Hornsby 1919 Stationary Engine Information Needed

past experience with cylindrical ground pistons, albeit relatively recent ('60s), they tend to lock up in the bore when hot. present day pistons are cam ground, oval that is. i once bought an 'unfixable' engine and the cylindrical piston was the culprit. it took a lot of head scratching til i found the problem. they are usually larger at right angles to the wrist (gudgeon) pin. just a thought. sam mayberry

This might help:

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk

My 1916 Mechanical World Year Book states under the section on gas engines "1 thou per inch of cylinder bore, more or less according to the designer's personal experience". Cast iron piston of course.

I suppose it depends how much hotter the piston gets than the cylinder.

Steve

Are you any good with a file? Patience, care, a micrometer, a nice new file, some chalk and a couple of evenings draw filing the skirt oval could be the easiest answer. The marks left by the file would hold oil well and it is the rings that do the sealing after all.

I've lost count of the tight ali pistons I've saved over the years by this method.

regards,

Kim Siddorn

I must confess to having fettled a piston from a nice lump of sapele mahogany. OTOH, that was in Rhodesia during the sanctions era. The landrover concerned ran for several years until it had a final meeting with a baobab one dark night after a few too many geeantees. Baobab 1 Landrover 0. A nice piece of ash would probably be as good as the cheese^Wcheap alloy that they seem to cast pistons from nowadays.

My father was a mechanic in a car shop in the 1920's. One of his first jobs was to turn up an oak piston for the rear cylinder of a pre-war Douglas. It lasted a surprisingly long time with asbestos string for piston rings. The end grain charred quite quickly and thereafter stopped the wood below it from becoming burnt. Eventually, the compression went down & it stopped firing. The new owner had had it for six months by then & competed in various road trials.

He was quite amazed, poor chap!

I had a wooden engine and it wouldn't go...

But I did come into possesion of a big chunk of ironwood and after it destroyed my table saw, and a few chisels I always wondered about it's potential...

However, my grandfather swore by wooden pistons. Top covered by tin, screwed no nailed, to help avoid erosion. Although I've never seen one and think it's an "urban legend". Mind you, in his time engines were very lightly stressed... There were a few other stories...

Jees, I think I missed something here. Do 1919 Hornsby engines have wooden pistons ?

If you want to discuss making engine parts out of wood, why not start your own thread ? If you are suggesting John would be better off making a piston out of wood to restore a 1919 Hornsby engine, then you are barking mad.

Steve