Dave, is this the one you're after? **Opitec Hot Air Engine**

Andy

Edited By Andrew Holdaway on 05/12/2016 21:52:36

There are one or two modifications I would suggest. (1) instead of brass tube for the main crankshaft bearings I would use ball bearing races. (2) I'm strongly against using an aluminium piston in an aluminium cylinder. The cylinder could be bored out and a steel liner pushed in with some Loctite retainer, thread lock would do, and a cast iron piston.

Ian S C

I built one of these when I first had a lathe. I couldn't get it to run, and – at the time – couldn't find anyone on the web who had either.

Now I've learned a few tricks, I might have another go. Ian's suggestion to use ball bearings rather than a plain bearing would be a very good start. I don't remember my kit using an aluminium piston in an aluminium cylinder, but that's the sort of thing I wouldn't have noticed back then!

I don't want to waste time flogging a dead horse if the design and materials are flawed. Can anyone confirm they've got one of these engines to run?

Thanks,

Dave

Edited By SillyOldDuffer on 05/01/2017 12:38:47

Thanks Ian. I'll give it a go. I suspected the steel wool was wedging, and hadn't thought of a hollow displacer.

Cheers.

Dave