58mm or 60mm Crank???

[inch71]

Hi

I'm gonna be fitting a new Mugello 198 kit to my Series 2 LI 150 over the winter. Whilst doing this, I shall be upgrading the crank to a MEC EUR. I'm not 100% what sort of crank is in there at the moment until I strip it down. I'm assuming it's probably a GP 200 crank, due to it having electronic ignition. I asked the lad I bought it off, but all he knows is that he had someone fit a new crank for him years ago after the old one twisted.
Anyway, my main question is, what would be the better stroke to fit?
Either stick with a 58mm, or go for the few extra CC's, & fit a 60mm. This will be fitted into a small block, so would the casing need to be machined to make the 60mm fit ok, or will it fit straight in without any messing around?
If anyone has any experience of fitting/using the 60mm, I would appreciate any feedback on how easy/difficult or any problems you came across

Cheers

Lee

[Solid Air]

Recently fitted a Mazzucchelli 60mm to my 185cc iron barrel. It was a straight swap for the 58mm... no messing around and takes it up to 192cc

Good luck

Mark

[bazza3004]

hi I fitted mec 60 mil crank to my indian small block a while back and had to grind a a little out of the casing as the big end fouled slightly. you may also need to trim 1-1.5 mm from your piston skirt due to the extra 1mm downward stroke otherwise it may foul the casing at bdc.

[Fat Trucker]

Same as above, mec 60mm in small block had to grind a little off casing where the big end part of the con rod protrudes out of the crank web. I used a flap wheel on inside of crank case and was very easy job to do. Also needed piston skirt cutting slightly to stop it hitting crankcase at bdc.

[neil64]

hello.

looking at all the above ,dont forget 2mm packing plate to lift up yer cylinder to keep yer port timings the same.
thinking of doing the same when mine goes.

[MickYork]

hello.

looking at all the above ,dont forget 2mm packing plate to lift up yer cylinder to keep yer port timings the same.
thinking of doing the same when mine goes.

Would'nt that be a 1mm packer on the 60mm ?

[stonerosesmod]

Any pics of the modified crankcases where they have been ground? I also have a mugello 198 and was considering going up to a 60mm crank.
Is there a noticable difference over a 58mm crank then?

[soullad]

hello.

looking at all the above ,dont forget 2mm packing plate to lift up yer cylinder to keep yer port timings the same.
thinking of doing the same when mine goes.

Would'nt that be a 1mm packer on the 60mm ?

Yep, everything else excepted.

For those thinking of fitting a 60 mm crank, I'd also be thinking about what length conrod too ? Then you may or may not need a packer depending on rod length / piston choice / desired tune and so on. Your engine is quite literally the sum of its parts, and performs best when everything is working in harmony.

[neil64]

yep , corrected 1mm keep things simple same rod length ?

[inch71]

Thanks for all the comments guys.
As above, if anyone has got any pics of the grinding work done, just so we can see exactly where it needs to be done, then that would be great

Cheers