hey, first engine im stroking out. so im having trouble figuring out what type of piston compression height i would need for a deck clearance of zero, and where can i find then for a reasonable price, because i know there not standard pistons. my info 10.2 block 4.25 stroke crank 119 cc aluminum heads different rods i can use 6.535 6.800 rods any help, i would appreciate it
contact the piston company of your choice and I'm certain they'll be able to provide you with what you need. custom pieces are never a bargain though.
Comp. Height 1.520 with 6.800 rod Stroke 3.76/2=1.88+Rod 6.800=8.68 Deck Height 10.200-8.68= 1.520 Comp. Height
I calculate compression heights of 1.275 inches for the 6.800 rods and 1.540 inches for the 6.535 rods.
hey, yeah i used this site http://www.kb-silvolite.com/calc.php?action=deck and i get 1.275 ch for 6.800 rods but when i type it in the deck clearence, its not at zero its at 1.7763568394003E-15 so so, confusing.
I can spit out all the formulas for arriving at this.......but call the piston co. your gonna use........tell them all your info and let them fix you up with pistons. Be sure to tell them all your info..........block deck ht., gasket thickness, cam spec's, rod length, crank type and stroke.......yada....yada....and don't forget to notch out your block for clearance at your pan rail area and the bottom of your cylinders.........double check everything!!!!!!!
Ok stand corrected i did not read your post right 4.250 is the stroke you are using not bore. Wiseco Piston #K238A3 Bore 4.310 Compression Height 1.270 Stroke 4.250 Rod 6.800 Deck 10.195
If you are starting with a used GM truck block, you'll most likely need to cut the deck to get it flat and square to the crank 98% of the time. So don't plan your parts based on 10.200". If you've got a new aftermarket block, you may not have to deck it.
I suggest that you also pick out your head gasket before deciding on your machine work. Zero deck is a term in vogue these days, but what you really want is the correct quench space for the application. On a street engine you can't get super tight - usually target .045 - .048. Some will say you can get by with as little as .035 on the street, but that's tighter than I like. So back to my point - if the headgasket you want to use has a compressed thickness of .039, and you decide on a .045 quench, you wouldn't want to zero deck the block.
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