DPY 596cc connecting rod length?

[alex.helf]

I need to know the distance from the connecting rod big end center to the small end center from a DPY 596cc Scott engine. Can anybody tell me how long this distance is? It must be about 6,125 inch or so. Thank you, Alexander

[efr215]

A ball park figure, (Jap vernier), is 143.33mm (5.643″) centres. This taken directly from one of my engines rods, (DPY 5103). I have to admit that I have never seem this pile of junk running or even assembled so be warned! I do have several rods and when it cools down a bit I’ll measure them all accurately if you want.

[Roger Moss]

I admit that I have never seen a figure written down or quoted, but I measured a good sample of rods to check this figure.
The rods varied up to 0.015″ in length,but some of this is to be expected as, when you take out the big end and little end rings to renew them, then both ends are at least 0.002″ oval.
We can therefore assume that the average rod has stretched a little in service. When looking at old designs, it is most usual that the dimensions are prime Inperial sizes in 1/64th increments not Imperial metric.
My conclusion was that
LS rod ctrs 5.8125″ (147.64 mm)
SS rod ctrs 5.625″ (142.87 mm)
Having renewed new big end rings and fitted undersize little end rings, I set up each rod with its big end over a location piece and the boring head positioned at the distances given above. A dial indicator is used to check the alignment and that the bronze will clean up to the required size. Sometimes I might have to move a little, but not more than 0.005″ to do this. There is usually a considerable clearence between the piston and the cylinder head, unless other changes have been made.

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