1927 Austin 12/4 Windsor

[Dave Mann]

This is a long shot, I have a friend with one of these beasts, flat out it does 35 mph and 15 mpg, it has a side draught Zenith carburetor similar to the 22FZB and the exhaust tailpipe is smaller than that on my RN saloons. Does anybody know anything about these cars such as what should the ignition timing be, what should the carburetor jet sizes be and what size should the tailpipe be.        

[Ivor Hawkins]

If no one comes up trumps here Dave, I’m a member of the Austin Ten Drivers Club and I could post a question on the club forum, there are some knowledgable chaps on there.

35mph top wack and 15 to the gallon sounds wrong to me, I had a 10/4 that would crack along at 55mph and did about 35 to the gallon.

Lovely car though, wouldn’t mind that myself!

[Colin Morgan]

This is copied from an advert... "Launched in late 1921, the Twelve owed its success to Austins superior build quality and the soundness of basic design, the model becoming a by-word for indestructibility. The Twelve engine was a five-bearing magneto ignition side-valve four, displacing 1,861cc from 1927 for which the factory claimed 27bhp at just 2,000rpm, sufficient for 40-45mph cruising, at which speed the Twelve returned around 26mpg."

Sounds as if there is room for improvement, as you would expect. Someone will know.

[Mike Costigan]

Definitely something wrong there. It's fifty years since I ran a 1927 Windsor, but I regularly drove it at 45-50mph, upper 20s mpg (i reckon I got better than 30mpg on a decent run), it was the first Vintage saloon to climb the VSCC Lakeland Trial Drumhouse section (top of Honister Pass), which it achieved in second gear 4-up, until the last hairpin when the Autovac ran out of fuel - fortunately the change to first gave sufficient vacuum to get some more fuel through! From memory the carb was a 30mm side-draught.

Someone in the VAR will surely be able to sort you out?

[Stephencrisp360]

Dads just got a 12/4 and a book for it. I’ll ask him.

[John Cornforth]

Hi Dave

I found a photo online of VB 476, a similar car. I won't post it for copyright reasons, but comparing its tailpipe size to the 3 1/2 inch high numberplate letters I make its Tail Pipe one inch internal diameter.

At an estimated volumetric efficiency of 80%, at 2000 RPM the engine will be flowing a modest 53 cubic feet per minute and the tailpipe gas velocity will be 109 mph. Probably not too much of a restriction, from memory even the 48 BHP Morris Minor of the 1960's had a "pea shooter" exhaust.

Using a typical value of 0.5 lb of petrol per BHP-hour and 20 BHP, that's 1.35 gallons per hour e.g. 33 mpg at 45 mph. So it would seem there is some room for improvement !

[Ruairidh Dunford]

Our 1926 H 12/4 has never bettered 22mpg in 40 years of ownership in near perfect mechanical state. It is happiest at 35mph but capable of a steady 50mph.

You need a light foot and patience, drive it like a Seven and 15mpg is the norm.

They are a joy, but woefully underpowered.

Nick Turley rebuilt our carb, a few years back, it is noticeably more alert since.

[Stephencrisp360]

Apparently this is a heavy and his is a light. I’ll go with Mr Dunford’s advice.

[Bob Olive]

Looks like a ‘Heavy’ to me, and if so should have a 30HZ carb, and be capable of comfortable cruising at 40-45 and about 25 mpg (in my experience). Jet sizes info will available from Vintage Austin Register.

[Dave Mann]

Many thanks for you responses.