Broke, Busted, Disgusted (Reprise)

It looked like it was going to be a great weekend for racing. We got the same paddock spot as we had for the last Blackhawk National race, and Saturday promised to be sunny, warm, and dry (for most of the day, anyway).

The first qualifying session went fairly well, but a nasty old problem resurfaced. The oil pressure slowly dropped from a pretty-good 40 psi at the beginning of the session to a dismal 20 psi by the end of the session. I wouldn't have been too worried except that we ran into a very similar problem last year, with very bad results. I got down to a 1:21, which was within three seconds of my best lap time, despite running much older tires. Still, that put me 10th out of 11 in the class.

We checked over the car for the second qualifying session and put on softer tires in an attempt to at least get close to 9th place. I also cranked the oil pressure relief valve screw in, hoping to boost the oil pressure a little. When I started the engine for the second session, the needle on the oil pressure gauge jumped to a very promising 80 psi, but then it began wagging back and forth between 30 and 50 psi as the engine idled. That seemed to be an improvement over the morning.

I followed Allen Wheatcroft for part of the session. His car wasn't handling well during the test day on Friday, and that had taken away a lot of his confidence. He just didn't feel like he could trust the car. That worked to my advantage, allowing me to draft him for several laps before he pulled in. I stayed out for a few more laps and turned a 1:20, which was faster than Allen's time in that session, but slower than his time in the morning session. I was still gridded 10th of 11, and the oil pressure was now hovering around 20 psi at 6000 rpm and dropping to single digits at idle.

We checked over the car again, and this time we also pulled the oil filter to look for any signs of bearing damage. The oil that drained from the filter housing was sparkly with tiny metallic bits, which was normal if a little excessive. The damning evidence was spotted inside the filter by Bruce Lindstrand: larger copper flakes, each one only a little bigger than the dot that a medium-point ball pen would make on a piece of paper. You could probably get one caught under a fingernail and never even notice it.

Those little flakes are shavings of material from the inner layers of the bearing shell. When the crankshaft has worn through the silver/grey outer layer and has begun scraping out the copper underneath, that means the engine is not long for this world. The crankshaft depends on the bearing shells for support. Racing the engine after that support is scraped away will subject the spinning crankshaft to horribly stressful forces and will eventually result in in a bent (or broken) crank and a damaged block. That's exactly what happened last year.

The wagging oil pressure needle now seemed to make sense. If the crank were already bent, the off-center journal would swing around inside the remains of the bearing shell, alternately getting very close to the oil passage (creating a tighter clearance and boosting oil pressure) and swinging away (opening the clearance and dropping the oil pressure). At idle, this could happen slowly enough to register as visible pulses in oil pressure. What a revolting development this is.

We put the car back on the trailer and called it a weekend. I later heard through the grapevine that Bruce Lindstrand drove another inspired race to finish 3rd in a very fast crowd. For someone who isn't out there to win, he's been finishing awfully close to the front.

Now we play the "If" game. IF the crank is not bent and the block is not damaged, we will replace the bearings (with a different brand, I think) and get back out fairly soon, depending on the budget. IF the crank is bent but the block is in good shape (unlikely), I will look into one of the new forged crankshafts which are supposed to be stronger than the old cast cranks I've been running. IF the crank and the block are both bad, then I may be out for good. These blocks haven't been made for about 20 years, and there are just no more available.

Besides, with the luck I've had with the Kent, I'm ready to start shopping for a Honda engine instead.