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Preparation Diary 4 This is it then, it’s a cold March morning and we are just arriving at Silverstone. The plan of the day is to do a few sessions, check the engine out and make sure the car is working properly before the race meeting on the 24th March at Brands Hatch. One of the first jobs to do before we can get on track is to bleed the newly rebuilt brakes. Normally this is a straight forward process that takes about 20 minutes to complete. The nice thing about the Willwood caliper is the bleed nipples are mounted in a brass adapter. So if you do snap a nipple you just remove the adapter and fit a new one. Easy….well…..that is unless the adapter shears off and leaves part of it in the caliper. Just want I needed and of course I hadn’t brought anything to get the sheared off part of adapter out of the caliper. After trying a few ideas that failed I was starting to think about packing up and going home. Then I had a flash of inspiration of using a torx socket to pull it out. Luckily for me Dave Edwards was more prepared than me and had a set in his tool box. A few tense minutes later and the broken part was out of the caliper. A quick clean and a new adapter fitted and we were in business. The brakes were bled but they didn’t feel great. I thought we’d do a couple of laps and see if they improve. So at last we were ready for the track, this was the last session before the lunch break. Out of the pits I gently accelerated up towards Maggots and got a feel of the car. It was apparent the brakes weren’t good at all. After coming into Priory the pedal went to the floor….I’ve never pumped a pedal so quickly in my life. I pull straight into the pits and we set about bleed the brakes through again. Soon we had a decent pedal, we topped up the fuel and got the car ready for the first session after lunch. Finally I get out on track with a car that both goes and stops…..a nice feeling. I started playing with the engine and seeing how it goes…and it does go! The engine is very smooth and doesn’t give the impression of accelerating but the limter in 6th gear comes up so quickly its frightening. Another give away is when you overtake something then look in the mirror to pull back on line and it’s a mere dot in the mirrors. After about 5 laps I came out of Copse and the engine missed. My stomach sank at the thought there was a problem. However the engine carried on pulling so I hoped it was just a blip. However the blip came back and the engine died coming out of Chapel. I was looking down at the gauges for some pointers on what the problem was and I spotted the fuel pressure had dropped off a cliff. Fuel starvation was the problem! well at least I know what the problem is now what is the cause. I call in the pits and we have a look around the car to make sure there is nothing obvious causing starvation. After a good check around I turn my attention to the tank design. The built-in swirl pot is on the left hand side of the tank so this might be an issue. To prove this we top the tank up and set out again on track. Sure enough with in 5 laps the surging started again. But it was only happening on left hand bends so the pick up was the most obvious culprit. This wasn’t something we could fix at the track so we packed up for the day and set off home. The biggest problem with the tank was the size of the swirl pot and pick being on the left and not central. When I designed the tank I was unable to put the swirl pot central because of the chassis members. Also I under estimated the amount of fuel the pump would circulate. So I was one the phone Monday morning to Spec-R to redesign the fuel tank. Unfortunately Peter, from Spec-R, was in the middle of a workshop move and couldn’t do anything for a week. This was ok but I was planning to be at Brands Hatch in 2 weeks time so this was going to be a tight time-scale. However the extra week did give me a chance to go through the various different designs of fuel systems. Ironically a chat with Justin saw the foundation of a new design form. I didn’t have room for a traditional swirl pot so the plan was to add a 4" section to the existing tank that would act as a big swirl pot. An additional low pressure pump (thanks Merlin again!) was added that took fuel from the main tank to the new one. Half way down the swirl pot was a horizontal baffle plate that ensure the fuel injection pump always had 2litres of fuel available to it. At the top of the tank there is a breather between it and the main tank which acts as a return for the low pressure pump. So we have a design, now all I need is Peter to make it for me. As with most things with this project time was slipping by and I was getting to the point of canceling my entry for Brands. On the Thursday before Brands I get a call from Peter saying that he’s up and running. I shoot over with the old tank and the new design and he starts work. Friday lunchtime I pick up the new tank, special thanks to Peter for turning this around so quickly. I start working on the car at 4.30ish, Justin arrives a few hours later and we finally finish at 9.30pm. We get the car loaded up on the trailer ready for the trip to Brands in the morning……still not knowing if the tank will work or if I have enough capacity for 24 laps of the Indy circuit hangs over us but we won’t know until we try. Check out the race diary to see what happens.
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