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| Another great photo by Pete Brown. There's an awful lot going on here. Stuart and I are bouncing hard. (Photo : Peter Brown) |
Regular perusers of my ramblings will already know about my taste for Austin 7 specials. We've had the Oliver Way designed Salamanda Special, the Reliant powered Cattley 7, a splendid MG and Austin 7 device that wowed the crowd at Wiscombe Park, Mrs Jo-jo, Mr Jo-jo, the baby Bugatti RA special and even Simplicity itself.
There are many others I would like to have a good look at and most recently it was the Austin 7 Ulsteroid of Stuart Palmer, Professor Emeritus of Side Valve Sorcery at the University of Torbay. This little car is an MCC long distance trials machine in Class O and last year I had the chance to passenger Stuart on the Camel Vale Motor Club's Presidents Trial near Hessenford just off the A38.
The Ulsteroid is based on a 1935 Austin Ruby long wheelbase chassis so there's enough legroom for Stuart's dad, who's taller than I am. I think the proportions are especially fine and this side shot from our rest stop shows them off to especially good effect.
Even long wheelbase Austin 7s are at a disadvantage in classic trials because of the narrow track. You can get the right hand wheels in the wheel channels or the left hand but never both. Also, what passes for long wheelbase for an A7 is normal for everything else so the tyres end up in the usual ruts if there's a restart to be done.
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The Ulsteroid is a snug fit in the purpose made trailer
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The chassis is constantly at work over rough sections and I got a profound sense of seat of the pants trialling over bumpy terrain. The chassis flexes a lot! However grip seemed pretty good from the passenger seat. Really thick mud stopped us but we didn't play around with tyre pressures much.
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Cable operated brakes
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The powerplant has a Phoenix crankshaft and Austin 7 rods, so there shouldn't be any crankshaft whip. Hardcore Austin 7 tuners used to skim the middle pistons in case the two bearing crank let them go a little further up the bores than intended to kiss the head.
A few years ago, I read a design paper on improving the efficiency of the internal combustion engine and a gentle kiss of piston to the head was proposed as desirable in controlled circumstances. I can't find it, now, but I seem to recall the idea arose from delivering the most effective combustion.
The Ulsteroid's cylinder head is a highly sought after Supalloy item. Compression ratio is normally 4.8:1 for 1935 engine but Stuart has increased this to 7:1, which is very high for a sidevalve motor.
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| It's a cheerful little car and lives in a specially made snug trailer |
Stuart has ported the engine and fitted bigger than standard inlet valves. The camshaft is a non standard grind of unknown origin but seems very fit for purpose.
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| Who were those masked men? |
On a 60 thou overbore capacity, I reckon capacity is now 789cc. Size matters when you start off with 747cc (2.2" x 3" or a bore x stroke of 55.88 x 76.2mm). Sixty thou over is 57.4mm. The Big 7 was 2.235" x 3.5" or 56.77 x 88.9mm for 900cc but the 750 racing club was all about the 750 engines so nobody really tuned the Big 7s much (big being a very relative term here).
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| Stand and deliver! |
BHP is adequate. In fact, don't it go well! With a lightened flywheel it revs away happily and - as The Blue Brothers might say after leaping across open bridges - pick up is good.
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Raw power from such a brave little powerplant
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A real world demon tweak is a downdraft SU carburettor, even if it is only a 1⅛". The inlet manifold is an Austin Nippy copy but the zorst is a banana manifold of Stuart's own manufacture. He will even make you one if you cross the Palmer palm with legal tender.
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| Just what your Austin 7 special needs (Photo : Stuart Palmer) |
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