Hi all

Today I bought 2 flywheels halves at kempton park

I have searched previous posts about how to identify what they are, M20 or M21 but have come up with nothing

Part references for m21 I know of are;

66 634
66 636

The flywheels I bought are;

66 635

Can anyone identify these, they have different numbers to std M21 - but maybe this is a material difference, steel or cast iron etc

With many thanks

Jo'b

email (option): Jonnyob1@googlemail.com

Hi John...66-635 are the 'unified' steel forgings that were used for M20/21/33 and B33. They were simply machined for application to provide the correct crank throw (stroke)
An M21 has a stroke of 112mm, an M20 94mm and B33 and M33 both have a stroke of 88mm...
So if you measure from the centreline of the mainshaft to the centre of the crankpin hole you can determine which ones they are..(don't forget to halve the figures given above)....Ian

Aha !!

Thanks Ian

Jo'b

email (option): Jonnyob1@googlemail.com

Hi Ian

Took a chance they might be m21 but with measurements taken they are almost certainly M20

Hey ho :-)

Jo'b

email (option): Jonnyob1@googlemail.com

Hi John...Unfortunately the steel M21 flywheels are far less common than the steel M20/M33/B33 type or the cast iron M21 flywheels...So a gamble on them being for an M21 hasn't got very good odds.. ....Ian