I am in the process of building a Blown TPI motor for my Son.The knock sensor was and is a big issue.A Forged TRW piston for that application needed .005 clearance.JE pistons can be fudged a little to .035.Had all else set to go,just deciding on pistons.Local and Nationaly recognized Boyds Racing Engines called me and said get on down here,you have to see this!

It was a well known Sprint car motor that had been so everloving hot the rods were black as well as the crankshaft and block main saddles.The friend said been pretty hot huh? I said yeah,big old boat anchor now then he handed one of the KB pistons out of it.It looked as if new still.I absolutley could NOT believe it. The rings were flaking as well but the piston was fine.
Will they replace the forged pistons? Nope.But suspect they would be a great choice for those not running high bearing clearances and reasonable spring pressures on the nose of the cam so one could take advantage of a thinner multi viscosity motor oil to protect them at cold start.They set up normally at .0015.That is a close tolerance piston indeed and the route I have now chosen to take on this engine.
Did not mean this to be a tech article of sorts,just thet seeing IS believing!I posted merely because KB quality issue has been brought up a few times.I was somewhat of a nay sayer at that time.Not now.Nothing like learning at someone elses expense!

All Hypereutectic pistons are not the same as KB.The KB site explains in detail.

 

Cool man, I plan on running KB's in my new motor. :) Glad to hear that the KBs have a pretty good rep with your machine shop.
KB105s, .1 solid dome. After learning about how junky the stock pistons are in the GW350, I gave up on building that one up and decided to build a new motor for the car. At least I'll be certain about all the components in the new one, this GW350 is a rolling mystery.
-Steve


[Modified by Pacin'California, 8:10 AM 3/14/2002]

 

That great. Makes all the problems I had installing them not so bad. The problems I had was the oil ring. I was using 6" rods so the oil ring was pretty high on the Wrist pin. They just didnt want to stay while installing them. The pin in the groove was something I had never dealt with. But I am happy now!

 

Years ago I bought KB Hyperuetectic pistons just to try them because they are made locally and becuase of the great properties they have. I put 50,000 bad mills on mine before one piston failed.

 

KB pistons are very heavy for a sprint car engine where the use titanium rods and even cranks to save reciprocating weight. :chevy

 

Clem 360 ci sprint cars like I work on don't allow exotic rods to keep cost down. But KB pistons have a so call limit of 7000 rpm so they wouldn't work on the motors I work on with nearly 700 hp and 8000 rpm with as high as 15 to 1 compression.

 

My son's KB's weigh a light 500 grams.Pretty good especially compared to a Race Manley Hollow dome @ 530 grams.Some of the of the JE's weighs in excess of 500 grams also.Our KB's now weigh22 grams less after reworking them .

To ad,also some KB's weigh 425 and 435 respectively for small Chevy applications.Very light in comarison to some of the TRW's and the above mentioned pistons

Sprint cars and Outlaw cars I believe to be worlds apart in respect to what is allowed motor wise.Might be wrong though.


[Modified by mountainmotor, 7:41 PM 3/14/2002]

 

mountainmotor. What are you doing to remove nearly 2/3rds of an ounce off of the pistons? The stock 4.030 KB's I had were two valve relief flat tops pressed pins and I would recomend them to anyone. It was just heat and high RPM that caused mine to smear and warp. If you would like i could take a pic of it. as I said i put allot of bad miles on them with weirdo blends of fuel with 2.055/160 10.7 C/R


[Modified by gkull, 9:07 AM 3/15/2002]

 

i too have used kb pistons in our oval track motors sportsman dirt especially and never had a problem with them.i prefer wiseco ultralight pistons,very light and strong.

 

>I am in the process of building a Blown TPI motor for my Son.

Dad!, Daddy!, what about me? :yesnod: