Jab31169 Posted December 3, 2018 Report Share Posted December 3, 2018 So our team has had poor luck with motors recently, so we decided to build one from the ground up. Well we had two blocks, one block #3 was egg shaped, and the other block was out of spec and needed a decently sized overbore that IMO, would cost us points. At this point, we were running out of time, so we decided to just drop one of the fresh heads on a motor that just recently blew the headgasket 1 lap in to a HPDE. This was the motor that we put in at VIR and ran for 12 hours without issue, also did a club race school. We knew the motor had an external water leak, just didnt know from where until the next HPDE after the race school. We pulled the motor and it sat for a month or so before we decided to just do the head gasket on it. Anyways, we put the head on, get it back in the car pretty quick. First start, fires right up but you can tell its got a decent miss. So we pull out the compression tester...zero compression on cylinder 2. This motor was a runner, never felt down on power and when we took a look at the cylinders before we put the head on, no gouges or anything...all looked great. So this kinda stumped us. Put some oil in the cylinders and that got us about 15-20psi on the dead cylinder. So we decide to just let the car warm up and run for a bit and see what it does. So we let it get up to temp, cool off a bit and just like that...150psi on cylinder 2. My only guess is a stuck ring? I had seen some stuff about putting seafoam/b12 down in the cylinders to free up stuck rings but we never got that far. Has anyone ever had this happen before? We drove the car sunday, feels good, smooth as butter. Quote Link to comment Share on other sites More sharing options...
Team Infiniti Posted December 3, 2018 Report Share Posted December 3, 2018 If it has compression now it's fine. Could have been stuck rings or debris/a little rough machining in the exhaust valve of that cyl. 1 Quote Link to comment Share on other sites More sharing options...
Ian Posted December 3, 2018 Report Share Posted December 3, 2018 Our spare did this when we stuffed it in trackside at BIR. Ran like butt, and puked oil into the catch can till we gave it a good old Italian Tune Up. Now its fine. 1 1 Quote Link to comment Share on other sites More sharing options...
Jab31169 Posted December 3, 2018 Author Report Share Posted December 3, 2018 Thanks guys! We were a bit perplexed by it but these explanations make total sense thinking about it. Quote Link to comment Share on other sites More sharing options...
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