Quench or no quench?

[mullinax95]

Can someone explain how to accuratley calculate quench with dish pistons???

Thanks in advance.................

Not to trying to sound like a a-hole but why would it matter? I believe knowing your compression ratio would be enough. Just curious. You do need to know the pistons dish cc however when calculating compression. Maybe if you add the piston dish cc with it in the block at TDC, and the chamber cc that would give you total quench. That wouldn't be quench at would it?

 

[AdamR]

Yes you need to know piston dish cc to figure quench. Quench is the distance from the pistons top to the combustion chamber.

If you run a flat top pistons at zero deck, use a .043" gasket you have .043 quench.

Now add a 6cc dish and you have a .049" quench distance.

If the pistons is a flat top and sits .024" in the hole with the same .043: gasket you would have .067" of quench.

Now change to a thin .024" gasket would bring quench back to .043"

 

[mullinax95]

Yes you need to know piston dish cc to figure quench. Quench is the distance from the pistons top to the combustion chamber.

If you run a flat top pistons at zero deck, use a .043" gasket you have .043 quench.

Now add a 6cc dish and you have a .049" quench distance.

If the pistons is a flat top and sits .024" in the hole with the same .043: gasket you would have .067" of quench.

Now change to a thin .024" gasket would bring quench back to .043"

I forgot about the gasket. lol

 

[moper]

Adam, the dish is not part of the quench distance. Quench is the tightest distance... On a full dish design, the only spot on the piston that contributes to the quench affect is the small flat surface dirsctly above the ring lands. The dished versions like Diamond and Ross are actually quench dish designs that specifically make use of that offsetting of the chamber. So you're quench with a full dish is still .043 at 0 deck, but the area of the dish under the head deck (not the chamber area) doesnt no contribut to the quench affect. The trend is very small chambers (under 50ccs) and full dish pistons with a wider flat around the perimeter.

 

[AdamR]

Thanks Moper, I didnt know that. :thumleft: