ameyam

There was definately some loss of compression percieved after changing the head, but that was only in the ear since the engine ran well and tuned fine (even inverted).

However, once through the cleaning, the engine did not do well for a long time. Finally after 2 weekends, it tuned well and ran stabilly. In fact on the day it went, it seemed to be working ok.

I have begun to feel that the engine was running too lean especially since the piston top is all black. I borrowed an 0.46 from my instructor standby as I used this oppurtunity to go to a low wing (Tiger40 on .55AX new). When I removed that engine this week, the piston was still bright. The head had externally burnt black varnish, that happens because the carburretor venturi keeps spitting out fine mist of fuel. To remove that, it has to be washed with methanol and he didnt want me to do that.

I am taking no chances with the new engine. Once I get a grip on tuning it (have not got a handle on that yet, earlier my instructor would do it), I am going to run it slightly rich (quarter turn back from the peak). Also exterior cleaning will be done once every three weeks and with methanol.

Ameyam