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Old 03-03-2013, 09:45 PM
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cobalt327 cobalt327 is offline
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Originally Posted by actmobmar View Post
i pulled the head off the pass side, piston to deck is .006-.008, so block has been decked. there are no numbers on the pistons, i think they are kb hypereutectics? they have a dish w/ 2 valve reliefs. i am thinking about porting the heads and putting the engine back together- everything inside looks perfect. what do you guys think? i just have alot of money to spend on other parts of the car
Someone put some thought into the engine. The D-shaped dished pistons are the best type of dish to have- they optimize the quench effect.

The KB 346 piston has a D-shaped dish, 17cc volume. That piston volume, combined w/a 0.040" quench will get you the 9.5:1 CR you were told the engine had. Unfortunately, the KB piston has the ID on the side of the piston (shown below), so you'd need to pull a piston and rod to see.

The forged Icon KB p/n 891 is 14cc IIRC. It has an intake valve relief of:
.199 deep x 2.140 diameter. Exhaust relief is .201 x 1.830"

You can still use the same procedure used to CC the combustion chambers to see what the dish volume is, by using some grease around the outside diameter of the piston to keep the measuring fluid from seeping out. Then using a clear cover made from scrap plexiglass w/a couple holes in it (one to add fluid, the other hole to release the trapped air) or use an old CD w/the plating removed (the center hole is big enough so you don't need another hole) sealed to the block deck w/grease, you can add fluid using a graduated burette or a large syringe (get them from a pharmacy or vet.

It'll take a little math to subtract the volume above the piston at TDC from the dish volume, but it's not that hard to do. If you choose to go this route and want more info just ask.


Last edited by cobalt327; 03-03-2013 at 10:04 PM.
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