I an I'n process of building 2.1 with 4g64 block. I have few question of any one can help me will the 4g63 head bolt right up with no modification to the head as having combustion area machined? One more question I'm using 156mm rod Is there any company that sells 10:5:1 compression pistons for this setup with out geting custom thanks

 

Bump

 

Yes you can bolt the head up without having the combustion chambers machined, however your compression ratio will not be 10.5:1 anymore...

Manley makes the piston in question...

606215C-4 86.5mm Bore, 156rod, 88mm Stroke, 1.375" Comp. Distance, -2.5 Dome Volume, 47 / 43 Cylinder Head CC, 10.5 Compression Ratio, Flat Top design, 352 Grams

606220C-4 87mm Bore, 156rod, 88mm Stroke, 1.375" Comp. Distance, -2.5 Dome Volume, 47 / 43 Cylinder Head CC, 10.5 Compression Ratio, Flat Top design, 360 Grams

 

If I brought manley pistons with 10:5:1 leaving the chamber not machined my compression will be higher ? Thanks man

 

Correct, a tad higher

 

Leaving it like that I'm gunna be running e85 either way... But leaving the chamber can that cause detonation only reason I ask it because I seen threats saying people have issues when they leave it thanks again man

 

this is NOT based on experience, but more rumors i've heard. nonetheless, worth doing some searching on...

Heard that not modifying the head can lead to head gasket failures, which people used to talk about a lot whenever the 4g64 was brought up. Don't hear it as much these days, but maybe everyone is modifying the head now too. But, i don't know, maybe the problems were form increased compression or something.

 

How does Manley arrive at the advertised comp ratio values for their pistons?

Assuming identical stroke and the same combustion chamber shape and volume and given the stated fact that both flat-top pistons, by definition, have identical non protruding flat top designs. Piston 606220C-4 should have a marginally higher compression ratio than piston 606215C-4 due to its slightly larger bore size compared to that of the other piston, all other things remaining equal. At least I would think so. Unless there is something else that I am no taking into account.

 

Yeah I'm wondering the same with unmachines chamber and manley 10:5:1. Compression what the compression be? An if I would have head gasket issues? I would like to hear from 2.4 guys and 2.1 making high hp.

 

No clue... I am not an engineer... This info was straight outta the Manley Catalog...

 

Thanks tho maybe dome other people will have input