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A Special Builder's Notes

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The Special Builder's Breakfast Club

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29 July 2020

Hooligans!

The MX5 engine is a sturdy lump, but when you put one in a Locost and whack the throttle against the stops continuously, a weak point shows up.

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It's not entirely Mazda's fault because we did modify the throttle cable bobbin by adding a bigger one to the existing arrangement.

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It made for much more controllable and smoother operation, but unfortunately, the bushing in the throttle body is not man enough for the racing environment.

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Just visible is a thin sleeve, in front of which is a rubber seal (removed). Fortunately, there's plenty of room to accommodate a decent size bronze bush. That was the easy bit. Removing the butterfly from a spare body to pull out a replacement spindle was a real pain. The butterfly was held onto the spindle with two screws which had been machine-peened over to prevent them coming loose. Drilling them out was the only option and at an angle which inevitably slightly enlarged the already biggish holes in the spindle - exactly where it breaks with the increased sideload on the original bushing.

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Anyway, it's done now and I put a blob of weld on the screw heads to hold them firm - and in the process probably made the spindle even more brittle. Learned Counsel will just have to be a bit more considerate with his racing style; more haste, less speed.

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I discover that the electric steering assist kit that I collected from Mr Holmes is from a Vauxhall Corsa. It weighs a whopping 9.4kgs - nearly 21lbs in old money and I'm beginning to have second thoughts about that mounted under the dash in a relatively light car. Putting it in the bonnet would expose it to heat and dirt - not good. I came across a firm at the NEC a couple of years ago with a setup specifically for classics - I shall investigate.

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I didn't know - or rather had forgotten - that Mr Slightly-Strange was something of a whizz with CAD. Anyway, the Riley subframe drawings had been with my chum in Milan for about three months and it was getting close to the stage where not being able to make progress on the construction was going to be a problem. I was talking about it to Mr Slightly-Strange over bacon and eggs and he reminded me of his skills in the CAD department. So, the following Monday morning I sent the drawings over and a couple of hours later, this arrived! We're halfway there already! I've sacked my chum in Milan and told him I'll never speak to him again. "That's alright", he said, "I've been reduced to incoherently babbling about self-levelling floor compound; you won't miss much!" (He's doing up a flat to a deadline, so he does have an excuse of sorts.)

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The usual suspects turned out for last Sunday's breakfast run....

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... plus a couple of Morgan's, a splendid V8 hotrod and an MEV Sonic 7 which has a 2 litre Zetec engine of 135hp and weighs about the same as a bag of feathers. Totally irresponsible.

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