So Alfa engines should rev higher than GM unit due to being over-square and short stroke. The 3.2 unit is even shorter stroke so could rev even higher that 3.0 as piston speeds will be lower?3.2 has longer stroke and shorter rods, so that the pistons dont hit the heads. Engine block is the same.
3.0 - bore 93.00mm x stroke 72.60mm
3.2 - bore 93.00mm x stroke 78.00mm
3.2 has different inlet cams
All in all 3.2 is a little more torquey engine and powerfull ofcourse.
GM based engine is totaly different: bore × stroke 87.50mm × 88.00mm
Changing rod length does not change stroke or capacity.Nice picture Alan, thanks. Did not realise 3.2 had different crank, I thought capacity increase was just the shorter conrods giving less stroke, therefore more combustion volume. Guess I was being too simplistic, although is does seems expensive to add new crank for 200 cc.
Thanks DavidCChanging rod length does not change stroke or capacity.
Engine capacity is the swept volume of the piston, not the size of the combustion chamber.
To change from 3.0 to 3.2 would mean new: crank, rods, pistons+liners.
There is no point doing it as an upgrade, going to 3.5 would probably cost less as it still uses the 3.0 crank.
wow alan ..a flashback to 5th year at high school over 40 years ago.:wow:3.0 revs the most
3.2 piston speed is bigger and that can be an issue, and also the angle of the rod when the crank is on quarter of rotation is bigger because rod is shorter and the crank has bigger stroke (not good and puts much more stress on components)
Sketch made in paint for understanding: