Piston dome cc?

[Rare Scottish Tree Badger]

What's a rough estimate of a piston's dome cc? About 4cc It's a 1mm over prolite if anyones's got the exact amount. ... Playing with corrected and uncorrected CR and mapping ports and timing.

 

I could work it out, but I've spilt enough kerosene on my livingroom carpet as it is!

 

If I can't ride it, I might as well know what I've got when it is going.

 

EDIT: It must be closer to 8cc.

 

Rare.

[RBD]

You really aren't going to find a big enough difference in actual dome displacement from one bore size to another...., and when you get up to + 1 mm the dome is stepped to maintain the same configuration.

 

Save your carpet and don't worry about it.

[Rare Scottish Tree Badger]

Ok, so I won't worry about the +1mm over. But I still want to know what the dome's displacement is. ... I don't think I'm far away with 8cc.

 

Rare.

[JKJK]

Here's a suggestion.Get a measuring cup with fluid oz increments on the sides of it.Insert the piston dome into the cup+see how much water it displaces.Or press the dome into a ball of puddy,remove it+see how much liquid it will accept.

[RBD]

Rare Scottish Tree Badger,

 

Using a little math and plugging in some numbers, the crown (dome) of the piston would be 6.467 cc's. This is using a figure of the crown radius of 130 mm and a 64 mm bore dia.

 

Ron

[Rare Scottish Tree Badger]

Thanks Ron, ... I did some maths aswell and got the same figure as you! (6.46749 cc). You must have used 4mm for the dome height too.

 

Thanks for confirming it.

 

JKJK, They were good ideas but with such a small volume, method 1 did nothing (no carpet stains - too much surface tension). If I hadn't found out how to do the maths, I might have tried the puddy (we call it putty/plasticine) or even just done it the right way. ... Placing the cylinder in the bore a known distance from the deck, sealing the piston/bore clearance with grease and then CCing the volume to deck height with the kerosene and then taking the volume recorded away from the volume above the known distance volume without the piston being there. (As if it was a flat top piston).

 

Anyway, thanks guys. ... Job done.

 

Rare.