, manifold or crankshaft. A bloke in Geelong had just made two crankshafts, at the request I believe of Will Bailey who bought one and I was able to buy the other. Colin Young supplied three Solex carburetors and manifold.

It looks as if mine was the "Touring" engine with a single carburettor, although as it seems likely to have been the 65th made, not a particularly early one.

Why would anyone want to buy a Bristol with a less powerful engine? One presumes the cars were originally bought, as now, by people who generally
wanted something better and faster than the usual run.

I cannot see what is at the rear of the block. The body is a tight fit and the block is only an inch or two from the bulkhead with the lip of the bonnet rim blocking vision. I'll see what I can do next time the car is serviced. The number stamped on the block by the starter motor is 1065, no prefix.

Perhaps Geoff's suggestion of a mistake by the man who stamped the plates is correct. I don't think we'll ever get to the bottom of this.

Regards,

Lewis