I have been studying the Listeroids and Changfas now for some time with hopes to obtain an engine or two as meager finances allow.  Being on a tight budget has got me thinking about purchasing a way over sized Changfa rated at say 20 HP @2200 RPM (like a 1115) and using it at perhaps 1/3rd of that speed where I guess the available HP may be around 25% or 5-6 HP.  That could power a 2-3 kW head.  This engine is close to the displacement of a Listeroid (around 1.2 vs 1.4 litres displacement).  If the Listeroid was capable of safe operation and efficient breathing to support 2200 RPM, it would put out 25 HP too.

The only worry I have without having a priori experience with Changfas is guessing that the flywheel supplied is going to be insufficient to carry the load smoothly at such low RPM, or even the engine ticking over smothly.  In my case the load would be a small gen head like an ST rated at 2-3 kW and 1800 RPM driven by a betl system.  I was thinking of putting a speed rated flytwheel on the high speed generator shaft.

The benefits of a heavy flywheel have been dramatically demonstrated to me while working with a DIY 1.5 litre VW diesel genset directly driving an ST type head at 1800 RPM where the factory flywheel at this low speed is no more than a carrier for the starter ring gear. Pulsations in the AC power due to fraction of a turn velocity modulation of the rotational speed, and attendant flickering of lights can be seen if one injector of four is not quite firing smoothly.  On the other hand, the truly massive flywheel on my one cylinder Petter (yeah, I scored a real one) can carry a rated electrical load even if the engine is shut off for a few seconds by slamming the fuel rack shut.  The power from this puppy is smooth, and the reserve for starting overloads is huge.

Seems to me that by operating a Cangfa at 1/3rd to 1/2 rated speed and lightly loading it would greatly extend the service life of such an engine, providing that it was thermostatically controlled and was processing enough fuel to stay at operating temperature and not run cold.

I'd be interested in any comments on this idea.  I have seen some of the discussion dissing the Changfa as a short lived engine.  It looks heavy to me.  If you completely blueprinted and balanced a Lister CS to be safe at 2200 RPM it wouldn't last as long as a Changfa I'd wager!

I am excited to have just discovered this forum and think it is right on topic for issues I am now dealing with in a serious way as I try to deveolp energy systems on my rural estate to assist in energy efficiency, self dependance and survival.