Steve,
When I bought my Elan back in '75 the PO cliamed that the engine was all steel. I wasn't much bothered either way as the car was a steal(!) but with this erronious information I reved the thing regularly to 7500 and sometimes to 8000.
I did this for about two months befor taking it apart because it was obvious that the cam timing was out and I wanted to find out what was inside.. It went like stink over 4500 but was a serious fire risk at low revs. (serious blowback and lots of petrol out of the carb trumpets)
When in pieces I found an ordinary crank, which I expect was had been toughened, 125 rods, short jackshaft, Cosworth forged pistons and BRM phase 3 cams timed on the standard sprocket timing marks. The big end bearings were crazed so I don't suppose the crank would have lasted long.
I rebuilt it with new rings, bearings plus Cosworth bolts and properly timed cams and it managed another 45k befor I changed to a crossflow blocked 1700. The original engine was very sweet and free reving to 7000, occasionaly to 7500, much nicer than the 1700.
Just for interest, I have the spec sheet for the Cosworth Mk 12 which quotes 140 bhp at 6500 on L1 cams, 83.5mm bore (1594cc) oil pressure 60-70psi running and 20-25psi tickover when hot. Max revs 7000 but 6500 in first and second gears. This on a cast iron crank and flywheel, balanced but no mention of toughening.
Oh, they also quote 95-100bhp as standard so the 85 at the rear wheels in another posting doesn't sound too bad.
Roy
'65 S2