KB hypereutectic pistons

[travis]

Would you trust them on a iron head 350 with 10.5-1 compression and an occasional blast to 7k rpm's, on 91-93 octane pump gas? This will be just a fairly hot driver.

[rebelrouser]

If directions are followed on skirt clearance, ring end gap, and ignition timing, yes. Years ago out of a dare I built a 350 SBC with a 671 blower for a mini rod tractor puller using KB flat top pistons. It ran for 3 seasons before breaking a rod.

[skinny z]

I asked that same question. Answers were kind of all over the map. But some support as posted above.

viewtopic.php?f=1&t=64901


Which ones are you looking at? There are a couple I'm aware of.

[F-BIRD'88]

91 and 93 octane are a lot different.. Which is it?
Can you set the top ring end gaps correctly?

[mag2555]

Is your budget really that tight that you can’t afford forged pistons for what must be the worlds cheapest motor to rebuild?
It’s those occasional rpm’s to 7k that concern me.

Don’t forget that the load on those type of recuperating parts doubles with every 1000 rpm!

[travis]

The pistons are .060 KB135's...18cc dish with 1.425" compression height. I bought them some 20 years ago for one of my own 388's but ended up changing directions on that build, so I've been dragging them around forever. With a 5.85 rod they will work in a 350.

I've got several sets of heads that I can use with these...56cc 601 castings, several sets of vortecs, and a set of ported 50cc chamber 200cc RHS heads that flow iirc 288@.550 or .600. I've been anxious to use these RHS heads, but it may be better to use one of the lesser heads with these pistons, and save the RHS heads for my roller block.

[dfarr67]

Are the Total Seal top rings suitable here for a DD?

[Mark O'Neal]

tuneup and tuneup and tune up.

I refuse to use no gap rings in anything. We'll Top Alchy maybe.

[af2]

Get a set of 4032 and forget about asking. My sons 355 lasted 1 trip to the lake pinging and knocked the top land off with .030 ring.

[af2]

Get a set of 4032 and forget about asking. My sons 355 lasted 1 trip to the lake pinging and knocked the top land off with .030 ring.

viewtopic.php?f=1&t=456

[rustbucket79]

How do you find KB’s? Normally in the oil pan.

Seriously, gap the top ring correctly and don’t detonate the engine and they’ll last longer than you have interest in the engine.

[af2]

How do you find KB’s? Normally in the oil pan.

Seriously, gap the top ring correctly and don’t detonate the engine and they’ll last longer than you have interest in the engine.

The clue is don't go into detonation.
The heads and valves an exhaust is where you find the carnage.

[af2]

How do you find KB’s? Normally in the oil pan.

Seriously, gap the top ring correctly and don’t detonate the engine and they’ll last longer than you have interest in the engine.

Just got the jist!!!LOL

[1980RS]

Wonder why all the fuss over hypers, darn near ever GM car and truck has had them since the late 90's. Sure don't hear anything about them other than the piston slap complaints on the LS hyper ones. My 5.3 has hypers and 250K noisy for the 1st 30 sec. after that the engine runs perfect. I say run'em but with KB you need to run more ring gap on the top ring.

[af2]

Wonder why all the fuss over hypers, darn near ever GM car and truck has had them since the late 90's. Sure don't hear anything about them other than the piston slap complaints on the LS hyper ones. My 5.3 has hypers and 250K noisy for the 1st 30 sec. after that the engine runs perfect. I say run'em but with KB you need to run more ring gap on the top ring.

The first thing is the fact the knock sensors?

I might be wrong but the ones I have seen are 4032..