Compression...
02-26-2008, 08:06 PM
#1
Compression... OK, my buddy has had hell with his 355 he had a shop build, it has aluminum 200cc brodix heads with 64cc chambers, the car was running on 93 octane but after failure to run worth a **** and three flat tappet cams later, i tore it apart today and found it has 2 valve relief pistons...with atleast a 1/4 inch dome, the builder claimed 10.7 to one compression...i say the 6....yea 6 broken compression rings were due to needing more octane, ill load some pics tomorrow if you guys like but i think it was more like 11.5 to 1 or so, what do you guys think?
03-08-2008, 12:32 AM
#2
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hard to say without knowing the CCs of the dome, I just haven't put that many together to be able to "eyeball" it like that.
But if I had to guess somewhere in the 14:1 range??... dunno
But if I had to guess somewhere in the 14:1 range??... dunno
03-08-2008, 11:50 AM
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a .100 dome is around 11-1 a .250 dome is around 12.5-1 depending on deck height above piston and head gasket thickness,but either way should not be used in a pump gas motor,flat top pistons are good with 64 cc heads,usually around 10-1
03-09-2008, 10:23 AM
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Agreed on without knowing what size the dome is hard to tell. My old 355 with 65 cc Canfield 195 cc heads and a 2 valve relief flat top piston came in at 9.7:1 compression. A small dome could keep it under 11:1 and pump gas friendly if the tune was spot on.
Derek
Derek