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? |
rfinegan |
Jul 13 2023, 03:25 PM
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#2
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Senior Member Group: Members Posts: 973 Joined: 8-February 13 From: NC Member No.: 15,499 Region Association: MidAtlantic Region |
A tip on piston to valve clearance.
The closest relationship is not TDC for the pistons to valve, but about 10 degrees before top center(piston chases the exhaust valve as it closes) And about 10 degrees after Top Center (valve chases the piston as it opens. I think I got that right... EZ to test Place play doe /clay in the piston relief and tighten head. Rotate the assembly minimum of 2 complete turns to have the valve compress the play doe. Remove the heads and measure the thinnest location on the play doe and that will be your piston to valve clearance. 0.080 exhaust 0.120 intake (I will check this in my notes) Memory only for now |
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