so, we were playing on the dyno last week and apparently n/a motors with 18 psi like to run rich. leaning it out to 11.5 or so and we melted a piston. no problem, pulled everything apart slapped a new piston (read "old") and i called napa for a head gasket (thought i would give them a chance since they are cheaper and nissan usually don`t have them in stock.) so get it all back together and she runns alright. get on the dyno to set the boost and she starts pinging at ~ 4k rpm 16-17 psi. mind you i made 360 hp @ 17 psi before the "pop" and had been running like this for quite a while. so now i`m pinging at 16-17 psi and only can manage ~290 hp. hummmm....that`s a big hp loss.
compression check showed 175 in 1,3,5 and ~150-155 in 2,4,6. ok....leak down test in 2,4,6 shows 3-4%. i can live with that. am i loosing it here or is it possible for the napa gasket (looked identical to OEM) to be thicker or not crush the same amount and cause the lower compression on that side? the right side with 175 comp is a OEM gasket. yes i followed the torqueing procedure exactly. 290 hp is no where near as fun as 360...
suggestions?
compression check showed 175 in 1,3,5 and ~150-155 in 2,4,6. ok....leak down test in 2,4,6 shows 3-4%. i can live with that. am i loosing it here or is it possible for the napa gasket (looked identical to OEM) to be thicker or not crush the same amount and cause the lower compression on that side? the right side with 175 comp is a OEM gasket. yes i followed the torqueing procedure exactly. 290 hp is no where near as fun as 360...
suggestions?
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