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milled head vs cool head


P-man

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A little off-topic, but could someone that knows they have a COMPLETELY STOCK head measure it, from say one of the flat parts where the bolt goes to the part that mates w/ the cylinder. I have a few stockers layin around and know some are milled but dono how much.

 

P-man, if i can figure out which one is milled i'll give it to you if you just pay shipping, or meet u somewhere in DFW to give it to ya.

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.020" will reduce the OEM chamber volume apx. 1.66cc. From what I have seen the heads w/2GUY-1 casting numbers are from early Banshee motors and have apx. 1.8cc larger chamber volumes than later 2GUY-2 castings to start with. Both castings are well within being 92 octane safe (assuming OEM deck height) and will result in a squish thickness of apx .060" (again assuming OEM deck height) w/.020" faced off them.

I'll let you do the rest of the math... If you need more info let me know.

Good luck

 

yea actually i might be interested, what would .20 raise the compression to here. im at 500 or so feet
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mopar, I have cc'd several of both castings and both have consistently been within 0.2cc from head to head. 2GUY-1 castings=24.20cc chamber volume. 2GUY-2 castings=22.40cc. Don't forget to add another .84cc to both for an OEM head gasket, if your using one, and/or trying to make some type comparison to one of the after market O-ring type heads.

IMHO, there are several things effecting what a proper squish velocity would be for a particular engine... Squish thickness just being one of them... I would really like more specific data before commenting. E-mail me private if you want. I can say that I have never needed to run less than .045" on any 2-stroke engine to get the MSV I needed for that particular application and that being only on extremely high compression motors. Normally I see .048" to .053" for 92 thru 110 octane set-ups with normal squish band widths (10mm +/-). At any rate, that's what works for me... However, MSV opinions vary... And unfortunately, it is quite often debatable...

I agree with brugal... For what one of the Noss or Chariot style head assemblies cost, it is not making much sense for someone to pay to have an OEM casting worked over, unless of course a person could get it done pretty cheap or is going for a sleeper look or something... Plus the OEM castings are pretty thin around the coolant in and out areas. It is not unusual to have to tig weld "plugs" in those two areas if more than .070" or .080" needs to be faced.

 

 

deckheight, do you know what the stock cc size is on a stock unmilled head? also, whats like the tightest that one would want to run his squish....like .040? for pump gas i mean.
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