Why is it bad to convert a gas engine to a stirling?

Discussion on Stirling or "hot air" engines (all types)
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eou_edu
Posts: 1
Joined: Sun Sep 23, 2012 11:03 am

Why is it bad to convert a gas engine to a stirling?

Post by eou_edu »

Sorry for the newbie question. I've read this forum for a few months now and this is my first post. Basically I have a lot of free time at work and I'm looking for my next project. I read on here converting a gas engine, AC compressor, or air compressor is a bad idea because "you make too many compromises." But now I want to know more. What kind of compromises do you make? To me making some compromises might be a good way to build the engine without a machines or abilities to manufacturer my own parts for a engine from scratch. So my question is, have people converted gas engines into Stirling before? If not what is the best way to convert and existing technology to a stirling engine? What does it take and how does it perform? I'm thinking a VW boxster style air cooled engine would be a good place to start. Now please tell me why this is a bad idea.
Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Why is it bad to convert a gas engine to a stirling?

Post by Ian S C »

eou_edu,One main reason is that IC engines, and compressors are far too heavily built, ie., the VW motor, don't know the hp, not great as engines go, but proberbly at least ten times the power of a stirling enginethe same size. Completely different pistons required (no rings, cast iron), a new crank case to get the 90* angle for the displacer to power piston, or the hot and cold pistons of an ALPHA motor, and a new lighter crankshaftwith the cranks altered to suit. Half the cylinders will require altering as hot cyliners. New cylinder heads. Yes use the VW cylinder barrels. If you want some power, you should consider pressurisation. You are going to need a machine shop, and welding, TIG for the stainless steel for the displacer, and its cylinder. Ian S C
Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Why is it bad to convert a gas engine to a stirling?

Post by Ian S C »

I recomend that if you can, try for a down load (free) of Andy Ross's book "Making Stirling Engines", this also confirms the unwise choice of trying to convert an IC engine, or a compressor to a Stirling Engine. Ian S C
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