064 to 066 conversion?

[thompson1600]

I bought what was represented to be an 066, but when I took it apart I am finding out that it is really an 064. The bottom end is really good and I want to rebuild it, but I have an 066 piston & cylinder kit for it. To convert an 064 bottom end, with an 066 top end what is necessary?

I have the original flywheel and ignition, original flywheel #1122 400 1201. The ignition module does not have a part number I can find, but has Bosch 2 204 222 on the flat face (so I am thinking it is a Bosch E1-V?) I also have a polymer flywheel I can put on that is part number 1122 400 1217. Would I be better off using the polymer flywheel and just getting a newer standard ignition module?

The carb is a Walbro WJ51. Will that have to be upgraded?

The serial number on the saw case is an older number X 18 680 177.

Thanks for your help.

Tom

 

[klickitatsacket]

Hey Tom. Lost my modem last night. get a chance give me a call about this thread that or I will IM you tonight.

 

[Jacob J.]

Tom- your polymer flywheel is not compatible with that bottom end, the crankshaft diameter is different for the polymer flywheel. Your ignition module is part # 1122 400 1300, and it is only compatible with the 1122 400 1201 flywheel and no others ( unless you modify the timing ).

To put an 066 top end on an 064 case is a lot of work. You have to modify the base mounting area on the 066 cylinder because the mounts for an 064 cylinder are narrower at all four corners and they use a smaller mounting screw. You will have to grind the 066 cylinder mounting holes inward diagonally and then fill the gap with an anaerobic sealant after having had mounted the cylinder. It's a lot of work. Plus, if it is an early 064 then you'll have to modify the 066 piston otherwise the saw will vibrate so badly it will not idle. Your carburetor is fine as is, in fact it's a desirable carburetor.