Aaron Scott’s Diary of British GT Championship Driver
Round 7: “(Death) Rattles and (Broken) Rollers at Rockingham”

Master Motorsport Ultima driver Aaron Scott tells the inside story of the team’s short and not very sweet race at the Corby speedway.

“After such a competitive outing at Oulton Park we came back to earth with a bit of a bump at Rockingham. Oulton was our best qualifying performance of the year so far and we expected to carry that momentum on to Rockingham, but in the end circumstances conspired against us once again…

“The Oulton Park problem turned out to be more than just an incorrectly set torque wrench. When the car was checked after the race we also found that the wheelbearing was turning inside its housing and the right rear wheel seems to have had a fairly big whack from a Mosler, which was probably why the wheel loosened in the first place. Both times the wheel has come loose this year, at Silverstone and Oulton Park, the car has been hit in the right rear corner. Having said that the wheels weren’t done up tightly enough either. The torque wrench was set for Newton / Meters rather than Foot / Pounds, the fact that they were looser than they should have been probably causing a small vibration. We managed to save all three wheels that had been damaged by re-machining them and we got some new wheel nuts so it was not as expensive to fix as it might have been.

“There was less good news with regard to engines. The new one that we’ve been trying to get into the car since the start of the season had another setback on the Tuesday before the race at Rockingham. Steven had been over at the engine builders working on the mapping of the new motor with an engineer from MoTec, who are supplying the fuel injection system. On Monday it was all looking good and 95% of the fuel mapping was finished. Then on Tuesday as the engine was doing another run on the dyno there was a clicking noise so the test was stopped. When Steven looked through one of the spark plug holes a piston was pitted so that put paid to running the new engine at Rockingham. We’re hoping it’s just damaged piston. If it is then it’s just a simple case of replacing it, welding the head up and the engine is ready. The mapping was done without restrictors so at Thruxton it will have to be adjusted, but otherwise it’s ready to go.

“So for Rockingham we had to again rely on the same engine that has done all of the 2003 races and quite of few of those in 2002 as well. It’s had new bearing shells and other bits as it’s needed them, but obviously the longer you run with an engine the greater the chance of reliability problems.

“Rockingham is not one of my favourite tracks. I really like drivers’ circuits like Brands Hatch and Oulton Park. You need a good car for Rockingham because the length of the corners makes it difficult to get a good balance and you can lose a lot of time with traction problems. Although the banking forms quite a large part of the lap, you have to set the car up for the infield and it’s those long corners that make or break your time. I personally find that the track just doesn’t flow well for me, it’s too stop and start for my liking. Having said that, it doesn’t give me any problems; a circuit is a circuit – you just have to get on with it.

“On arrival we were surprised to find that the track we were running on was actually different to the one that was used in 2002. In the back section there used to be a tight right-left chicane into a tight left hand hairpin on the long straight up into a left sweeper. That was changed to a very long sweeping left and a short straight into another long sweeping left. Steven drove the Rockingham race solo last year and was flying through that tight and twisty bit, but with that part of the lap gone our set up was a bit off. Those teams that did the test 10 days before the race found out that the track had been changed. We turned up on Friday without that prior knowledge and spent a lot of time with the back end sliding around at high speed. The car doesn’t like long sweeping bends because it’s quite short compared to something like a Mosler or a TVR. They are not really downforce corners either, so adding or taking off rear wing doesn’t help, you really need more mechanical grip.

“I drove for quite a lot of the Friday test session and we started off trying rear end changes to address the oversteer, but we were not achieving what we really wanted so then we concentrated on the front end and that seemed to take us in the right direction. Eventually we got the car working pretty well and managed to set a reasonable time considering we were on old tyres. We very were close to running flat out through the banking section of the track but I think it’s no problem for the Moslers. They are also very strong through the long corners, I think that’s where they pick up time, they seem to be very well balanced.

“With our set up changes appearing to be working we were looking forward to a strong run in qualifying. Our plan was for Steven to start the session on the new tyres and then I would get into the car about halfway through. We are pretty well matched on times so I don’t think it really makes a big difference who has the new tyres first. We ran a harder rear compound than usual, partly to address the understeer problem but also because Rockingham is quite a tight and twisty circuit which can give a car problems with traction. We thought the harder tyre would give us a better chance of the lasting the race without a problem.

"Steven managed to cut about three seconds off our best lap time at the start of the session and we were making good progress when the car stopped out on the track. Steven radioed in to say that the oil pressure had disappeared. When we got the Ultima back to the garage we found that the drive belt to the oil pump was broken. That meant that the engine had to come out so the crew could check for internal damage.

“By six o’clock the oil pump was being stripped down and soon after we found out what had caused the broken drive belt. A roller on one rocker had broken up and some of the debris that dropped into the sump pan and was ingested by the oil pump. This jammed the gears in the pump, seizing it and snapping the toothed rubber belt. Steven said that he switched off the engine immediately but reckons that the engine ran for about ten seconds without the oil pump working. That led us to fear that the main bearings were damaged but on inspection they looked all right, at least as far as you can tell by a visual inspection, so we decided to go ahead with a rebuild in the garage at the track for the race. That meant a trip back to the workshop in Bicester for one of the guys to get spares. On Sunday morning Steven’s dad, Jimmy Brady, replaced the broken rocker, reassembled the engine and fitted the rebuilt oil pump. Of course we missed the morning warm up but the job was finished about an hour and a half before the scheduled start of the race. Although the engine was ready in time we knew that there was a high likelihood that there was still debris inside. Rebuilding the engine at the track and in time to allow us to start the race meant that we didn’t have enough time to strip it down completely and in the end that cost us.

“When we fired it back up after the rebuild it was only running on seven cylinders, we’d lost number eight and that wasn’t the one where we had the first failure. So it seems that there something was already wrong inside. Steven said that on the track the engine seemed to run all right. When he got the revs really high it felt like it was running on all eight and he was keeping up with the GTO cars, but when he changed gear the power dropped immediately and he fell away but as the revs picked up again he pulled them in again. It could be that one of the parts that was changed was not set in the correct orientation or something had gone through the oil pump again.

“Either way the oil pressure light came on as Steven entered the pit straight at the end of the first lap and he turned the engine off and parked it. Jimmy and the crew did a fantastic job just getting the car to the start of the race and it was a real shame that it was over so quickly for us after all their hard work. Now we are looking forward to the next race at Thruxton, where I hope we’ll have the new engine and a more successful race to tell you about next time.”