26cc dome

[fastest440ex]

Does anbody offer a 26cc dome for a cool head on a 295 resleave.
I have a 23cc but have to high comp and want to lower it.

[fastest440ex]

any ideas?????

[bluetrx]

my compression was too high with my cool head also. i took the dome to a local engine builder and he put the dome on his lathe and took material out of the combustion chamber. got it down to 225psi. he charged me $20

[fastest440ex]

thats what i just did and am waiting for a new gasket to try it out

[86 Quad R]

what are yall's dome profiles based on? did the machinist mimic the old one?

[bluetrx]

yes the profile of the dome basically mimics the profile of all 2 stroke heads, theres a quench ring around the edge that parallels the piston dome, and a hemispherical combustion chamber in the center. im not sure what the dimensions should be for the quench surface but i do know its a critical part of the job. andrest, the guy who did mine builds r motors for shifter carts so he knew what he was doing, he set me up with a cr gasket and actually shaped the quench surface of the dome to get the quench he wanted ( it seems like he said .035''-.040'' ). im sure you wouldnt have a problem taking the dome to any machinist if you tell him to take material frome the hemispherical combustion chamber part of the dome only, this will maintain the coolhead factory quench setting with an oem headgasket. idealy the quench surface should be mirror polished and the combustion chamber should have a slight texture. andrest put sandpaper to mine while it was on the lathe but im not sure what grit, it looked coarse like 80. it was a trial and error process hed take some material bolt it all together, solder check quench, then check cranking pressure with a compression gauge. it took him 3 tries to get it where he wanted.