Post by eticket on Aug 13, 2015 15:07:44 GMT -6
Don't know how to post pictures, but during the 3rd dyno pull there was a big poof of blueish smoke. Thought I saw some on the pull before but not sure. The hp on the 3 pulls was about 100 down from 2 years ago with air conditions being better now vs last time. This is what was found. Pulled heads and #4 has the top edge of the piston melted down and you can see the top ring. What would cause this? Pistons have a thermo coating, egt's never went over 1100 and at the time of the poof this cylinder was only 1045. Nozzle did have a little goo in it but not completely closed, fuel pressure @ 7200 was 125 and at no time during the 3 pulls did the egt's go over 1100. what am I missing. It seems to me like a case of extreme lean out but why didn't the egt's reflect it. Also there was no metal on the insulator of the plug but it was gray. The other 7 pistons don't even look like they had been run. I had a clogged injector on the old 565 and the egt's went over 2000 but with the coating the lean condition didn't even bother the piston. So what went wrong or was different this time? Coating? Bad egt readings? Extreme lean condition? or something else we / I am missing.