View Single Post
Old 12-07-2009, 08:26 PM
Riding Rich Riding Rich is offline
Join Date: Aug 2009
Location: pa
Posts: 349
Default Re: Do slant heads really make a difference in power?

Here's some numbers for ya.
But they apply directly to the PK80-J Slant Engine.

The stroke length will detirmine the swept area of the piston which is the volume being compressed into the head.

As far as i know there ar two different happy time strokes out there.
Different location of the piston wrist pin.

The voulme of the head is approx 8cc / same as 8ml

The volume of the compression chamber with the piston at TDC = 5cc / 5ml with 2 head gaskets.
This is possable because the piston dome is above the top of the cylinder inside the head.

the swept volume of this engine is 47.1291 cc.

47.1291cc / 5cc = 9.43 : 1 "SOUNDS LIKE TIRE SKIDDING TO ME"
I wouldn't reccommend going much higher without some serious octane.
This is also about the same as the Rock Solid Billet head.

Even at a 6cc / 6ml combustion chamber the ratio = 7.854 : 1 "not bad"

now say the piston was a flat top.
the combustion chamber would be 8cc / 8ml.
The ratio = 5.89 : 1 probably typical for the Happy Time.

So if you put the PK slant head on a motor with a flat top your not helping much.

But that dome shape piston and the head combo make a real winner.
Reply With Quote