RJRacing

FONTANA, CA – The team descended on Auto Club Speedway with a goal of getting the car on track and testing the refinements from the off season. While the weekend was a success, scoring podium finishes in both Performance Touring “E” races, the real story was in between the races.

The team had embarked on its first engine rebuild in the offseason. After holding up for more than 100,000 miles, over 10,000 of which were spent in the upper reaches of the tachometer, the bottom end of the engine was due for a rebuild. Always looking at maximizing the ruleset while staying within budget, the team opted for a conservative, but still performance-oriented engine build.

The block was first cleaned using a thermal engine cleaning process, magnafluxed to verify that the block had no cracks, and line bored to ensure that the crankshaft would sit perfectly perpendicular to the cylinders. Then the cylinders were overbored by 0.020″ and compression was increased from the stock ratio of 9.0:1 to 9.5:1 by using Mazda overbore pistons from a 1999 Miata. The crankshaft journals were polished and ATL race bearings were installed. In addition, brass freeze plugs were installed to further aid in preventing corrosion. The clutch and flywheel used during the 2009 25 Hours of Thunderhill were inspected and looked almost brand new, so they were reinstalled. And the team fitted a new rear main seal and oil pump with new front crank seal.

After seating the rings, it appeared that the engine had a small oil leak at the front of the engine, which appeared to be coming from the oil pan seal. Monitoring the oil leak before the race weekend, it appeared to be minor at best. So it was decided to run the Auto Club Speedway weekend just as intended, as a test weekend, and to further monitor the oil leak to determine the source and possible fixes.

Big mistake.

Rob, John, Norm Sandstrom, and new crew member Sean Trabue arrived early Friday morning for the test day to tweak the setup. Since this weekend would be Rob’s first time behind the wheel since the September 2009 NASA Nationals when he broke his wrist, it would take him a little time to get reacquainted with the car. So John took the #23 Mazda Miata out on track for its first hot laps of the 2010 season to check the engine performance and the status of the oil leak. John reported that the engine felt great, with a noticeable increase of power using the good old butt-dyno.

After two laps, John brought the car into the pit lane and both Rob and Sean immediately noticed a small stream of oil coming from the front of the engine. The car was immediately taken back to the garage area, where it appeared that the oil leak was coming from both the oil pan seal, as well as, behind the oil pump. This was going to be a big job.

In order to reseal the oil pan, either the engine has to be pulled, or the front subframe has to be dropped while suspending the engine. The latter was chosen and the front subframe was quickly out of the car, with the engine hoist suspending the engine in the air. The oil pan and oil pump were removed, which revealed some scoring on the crankshaft nose where the crankshaft seal is placed. Upon inspecting the crankshaft seal, it appeared that the spring which provides tension to the seal had popped out of position, and had pressed against the crankshaft nose. The big job just turned into a bigger job, because now we had to polish the crankshaft so that no further leak could happen.

Norm got to work on the crankshaft nose, John went to pick up replacement parts, while Rob and Sean began prepping the oil pan and oil pump (a seemingly simple task until the amount and nastiness of the sealant is taken into account).

The crank nose was polished as much as possible, but when attempting to refit the oil pump, the new crank seal popped its spring out again. Going back to the Mazda factory workshop manual, we verified the correct procedure, which involved installing the front crank seal into the oil pump, and then installing the oil pump on the block. Each time this was attempted the spring popped out. So we went “off the menu” and first installed the oil pump, followed by the crank seal. This worked like a charm. So now we knew why the original spring popped out. While the Factory Workshop Manual is great in many respects, it was made by humans and there are mistakes we’ve found. This is just another one.

The oil pan was reinstalled and the front subframe was put back in place. The work was long and arduous, but done. After taking a reconnaissance lap around the paddock, the front oil leak was not gone, but it had been minimized to a manageable level.

Saturday promised to be a busy day. In addition to running the PTE race and Time Trials, the team would be joined for the weekend by members of the Pit Crew for a Day program run by Dennis Flaherty. This program matches engineering students with race teams to gain some real world experience. Joining RJR for the weekend were Craig Tsurumoto, Sean Ryan, Serguey Piatrovich and Brandon Mok. The team had rapidly grown to eight members.

Putting the car back on track for the first time after the monumental repairs the day before proved successful. The oil leak had been minimized to the point that we could at least run the races. Rob immediately felt the improvement in engine performance, with the car easily powering through 5th gear down the straight, as opposed to winding the engine out in 4th prior to the rebuild. Rob qualified 3rd with a time of 2:02.452, nearly a second faster than the team’s previous fast lap at this track.

During the race, Rob passed for 2nd place and the car felt solid throughout most of the race. In the last few laps the clutch began slipping, caused by the trace oil coming from the rear of the engine getting on the clutch and flywheel. Rob feathered the throttle for the last few laps, but had gained enough of an advantage over 3rd place that he was able to limp home in 2nd.

Hoping to avoid pulling the transmission, the team tried a few “old school” tricks for cleaning up an oiled clutch disc. Racing clutches are made from carbon-metallic materials that do not absorb oil, so as long as the clutch is able to burn off the oil, it should still perform.

Sunday morning’s warmup showed that the rear oil leak had become worse. John’s ran 5 trouble free laps but then reported the clutch slipping. Back to the garage, and the entire team descended on the car to pull the transmission, hoping that the rear oil leak was caused by the rear main seal. In only a few hours, the transmission had been removed, the rear main seal replaced, and the transmission reinstalled with the team’s spare clutch and pressure plate. The team even had 40 minutes to relax before the PTE race. Unfortunately we had missed qualifying so John had to start at the back of the pack.

John plowed through the field, reporting that the clutch felt great. But once again about two-thirds through the race, the clutch began slipping. John held onto 3rd and brought the car home.

With all of the problems, the team still placed 2nd and 3rd in the PTE races and 2nd place in Time Trials. Not a bad result considering that both the front subframe and transmission had been removed over the weekend.

Now it was back to the drawing board to diagnose and fix the oil leaks.