[304065]

Hmm, you are right.

Tolerance Groups for Cylinder Heights, 2.0 Liter Engines, 1969-models

Marking A
5 82.200-82.225

6 82.225-82.250

Replacement Parts
R5 81.950-81.975
R6 81.975-82.000

Tolerance Groups for Cylinder Heights, 2.2 Liter Engines, from 1970-Models
Marking A
5 85.400-85.425
6 85.425-85.450

Replacement Parts
R5 85.150-85.175
R6 85.175-85.200

From the little white book p.38 (3M XII/71 M) 1st English Edition.

This causes me to rethink my engine geometry worksheet-- with different cylinder heights, this means the 2,2 cases have a different spigot height.

66mm stroke
130mm rod center-to center length
34mm compression height (for all 2,0-3,0 pistons)
1.0mm deck height

Half the stroke is 33 + rod length 130 + compression height 34 + 1mm deck = cylinder head mating surface is 198mm above the centerline of the crank, minus 82.200 for the cylinder height + .25mm spacer is 82.450mm, this puts the spigot base at 116.05mm

For a 2,2, same calculation except you deduct 85.400+.25mm or 85.650 for a spigot base of 112.350.

For the 2,4, half of 70.4 (35.2) + 127.8 = 163 + 34mm + 1.0mm =198mm (that part matches).

Hmm so IF you use 2,0 cylinders on a 2,2 case you end up with higher compression because the spigot base is 3.2mm closer to the centerline of the case. This has the practical effect of pushing the piston closer to the head. Let's add it up . . .

112.350 + .25mm + 82.200 = 194.8mm. If you use a 66mm crank and 130mm rods and a normal piston, you end up with a reciprocating assembly that protrudes 195mm from the centerline of the crank-- for a deck height of NEGATIVE 2.2mm.

I never read this anywhere!