pistons

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winstoninwisc

winstoninwisc

Taint easy livin free,season ticket ona 1wayride
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speed pro vs kb107 2 valve relief flattops


wich is the better piston and ring combo hypers



better $s worth
 
the kb 107 are lighter...and have a higher compression height which raises compression a bit.....

with the kb107 you just need to set the top ring gap correctly....
 
Funny how this is the first thread I clicked on after sitting down from pulling the heads off my street motor. This is a KB 191 .040 after 20k. The motor has run fine until last week when a piece of the piston wanted to exit through the exhaust valve. I don't think I'll use kb's again.
 

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  • 2013-03-02_18-00-50_654.jpg
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look at your valve its probly bent or the push rod and check the spring

hard to see pic clear
 
Each piston has it's advantage. Like Tony said the KB107 is lighter. I like light stuff for performance engines. 2 drawbacks with them is because of them being lighter you must have the rotating assy. balanced and their particular about having the ring gap set right. If you don't have enough gap the top ring will butt together and bad things happen. Can't really tell for sure what happened to tomanymopars KB but that may be the case as it looks like there's a chunk above the ring land broke out.

Sealed power pistons are real close to stock piston weight so they don't require re-balancing the assy. They also have coated skirts that supposedly reduce friction during break in. They come in 2 compression levels, the 108's (I think that's the number) are rated at 9 to 1 compression and the 116's are 10 to 1. They don't take any special ring gap so their a slap em in and go.

All in all I usually go for KB's and do what it takes to make them work. I think in the end your ahead.
 
He also said a cam would sound smaller if I stroked my 318,can't have that,still trying to decide, lookin for a shop that knows mopar's.
 
sleepyswinger said:
He also said a cam would sound smaller if I stroked my 318,can't have that,still trying to decide, lookin for a shop that knows mopar's.
Click to expand...

Actually, he's telling you the truth (the way he stated it is a little off from the common way). Strokers need more/bigger cams because they absorb a lot of cam vs a stock stroke motor.
 
sleepyswinger said:
He also said a cam would sound smaller if I stroked my 318,can't have that,still trying to decide, lookin for a shop that knows mopar's.
Click to expand...

That he is correct about.

sleepyswinger said:
Good,does that means I can go a little bigger on the cam as long as I match it with the rest of the build ?
Click to expand...

Yes. Cubic inches has quite an effect on the cam choice. I assume when you talk stroking your teen you mean using a 4" crank. If that's the case, going from a 318 to 390'ish cubic inches you'd want to add at least 10-12 degrees duration at .050" lift for it to operate in a comparable rpm range
 
yes would be a 4" and all forged its a fading dream for now but i aint in the box yet then i would put the 308 conp cam in
 
I use the KBs on pretty much anything in terms of a milder build. They run a tighter piston to wall clearance which creates a more stable ring over time, they are lighter which as noted is only good, they have the deeper valve reliefs (compared to a factory piston), and the higher top ring reduces wasted space in the chamber. I don't see anything particularly "wrong" with the SP. I just prefer the KBs for those reasons. That beign said - the builder has to know they need the tight piston to wall and make sure the machine shop gets it right or they may be loud. It's not the piston - it's the bore that gets tighter as things get warm. They also have to know about the top ring issue - or you get the broken ring land as pictured above. That's from either a mistake, or detonation. Not the piston's fault in either case.
 
Good info fellas,I'm still putting together a build in my mind for a street ride mostly,but still need the feel and SOUND of muscle,50 to 150 mi. Road trips with my with wife when not at local cruise nights etc. ,so I'm looking for longevity with performance,maybe sp's or ? Or maybe a good machine shop,(still lookin).
 
hi, in all the years I have installed sleeves in blocks and bored and honed blocks, I have yet to find a bore shrink with heat!!!! we heat the bore and freeze a sleeve to install it!!! the bore expands couple thou. the piston expands because its alum. If the bore shrank, you'd have to increase the clearances. just food for thought,
 
fishy68 said:
Each piston has it's advantage. Like Tony said the KB107 is lighter. I like light stuff for performance engines. 2 drawbacks with them is because of them being lighter you must have the rotating assy. balanced and their particular about having the ring gap set right. If you don't have enough gap the top ring will butt together and bad things happen. Can't really tell for sure what happened to tomanymopars KB but that may be the case as it looks like there's a chunk above the ring land broke out.

Sealed power pistons are real close to stock piston weight so they don't require re-balancing the assy. They also have coated skirts that supposedly reduce friction during break in. They come in 2 compression levels, the 108's (I think that's the number) are rated at 9 to 1 compression and the 116's are 10 to 1. They don't take any special ring gap so their a slap em in and go.

All in all I usually go for KB's and do what it takes to make them work. I think in the end your ahead.
Click to expand...

Do the sealed powers have valve reliefs?
 
2manymopars said:
Funny how this is the first thread I clicked on after sitting down from pulling the heads off my street motor. This is a KB 191 .040 after 20k. The motor has run fine until last week when a piece of the piston wanted to exit through the exhaust valve. I don't think I'll use kb's again.
Click to expand...

what was your ring gap for the top ring? KB's are real specific in regards to that and will lead to the problem you had if not properly followed.
 
I tried to find the pistons on summit but had no luck...are they a dish as well?
 
Cool thanks for the link and info Fishy!
 
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