Piston Choice...Too Much Compression?
06-18-2007, 03:31 PM
#16
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im off today so ive been doing nothing but sitting in front of this damn computer weighing my options. sounds like a custom piston might be my best bet. ive already dropped way too much money into this car and i want it to perform the best it can so no compromising unless i have to. a 9cc piston volume would give me 12.1:1 with a .035 gasket which sounds decent. i think the reason my chambers are so small is because of how much they were milled. looking at the spec sheet it says they were decked .032". any recommendations on a company to do a custom set of pistons? preferably less than $1k to make, closer to $800. Ron also said they might be able to change valves and with a vj gain a few cc's
Rich
06-18-2007, 06:29 PM
#17
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i thought one of the main reasons you ran a tight quench was to resist detonation? if thats not true why do people recommend setting up quench distance of ~.03-.04? just trying to learn not, questioning your knowledge by any means
06-18-2007, 07:16 PM
#18
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Rich
06-18-2007, 09:33 PM
#19
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Also to add a quench off .035 is to small with a true zero decked block you run the risk of slapping a piston at high rpm minimum i would go on a zero decked block with that chamber size is .039 which i believe most people use
06-19-2007, 04:22 AM
#20
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And to add some more. You better check each hole individually if you aare trying for a quench as tight as 0.039". There is often variation of up to 0.005-0.007" from one hole to another. This reflects the precision of the machining, stacking of tolerances, etc. 0.035" is about the thickness of a 3x5 index card. If you try to run a very thight quench, even something as "minor" as a little extra piston to bore clearance can cause contact between the piston and the head due to piston rock.
In any case, I don't see any practical difference between 0.040 and 0.050" in a situation like this. Just my $0.020.
Rich
In any case, I don't see any practical difference between 0.040 and 0.050" in a situation like this. Just my $0.020.
Rich
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