Is the 064 crankcase interchangeable with an 066 crankcase

[zgzmithr]

As the title states I have an 064 that needs a PTO side crankcase half, while I can find an OEM crankcase half, the 066 crankcase is newer and more readily available.
So the question is, can I replace the entire case with an 066 case, and everything else bolt up correctly from the 064?
Or better yet will just the 066 PTO side and 064 flywheel side work together

 

[jacob j.]

The 066 uses a different oil pump, so whether you use the PTO side case half or a whole case, you would need the 066 oil pump.

Also, the bolt spacing for the 066 cylinder is different from the 064 cylinder, so you would run into issues if trying to bolt an 064
cylinder to an 066 case (or PTO side case half). I'm not sure if there's enough meat on the 064 cylinder base to slot the holes
outward to fit an 066 case.

Also, some of the early 064 cases had different ignition mounts so if you plan on using an 066 case, you would need to make sure
you have a compatible ignition (and flywheel if your 064 uses the rev-limited ignition).

 

[zgzmithr]

Thank you so much

 

[Sauen]

Additionally, the later 066 and 660 had a longer case, so those do not line up with the 064 nor early 066 cases

 

[drf256]

Find an 064 crankcase in the trading post here.

There are quite a bit of subtle differences like JJ said. M6 vs M5 cylinder bolts in multiple areas, starter cover, coil mounting bosses, etc…

Also, you’d have to find the rarer 066 short case. The cranks and seals are different between the early 066/64 cases and the later cases. You could find yourself in a position where no seal exists. I can’t recall the exact combo, but I think that the 064 crank in the later 066/660 long case will have an ID/OD PTO side seal area for which nothing exists.

Not as much, but it’s the same shít with an 034/034S/036/360. Minor differences in them, then you get it 90% together and realize stuff doesn’t fit.

I think I have an 064 case “somewhere”.