[JP Noonan]

That makes sense to me. I always think of it as the wrist pin location but you're more correct. Anyway, I had a 2.0L crank and rods and used an old set of 1.7L P/C's in a mock up before I bought some 1.7L BB P/C's. The piston comes about 3/8" out of the bore, so the two cranks aren't interchangeable with P/C's. My reasoning was that I had some good, (high compresion, and have 1.8L valves) 1.7L heads and the 1.7L BB at the time was only $160 vs rebuilding my 2.0L heads $200 and 2.0L P/C's $400-450. Maybe all the 100mm,103mm, and 104.5mm are the same but I don't think the 1.7/1.8 are compatable with the 71mm (2.0L) crank. If shims were used to make the 1.7L P/C's work (FATS make made to order shims) then valve train geometry would be all kinds of off. Longer pushrods would probably cure it but the tin ware wouldn't fit right, and by then you're up to the price of 2.0L P/C's.

Funny thing is I have a 1.8L rod and a 2.0L rod in front of me and it seems the 2.0L is shorter which would indicate that your mechanic is right and the rods are different but piston pin height is the same. I dunno, remind me in a week and I'll dig up my old 1.7L,1.8L and 2.0L pistons to comare, along with the spec book.