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Discussion Starter #1
There still seems to be a lot of confusion regarding head and cylinder surfacing.
The 100% ideal way, is in a lathe turning the head or cylinder on an axes symmetrical to the bore/fire ring.
Doing them in this way, doesn't leave any machine marks/grooves to give less compression on the gasket across the fire ring or a path for cylinder pressure to leak.

See attached pictures:
#1 face milled and ran. As you can see, the peaks and valleys (machining grooves) run across the fire ring so you have high gasket compression on the peaks and low gaskets compression in the valleys. The valleys run straight from the combustion chamber to the coolant passages on the front and back of the head or cylinder.

#2 Faced in the lathe, peaks and valleys are concentric with the fire ring. No valleys lead to coolant passages and the peaks work like 100 fire rings gripping the gasket against the direction it's being pushed.

#3 lathe machined cylinder

#4 Lathe machined head after running, you can see compression of the gaskets was uniform all around the fire ring.

#5 Lathe machined head, X10 magnification
 

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so youre saying i shouldnt use a belt sander with 80 grit? :eek:

Good Info here! Makes sence to me and i'm not a machinist!
 

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Discussion Starter #5
Ray looking at the combustion chamber of the did you sand it? Does this help with hot spots?
Te reshaping of the combustion camber is mainly for flow, the chamber is part of the intake and exhaust track. The smoothing does help with hot spots as well as any raised or "pointy" area's (higher surface area per smaller mass) will absorb more heat during the power stroke and can increase the chances of detonation.
Thanks,
Ray
 
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