Some of this is redundant and on another post so sorry if it’s long . My intention is not to build a “performance” engine but a larger, higher compression version of the stock engine. I want to go with the iron block for simplicity and to retain some form or originality. The extra weight is not that big of a deal. By using a 5.6 crankshaft and rods in a 4.5 engine one can increase the stroke from 85mm to 94.8mm bumping the displacement to 5041cc and also increase the compression ratio from 8.0 to about 9.5:1. The problem is there are no “stroker” pistons for this application. The piston tops need about 5mm taken off the top. Fortunately the K-jet engine has pistons with a 9mm dish so there is somewhere to take the material from.
Stock engine specs:
Bore=92mm
Stroke=85
Connecting rod bearing=52mm
Main bearing=64mm
Piston compression height=48.5mm
Block height=245mm
Rod length=154.55mm
Displacement=4520cc
K-jet combustion chamber=45cc
Piston dish about 30cc
Stroked engine specs:
Bore=92mm
Stroke=94.8mm
Connecting rod bearing=48mm
Main bearing=64mm
Compression height=43.55mm
Block height=245mm
Rod length=154.55mm
Displacement=5041cc
Piston dish cc
TBD after the valve pockets are cut
CR about 9.5 to 9.75:1
rod ratio=1.63 which is ideal.
Should be a really strong bottom end.
The lighter pistons(compared to the 5.6 ones) will require the engine to be rebalanced so everything from flywheel to front pulley is going in for balancing. I have not decided what camshafts I am going with yet. I plan on using a 5.6 intake and port matching it to the heads. I’m using megasquirt and EDIS ignition. To go further gets expensive(head work and custom cams) and I’m not going for all out performance but a decent power increase for not much more $ than a stock rebuild.
This is a major distraction from my restoration but the idea intrigued me and I went with it.