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KB quench pistons W2 head clearence ?

Posted By: The Shocker

KB quench pistons W2 head clearence ? - 12/31/12 01:06 AM

Just had my Econos redone for the new cam i installed in my LA 408 stroker.The guy that did the head work for me resurfaced the heads and knocked of .006.Today it started to concern me as the 408 has quench domes on the pistons.So i clayed the tops of the domes with plumbers putty and used one of my old head gaskets to check clearence between the piston and head.I brought the piston all the way up and over by hand. It was real difficult to measure ,but i got about .035 clearence or so in the middle part of the dome ,but its seems a bit closer on the corners .I have clearence every where as it didnt completely flaten out the clay or punch through it anywhere .These are open chamber heads and it worked fine with these pistons and heads for years of racing.Should the .006 more being milled off be a problem or not ? Im using the exact same head gaskets this time around that are .028 compressed ,but i do not know how much clearence was there before or how much the blocked had been decked before ...
Posted By: skrews

Re: KB quench pistons W2 head clearence ? - 12/31/12 01:35 AM

could use some 1008 Felpros .039-.038 thick to give you .003-.004 more clearance than you had when you started
Posted By: Crizila

Re: KB quench pistons W2 head clearence ? - 12/31/12 02:31 AM

Quote:

Just had my Econos redone for the new cam i installed in my LA 408 stroker.The guy that did the head work for me resurfaced the heads and knocked of .006.Today it started to concern me as the 408 has quench domes on the pistons.So i clayed the tops of the domes with plumbers putty and used one of my old head gaskets to check clearence between the piston and head.I brought the piston all the way up and over by hand. It was real difficult to measure ,but i got about .035 clearence or so in the middle part of the dome ,but its seems a bit closer on the corners .I have clearence every where as it didnt completely flaten out the clay or punch through it anywhere .These are open chamber heads and it worked fine with these pistons and heads for years of racing.Should the .006 more being milled off be a problem or not ? Im using the exact same head gaskets this time around that are .028 compressed ,but i do not know how much clearence was there before or how much the blocked had been decked before ...


I never had much luck reading the clay. I always used a depth mic on the heads and pistons to get my numbers - along with the gasket compressed thickness. If you are running KB Hypers, you are probably running a pretty tight piston to wall clearance - in which case you will be ok with .035", as there won't be much piston rock. I have run them as tight as .032" with .002 /3 PtoW clearance. Make sure you measure the chambers in atleast 3 spots over the quench area as I have seen the cast chambers very a bit - in which case you may have to do some minor grinding on the high spots.
Posted By: emarine01

Re: KB quench pistons W2 head clearence ? - 12/31/12 03:39 AM

I check by measuring the piston rock.. push the piston down @ tdc so to rock it each way then measure the high spots, its different with each skirt design and piston to wall
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