RE: How do you identify a genuine Mills P-75 Diesel?
Dan your engine certainly looks a genuine Mills to me-BUT your front end is a bit suspect. The spinner nut looks too big, the prop washer too shiny and the prop driver is not right. The Mills 75 has a simple knurled face, flat disc prop driver with a truncated circle centre hole that matches the two flats on the crankshaft-yours seems to have a centre boss as well-which would be right for the 1.3 but not the 75. Either that or the spinner nut has a shank on it-a la ED Hunter-which is also incorrect for a Mills.
A genuine Mills should have the black crankcase (fairly dull, not glossy like the late model Indian ones) as a result of the chromate bath used to protect the magnesium crankcase alloy, a similar cast, treated backplate with two internal webs for a spanner to locate on for screwing in (most of the replicas have the more common diametrically opposed slots in the rim), no webs on the crankcase bearing housing, and sharp corners (no bevel) on the mounting lugs, plus serial numbersd stamped on the top surface of the mounting lugs-normally 2 digits on one and 3 digits on the other. Tank is a fairly thick perspex moulding which often crazes with age, and is retained by a couple of small tabs on the tank top bent over the rim of the tank.
Early Indians are grey, and have 'India' stamped in the centre of the backplate, a sharper tapered tank, and no stop pin hole in the head. Later ones have a black crankcase-which has a painted rather than treated look. Doonsides have 'made in Australia' and "Taipan' stamped on the backplate, plus a fully machined carb and tank top, a nylon tank retained with an internal circlip in the tank top, and a fairly heavy duty spring with properly ground ends, on the needle valve. The Mk2 Doonsides have webs on the case and a plain silvery crankcase, with anodised heads in a multitude of colours. The Russian-made Doonsides (effectively a Mk3-though they were never designated as such!) had a 3mm replaceable prop shaft stud-with a splined on prop driver-some were ABC cylinder technology as well.
Irvines had a serial number on the edge of the mounting lug, a taper mount prop driver and thicker shaft, and a male threaded tank which screwed into the female threaded tank top. The very last ones had a single ball race.
The exceptionally rare NZ made HPE Mills 75 replicas (there were only about 10 completed) had the tank top , needle valve block and venturi as a single unit casting, not separate machined components.
The first model Boddington Mills 75 looks quite a bit different from the Mills, so cannot be confused-the second model is a much closer replica, but I do not have one, so can't describe its key differences
'ffkiwi'