ir3333
Well-Known Member
Keith Black or Sealed Power hyper pistons... what's your preference?
..are Keith Black trickier to install?
..are Keith Black trickier to install?
Keith Black / Sealed Power pistons
- Thread starter ir3333
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ir3333
Well-Known Member
otherwise both are comparable quality wise?
Retroboy
Well-Known Member
KB pistons are nice quality and when I was looking around a year or two back they had a better pin height so the pistons sat higher in the block - closer to the deck for a little more compression than the others.
The picture shows the difference between a standard replacement FM piston and a KB 190 for a 360.
Cheers
Tony
The picture shows the difference between a standard replacement FM piston and a KB 190 for a 360.
Cheers
Tony
ir3333
Well-Known Member
340 small block...
nm9stheham
Well-Known Member
KB's for a 340 are going to be a LOT lighter so be ready to re-balance. But, that keeps rotating mass down and stress off of the rods and crank. We used KB243's and SCAT rods in my son's 340, and ended up with a piston+pin+rod+ring+locks+bearing weight total that was 56 grams less than a stock 273 combo. Bobweight was less than the 273 and the machinist just had to take weight OFF a stock 273 crank at the balance time.
That was an inexpensive balance job because the KB's and the SCAT rods come weight balanced within a gram or so. You can look at it this way: part of the KB price offsets the balance work on the pistons, and part of the SCAT cost offsets the big and small end balancing on the rods. With those parts in hand, we just computed the bobweight from weighing the other parts, and handed that bobweight number and the 273 crank to the machinist and said "Balance to this bobweight". it cost us around $95 for the balance work on the crank.....for real.
I was concerned the first time I used hypers; that was on a full blown rally turbo engine. Held up fine with 14-15 psi boost. I don't worry about hypers anymore. But forged is still stronger, just heavier. For really tough racing abuse, I'd try to use forged; I ended back with forged in the turbo rally engine just for safety margin, but the hypers were fine when I pulled them out. They were not any special quality brand.
That was an inexpensive balance job because the KB's and the SCAT rods come weight balanced within a gram or so. You can look at it this way: part of the KB price offsets the balance work on the pistons, and part of the SCAT cost offsets the big and small end balancing on the rods. With those parts in hand, we just computed the bobweight from weighing the other parts, and handed that bobweight number and the 273 crank to the machinist and said "Balance to this bobweight". it cost us around $95 for the balance work on the crank.....for real.
I was concerned the first time I used hypers; that was on a full blown rally turbo engine. Held up fine with 14-15 psi boost. I don't worry about hypers anymore. But forged is still stronger, just heavier. For really tough racing abuse, I'd try to use forged; I ended back with forged in the turbo rally engine just for safety margin, but the hypers were fine when I pulled them out. They were not any special quality brand.
i just finish a 340 + .06 w/ floating pins with kb's set , .02 in the hole by machining a bit off the top . the machinist like them for this build , tight in the hole as well , no noise street set up , short cam and adjustable rockers , keep the dcr up , just sweet driven stocker for the street . hope your build goes well .
ir3333
Well-Known Member
..lots still to be decided
nm9stheham
Well-Known Member
It's the fun phase of the project.... soon to be followed by the "Did I screw up?", second-guessing phase after the parts all arrive... LOL
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