When I have the money and the resources I will be running a 12:5:1 ratio....to keep it from piston slapping like a pimp to his 2 dollar whore. I will raise the deck lid....ballpark what kind of cost will this run me?
Performance: Stuff that makes my car run better or go faster
Looks: Stock because looks doesnt make my car go faster or run better
Weight Reduction: CF Hood, No A/C or Powersteering Accessories, No rear interior
#113994, "RE: Raising the deck lid" In response to Reply # 0
To my knowledge this isn't needed. I thought the 12.5:1 C.R. pistons were made not to slap on stock head with stock gasket. If you start milling the head then maybe... but I thought they'd run fine. Where did you hear that they wouldn't?
#113998, "RE: Raising the deck lid" In response to Reply # 4
then if you want to buy everything yourself you have to do the figures on custom pistons so they will work without hitting the head and with deep enough pockets for .500 inches of valve lift. They have already done this for you. Either way there are a few companies that carry pistons for the 420A in high compression, they should have done some research so any of the 420A pistons should be fine.
#114000, "RE: Raising the deck lid" In response to Reply # 6
I had je 12.5:1 pistons in my sebring long time ago. Without thicker head gasket (or raising the deck) i was putting ~15:1 compression. It WILL work but i wouldnt recommend....
Oh those were the fun days.
_________________ Vinnie Lima vinnie.lima@jvllogistics.com AIM: Kiku888 1997 Chrysler Sebring "Silver XTC" I4 420a w/ HRC Stage 2.45 w/ FMIC 14.7@97 mph@6psi Proud member of the ASOG BoOsT JuNkIe Crew
#114001, "RE: Raising the deck lid" In response to Reply # 7
Didn't you have a milled head also Vinny?
If you have the head ported and polished then that is going to lower the overall compression ratio since material is removed from the head so there is more airspace in the combusion chamber at that point so that may be something that you want to have done before 12.5:1 pistons are put in.
#114002, "RE: Raising the deck lid" In response to Reply # 7
Hey Vinnie, who did the calculations on the compression ratio for you on the head? I had the machine show I'm using clean up and get the head ready with a minimal mill and they checked it giving me an estimate of .015" milled off. I thought you had more taken off than that.
Kyle, do you remember the volume in a stock cylinder head?
#114003, "RE: Raising the deck lid" In response to Reply # 9
If my calculations are correct,
1996cc engine divided bt 4, 1 cylinder is 499cc divided by 9.6 (compression ratio) and you have 51.99cc for the combustion chamber. Other than that, I am not 100%.
Someone needs to cc the head to see how much volume there is up to the HG. and then we'd know what the head has volume wise and what the block has volume wise with the piston at TDC.
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