Ericshere03 Posted February 12, 2007 Share Posted February 12, 2007 I plan on Purchasing a set of custom JE Pistons for my turbo project, i have the Quenched P90a (hydrolic, but irrelivent) and was planning on these specs: 88mm 21mm wrist pin 33.350 pin heigth (will be even with block) and a -10cc D shaped dome (dome under spark plug) 1mm Head gasket (HKS Metal i guess) This would yield a 8.230:1 compression ratio (1MM Head Gasket), and will be even with the block deck, while this sound ok on paper, is this ideal to take full advantage of the quench design of the p90 head? i worry that if all of the inital combustion takes place on half of my piston that it will cause my piston to want to rotate on the wrist pin and cause unnecesary stress on my piston skirts. Do i have to worry about valve reliefs, i will run a stock cam, maybe upgrade to a MSA unit (i dont know what affect that would have, in the case of an NA i do). Why can we just keep cars stock ? Thanks, and i did search () Eric Wolf Quote Link to comment Share on other sites More sharing options...
510six Posted February 12, 2007 Share Posted February 12, 2007 I would make sure that valve relifes are machined in the pistons.You might decide you would like to run a large turbo cam at a later date.For my turbo motors WEB is the cam maker that I have used and have been very happy with. http://www.webcamshafts.com/ Quote Link to comment Share on other sites More sharing options...
1 fast z Posted February 12, 2007 Share Posted February 12, 2007 You want to run about .025" piston to head clearence, for maximum quench. WIth your current setup you are at .040" and that extra .015" actually makes a difference in detonation resistance and power. So you need to pop those pistons out of the bore .015". Thats the setup I have been running for a couple years now. As far as valve relifes I dont think youll need them. You should NOT put them if you dont need them, PLUS your dish will be in the valve relife area anyways. I run over .500 lift 280 duration cam and still have .120" clearence on the intake and .220" on the exhuast piston to valve clearence with a flat top piston. Technically you should get your pistons to have a PERFECT mirror image of YOUR p90 head for maximum quench. This is done by assembling your engine for mockup, and inserting each piston in one at a time and then put your head on, and "bump" each piston to the head with prussian blue on it then scribe your combustion chamber and mill out ONLY that area and NEVER go outside that line, THEN you will have the MAXIMUM quench you can optain. Most people skip this step and mess up, P90 heads are worthless without all of these steps. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 12, 2007 Share Posted February 12, 2007 1fastz, I assume you're talking about if you have to cut into the piston? Would a flat top piston would have better quench characteristics than anything with a dish? Dave Quote Link to comment Share on other sites More sharing options...
Ericshere03 Posted February 14, 2007 Author Share Posted February 14, 2007 now does anyone know where to get cheep JE pistons? It frusterates me that i can get a set for 550 for a buick V6 but for an L6 they are 750.....WTF!!!! i wonder if i should have some "Buick" pistons custom made for my Z....lol. i guess i am being cheep, ill probably suck it up and buy from RaceTEP, BUT id anyone knows where to find them cheeper LET ME KNOW!!! Thanks to all, Eric Wolf Quote Link to comment Share on other sites More sharing options...
PETEW Posted February 17, 2007 Share Posted February 17, 2007 JE for our cars are not cheap, no matter where you go. If you order through Summit, you can get Wiseco or Ross, for a much better price. There are a bunch of people on this forum using both pistons with good success. Hope this helps. P.S. Does anyone know what the deck height of the ZXT block. I have heard 207.85, 207.87, and 207.95. Not big differences but I would like to know which is correct. Also anyone know the ring radial thickness of Total Seal rings? I can't get a hold of them and need this to order my pistons. Thanks. Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted February 17, 2007 Share Posted February 17, 2007 Also something to think about is metal head gasket availability. I just had to replace mine and the only one that I could purchase was the 2mm metal head gasket. From what I have been told the 1mm is no longer being made so this may change your plans. Just a thought. HB280ZT Quote Link to comment Share on other sites More sharing options...
Ericshere03 Posted February 22, 2007 Author Share Posted February 22, 2007 Also something to think about is metal head gasket availability. I just had to replace mine and the only one that I could purchase was the 2mm metal head gasket. From what I have been told the 1mm is no longer being made so this may change your plans. Just a thought. HB280ZT That sucks..... ill keep that in mind, maybe i can revove some of the layers of the 2mm HG to make it 1mm, from the looks of it a 2mm is just 2 1mm stacked, or use a felpro at 1.25 and tack it down using a can of copper spray. Thanks for the tip, Eric Wolf Quote Link to comment Share on other sites More sharing options...
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