• MGAlzheimers

YD1/2497 - MGA Twin Cam - Firing On All Cylinders.....Mostly!

Updated: Feb 20

The engine in the Twin Cam was designed for an MG record breaker - codenamed EX181 - driven by Stirling Moss and Phil Hill. To this day it holds the record for being the fastest ever MG - 254.91mph! Before production two versions of the Twin Cam power unit were produced - one by Austin and one by Morris, pictured below. The Morris version won the day.

A goldmine of information on the MGA can be found on Barney Gaylord's legendary site MGAGuru and specifically more detail there on EX181.

The MGA Twin Cam's reputation was tarnished by its initial engine design. I remember being told that over 90% of early cars had replacement engines in their warranty period. Whilst I'm not certain how true that was, one thing's for certain, the high compression ratio, fuel octane rating and aeriated fuel (caused by vibration from block to carburettors) saw cars run hot and lean. Holed pistons and burnt out valves were a by-product on early cars.

As is always the way, the issues were resolved when the factory installed lower compression ratio pistons and a modified mounting pad between engine and carburettors - but it was too late to recover the model's reputation and, after just 2,111 examples rolled off the production line, it was canned. After Twin Cam production ceased, Rob secured an ex-works crated engine from the factory. A few noted Twin Cam aficionados were advised by the factory to "come and get the parts" as they were due to be skipped.

The car suffered a burnt/dropped valve in Rob's hands; on the way back from racing at Silverstone in the late 1960s. Sadly the holed piston and detached valve head were lost in Canada but Rob had kept them all those years as a reminder. The original head, with damaged 4th cylinder, was left in England when the car left for Barbados in the 1980s. James held onto it until 2017 when, with the MG leaving the family, he sold it. Happily James has subsequently formed a great friendship with the buyer and the head has been repaired and re-used - letting new aluminium into the head and machining it. Fantastic news.

"The MG's mileage as it exited its restoration was 84,136. When it came into James' life, 30 year later, it was showing a mere 96,000"

The ex-works crate engine and head that Rob secured from the factory is the engine currently fitted in the car. It was installed in Barbados during the mid 2000's when Rob also hooked up the Shorrock supercharger. The blower's spell was brief, with Rob saying the engine was "too powerful" for the configuration. Praise indeed! Evidence of the fitment can be found at the front of the car - the valance was cut away to accomodate it.

When the MG was sold and left the family in 2016 the original engine block and all spares went with it, presumably going on to power another car in the US as James could not subsequently track it down. At the time of its sale strong engines were selling for $25,000 dollars. So the good news is the engine in the car currently has only travelled around 6,000 miles from new! Sad that the original "matching numbers" block is not fitted (despite having that replacement head) but all that is part of the unique history of this car.

In searching my files I came across a letter that Dad had sent me detailing the first time he restarted the original engine in Barbados - in February 1989 - following the MG's chassis restoration:

"I had poured one film canister full of oil through each plug hole about a week before the big event. The batteries would not do a thing apart from click the starter solenoid, so I borrowed one from the GTI. I then discovered the fuel pump was not doing its stuff, so off that came. It was just a 'contacts and tighten all screws' exercise and then the glorious nostalgic tick, tick, tick of a high delivery SU fuel pump. I had not checked to see if there was a spark at the plugs but the wiring loom had gone in easily and I was confident that all was well. I had timed the ignition and replaced all the fluids in the engine. The engine turned over about three times, caught on one cylinder, then two, then three. Smoke belched out the back and it popped and banged a lot, but it was running. The smoke began to thin and the fourth cylinder began to fire, it was still pretty ragged though, due to the oil. As the engine warmed up it got smoother and smoother. Now there was no smoke and it was sounding as good as it ever had - crisp and powerful"
  • The Film Canister - Rob was a professional photographer, as ever hands on and re-purposing the item.

  • The Batteries - these were the two original 6v batteries, as fitted in England, by that point must have been at least 10 years old and having little use in latter years.

  • The GTI - Rob had one of the first Peugeot 205 GTi's ever registered on Barbados. With outrageous import taxes it landed at three times the price of an equivalent UK car.

Great to capture this as part of the MG's history - especially in Rob's words. We miss him so much.