I am working on pressing out a timing side shaft of a b33 flywheel and putting it into an m20 flywheel for my m23 build. Can I use roll pins instead of rivets?

The shafts are a fairly light press fit into the flywheels and the rivets serve to clamp the shaft flange to the face of the flywheel as well as to retain the shaft itself...

This is required to give the shafts pressed joint additional support and makes the assembly stiffer...

Making a correct job of the riveted joint is an awkward procedure to say the least...

I know that in Gold Star circles (for racing) the rivets are often replaced for that reason...
I haven't done it this way myself but I understand the flywheel rivet holes are tapped out (check the thread size and tapping drill size to be used) and then high tensile screws are fitted in place of the rivets, with some Loctite used on the threads...

It should be noted the timing side shaft of M20 flywheels can be machined down to fit an OHV engine (an additional turned spacer is also required) and that removes the need to swap shafts at all...Ian

email (option): ian@wright52.plus.com

I had a spacer made. Should I drill the shaft flange for a pass hole and tap the flywheel or press them together then tap both together and set the screw? It looks like I will have to counter sink the bolt heads some, as clearance to the con rod in minimal.

Adam

Most certainly drill the flange for a pass hole. Also countersink the flange. Cut the screws to protrude the flywheel by about 2 threads then peen them over.

email (option): pvlietstra at gmail.com