Hi,
New on here, although been lurking here as a guest for a while and been collecting engines for 25 years.
Just aquired a lovely original CS 3-1 from a farm in Norfolk, it will fire up, but I'm going to strip it right down as the insides are absolutely blocked solid with sludge and bits of debris, I'm just not happy I can get it cleaned out properly without stripping it.
Anyway, all coming apart easily, flywheels etc off but can't get the changeover valve out .
The outer plug cap came unscrewed easily, but the inner parts are jammed solid with carbon etc. I've tried the "compression" method several times, and I'm not brave enough to actually start the engine to try to blow it out. My plan maybe to let it soak a couple of weeks in something that softens carbon (diesel or redex maybe) and if that doesn't loosen it may try to rig up a steel plate over the combustion chamber with a 1/8 grease nipple and use a grease gun to hydraulically push the chambers out.
Can't get in with any heat without risking damaging the valve stem or spring.

Hate the thought of destroying something that's lasted 70 years and replacing it with some Indian rubbish parts.

Anyone any ideas for getting it out?