5 replies to this topic

[darkrider]

I'm sort of hoping that someone can give me some info.If an engine is 1098cc with flat top pistons, would putting in dished pistons make it bigger?

 

[Dannyboolahlah]

No. The engine capacity is measure by the swept volume, which will not change as the dish is still there at both ends of the stroke. Swept volume is the area between the piston at the top and bottom of it's stroke

What the dished pistons will do is lower the compression ratio, by increasing the unswept volume of the engine.
Unswept volume is the anything above the piston at top dead centre: any piston dish, the head gasket volume, and the combustion chamber in the head.

Compression ratio is (swept + unswept volume) divided by swept volume.

If you're after more power from increasing the engine capacity; adding dished pistons alone will lose power due to lower CR.

[dyshipfakta]

As above unless you turbo it anyway!

[Dannyboolahlah]

Well, yes. Boost solves everything.

Edited by Dannyboolahlah, 26 February 2020 - 08:18 PM.

[darkrider]

Thanks because I bought a car with 1275 dished pistons on a short stroke engine with a 399 degree cam. They tell they use that for racing.

[nicklouse]

So what do you want to know?