Deck height, compression ratio, and valve relief flat top pistons, In a 2.0 |
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Deck height, compression ratio, and valve relief flat top pistons, In a 2.0 |
emerygt350 |
Jul 13 2023, 11:41 AM
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#1
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Advanced Member Group: Members Posts: 2,144 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
Ok, my question of the day:
Put my new 96mm pistons and cylinders on and measured deck height, .033 all the way around. Let's say .032 to be conservative. I will not be running head gaskets. The calculator gives me 8.8 CR at .033 8.6 CR at .043 8.4 CR at .053 The pistons have a valve relief (pretty large) cut. I am shooting for 8.4 CR. Heads are in the shop so I can't check the CC yet. Everything I read says .04 - .06 for deck height. With the valve relief do I need to worry about going lower? If I had dishes would you measure from the edge of the piston or the dish? |
emerygt350 |
Jul 21 2023, 01:29 PM
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#2
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Advanced Member Group: Members Posts: 2,144 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
Did a real thorough job on the deck height today. Measured all the sleeves and tried to do some matching. I don't think it mattered much, it doesn't look like my case has ever been cut.
Bolted down nice and snug I got .028 .031 .023 .028 So I guess I am pretty much stuck with a .03 shim. When I get ready to put it back together I will see if swapping cylinder/piston combo on the .031 with the .023 makes any difference. Looks like around 8.3 for compression ratio, which is what AA said for the combo. |
Jack Standz |
Jul 21 2023, 11:24 PM
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#3
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Member Group: Members Posts: 281 Joined: 15-November 19 From: Happy Place (& surrounding area) Member No.: 23,644 Region Association: None |
Did a real thorough job on the deck height today. Measured all the sleeves and tried to do some matching. I don't think it mattered much, it doesn't look like my case has ever been cut. Bolted down nice and snug I got .028 .031 .023 .028 So I guess I am pretty much stuck with a .03 shim. When I get ready to put it back together I will see if swapping cylinder/piston combo on the .031 with the .023 makes any difference. Looks like around 8.3 for compression ratio, which is what AA said for the combo. Case hasn't been decked? In a perfect world, send to the shop and get it machined. That way, you won't have any regrets (or hopefully leaks) later. But, then how many of us live in a perfect world?? |
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