Of course cylinder head temperature matters. If it didn't, then we wouldn't have to be concerned with engines overheating.

I have in front of me an engine review of the OS FF-240 4 cyl. 4S done some time ago by Clarence Lee. Clarence measured the cylinder head temperature under the glow plug of the front and rear cylinders on one side of this flat four with a thermocouple and pyrometer. Both cylinders measured the same at 280 F. This is, of course, a four stroke engine that needs to run hotter than a two stroke engine that fires every revolution. The temperature range of 180 to 240F supplied by Oakley seems reasonable.

A glow engine can run too cold as well. If the head temp. is not high enough, then the glow plug will go out. The old K&B 45 Sportster was an example of this extreme. The cylinder had too many fins and was overcooled. This in turn cooled the head and after prolonged idle, the engine would quit. Toward the end, K&B machined the fins off the head to increase the head temperature and keep the glow plug lit.

Bruce