75 HP Bristol engine.

[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

[Lewis]

I need some advice.

Could somebody post a short, simple, chlld's guide to tuning triple Solex downdraft carburettors. I suspect Geoff Dowdle may not be able to resist.

And nobody is to fall about laughing. I have done it before. When I bought my first 403, back in 1965, I had one of those marvelous carburetor balancing devices and used to happily play with mixture and throttle settings, but the device was sold with the car and I have never found another.

Reason for all this is the alteration of the linkage from accelerator pedal up to the carbs to eliminate most vibration when I hit a bump. Inevitably carburetor balance has suffered and I would like to confidently go back to square 1.

Regards,

Lewis

[Ashley James]

Until Geoff recovers from his trip to Thailand you could try the
workshop manual, which is a download from www.jel450.com
Hopefully you'll be starting with the correct jets which was more than
I had. It months and guidance from Geoff to get my 5000 rpm!
Ashley

[Brian Cuddigan]

Hi Lewis, There are balancing devices available from Holden. I had the
Balance meter SD/090.33 and there is also a carburettor synchroniser
SD/090.043.
Go to www.holden.co.uk The only problem with the balancer was that there is
not enough room beneath the bonnet for-aft bar so I had a rt. angle plastic
pipe joint to use it sideways! Brian

[Lewis]

Thank you Ashley James. www.jel450 was exactly what I wanted. Having read the relevant bits of the manuals I now remember what it was I did so many years ago. Now if my youngest son (who is at that wonderful age where he knows everything) will spare a moment to persuade my computer to correctly size the pages for printing I will be in business.

Regards,

Lewis

[Lewis]

And thank you Brian Cuddigan. Christmas is early this year. I recognise Holden's carb. synchroniser and will have no trouble using it as my small bonnet lifts off, no hinges. I will discuss synchroniser and balancer with my local garagiste. A wild man in his youth (once apprehended by police for driving to work at 130 mph in a 60 zone; having set up roadblocks to catch him they couldn't prove his speed and he got off) he has endured years of servicing Japanese jelly moulds and was intrigued when I came along with the eccentric HRG Bristol. He now looks after six Bristol engined cars, says they are beautifully built and easy to work on and plans to expand his business. Minions will endure the bread and butter work while he plays with proper cars.

Regards,

Lewis