Modified 140bhp 1975 MG Midget

Modified 140bhp 1975 MG Midget

It may be tiny but Stuart Simons’ nitrous-equipped Midget packs a heck of a punch…




RED DWARF! — Stuart Simons’ Midget really packs a punch

A background in competitive motorsport through the Seventies and Eighties means that Stuart Simons is a man with a need for speed; a need he has satisfied by building his dream MG Midget. Don’t be fooled by its diminutive appearance because Stuart’s MG packs an incredibly powerful punch.

1975 MG Midget


“Having been very active in competitive motorsport, building and rallying Mini Coopers, Hillman Imps and Ford Escorts, I was never afraid of working with a variety of cars,” said Stuart. “But the BMC A-series engine is perhaps my favourite.

Modified 140bhp 1975 MG Midget

“I progressed to competing successfully in the National Autotest Championships towards the end of the Seventies with Minis and my Mk1 Escort Mexico, in which I was proud to be a member of the England Team on one occasion. Many of my co-competitors were driving the then sports car of choice: the MG Midget/Austin-Healey Sprite and I was lucky enough to use theirs on occasion. I loved them.” This sowed the seed for Stuart to one day acquire a Midget of his own so he could make the most of its performance and potential tuning opportunities. “Having searched for a sought-after, round-wheel arch example, I found my Damask Red 1973 in Bristol, miles away from home. It had been subject to a partial rebuild and respray and fitted the bill for further improvement admirably,” he said.

Modified 140bhp 1975 MG Midget

Once home, it became apparent that it needed a mechanic’s touch to sort out a number of fairly minor, but niggling, issues; something that was no problem at all for Stuart to sort out. “Digging deeper into the engine bay, I discovered that the engine was close to a race tune but there was a lot of mismatch with regard to the tune, which prevented the engine from reaching anything near the tune’s potential,” he added. “It was a +0.020”-rebored block, making it 1293cc, and fitted with standard crank and rods but flat-top racing pistons. A cam that was the equivalent to the C-AEA 649 race cam, probably better described as mild race or fast road by today’s standard, but an untouched cylinder head, standard exhaust and incorrect needles in the otherwise standard twin 1.” SU carbs.

Modified 140bhp 1975 MG Midget

“I calculated the compression ratio to be from about 13.8:1 down to 12.9:1 across the four cylinders. The poor engine was struggling to breathe!” A replacement, gas-flowed cylinder head, with larger valve sizes and a consistent 12.6:1 compression ratio, was acquired, matched to a pair of 1.” SUs and suitably set up with a Maniflow long centre branch exhaust manifold. It transformed the engine’s performance. “A trip to Jersey for the Jersey MGOC’s annual Jersey Rally in 2007, including entering and winning their Car Park Test, effectively an autotest in all but name, rekindled my desire to have more motorsport-oriented fun with the car,” said Stuart.

Modified 140bhp 1975 MG Midget

“By this time, friends had interested me in a hitherto unexplored area of motorsport for me and, as there were no rallying or autotest opportunities afforded in my local area. Visits to the home of British drag racing, just five miles away from home at Santa Pod Raceway, became a regular feature, including piloting the Midget, now christened the Red Dwarf by the group of MG drivers and owners that I was now a friendly part of, down the quarter-mile strip at the numerous Run What You Brung ‘RWYB’ days.

Modified 140bhp 1975 MG Midget

“I was initially running a very modest 18+ seconds so my old desire for more and better kicked in. Wishing to keep things as stock as possible, the lowestcost option involved giving the engine a decent whiff of nitrous oxide. With the help of friends within the drag racing community, tus the Red Dwarf was duly equipped.”

Modified 140bhp 1975 MG Midget - engine

Things didn’t always go according to plan, by Stuart’s own admission: “There are a couple of things one has to be aware of with nitrous injection: the gas is a means of getting the oxygen into the combustion chambers which, if just injected in that way, would lean out the mixture and melt pistons in seconds, so fuel is also injected at the same time to ensure the mixture doesn’t lean out,” he said. “The second thing is that this injection mix is only supplied into the inlet manifold at full throttle and gives a bit of a shock to the drivetrain if you apply it too early in first gear. This will result in the spread of gearbox casing and components over the strip… ask me how I know.”

Modified 140bhp 1975 MG Midget

Whist that mishap-driven gearbox replacement was being carried out, Stuart decided to carry out some suspension upgrades to make sure the car put its power down in a straight line. At the rear, four changes were undertaken: anti-tramp bars and a Panhard rod now hold the axle securely, preventing spring wind-up and providing maximum traction to both rear wheels. He has also fitted a limited-slip diff and telescopic dampers. At the front, a telescopic damper conversion and a larger-diameter anti-roll bar were fitted and all-polyurethane bushings replaced with stiffer ones.

Modified 140bhp 1975 MG Midget

“Still keeping the 1293cc engine and standard ‘box, we found the SUs started to shut down when the nitrous was being used — the injection taking over from the natural aspiration elements of the SU setup,” Stuart said. “A switch to a 45 DCOE Weber solved that issue and 100bhp at the flywheel was recorded on Bletchley’s Marlin Motors rolling road but, due to the high compression, only a further 25bhp was capable of being added by the nitrous system before any problems started to occur.

“This state of tune did, however, lower my standing quarter-mile times down to the 15-second mark and, in doing so, surprised quite a few VW Golf GTI, Vauxhall Astra GTE and even Subaru Impreza drivers.”

Modified 140bhp 1975 MG Midget

Stuart wasn’t done yet. “It was always my intention to build a race engine suitable for some form of forced induction, nitrous injection being one form, and, having found a standard, late 1,275cc Midget engine, I started the task of building my own,” he said.

“Unfortunately, at the beginning of 2013, I was diagnosed with a cancerous growth in my throat and all thought of drag racing, Midgets and engines were obviously pushed from my mind.” Following successful treatment and recovery, Stuart celebrated his good news, and his 60th birthday, by buying a friend’s MGB GT Costello V8; one of the original V8 MGBs. This then became the focus of his attention for a couple of years whilst the Midget languished in its hideaway, still loved but unused.

Modified 140bhp 1975 MG Midget

“When I did restart the engine build, I decided to go big!” he said. “I enlisted the services of Leicestershire-based classic Mini tuning specialists, MED Engineering [] to offsetbore the block to 73.5mm, giving a capacity of 1,380cc. They also did the machine work for steel main bearing caps with a four-bolt centre main cap plus various other operations.”

Omega racing pistons, steel rods, lightened flywheel and racing clutch all featured in the build, together with a Newman Cams camshaft and Cometic head gasket. These, and other components, finally came together early in 2023, having been sat in boxes for some time due to a house move and other Covid projects preventing further progress.

“The engine has a lower compression ratio than the current one and should be capable of taking up to a 50bhp nitrous boost on top of the projected 130-140bhp power output in naturally-aspirated guise,” said Stuart. “I shall still retain the standard 1,275cc A-series drivetrain and see what breaks first. My suspicion is probably a half shaft, if I don’t feed the power in sympathetically, although I won’t rule out another gearbox. In which case I’ll look at either a straight-cut or even a dog gearbox before giving up on BMC’s best. But, for now, I’m happy to experiment.

Modified 140bhp 1975 MG Midget

“I still have a car that is great fun to drive and turns heads when out and about, largely thanks to the road-legal race exhaust or maybe my trademark Union Flag on the bonnet, taken from my Mini rallying days when I had the Union Flag painted on the car’s roof, long before anyone seemed to think of it. “With the car weighing around 700kg, it’s extremely quick and, with the suspension upgrades, handles like a dream, if a little tail happy when pulling out of side turns, due to the LSD, but it never fails to put a massive smile on my face every time. This is very much my toy.”

Stuart believes that, like any other project of its type, the Red Dwarf is a never-ending story. The race engine still needs installing and setting up, the planned EDIS distributorless ignition system will need programming and the car is at a stage where it’s ready for a good body fettle.

“Will it get done?” we asked Stuart. “One day, for sure, but I’m retired and that means I’m far too busy with too many other things going on. Meanwhile, my Costello is calling me… now that’s my pride and joy and a story for another day.” Look out for Stuart’s MGB Costello in our special V8 issue of MGE, in November 2023.

Article type:
No comments yet. Be the first to add a comment!
Drives TODAY use cookie