I believe the end thrust is taken on the rear main bearing insert, against a flange on the crankshaft. The maximum end float should be around 0.15mm. The cranks do wear more on manual cars than autos, but it's hard to believe that it was within spec when built and deteriorated that much in 2 hours of operation. That end float would be due to large amounts of wear, and you expect to find lots of the crank and rear bearing shell on the sump plug or in the oil filter.
I don't believe there is a separate thrust washer, at least in the standard crank setup. It shouldn't have hurt the block though.

Thanks for your responses. I really appreciate the dialogue that takes a lot of your time. Anyway.. sighted the crank today and it is a counterbalanced 3.3 which is a blasphemy with some of the engine experts it seems because they are a poor casting??
As an old Auto elec I am on a steep curve here!
so to describe the wear, total c/shaft axial movement was 2.46mm. Thrust bearing has its thrust side brand new looking on the harmonic balancer side and worn wafer thin on the clutch side (as expected and caught just in time i hope). The main bearing cap showed signs of blue as the slightly over length by a thread or so flywheel bolts had started to gouged it! Oil in the area of contact had fused to a hard layer of black stuff that I had on end of my finger, tasted like, well, hard oil! (not chicken). The other main bearings showed spotting of metal in the alloy bearing material from the grind down of fragments. But no journal damage. luckily also the floating small end bearings saved more damage.
I have used a small but very powerful magnet right near the rear main on the outside of the sump(near oil dump plug) and slide it off each time I dump oil, and a hugging magnet on the (small type)oil filter which i believe both may have helped save metal migration thru the whole engine. All this metal could send $7k to the bin..PDQ
I worked out the run hours (not include dyno time ) as 50laps at 65secs per lap (lakeside) 59 at 1min 30secs per (QR National) add a bit for tune time. so more than 2 hours but still minimal. It was when i collected the car from dyno guy after the first 50laps that the first minor drop of the oil leak was apparent on their dyno floor. So before going to race at QR, so after about 59 x 1 � minute laps wear was happening very fast disrupting the neoprene seal. At near the end of this meeting the car could no longer go out. From underneath i did notice the clutch lever had a close no-gap feel. Still felt fine to drive onto trailer.
I believe (my theory only)that the clutch master cylinder plunger(and lever) is not fully returning and heat expands the fluid inline causing much more fork pressure. The pedal would drop a tad and could be brought back by under pulling back by foot. I think heat exasperated all this and although the clutch plate is not slipping and the throw bearing is fine, a large push pressure was applied to the crank. This is my best shot at knowing why the crank has chewed its self(maybe) into the bin. It will need spray metal building up 2.1mm at the bearing surface. Is it worth this or look for a new crank?
It�s journals are only 20thou under and has had lots of work done so i am hoping the metal spray can work...find out if it can be done on Monday.