Ouch - Again

Spent the vast majority of the weekend trying to fit the spare MX-5 gearbox to the GT6's replacement chassis, which required a fair bit of cutting and grinding of aluminium and some delicate (well, not that delicate) cutting of the chassis rail metal.

I was initially held up by a great lump of casting on the right-hand side (the one with the 2 holes in it). It’s not critical to the gearing - just an oversized chunk that Mazda clearly thought would be a nice bit of structural bracing for their own chassis. Absolutely nothing inside it, so it met my old friend the angle grinder.

Even after that little amputation, the GT6 chassis still needed about 10 mm carving off the dip on once side, where the original gearbox sat. That area will be reinforced from underneath with plate once the trial fitting’s done. I also need to remove the old welded-in crossmember and replace it with a bolt-on one so I can drop the gearbox out in situ for future clutch changes. That, however, is a job for another day. Now, before you tell me off, I was wearing my usual welding and grinding protective clothing - shorts and flip-flops - and this happened:

Could have been worse. If I’d been wearing trousers or overalls, and a grinder (especially one with a wire wheel) caught the cloth, it would have wound itself in and chewed away merrily at my leg, as it did with a neighbour to whom that happened while rebuilding his TR6. He has to be hospitalised, whereas I merely applied some Corsodyl mouthwash to the area.

My theory is that when a grinder hits skin and bone, it tends to bounce off or at least head for the floor fairly quickly. With cloth, it just digs in. It’s a valid theory - though admittedly, one backed by anecdotal evidence and poor life choices rather than peer-reviewed research. 

Still, I now have a wound that looks like I’ve been attacked by an irate badger with a vendetta. On the bright side, the badger lost - the gearbox is in, the leg still works, and I’ve got a new scar to wave at the grandkids when they’re old enough to ignore my advice on safety gear.

The plan is to have the 2nd gearbox (I bought two for £60 - one for trial fitting and another for actual fitment) professionally rebuilt and strengthened, and also have the excess metal milled off cleanly, to my spec, using the test gearbox as the pattern. Rebuild and strengthening of 1st and 2nd synchro, along with harder bearings, will probably cost me about £800, but if it's to support the thrust from a turbo-charged, 1.8 Mazda MX-5 then it needs to be done.

The problem with the MX-5 gearbox (along with the sheer size) is that it goes a long way further back than the original gearbox and interferes with the handbrake. My solution? Delete the handbrake lever and use an electric cable actuator, like most modern cars. Even then the gear selector will need modification to bring it closer to the natural position, as shown in the conversion below. All doable.

I'm rapidly coming to the conclusion that by the time this car is finished, by knees will be totally shot and I won't even be able to get in our out. I need to double the pace of the work - and the concomitant expenditure.