hello, taking a 903 coupe engine to bits, inspecting before i attempt a start, on measuring the bores which should be 65mm i found they vary from 64.5 to 64.7, the pistons are stamped B-2, does that mean anything to anyone, put the top compression ring in the bore and measured top and bottom and it appears the gap is way out of spec, the bores are not scratched no ridge at top, thanks for your thoughts regards dave

Hi Alonso/Dave.

Give us a bit of history of the car it might help us. age etc

but my first suspicion is you may have one of the American 820cc 64mm bore engines that's then been rebuilt with plus 0.6 pistons giving a piston of 64.6mm and hence some clearance.

what does the engine casting say on the side 100g or 100gb 100gbc 100gl

what is the stroke of the engine,

Tim

hello tim, engine came from a 68 sport coupe, it has 100GBC stamped on the block so i presumed it was a 903cc, i have a 64 850 saloon was doing this engine up for that car, the crank has GBC stamped on it cant remember the piston diameter needless to say it fitted in the bore so piston was less than bore size, do you know what the B-2 stands for, rebores and bigger than standard pistons are usually stamped plus, strange one for sure going to test piston in bore clearance next, thanks tim dave

Hi Dave

sounds like a std 52hp coupe to me, not sure why its under 65mm or what the -b on the pistons is.

Tim