Hi All
Over the last 6 weeks I've got my plane to the airport, assembled & running. Now wouldn't it be great if it was just that easy.
Firstly I found when trying to start the engine, it didn't want to start, everything made right noises but 0 fuel, I mean absolutely no fuel would flow through any of the injectors, which annoyed me as they only had about 10 min running time from a couple of years ago. Got them cleaned & all good.
Almost every day since I've been trying to tune this thing. Seems easy enough after re reading Tracy's manuals a couple more times, in practice has been a bit of a pain, at each start it seems previous fuel map settings were wrong, today I think I may have found the issue.
Fuel could be pooling in the intake runners at low rpm then creating a rich situation as it is consumed. My intake runners are fairly short at about 12", from the flange they are angled down about 1 dia then turn up into the bottom of the plenum extending to the top. I thought this would be ok as at flight rpm should be enough airflow to keep the fuel moving, just to get to flight rpm!
Have managed some high rpm runs after tying the plane down, get to about 7200rpm before oil temp and blistering paint on the cowl stops play pretty quick. Seems to happen too quick to write down all temps & pressures but coolant seems to max out at about 180 oil just keeps climbing at anything more than about 4000 rpm but can get it below 200 after idling.
So me thinks, need to set higher minimum pitch on prop, maybe a oil to coolant heat exchanger, maybe something similar to what Tracy done early on, in the oil pan on his rv4. Some heat shielding on cowl, Then wait until all pooled fuel is gone each time before trying to tune.
Engine is a 4 port Renesis, heat exchangers are against the firewall with cool air ducted from just under the spinner, under the motor then up the firewall. hot air exits on top front of cowl. Other than the oil temp seems to work quite well, heat exchangers share air but coolant one might be getting more than it should.
Fun times.
Andrew