Well we made it to the Birkett. The road has been long and arduous, and the pathway is strewn with my broken promises about finishing my wife’s 1979 1275gt mini about which I feel very guilty… But here we are..we’ve made it 
. and the Mini will get done before the spring!
For those of you who I haven’t bored to death about the Birkett, it bears a little explanation. It is a 6 hour, team endurance relay race, which any closed wheel race car of any vintage can enter. This means you get massive differences in machinery , so it is also run as a handicap race In the past we’ve had Radicals, racing RGB cars, racing Citroen 2CVs and classic Jags. What this means is that in practice, there are 60 cars of loads of different types on the track at any one time, 6o teams in the garages, you’ve four or five team mates in the garage with you (along with their cars) and a large number of mates helping out. It’s an all day endurance event, but because your handicap is based on your best ever lap you have to drive your stints 1oo% balls out for the whole 6 hours, and minimise mechanical mishaps if you’re going to win.
It makes you feel like a proper racing driver. On the track you typically get a couple of stints out on the track and it is one long overtaking fest, as you try and catch the classic mini, while overtaking a classic jag, avoiding the MR2 and keeping an eye out on the bewinged Radical bearing down on you at 150 Mph…. it is simply great fun. go and Youtube ”Birkett”… for some great footage. So that has been my aim to get in this most thrilling of races with this new car, it is I think either my 5th or 6th year of attending.
However… you do really want a well tested and reliable car before you mix it up in this company.
So after the aborted Snetterton test, I still had a load of work to do to get this car race legal and compliant with the Blue book regs. The important thing is that test days are non scrutineered, so you can cut the odd corner (like lights) but races are properly scrutineered, so I had to get the car right before heading to the Birkett consequently, another day from work was required, and I cracked on with the essentials.
- Front lights
- Emergency Labels (Tow, Extinguisher, Cut off etc)
- Indicators
- Numbers + Letters + Race backgrounds
- Fit rear floor.
The Friday test dawned, a bit damp, but generally dry and my nerves had me up at about 6:30
Before venturing out onto the track, It made sense to at least drive it around about a bit, Silverstone is blessed with a large wide expanse of tarmac known as “The old runway”, and I spent a good twenty minutes driving around in circles and figures of eight, checking steering, feel and alignment, going up and down the gears and generally just checking the basics work. She stopped, she goes, the gears work and so on.
Most gratifyingly she was working well, the steering was aligning well, but the wheel wasn’t quite level with the straight ahead position, which Duncan and I corrected before the first practice. She also had an odd clonk from the front right when coming on the brakes at low speed. We checked everything, but in the end decided it must have been a worn rose joint, or the disk just moving a little on the studs, as we checked everything else and it was tight.
Session 1
So out we went in session 1 of 3. The first couple of laps were very tentative, but generally she was going ok.
There were a long list of small teething problems. She was pretty tail happy, but very grippy at the front, She was bouncing around a bit under braking and the brake balance was all over the place. The nose leapt up a couple of times when I came off the brakes. We also has some odd vibrations at medium to high speed…. one which was clearly bodywork or front floor flapping around and a second lower pitched vibration that was related to speed…only kicking in along the straights.
Eventually the session was red flagged when someone dumped it in the Gravel.. so I came in and we made a few changes.
We raised rear gurney flap to aid rear grip, adjusted both bump and rebound damping to quieten the front down under braking and at brake release.
After the red flag I went out again and pushed a bit harder. I had one excursion across the grass, when I went for an apex, but didn’t think the tin top I was over taking had seen me, so deliberately opted for the grass. The handling was better, and I was dialing the brake balance progressively forwards until I got it somewhere close to where it needed to be.
However I curtailed the session after 1 lap as she was kicking out white smoke in the exhaust, and I caught a flash of flame in the mirrors. On inspection, there was oil in the engine bay, and oddly in the battery tray too….. there are no oil components over that side of the engine so it was very odd. This led me to the to airbox fluid drain which was full of oil. And the final diagnosis was that engine breather from the gearbox was flooding the intakes with oil mist inside the airbox, and this was altering the engine fuelling, and burning it in the exhaust.
We disassembled the airbox, and it was indeed swimming, so we mopped out the oil. The fundamental problem is that I followed the bike’s standard breathing circuit, and connected the gearbox breather to the airbox. This is normal on the bike installation and works effectively…. but of course in our installation and particularly at Silverstone we are at full throttle much more than the normal road bike, and this clearly overwhelms the breathing system and actively sucks oil up the breather to the airbox.
As a stop gap we simply rereouted the breathing system directly to a catch tank, and topped up the engine and cleaned the spilt oil out from the engine. The catch tanks was the traditional 2 Ltr drinks bottle taped into the engine bay, and Tim Kindly donated a length of hose to allow the breather to reach it.
In session 2 the damper changes have helped a bit and the raised Gurney have added rear grip. However, this time the session was curtailed by a red flag after only a couple of laps and as I came into the pit lane Duncan waved me into the garage. The front floor had indeed been flapping around and had torn one of the mounts out of the floor where it connected it to the front bodywork. As a consequence the floor had been rubbing on the tarmac, and had been gently machined to a sloping taper. I clearly couldn’t go out again like that… so we broke out the fibreglass supplies, (Scrounged from Austin’s dad Ken) Duncan glassed up the reapir and I made up a reinforcing plate to rivet on and support the the fibreglass while it went off.
Session 3.
In session 3 I did about 6 laps. I still had a front floor vibration and that odd low frequency one at speed that had stuck around since the first session, but the car was definitely starting to come to me and feel like an RGB car. It was really missing the rear undertray… but generally I could start to lean on her now.. and start to work the brakes hard as she was mostly stable under braking. The only other thing was the gear lever rest position was moving towards me which meant that the threaded actuating rod\turn buckle was unscrewing.. so we attacked that with some thread lock in the absence of an additional left hand locknut.
There then followed as typical RGB evening when everyone helped me sort out the new car. Andy turned up with the new rear floor, so I set about fitting that.
At the front we still to fix the front floor vibration and make it rigid so it didn’t flap about.
Initially we looked at simply adding bulk and weight to the ply to stiffen it. but when Derek Jones and John Shaw (my AB Performance stable mates) turned up they quickly identified that we’d failed to tie the floor to the bodywork effectively. The floor has a horizontal “return” edge, and what I’d failed to notice is that this should hook under a transverse lipped section which runs across the front of the floor itself. This locks the two components together and stiffens the whole structure mightily. It was John who noticed this, an he set about cutting some interlocking bits from a piece of old Genesis floor that I’d been carrying around in the Winnebago for 3 years. That he did this using a metal hacksaw blade, without a frame because we didn’t have a wood saw is a testament to his generous nature, great skills and dedication to getting another Sabre out on the Grid. Once he and Duncan had finished the 20 or so trial fits necessary for this to work, we were about 80% there. But even with this new horizontal lip\brace the floor still needed some corner braces to fully stiffen it up.
Enter Matt Newton a CAM7 mate, who was heading over to Silverstone from Cambridge, and passing (ish) my house on the way. So he very kindly dropped in to my garage and picked up a couple of tools, my Rivnut tools and some lightweight tube.
So in the best RGB tradition at midnight before the big race, we were fashioning some front floor braces from some thin wall fuel tube, and a bit of old Genesis floor, using the skills and good wishes of half the RGB paddock, a big hammer and some handy Silverstone structural steel pillars to use as an anvil and flatten the tube ends. As always I owe my thanks to John and Derek, Andy, Austin, Ken, Tim, Bob, Matt, Dan and many others, these folks are all owed big favours from me and I’m pretty sure they’ll get paid back in similar, but reversed circumstances in the future.
That really is the joy of the RGB paddock… no quarter given on the track… no effort spared to help out if you need it in the paddock.
So at 1:15am and after precisely 8 laps of testing of the car, and my only 8 laps of seat time since last year’s Birkett we were ready for longest, most taxing, potentially most dangerous motor race of the year… what could possibly go wrong?
Looking forward to the next episode
Quite.