I spent the day today checking the car over, trying to find the source of a knock that you can hear in the videos as I go down craner curves and doing a couple of other small jobs.
The knock was very similar to a noise I had at Abingdon, which turned out to be the prop-shaft guibo (rubber doughnut) and replacing it solved it completely. I was hoping not to have to replace it again (as they are £100+vat from BMW) but this time it seems fine and crack free.
The only thing that looked out of sorts was a lose bolt on the bracket that holds the prop shaft centre bearing in place, which was loose. The thread wouldn’t allow me to tighten it, so I re-tapped and replaced the bolt.
I also noticed that my exhaust was sitting very close to the rear subframe and could well have been hitting on that, so I lowered it slightly.
The next job was to cut a bit of the bonnet away after Charlie Brisker, a competitor, advised it might save an argument with a scrutineer when they test my safety pulls. Easy enough - cut, sand-back the sharp edge, and paint with red Hammerite. Not pretty, but it’ll do. I also greased up the lines a bit, and they seem much better. I’ll give them another check a few days before we set off for Rockingham to make sure they still move smoothly.
At Donington I was more focused on just getting round the track than being anywhere close to minimum weight, and I think I was about 50kg over. This time I hope to get a little closer.
The car with half a tank of fuel, the passenger seat, and me with my gear on was 1130kg. The minimum weight is 1125kg, so I plan to remove the passenger seat, add some ballast, and remove some fuel. Solid ballast should prove less of a handling handicap than a sloshing fuel load.
I removed the passenger seat, and set about finding something to use as Ballast instead of the ”afull fuel tank method”a which I employed previously. The easiest solution looks to be a ”aVibration Damper”a from an E30 Cabriolet - essentially it’s just a big 22kg lump of iron, with 4 holes to allow it to be mounted. Perfect! I’ll find one and mount it in the passenger foot-well with the correct bolts as mandated by the regulations. (I left the seat rails in place as they are nice and heavy, and low down so won’t do any harm).
I also gave it a clean and a bolt-check so there are fewer jobs to do before the next round at the end of May.
