Is Mach 1 piston same as Mark 3?

[Settio]

Hi
I need a 75mm piston for my Mach 1.
I have just found a Mark 3 widecase piston at a good price, I believe they one and the same, but am hoping for confirmation from those with greater knowledge.
Attached is a dimensioned drawing of the Mark 3 item.
Thanks in advance, Richard

[Bevel bob]

The Mach 1 and Narrowcase Mark3 both used the Borgo forged piston with the raised ridge in the center. Nominally 10 to1 CR but probably more like 9 to one . I suspect the Widecase piston would be similar , but cant be sure.

[Duccout]

I think, from what it says on the Lacey web site, that their wide case piston gives a lower compression in a narrow case engine; but I am not sure.


Colin

[Bevel bob]

The pictured piston is definately different to an orriginal M1 Borgo. But may be perfectly suitable . checks need to be made for squish and valve clearance .

[Eldert]

Hi Richard

piston looks the same . could be a Wössner piston drawing

keep in mind they use a odd size piston rings . if you need a replacement you have a hard time finding them .

Eldert