I would probably never have a need to flycut pistons, but just for my knowledgebase, wouldn't this lower your compression? It seems like the combustion area would increase (as would the BDC area) but since it's a ratio the same increase in TDC are would raise compression slightly.

 

Negligible.. you are taking a small relief cut of maybe .030 in 1 little area, though I never measured it, think of it in cubic centimeters. 1/2? maybe? Taking .006 off the deck for the whole combustion chamber is roughly 1cc, and I can't see it even being NEAR that.

 

Yes flycutting will lower your SCR, but this is usualy done with a head mill to gain more SCR yet increase PTV. valves are at 15* angle, so let us say you cut .080 (PTV gain) loss 2cc, but you mill heads 4>5cc, you get my drift.

 

Flycutting is usually accompained my a head mill, and the head mill compression will usually be a lot more than the compression loss from the cutting alone.

Me having the -2cc pistons allowed me to mill the **** out of my heads to get nice high compression, use a thin gasket for tight quench, and still have good clearances.

 

The answer is yes.

 

Thats interesting stuff. You learn somthing new every day I guess. Dont wanna high jack this thread but does fly cutting a piston weakin it at all? As far as a stock piston goes.

 

thanks guys. Honestly a senseless question on my part because I don't think i would ever have a cam large enough for that to be an issue, just curious. Cheers!

 

Yes a little bit but not enough for me to be concerned about.

 

cool thanks.

 

Flycutting is one thing that I would like to do in the near future. I figure I can then go with a slightly bigger cam, and then go with a 0.040" head gasket and keep my scr and dcr but have the benefits of a larger cam.

I just am a little hesitant doing it on my own the first time.