Just as a side drift here (mods/nazis will shoot me no doubt) I was chatting to an owner of an experimental thingy today (can't think of it's name, low wing all metal & no not an RV anything) that had one of those toy 6 cyl engines in it from Bundaberg, 3.3 ltr? Anyway he's had this thing since new about 3 yrs & has had no end of trouble with it. Heating probs & mixture probs. Changed the oil cooler to a decent one, modified the cowl, cowl exit holes area etc. He's no amature by the sounds of things (mature chap owned many planes) Sounds like the 6 cyl is a troubled engine, any comments to support same 4 or 6? Now I know why I'd stick to the spam cans, old, dated, slow but RELIABLE!
CW