Thanks to everyone for the advice, looks like im worrying about something thats normal!!!

Very interesting to read all the info, I dont have any high performance glow engines like the Nelson, all the 2 stroke engines I own have brass sleeves, certainly the MDS and Irvines, I also think the TT pro engine I have is brass sleeved too?

I guess I'm a good bit behind the times on whats good in a glow, Im going to stop worrying about it now and just fly them!

Regards Angus