Recapping the 2023 1000 Miles of Thunderhill

Recapping the 2023 1000 Miles of Thunderhill

Written by Anthony Casson

Date: November 17-19, 2023

We resumed our racing activities for the final round of the 2023 Lucky Dog Racing League (LDRL), the 1000 Miles of Thunderhill, in what would be our first time getting the #541 BMW E36 back on track to race since The Ridge last spring. With the year overshadowed by difficult mechanical reliability that has kept us from competition, returning to racing was all we really wanted before the off season.


The weeks leading up to the race were busy, with Josh Murray, Arcflash owner and driver in the #541, getting a freshly rebuilt S54 motor installed and prepared. The motor had overheated and failed two months prior during testing at Oregon Raceway Park, which had eliminated us from contending at The Ridge in September and the Halloween race at Portland International Raceway late October. The last time we were able to make it to an LDRL weekend was in June at Pacific Raceways, only to be dealt with a transmission failure on Friday testing.


We were feeling optimistic with the new motor installed and the car running on our dyno. The numbers looked as good as they usually do, and there wasn’t a whisper of a problem. We were also going to race with some new additions. During the summer we had been testing a new floor and diffuser for the car, along with some new features for the diff and trans cooling, all made in house at our shop in Bend.



The team for Thunderhill was five strong, including our three permanent drivers Josh, Dave Baker, and Greg Guise. We made the drive south to Willows, CA, and settled into the paddock Thursday, the evening preceding the weekend activities. Forecast had called for good conditions except for the start of the race on Saturday.



Friday morning came quickly and we had the car running soon after the 9 AM green flag opened the day’s testing. Josh gave the car an initial shakedown to bed the freshly padded Brembo GT-S brakes and scrub a new set of Hankook RS4 tires. The new tires were swapped out for a well-loved set for the remainder of testing, and Greg and Dave got to start their rotations. Getting the car running on track and putting it through the paces after months without driving was a satisfying start, but we would soon be given a glimpse of some fresh challenges coming our way.



Braking for turn one after the long home straight, we saw a trail of light smoke escaping the exhaust on the car’s left-hand side. We couldn’t spot it at any other point on the track, but it consistently appeared heading into the first turn. This was new. The one positive was that it wasn’t getting any worse on Friday, and data was showing we were looking fine on the internals. However, we started to see something unusual–the oil level was dropping, sometimes as much as a quart an hour in early samples, and there was no oil touching the ground.


Raw performance of the car and our drivers was great. Everyone was happy about the times and how the car was feeling; track time felt good. But the looming oil issue was starting to dampen our spirits. We had to decide whether we would race despite the oil consumption–and whatever the internal problem might be–or pack up and save the car in whatever state it was.


Running the car in timed stints during practice allowed us to get a reasonable feel for the oil consumption rate. If we were going to qualify and race, we needed to be sure we weren’t losing enough to cause us earlier pit times that would immediately put us deeper down the field and well from contention. Risking something catastrophic without being competitive wasn’t what we wanted. Fortunately, oil levels were dropping at a manageable rate. We decided on an oil refill procedure during the pit stops and committed to racing, knowing we were at least fast but unsure how the car would ultimately behave over a 1000 mile event.



The good-weather day of testing faded into increasingly harsh conditions overnight. Heavy rain and wind strained every canopy, awning, and exposed piece of equipment at the track. We woke up to the same conditions and to a neighbor’s RV awning breaking and dumping hundreds of pounds of water beside our carrier and extra sleeping tents. We knew the weather would be interesting but not this interesting.


We survived a wet, windy 9 AM qualifying session thanks to Dave’s driving and got queued in P7 of over 80 cars for the start of the race at 10 AM, with Dave still at the wheel. Our car performing well, we wanted to get a full stint in with the goal of staying on the lead lap after two hours minimizing the time we know we would lose during the wet window. Our car performs much better in the dry, and the majority of the race was scheduled to be dry track conditions.



The start began well enough with some of the expected contentenders immediately opening a lead. The field behaved and the track stayed green despite damp conditions, a stark contrast to Friday when yellow and black flags were a regular presence even with good weather. Dave did great work keeping things going and staying on track, getting lap times closer to the current frontrunners.


The stint ended and we had our first chance to check oil levels. We needed to add over half a quart, but for a two hour stint it was remaining a manageable prospect. Our pit stop was quick as usual, thanks to good practice, coordination and teamwork. It is a defining aspect of our team, the ability to plan and execute well even under unusual circumstances. We got Greg in for another full stint and on his way.



Aside from some continued smoke releasing from the exhaust in turn 1 like the previous day, the car was operating well, and Greg was able to start closing the times with the track dry. We were able to see who was going to be putting in consistently fast times alongside us, and the competition was looking great for the remainder of the race if everything held together.


The second stint came and went, then we got Josh in the car. We needed another quart of oil–still manageable, but also a frustrating unknown to grapple with under race conditions. Josh was able to climb through the remaining field with more strong, consistent driving and a fortunate full course yellow that bunched the field back up. We had gone from as much as three minutes behind the leader all the way to P1 near the middle of the third stint. A competitor took an early pit stop during another full course yellow and was able to leap ahead, putting us in second for the end of the first day, with Greg wrapping up the final hour of racing before heading into parc ferme. It was a smooth finish minus getting a Super Dog time–a 3.14.939 to the restricted 3.15.0–resulting in a drive-through penalty that was unnecessarily extended due to some marshal confusion. We still came out in P2, fortunately.


We had a strong first day, and the weather cleared. The forecast was great for Sunday. We were continuing to feel more optimistic about our performance and our potential to contend for an overall win going into the second day. But every endurance racer knows not to get too optimistic too soon. Our car was still hiding something that could potentially ruin our day.


An uneventful evening for us passed in the paddock, with the sounds of late-night work carrying on for other teams trying to deal with whatever gremlins were interfering with their race. Morning came with clear, cold temperatures. The driver’s meeting was short and recapped some safety expectations for the day ahead, then we were back unwrapping the car in the hot pit ready for the race to resume.


Josh opened the second part of the stint carried over from Saturday. A large train of traffic sat between us and first, with some fresh competition not far behind. The race resumed and we sat in second for a while before getting passed by a strong charging team with an E46; another E46 loomed behind us well, and the prospect of this kind of competition felt exciting. Until things began to show signs of unraveling.




A full course yellow bunched the field again about 45 minutes into the restarted session. Within our pit window but not as far as we anticipated, Josh radioed in about increased smoke coming from the engine–he was pitting just as the race was going back to green flag. The surprise stop resulted in losing about a minute on track, having to ready the jacks, inspect the car and engine on top of our usual pit procedures. Unfortunately we discovered the oil catch can filled near capacity, requiring time to drain it and top off the oil. The excess smoke was likely from oil coming out of the overflow tank and burning. Naturally, these things started to become more concerning; we had plenty of power, temperatures were fine, but we were still consuming oil, and now we knew oil was pushing into the overflow tank. We wrapped things up and decided to keep running, with Greg setting out for another full stint.


Corner marshals let us know they were seeing increased levels of smoke from the car. We weren’t dropping oil, and we knew there was nothing we could really do about the situation, so we kept going. An hour into Greg’s stint, the clutch let go, and we were disabled on track–race finished with another five hours still remaining.


It wasn’t entirely surprising, even if it was the clutch that stopped us rather than the motor alone; we had chosen to risk it and give the race a shot, having come off a frustrating reliability year. The reaction was mixed–disappointment, though glad we took a shot.


What exactly happened? That is still being investigated. What we do know is that the valve cover gasket was pushed out, likely as a result of crankcase pressure rising, which was likely caused by a blocked vent system stemming from a full catch can. Whether it was enough oil interfering with the clutch to cause it to fail as a result of a rear main seal or other factors that caused the clutch failure is unknown as of this writing. Seeing a newly rebuilt motor and high-quality dyno results a week before suddenly evolve into this series of events is interesting (and frustrating) to say the least, but we will no doubt have new experiences from which to draw from in the future.


The LDRL season is now done, and that means the active in-house racing effort at Arcflash heads into the off-season. Plans for our 2024 schedule and services are underway, and we will be sharing more as we know.


A major thank you to everyone in the Arcflash family–drivers, crew and our community of friends–for without you we cannot get out and compete or help others compete in this sport. Also a big thank you to everyone at Lucky Dog Racing League and to our awesome fellow competitors; congratulations on another great season of racing. We will see you all out there soon.


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