Dep-O Magazine

B-Series

Simon Charlesworth April 7, 2011 1 Comment on B-Series

Dep-O - B-SeriesTHE B-SERIES – a boat anchor to some, one of the last properly engineered old school British lumps to others. It may be heavy and it may not have a crossflow head, but thanks to the competition careers of cars like the MGA, Riley 1.5 and (don’t groan) the MGB, there’s plenty of tuning potential within its cast-iron walls.

This one belongs to our old chum Mr Swingler and given that Mad Mark’s brain is packed with Triumph know-how he decided to talk to someone who really knows their B-series. So he got on the phone to Peter Burgess and Bill Richards.

“Peter told me that the camshaft and cylinder head should be the best that I can afford. He suggested heavy-duty double-valve springs, unleaded valve seats, 1.69 inch inlet valves, 1.343 inch exhaust valves and bronze guides – it’s basically the same as BMC Special Tuning spec.

So the cylinder head has been ported by CTM Performance Cylinder Heads, but the ports haven’t been hugely polished, instead they have a satin-sheen finish. Meanwhile the valve-guides have been reduced back into the port so that they don’t get in the way of gasflow and the oil pump has been machined to create a high capacity unit.

“The camshaft is an HRT85 with 288 degree duration with 405 thou’ of lift with 37/71 71/37 timing and there’s an installation figure of 107 degrees. Piper Cams reprofiled my own cam for £44 plus VAT so I didn’t end up putting non-match worn cam bearings in my engine and then I had a set of late followers,” says Mark.

“I’ve been told to run it with a pair of HS6 SUs, a long centre-branch exhaust manifold, an MGB Duplex timing chain, uprated head gasket and a standard distributor running Aldon Ignitor electronic ignition.”

What sort of spec will this lead to ultimately? Bung in a set of roller rockers, get it set up on a rolling road and there is a very real possibility of seeing 140bhp at around 6000rpm, but as Mark admits: “I’m not entirely sure whether I’m going to press the loud pedal that loud. I’d rather have it hang together at 5000rpm and for it to live a long time instead of trying to get more out of it and regret it, because the bloke behind ends up wearing half of it when it lets go.”

OK, by now you’re probably wanting to know why this engine is being built and what the MGB will be used for. Well, the more observant of you out there will have noticed this B-series’ sump, which is clearly designed for a transverse application. Of course if you know your BMC fodder this means only one thing – a big, beautiful Landcrab…

Indeed when Mark was speaking to Bill Richards, when the idea of bolting on a set of HS6s carbs was being discussed, another useful nugget of information bubbled to the surface: “He told me that HS6 SUs have the same same four-bolt fixing as HS8s, so I then went and got myself a pair of HS8s.”

So whatever happens, it’s looking that this is one ’Crab which will be served up hot and rather spicy.

Next time, we’re talking bodywork and arguing about paint colours…

Dep-O - B-SeriesIn Period…

Late November 1967 and BMC announced that it was to start marketing Downton Stage I tuning kits for all its front-wheel drive cars, following Vauxhall’s success with its Brabham tie-up.

Designed to produce torque and efficiency rather than BHP and silly RPM, the Dowton kits not only provided better MPG and up to 25% more power than the standard car’s, but neither do they invalidate the car’s warranty.

The Downton kits were available for the Mini, 1100, 1300 and 1800 from local BMC dealers as either a kit or fitted – the DIY option saved you £10 in labour charges. The kits consisted of a fully flowed, high compression cylinder head, modified valves and springs, a free-flow exhaust and adjusted carburetion.

My own favourite was the Stage 1 1300 which is claimed to do over 90mph and reach 50mph from rest in under 10 seconds – comparable with a Mini Cooper, Alfa 1300GT and Triumph 2000… For sheer, uncanny flexibility though, the 1800 gets first prize. Not only would it pull from 10mph in top gear but it would do so utterly smoothly and very strongly so that gear changing – not the most pleasant operation in an 1800 – is kept to a minimum.

Roger Bell, ‘Motor‘, 9th December 1967

 

Austin 1800 Data

  • Standard manual car quarter mile: 21.1 seconds
  • Downton Stage I manual car quarter mile: 19.6 seconds
  • Standard manual car power: 81bhp @ 5200rpm
  • Standard manual car torque: 100lb.ft @ 2100rpm
  • Downton Stage I manual car power: 93bhp @ 5300rpm
  • Downton Stage I manual car torque: 103.8lb.ft @ 3000rpm
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