Planning on KB137 pistons, Negatives?

[Mighty Thor]

I have been looking at options and I think that I like the looks of the Keith Black 137 Pistons for My 460 ford, they are where I want to be for compression and price looks pretty good to me as well, anyone have any Negative experiences or warnings ?

[1BIGJIM]

Ok, nobody will bite so here is my 2cents :rollside:
I have used them a couple of times and had no problems at all. I would only use them personally in a mild engine. I am building a spare BBC :smile: and will be using them to keep the cost down. Remembering this is a mild engine, and will only spin it 5,000RPMs.

[spectras only]

I put them in my 429 in my jetboat .Sold the boat to a friend a few years ago . Built that engine back in 1989 and still running . CR is 9.3 : 1 .

[Mighty Thor]

Thanks guys, this will be the engine for my "family" jet boat, a Glastron CVX 20 and this summer's experience has shown that the vast majority of the time the engine will be turning between 2500 and 3500 rpm pulling toys and cruising up and down the river here. All of the negatives I have read about the Hypertuetic pistons don't seem to apply to the Keith Black pistons, they seem to be the exception. I am planning a second motor for a later Hondo project that might get a little more spendy but I want to get going on this one first so I can have it ready to go next spring.

[1BIGJIM]

My best advise is make sure you set the ring gap to there K.B.specs. From memory I think its around .030. I know it Sounds high :jawdrop:

[058]

Why run the Hypers when you can have a forged TRW piston for a few bucks more? Summit has the L2404F pistons for $287.00, The KBs are $261.00... not enough dollars to make a difference in the total price of the build. Peace of mind is worth more than $26.00

[GofastRacer]

Why run the Hypers when you can have a forged TRW piston for a few bucks more? Summit has the L2404F pistons for $287.00, The KBs are $261.00... not enough dollars to make a difference in the total price of the build. Peace of mind is worth more than $26.00
Bob, you mean Hyperjunk :D I wouldn't even put those in a street machine!.. :D :D

[LakesOnly]

Both pistons have their advantages.
For sure, the TRW has the advantage that it is a forged unit.
http://static.summitracing.com/global/images/prod/large/trw-l2404f30.jpg
TRW Advantages: It is forged.
Disadvantages: BUT the TRW has a 22cc dish and will make for poor compression ratio, compared to the KB137. Also, the dish is round and this takes away from the anti-detonation effect of the quench pad. I confess that the .300" or so perimeter around the piston will ITSELF probably provide enough quench to get the a/f mixture motion doing what it needs to for anti-detonation, BUT the pin height is 1.756" and puts the piston crown too far from the cylinder head's quench pad (eliminating quench). Detonation resistance is dramatically reduced. I cannot say for sure but while I agree that this is one rugged piston, I suspect it is somewhat heavier than the KB (although this is not likely noteworthy in MT's application).
http://static.summitracing.com/global/images/prod/large/uem-kb137.jpg
KB137 Advantages: Flat-top design across the piston crown except for valve relief gives the compression ratio desired and ALSO provides superior quench. Further, the piston pin location is at 1.772", which puts the piston a whopping .016" closer to zero deck (assuming the D1VE block). In other words, KB had the forsight to adjust the pin location for the later blocks and get the proper quench and reduce (if not downright eliminate) detonation. It can run with a tighter bore clearance, and I suspect it is a lighter piston.
Disadvantages: It is a hypereutectic piston. And with that, others may say that none of the KB's advantageous features matter because it's a hypereutectic piston and will crumble under pressure. But if in fact Mighty Thor's CVX20 will really see typically 2500-3500 rpm, then personally I feel the KB is the way to go. It can handle those rpm's and much more.
Finally, even if we compare apples to apples, the KB is the way to go, unless price is no object.
Comparing Dish Tops:
http://static.summitracing.com/global/images/prod/large/trw-l2404f30.jpg
The TRW has the round 22cc dish which eliminates the quench area, while
http://static.summitracing.com/global/images/prod/large/uem-kb138030-8_w.jpg
The KB138 has the D-cupped 22cc dish which mirrors the combustion chamber and saves the quench pad.
Comparing Flat Tops:
http://static.summitracing.com/global/images/prod/large/trw-lw2602f30.jpg
The new TRW LW2602 flat top is a fine new forged design, but the pin still puts the pistons .016" in the hole AND these pistons are over $410 retail for a set.
http://static.summitracing.com/global/images/prod/large/uem-kb137.jpg
The KB137 is priced about $150 less and will suit the application just fine.
LO

[GofastRacer]

Paul, what's wrong with the L2404's, they're almost half the price?? :confused: I still wouldn't use that Hyperjunk if it was given to me!.. :D :D

[058]

Paul, what's wrong with the L2404's, they're almost half the price?? :confused: I still wouldn't use that Hyperjunk if it was given to me!.. :D :D
Art, What troubles me about hypers is the heat they hold, why else would you need to run .030-.032" top ring end gap? IMO that would promote more detonation than a .015-.020" negative decked piston. I will say the hypers are relativly strong [for a casting] but they are also brittle and when you reach the detonation threshold they can shatter like glass. At least when they break the small pieces are easy to clean up :D

[LakesOnly]

GFR,
The piston Mighty Thor is considering is a flat-top design, while the L2404 is a 22cc dish.
The L2404 was recommended in place of the KB137 and they are only $26 more, not twice the price.
In my post above, the first comparison was of the very two pistons being recommended, (L2404 vs KB137) but the second comparison(s) was of flat-top to flat-top, and then dish-top to dish-top, which is more proper a comparison, if compression ratio was a factor...and MT said that the flat-top KB137 gave him the compression he desired.
I have bought grenaded 460's before and the motors essentially had gravel in the bottom of the oil pans...from the disintegrated hyper pistons. Indeed, hypereutectics have their limits. In my above post, I emphasized that IF this motor will really see only 2500-3500 rpm most of the time, then Mighty Thor should be fine.
Finally, I don't disagree with you or 058; without getting into long paragraphs, let me just say that the KB pistons are the only hyper's I would recommend in a motor build, and a mild one at that. :D And in this particular case, I just don't believe the are flat unsuitable for the build.
I thought that I laid out the differences between all those pistons pretty thoroughly...
LO

[Mighty Thor]

Thanks Lakes, You have covered my issues exactly, with the Keith Black pistons and My heads I will be around 10 to 1 or so compression, with the dish pistons and my heads I will be around low 8s in which case I could just go with factory cast pistons. The Keith Black pistons fit my compression requirements and are within my current budget for this engine rebuild. I am running an AA impeller (with a nasty ding to be repaired soon) in a Berekely JE pump and the stock 460 that was in the boat would not pull 5000 rpm with that set up. Top speed was 55mph indicated at about 4700 rpm. This engine should certainly pull higher than that, but ride wise the water around here isn't really suited for that kind of sustained speed. Neither is my Wife. I am comfortable that the pistons are suitable for short runs of 5500 as long as the proper clearances are put in at set up. I have read all of the recomended clearances on the various KB sites and think I understand the reasoning behind it all. I also read all of the opinions on Hyper pistons, but noted that no one had acutally reported a failure of the KB pistons.
I have also studied the 460's themselves and everything I read says that they are less prone to detonation at higher compression than the chevy big blocks. Reports are that even at 11 to 1 detonation is not really an issue unless the timing gets radical. I will be far below that compression and my Cam and timing will be fairly calm by most everyone's standards. We are currently looking at cams with 110 degrees of separation although I am much drawn to the cams you have suggested earlier.