What's wrong with KB162 pistons? Never used them just curious

I recently built a 383 with the L2315 Piston which seems to be similar to the old TRW's. For an off the shelf piston it seems best compared to the other choices currently on the market.

I sold a set that were cores about a yr ago for $275 , I must have let them go to cheap ?

They are too far down in the hole and have a HUGE valve canyon , err , valve relief. If you don't have a head with close to 80cc chamber and deck the block to bring them up in the bore you end up with less than 9.0 compression.

By the time you pay for all that machining you could have just bought a piston wit ha higher compression height.

The speedpro LF2315 is a good piston but it's HEAVY and it has no valve reliefs.

The best choice for a 383 is the Diamond piston , but it could stand to be a little taller CH than it is , the good thing is you can have that adjusted by them for not a lot of dough.

I guess so John, seems bare cores are $500, complete 1000+, and I've lately seen fresh rebuilt at 1800... Gulp! Free to ask what you want for your stuff but dang! Maybe geographical too as out west the stuff is harder to find and people seem proud of it.

I'll second what John said on the 162's as my experience as well. Pin is high, relief is claimed as 5cc but looks bigger. Never checked it. Diamond is 4cc and looks more reasonable in size. Plus hypers are fragile, maybe stronger than cast but glass is stronger than aluminum but when it breaks it makes a big mess. The hypers are perfect for a low CR cruiser build, but if your going to push them the risk of detonation shattering one and sending the shrapnel through the engine is unappealing too. I know they're using them in z06 vettes but they're computer controlled most bbm are not. Plus if you ever get a wild hare nitrous is a no-no too.

JohnRR, I'm curious. Would you recommend Diamond make them with a 1.932 CH? (I think they are 1.916 standard). The way I see it is that the block could be squared, and maybe not have to be decked a lot or at all, to bring the CR into a reasonable ratio with a closed chambered head. Please correct me if I'm wrong.

kb 400 is a good pistion but block still needs to be deck cut.
the dome is so small it is not much higher than flat top.
5cc.

Square the block FIRST , once you know what the deck height is, and mock it up with the crank and rods you plan to use you can decide what CH you actually need and tell Diamond what you want. Their piston comes with a 5cc valve relief , the set I had done got a 3cc relief because I wanted a little something incase I changed my mind ... again ... and put in a cam that wasn't stock.

The good thing with Diamond is you can get a piston that isn't really available , I needed a .040 piston because of prior machine shop screw ups. I ended up with their 1.916 piston also because of 2 different shops screwing up when squaring the block. I'm probably the only person on the planet that has $5k into a STOCK build 383 short block ...

Another thing to consider is that the KB pistons aren't cheap anymore. Over the years they've been steadily increasing in price, to the point where a forged piston isn't that much more.

R.

Thanks for the info. Sorry for the hi-jack.

My issue with the 162's are high pin, large valve reliefs, and if it's a performance build there's a very honest chance somewhere down the line the idea of throwing some squeeze in the mix might just come along... Nitrous and hypers is a no-no. Plus they're fragile, easy enough to knock the top land off with detonation. Just better choices... You can change a engine around pretty easy but piston, rods and crank selection are pretty much married to the initial build. Choose wisely.