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Having built up a bottom-end using some old 500 crankcases I had kicking around, I discovered with a foul oath that although the stud-spacing is fine, the liners of the 501 barrel/top-end i intended using, wont fit into the crankcase mouths. I never even imagined this would be an issue, and dont recall it arising in conversation in 30 years of Morini ownership

Steve of Piston Broke engineering -who're mentioned on this forum from time to time- has finally admitted defeat after having them for 2 months

Any thoughts welcomed; just dont tell me to machine the liners down, they won't stand it....

Hello,

You should have searched the forum. A quick search of 501 barrels would have got you to 'More barrel questions' thread from 2010.

Mike.

There was I searching for "500 crankcase(s)" to no avail....

Computers are too literal...

2mm makes all the difference, apparently!

The 501 is a wider bore. The 478 has iron liners, the 501 Nikasil coating. Amazing that what we think of as little development was not true. I wonder if the later, nikasil, 350 barrels fit the earlier cases?

Simon, see my e-mail to you, I have alluded to you how to do it and if stuck will do it for you, as I fitted the bigger barrels to 500 crank cases very simply. The liners are not aluminium on the bigger barrels but simply coated iron ones pressed in.

Cheers Harry...am getting the cases and barrels back today hopefully. WIll be in touch

The barrel spigot is obviously weaker in Aluminiun than it is in Iron, so with the larger bore too, Morini played things safe and beefed them up.

From reading old ATGs, people used to skim the barrel spigots down to fit them onto 500 crankcases.

I may have to solve the opposite problem, fitting 500 barrels onto 501 cases for a class limit. I can shrink some Aluminium rings on, then skim them down. I have expanding mandrels just for such jobs.