Gamma engine dimensions

[GG]

Does anyone know the cylinder spacing on the Gamma motor? Could be measured from spark plugs, or on the block, needed only on one side (cyl 1-3 or 2-4). I've come across a 1970 Lancia engine drawing for a 2 liter flat four from De Virgilio, and wondered if it might have any relevance to the Gamma motor, which was thought to be designed by Zaccone Mina.

Any help would be appreciated! Thanks!

Geoff

[Charles]

Measuring from a cylinder head gasket from a 2500cc motor, I get 36mm between bores.  The bore of each cylinder is 102mm so the distance between the centres of the cylinders is 138mm.  I don't have a gasket for a 2000cc motor but assuming that the crankcase overall dimensions are the same as for the 2500cc motor (which I think they are), the distance between the cylinders must be 46.5mm as the book tells us that the bore of that motor is 91.5mm.

[GG]

Charles -

Thanks for this. De Virgilio did two drawings for a flat four in 1970 - one with shared conrod journals, and 110 mm from cylinder centerlines (1 to 3 or 2 to 4), the other for a crank with four conrod journals  and 130 mm between the cylinder center lines. The larger one shows 48 mm from cyl 1 to 2 and then 82 from cyl 2 to 3, giving 130 mm overall from CL of 1 to CL of 3. Interesting, but certainly not conclusive. Now all we need are Zaccone's drawings.... which have not been seen yet!

Is the firing order on a Gamma 1,3,2,4?

Geoff

[Charles]

Yes; first 1 and 3 on the left hand side and then on the next engine revolution - 2 and 4 on the right hand side - not what you might expect.