79mm nikasil liners compared to 76mm iron liners

Trevor let me take some measurements off of a T595 liner. I didn't have my camera with me so I can't post pics of it. The pictures below are from an old T300 liner I have had for ages. There are three important circumferential measurements: the depth of the spigot that fits into the top crankcase, and two distances across the upper portion of the liner. There are two of these because two sides of the upper surface are machined flat to allow the set of liners to fit side by side in the crankcases.

Spigot measurement; machined flats visible above

 I made a diagram to show how the liners compare. The nikasil liner for the T595 79mm piston looks very different from the iron liner pictured above. The ally casting includes vertical flutes in the upper portion, presumably to add strength and to aid in heat dissipation. The upper and lower circumferences are wider, as expected but not by a great deal. The lower spigot is 84.5mm compared to 82mm - so 2.5mm would have to be machined out of the upper crankcase for them to fit. However, the flats in the wider part of the casting make it effectively identical - 87.5mm compared to 87.2mm. In fact, that difference could just be down to my inexpert use of the vernier caliper.

Comparing dimensions of T300 iron and T500 nikasil cylinder liners

I also measured the distance across the top crankcase to make sure the wider nikasil liners would fit without having to thin down its walls - something I would worry about. It is 105mm so no problems there. I'll measure up the internal dimensions again when I manage to get the liners out of my 2001 Trophy 1200 engine.

These other pictures show the gunk around the iron liners in the 2001 motor. It appears to be an oily carbon paste. However, the bores look to be in very good condition. Most puzzling.