Cranks and cases

[Allen507]

Hi,

I'm sure all you Greeves experts out there will be able answer my questions easy enough!!!

Are all Griffon cranks and crank cases the same?

I have two 380 QUB's and would like to get hold of a crank to keep as a spare. There is a 250 complete bottom end on ebay and wondered if it would be suitable.

Many Thanks,

Allen.

[Bearingman]

Hi,

I'm sure all you Greeves experts out there will be able answer my questions easy enough!!!

Are all Griffon cranks and crank cases the same?

I have two 380 QUB's and would like to get hold of a crank to keep as a spare. There is a 250 complete bottom end on ebay and wondered if it would be suitable.

Many Thanks,

Allen.

Cases are different between 250 and 380...later cases were cast differently for Motoplat as well, also Greeves changed out the timing side main shaft for Motoplat.

250 has big end pin location closer to center of flywheels...hence a shorter stroke for the 250 than your 380. They both take the same rod on the Griffon engines with the same wrist pin size.

Watch what you buy! Good luck! I hope that helps!

Kenny Sykes

[scott151]

Hi Allan

The 250 bottom end crank/crank cases are quite a lot smaller than the 380 versions.. So you can't interchange..

Regards

Scott

[druid]

cases and cranks

Something else to watch out for is that the early 380 cranks didn't have thrust washers either side of the rod. You can use them if you machine pockets for the thrust washers in the flywheels but the wheels are hardened.

Druid