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On Sunday morning prior to the August points races, I was leading COMMA class PA in championship points and feeling pretty darned good about it. A huge lead over 2nd place in the standings, at 910 points to his 695. Essentially, all I had to do was enter and finish the rest of the year's races (Aug, Sep and Oct) and I'm PA champ with points to spare. And to top it off, I had just qualified on the pole with a new personal best lap around Hallett CCW at 1:32.2. Cool!
The green flag drops on the first of two points races for the day, a 6 lap qualifying race that sets the grid for the start of the 12 lap feature race. I am on the inside, with a fender on the 2nd place 240Z as we approach turn 1. The engine is at a little over 7000 in 3rd when I get off the throttle and begin braking for the turn. Uh-oh! What was that noise??? Continue into the turn and begin to pick up the throttle at the apex. Double uh-oh! Three cylinders and a lot of noise and vibration from the engine. I started waving cars by, and instinctively killed the ignition. Over the hill and through turns 2 and 3 on momentum, time to re-affirm what I thought I heard. I bump start it in 4th at about 30 mph and listen carefully, but not very long. I also see nearly zero oil pressure at idle! Wunnerful. Coast off the course and parked behind the turn 5 corner worker station.
Today I got the engine out and disassembled far enough to confirm the problem. Number 4 piston is broken circumferentially, in (or just above) the oil ring groove. Not pretty. The top half of the piston still in the bore, moving freely but broken in half diametrically. The rest of the piston (everything below the 2nd ring groove) is fragmented beyond belief. The oil pressure problem was because the pump screen had been absolutely covered with aluminum bits. The largest piece of piston I've found is about the size of your thumbnail. The block is thoroughly trashed, as you would expect as the result of a rod and piston pin running up and down in a bore without a piston attached. Head looks okay, crankshaft is probably okay also, but all of this will obviously have to be confirmed on complete disassembly.
Anyone got a good set of B20 .030" pistons they want to peddle at a decent price? No cracked pistons, please! :)
I have pretty much everything else I'll need for the rebuild.
Gary L
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1971 142E ITB racer, 1973 1800ES, 2002 S60 T5
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