Pre-war inlet manifolds

[ian Howell]

Job for Henry here I think!

I notice that a lot of pre-war cars, stationery engines and the Bristol crawlers have different styles of inlet manifolds.

I believe from recent comments in the 'Pr-War' section that cylinder heads on stationery engines may have spark plugs set at a different angle to car engines, also they appear to have TWO? oil filler caps.

Is there any definitve document to identify these variations? I know of a couple of definitely Jowett engines and a manifold that need new homes but I am not at all sure that they are actually Brisol Crawler engines as the owner believes.

[Keith Andrews]

Are these the manifolds with 4 rather than 3 mounting bolts?

[David Morris]

Hi there,

I have several WW2 stationary engines and I am told these are basically similar to a CA/CB Bradford engine? They have four mounting studs on each end of the manifold and the big difference is that the carburetter is an updraught Zenith and therefore sits under the inlet manifold.

The ignition is by magneto and this means there is no distributor as such. The oil filler is a small filler pipe fitter to the off side of the engine. There is only one filler.

I am not sure what was fitted to Bristol Crawlers, but I did see a photo of one at the Dorset Steam Fair last week, and it looked as if a Jowett four cylinder engine was fitted.

I have ( hopefully! ) attached the Jowett WW2 Instruction book on the stationary engines, which shows diagrams of the engines.

I hope this helps?

All the best,

David

[David Kemp]

Just read this manual, does someone know why Jowett used chrome steel cranks in their industrial motors ,but low grade cast iron for Bradfords?

[Keith Clements]

Either because the War Department specified it or they were able use such steel for war application.

[ian Howell]

I will have to make another trip to check out the Bristol Crawler bits when I get back to base.

Does anyone know how many variations there were on pre-war manifolds, say from mid 20's on?

Were there changes in post-war manifolds too?

Now this bit about chrome steel cranks might be better placed in the Bradford forum? Are they interchangeble?

What have I started?!

[StevenGray]

(Now this bit about chrome steel cranks might be better placed in the Bradford forum? Are they interchangeble?)

Not unless you can add a spigot to the flywheel end to support the cluch bearing

[ian Howell]

I suspect the answer is 'NO' and it is 50 years since I last owned a Bradford, but might it be possible to turn up an adaptor and bolt it to the flywheel?

Or there may be another way to achieve the same effect? I know a man in OZ who would be very pleased to have this problem solved!

[StevenGray]

In engineering tems it would be an easy modification to set the crank up in a lathe drill & tap the end and screw a spigot in.
Would only be of suitable for CA,CB Bradfords the CC has larger main bearings and a different clutch arrangement
The CA,B have 4 bold mounting inlet manifolds with a downdraft carburetter the CC has a 3 bolt mounting

[EngineRegistrar]

Hello All,

I'm afraid I cannot really comment on the different types of inlet manifold since I have only come across two variations that I saw on the engines formerly owned by Allan Nessfield.

However could Ian Howell please give me some details of the engines that require a home so I can see if I can find somewhere for them?

Thanks

Henry

[ian Howell]

Henry:-

Due to the sensitive nature of the source of this information I will PM details if you don't mind?

The sensitivity arises from a previous experience by the owner who also runs a camping site. His collection of about 3 acres of rusting machinery - from full-size railway locomotives to rusty tractors and combines - was made public by a journalist who happened to be camping in on the site.

The resulting torrent of phone calls, unannounced visits at very inconvenient times and offers to buy/requests to view, so incensed the owner that he now refuses to talk to anyone about possible purchases. However, when James and I found him by accident he was more than willing to show off his collection and mentioned the possibility of sellingthe Bristol tractor and bits.

[george garside]

There may be a bit of confusion over crankshafts. All pre war & Bradford CA/CB shafts were forged and my well have been made from chrome steel ( as were humble model T Ford carnks) Only the Bradford CC shaft was cast & I presume this was cast of steel rather than cast iron. The cylinders with 4 stud induction pipes were first used on the 1940 model cars ( and possibly on soe very late '39 models). The 1940 cars had alloy heads with horizontal pougs facing towards the wheel and also a thermostat in theinduction pipe as per CA Bradford. There may have been some difference in teh 1940 crank compared to 39 & earlier but not sure about this as have never seen either a drawingof one or one in the flesh - it had a different flywheel with replaceable starter ring and borg & beck clutch. The Borg & beck clutch while fitted to all Javelins sid not reapear on the twins untill the CC Bradford of 1950.

It is possible that the WDstationery engines were based on the 1940 rather than earlier engines but asinfo on the 1940 is limited I am not sure. Presumably Jowetts published a handbook & spares list for the 1940 models but I have never seen one - has anybody got one?

george

[David Morris]

Hi there,

The WD two cylinder engines may well have been based on the 1940 engines, as this would seem logical, but mine have cast iron heads, although there is a thermostat in the inlet manifold.

All the best,

David

[george garside]

as far asI am aware only the 1940 cars had alloy heads - the 1940 vans were cast iron so it would have been quite logical for the industrial enines to not have ally heads..particularly as they would not have offered any advantage ( and there was a shortae of alluinium) on an engine governed to around 2000rpm.. The alloy heads on the cars would have allowed a higher compression ratio but I don't know if Jowetts took advaantage of this.

The only other alloy heads for the twins were some aftermarket ones aro;und 1934.

AS to the induction pipes with the updraft carbs I assume this was because an updrat carb is far less likely to flood the engine which would be quite imporant with only hand starting and a great need for reliable operation under arduous conditions

george