[304065]

Hmm, Henry makes an excellent point.

If you look at JE's web site the "compression distance" is listed as follows

3,0 95mm x 70.4 -- compression distance 34mm
3,2 95mm x 74.4 -- compression distance 32.8mm

So there is a difference of 1.2mm between the two off-the-shelf pistons JE offers in 95mm size. 1.2 mm = .047" for those using the decimal-inch system (It won the War, didn't it?)

So. . . you can backsolve into spigot height for a Porsche engine. . .

74.4 stroke divided by two equals 37.2, plus 127.0mm rod length, plus a compression distance of 32.8mm =197mm "TDC Height."

197mm TDC height PLUS 1.0mm for deck height minus 85.4mm for the cylinder height minus another .25mm for the spacer leaves you with 112.35mm for the distance between the seat face of the spigot and the centerline of the crank.

Plug those numbers back into a standard 2,0 engine for fun. . . half of 66 is 33 plus 130.0 rod length plus 34mm compression distance = 197mm TDC height.

Ahh, fun with numbers! Once I get my case on the surface plate with a height gauge I will confirm the spigot height.

Anyway, Scott, back to your problem. What was it again? Just kidding.

If you plug a compression distance of 32.8mm into the above calculations. . . 33 + 130 + 32.8 you end up with 195.8mm TDC height. In order to get that back you would have to deepen the spigot bore, lengthen the rod, offset bore the pin, shorten the spacer, trim the cylinder or have new pistons made. Of those, the easiest is probably offset boring of the rod, which would alter the rod-to-stroke ratio to an even 2:1, not necessarily a bad thing.

edited to ADD the deck height to TDC height before subtracting the cylinder and spacer to get the spigot height.

edited: 2,0 and 2,2 cylinder height is 82.2 mm-- so the spigot height must be different on those engines.