Piston Planning

[CTX-SLPR]

Since I am getting custom pistons anyway I was wondering if anyone know the best way in terms of durability, power, detonation resistance,... ect to get a certain compression ratio on our engines? The details, I will be using 8445 heads, stock rods and some form of Cometic gasket. Is it better to:

A: go zero deck and run a thin gasket and a big dish
B: go zero deck and run a thick gasket and shallow dish
C: stay .030" down and run a thin gasket and a big dish
D: stay .030" down and run a tick gasket and shallow dish
E: Some combination of the above
?

I will be getting custom Diamond pistons made for my 4.1 and I'm currently looking for about 8.3:1 compression since I will be running lower boost and want to make low rpm power to cut down on engine loading due to high rpm power. Any suggestions, modifications, or general refferals to a psych ward with a nice shop are appreciated

Thanks,

 

[gofstbuick]

I'll take a stab at this. IMHO, you want a zero deck. I suspect you'll encounter more detonation if you go 0.030 down. Possible hot spot from the edge of the block. If your trying to affect compression, you can accomplish that with HG thickness, valve seat height and/or head pocket work.

 

[CTX-SLPR]

Stock GN pistons I've read are .030 in the hole, I agree that you want as much squish as possible so I'm thinking moderate gasket and moderate dish. Something I just thought of is what about adding a thermal barrier to the pistons, would that require me to dump more compression due to the retained heat or just make the pistons more durable? I'm trying to get this figured out so I can order my Diamonds on Monday.

Thanks,

 

[gofstbuick]

I'm using Sealed Power hypers and putting a new engine together. I'll verify the deck height Friday or this weekend. I was under the impression that I was at zero deck height. If you cantact Nick Micale, he can answer most of your piston questions. I have some valve changes, and the new valves have no dish in them at all, so it will be interesting to see what happens to performance. The stock valves are dished, so I know the valve changes will affect compression.

 

[Nick Micale]

We do not go zero deck. If you blow a head gasket or somethng else, you may need to clean the deck a few thou.

 

[xlr8ngn]

If you are getting custom pistons, why not go with longer rods and make more power. It is not a problem to fit 6.5" rods. You can run chevy tool steel floating pins to lighten the mass. The only bad thing about longer rods is the detonation is more severe.

 

[CTX-SLPR]

The long rods are out of my reach and out of my power making range. I bought the Eagle crank because I couldn't afford the wide journal rods I need to make the $600 BMS crank work. This engine is going to have enough strikes against it as it is for weak points, I don't need to add something that will increase the severity of the inevitable detonation and crack the webs since the crank probably won't let go.
Right now I need to know what compression ratio I should be running and how I should go about using pistons and gaskets to do this. I am also wondering what worth the thermal barrier coatings is and thier effect on compression ratio.

Thanks,