When Don Arnott bought his BGT, it looked great but ran like a dog. Putting it back to standard spec was the answer

This MGB GT used to belong to my son, Steven. Around six years ago, he realised that he had too many classic cars and it was the MG that was, as it were, parked closest to the garage door. I had never owned a classic car at that point, having run company cars for the previous 20 years or so. But retirement was looming, I fancied a hobby car and since I had always liked the look of the BGT, I told Steven to hold off the sale until I had had a chance to give his car a test drive.

The MG had been restored before Steven bought it, and it looked a treat. Unfortunately, the driving experience didn’t quite match up to the looks. A previous owner had bolted on all sorts of tuning mods, but the car would pink badly and popped all over the place instead of running smoothly. Still, I knew the car had great potential, so I bought it and contacted Roger Parker at the MGOC for some advice.

I explained to Roger about the running problems and the fact that the car had been fitted with oversize carburettors, a high lift cam and electronic ignition amongst its many mods. Roger described the changes as a bit of a mish-mash, and reckoned I would never get it to run right with those big carburettors unless I did some complementary tuning to the head itself. In fact, he told me that he receives lots of queries similar to mine, and it nearly always boiled down to a well-meaning owner bolting on go-faster goodies, but not carrying the job through with internal modifications to the engine as well.

You simply cannot make such changes in isolation and expect miracles from the car. In fact – as was the case with my car – it is actually very easy to spoil a good vehicle in this way. Ultimately, I decided that as I had such a nice and original-looking car, I should put it back to original spec first and get it running properly. I could then decide what, if any, tuning mods I wanted and integrate the changes as an overall package that worked together, rather than as a series of ad hoc changes.

I was already leaning in this direction anyway, but was pushed into doing something about it when the camshaft was found to be worn out. Steven had already replaced this during his ownership, and 9000 miles did not seem a very impressive distance for a cam to last. It took a long time to track down the problem, but after talking things through with Steve Illing at Abingdon Car Restorations, we eventually figured out that the engine had been fitted with stronger valve springs in the hope of being able to rev a bit higher.

To read more pick up the December 2011 issue of MG Enthusiast -

available here.

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