Piston help

[evilmopar]

Hi everyone! I have a .060 over 400 block with KB hyper pistons, i replaced one last year 'cause of a broken skirt and now i have bad knock from another, so instead of replacing that one or all of them, i want to know if there is any manufacturer that makes forged hi comp ones (not custom hi $$$ ones), or should i junk that block and try to get a std bore block?

 

[Lefty71]

I personally would not spend $600+ on a set of pistons for a .060" over block. I would definitely spend even more and start over with an unbored block, since they are still quite easy to find. Of course, you may luck out and find a cream puff that you wont have to buy pistons at all for, they are still out there. It all depends on your intended use and desired performance level. HTH, Lefty71

##EDIT## I didn't notice that you were in Sweden, but that still may not change my opinion much, just makes the cost even more..... if you are knocking, you probably need a bore job, and you are already at the end of the road for that block.

 

[66Satellite47]

I sure wonder why you break pistons.

 

[evilmopar]

I sure wonder why you break pistons.

I've been running the engine turbo charged for 6 years with 12-14psi of boost but now i threw the the turbo away got hold of a set of doug's fenderwell headers for my 64 sport fury so i decided to go N/A. I think the skirt broke due to unsafe handling of the piston outside the engine. But now i have no clue. Will tear the engine down in a few weeks and examine it closer.

 

[evilmopar]

I personally would not spend $600+ on a set of pistons for a .060" over block. I would definitely spend even more and start over with an unbored block, since they are still quite easy to find. Of course, you may luck out and find a cream puff that you wont have to buy pistons at all for, they are still out there. It all depends on your intended use and desired performance level. HTH, Lefty71

##EDIT## I didn't notice that you were in Sweden, but that still may not change my opinion much, just makes the cost even more..... if you are knocking, you probably need a bore job, and you are already at the end of the road for that block.

I travel to the states pretty often and have good shipping connections . My performance level is...i wanna run high 10sec - low 11sec runs in my all steel 64 sport fury. I have a 727, cope manual valvebody and more with 4K stall, Dana 60 4.10 gears. Engine has trickflow 240 heads mech 1,6 rockers, team g intake, quickfuel 950 race carb, hyd 303/312 duration, .504/.528 lift, need new solid cam and more compression at least and a better intake and maybe a 150 shot

 

[Lefty71]

I travel to the states pretty often and have good shipping connections

Oh, ok, so that reinforces my original opinion.
So if no one else hooks you up, or you can not find something to your liking, let me know. I've got a selection of 400's here that are stored inside, prolly all standard bore, just waiting to become strokers. I've no clue what a good price would be, but im sure that can be dealt with. HTH, Lefty71

 

[Challenger340]

There is the difference between theory and reality.
The "theory" being that KB Hyper's are just ducky for Boost/Turbo or Nitrous applications.... ***-u-ming... a patent tune can be maintained to stay away from things like detonation, which invariably the "reality" is that almost never happens.

IMO,
start afresh with a new Block, default a FORGED Piston this time, and more importantly look for a 2618 Alloy FORGING,
NOT....
the cheaper 4032 Alloy Forged Offerings which are also similar to a Hyper in high silicon content and NOT rec'd for Boost/Nitrous beyond maybe 100 shot or 6-8 psi MAX assuming a good tune.

If you are still contemplating 12-14 psi Boost, you should be talking a Custom 2618 Forging, Cam & Barrel design Skirts, Heavier Pins, and moving the Top Ring Land downward away from the Heat.
Get off your wallet !

 

[Challenger340]

I travel to the states pretty often and have good shipping connections . My performance level is...i wanna run high 10sec - low 11sec runs in my all steel 64 sport fury. I have a 727, cope manual valvebody and more with 4K stall, Dana 60 4.10 gears. Engine has trickflow 240 heads mech 1,6 rockers, team g intake, quickfuel 950 race carb, hyd 303/312 duration, .504/.528 lift, need new solid cam and more compression at least and a better intake and maybe a 150 shot

A well built 440 can do that easily, the 150 shot just pushes farther down into the 10's.

Go read up in the builds section, plenty of ideas there as more then one way to "skin a cat" so to speak.

 

[zyzzyx]

I have no experience with turbocharged car engines, but putting 10 psi. boost on Hypereutectic
pistons does not sound good to me! Cast an Hypereutectic pistons have different amounts of
porosity in them, and so they can't get rid of the heat fast enough and they fail. Forged pistons
are dense, and therefore they can dissipate the heat better. Also, if you put the correct pistons
in your motor for 10 psi. of boost and then went N/A That would be too low of a compression ratio.
I would definitely start with a fresh block and go from there.

 

[vance.dykes]

I travel to the states pretty often and have good shipping connections . My performance level is...i wanna run high 10sec - low 11sec runs in my all steel 64 sport fury. I have a 727, cope manual valvebody and more with 4K stall, Dana 60 4.10 gears. Engine has trickflow 240 heads mech 1,6 rockers, team g intake, quickfuel 950 race carb, hyd 303/312 duration, .504/.528 lift, need new solid cam and more compression at least and a better intake and maybe a 150 shot

the cam is a little small 11.5 to 1 comp, and NO N.2.O DON'T NEED IT i ran 10;67 @ 127.65 3400 pound car.

 

[evilmopar]

I have no experience with turbocharged car engines, but putting 10 psi. boost on Hypereutectic
pistons does not sound good to me! Cast an Hypereutectic pistons have different amounts of
porosity in them, and so they can't get rid of the heat fast enough and they fail. Forged pistons
are dense, and therefore they can dissipate the heat better. Also, if you put the correct pistons
in your motor for 10 psi. of boost and then went N/A That would be too low of a compression ratio.
I would definitely start with a fresh block and go from there.

Yeah iknow about the hyper pistons and boost, they didn't fail on me.. i was lucky . I ran e pretty safe tune pretty rich and not so much ignition. I did get the thinnest headgasket to get as much compression as possible (150psi on starter) with a fresh set of rings. Thats why i wonder if anyone makes a of the shelf forged piston to a 0.060 over 400 block or do i have to junk the block and get a std one and build a stroker? Or if i should just replace the failing piston be happy and save $$$ and buy a 572 Hemi

 

[evilmopar]

There is the difference between theory and reality.
The "theory" being that KB Hyper's are just ducky for Boost/Turbo or Nitrous applications.... ***-u-ming... a patent tune can be maintained to stay away from things like detonation, which invariably the "reality" is that almost never happens.

IMO,
start afresh with a new Block, default a FORGED Piston this time, and more importantly look for a 2618 Alloy FORGING,
NOT....
the cheaper 4032 Alloy Forged Offerings which are also similar to a Hyper in high silicon content and NOT rec'd for Boost/Nitrous beyond maybe 100 shot or 6-8 psi MAX assuming a good tune.

If you are still contemplating 12-14 psi Boost, you should be talking a Custom 2618 Forging, Cam & Barrel design Skirts, Heavier Pins, and moving the Top Ring Land downward away from the Heat.
Get off your wallet !

No i've given up the turbo thing, generates to much heat and hard to fit a good setup under the hood without gutting the car. So my goal is a well built N/A engine with just a splash of nitrous if needed. I run studs and girdle on the bottom end at the moment but no boost or nitrous due to missmatched parts. I have a brand new set of puschrods and solid lifters for the B-block on my shelf so my aim is a good empty 400 block to start fresh. I have good heads and a good carb so some money do i save there

 

[vance.dykes]

call https://www.manciniracing.com/ they have what you need and they are a mopar parts house. i used wiseco pistons and there forged well worth the money stage 6 alu, heads 600 soiled cam by crane 950 holley

 

[33 IMP]

I've been looking at Icon pistons, they seem to have a nice selection for mopars. I also believe one of our members here has a son/brother/cousin (sorry i don't recall exactly) who works for icon. You could maybe start a thread to ask.
I have found that the icons seem to be cheaper at jegs, than summit. The ones i was looking at were $30 cheaper plus a $50 promo discount.

 

[Cranky]

There's no way I'd run boost of any kind or even the laughing gas on a cast piston. The KB hypers are just a better cast piston. A small shot of the gas is usually ok on a cast slug but you still need to know what you're doing to make the piston last.

 

[BSB67]

For 30 years everyone ran 0.060" over blocks. Now, apparently, they are strictly taboo.

Your power requirement just is not that much. Take it apart, take it to the machine shop, have the holes measured to see where they'll clean-up to, and do a thickness check. Then you can make an informed decision. To think that a 0.060" is bad, but a 0.030" block is good is just silly. You don't know what you have until you measure it.

Is this a std stroke 400? Off the shelf piston options will probably be limited.

 

[Challenger340]

No i've given up the turbo thing, generates to much heat and hard to fit a good setup under the hood without gutting the car. So my goal is a well built N/A engine with just a splash of nitrous if needed. I run studs and girdle on the bottom end at the moment but no boost or nitrous due to missmatched parts. I have a brand new set of puschrods and solid lifters for the B-block on my shelf so my aim is a good empty 400 block to start fresh. I have good heads and a good carb so some money do i save there

If all you wish to do is run low 11's / High 10's NA.... with the odd shot to push lower 10's occasionally ?
and,
you already have TF240's ? the Car setup with 4,000 stall / 4.10's and some Traction ?
just say'in here...
dunno your weight.... but just sounds like a KISS Formula albeit "well built" .030" over 440 Forged Crank combo to me ? and pretty much Solid F.T./ 91 Octane range ? (with C16 in a 2 Gal pony tank/pump for the NoX shot, Pump Gas normal)

You at some kind of weird HIGH Elevation or something ? What's the problem ?

 

[Challenger340]

For 30 years everyone ran 0.060" over blocks. Now, apparently, they are strictly taboo.

Your power requirement just is not that much. Take it apart, take it to the machine shop, have the holes measured to see where they'll clean-up to, and do a thickness check. Then you can make an informed decision. To think that a 0.060" is bad, but a 0.030" block is good is just silly. You don't know what you have until you measure it.

Is this a std stroke 400? Off the shelf piston options will probably be limited.

I agree ?

 

[33 IMP]

Parts, cores, and american engine expertise harder to come by in Sweden.

 

[evilmopar]

For 30 years everyone ran 0.060" over blocks. Now, apparently, they are strictly taboo.

Your power requirement just is not that much. Take it apart, take it to the machine shop, have the holes measured to see where they'll clean-up to, and do a thickness check. Then you can make an informed decision. To think that a 0.060" is bad, but a 0.030" block is good is just silly. You don't know what you have until you measure it.

Is this a std stroke 400? Off the shelf piston options will probably be limited.

I just assume the block to be junk since no one makes pistons for it except KB the hyper ones i use and headgaskets are pretty limited with the 4.4" bore (i know summit has some mls gaskets i've used them)... and as a said before, i've been running this engine (pistons, rods, crank) with up to 14psi of boost without any problems for 5 years. But now when i need more compression and "better" pistons no no makes them, if i don't wanna spend $$$$.