Originally posted by Twisted6 I.I #3220:
Yeah AB it is always 99.9% of the time on that side due to the way the bolt pattern is. and for what i have seen it's mostly close to being Dead center. Because of this bolt pattern The head you could say seems to Float/Pushed up due to the HIGH compression Esp. If the block has not had studs Put in it. and even then after a certain
point/compression 13-1. O ringing the block is pretty much a Must do, This helps.
Have you tried this groove Less then.040 to see if it still works as it should?? Or is .040 pretty much the Min.
It looks like GM put the head bolts too far from the bore, well there’s not much you can do about that. You say “The head seems to Float/Pushed up due to the HIGH compression”. I wonder if it’s pressure, detonation or rather liquid fuel being trapped in the squish area that floats the head.
What ever it is I’ll tell you what I would do. Most people will tell you I don’t know what I’m talking about when I say this so take it like you want.
What I would do is to put a groove right in the middle of the squish pad all the way to the gasket to relieve the pressure. In addition I would open the piston to head clearance to 0.060” to 0.070” to keep from building pressure in the squish area. Compression will be lower but performance will improve.
With a 0.100” thick deck you have no choice but to put the groove in the piston, this you said you already did so you may have begun to solve the head gasket problem.
With the SBC we don’t see many head gasket problems, the condition you describe exists but with five head bolts close to the gasket it holds up.
I tried the groove with tight squish clearance < 0.040” and wide squish clearance > 0.050” and it works best with the wider clearance despite the compression being lower.
With the grooves we change the oil by counting the number of runs because it never gets black.
