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BROKEN PISTONS at 7 PSI

49K views 27 replies 10 participants last post by  LivernoisMotorsports 
#1 ·
I have broken the upper ring lands on 4 pistons of the drivers side of my procharged 6.4, but the pistons are perfect on the passenger side. Anybody have this happen before? Engine = P1 blower with 7psi, stock pistons, stock shorties good exhaust. Reputible tuner....I think its strange that all 4 on one side are bad and the other bank isnt. Can the knock detector or o2 sensor affect only one bank? I am rebuilding with good parts but want figure out why I had this issue on one bank only so I dont do it again.
I have pix but cant figure out how to attach them... Any help is highly appreciated.
 
#3 ·
That's EXACTLY why most put the 6.1 intake on. The angle in the neck of the 6.4 intake causes one bank to be rich and the other to be lean. Tuning boost with that intake is tricky at best.

There are actually several threads around where is has been discussed along with the boost limit of ~6psi for stock pistons.

I hate that it happened to you but hopefully the damage isn't horrible.

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#6 ·
If there was shrapnel, whatever you do, don't reuse that intake!!!! That hot metal melts into the intake and won't come out until it all gets hot again, then it gets sucked right into the engine and you'll be starting all over again.

There are some 6.1 intakes on car-part.com in the $350-$400 range. You should be able to score one reasonably.

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#10 · (Edited)
Being that I'm running a Stock BGE with a SRT cam from a 2017 Ram at nearly 11psi, short bursts, nothing long. What did the eng do when you lost the ring lands? Just so I know what to look for, just a matter of time I guess. I want to see what this engine is made off, then it will become a 426 when it does go. That was 10.7psi at 4100rpms, haven't pushed it to redline, not sure how much boost i'll have at redline, still tweeking tune.
 
#11 ·
The motor started to miss when a piece of the ring land closed the plug gaps in one cylinder. Honestly had it not been for the miss I wouldnt have looked at the motor. I jumped on it getting on the freeway broke loose a bit, no big deal, minimal rpms and boost. I drove a few more miles on the freeway in building traffic and held second gear at about 3500 for a minute or so when the miss started. Other than the miss due to the closed plug gap there was no other signs, no smoke no sudden change in power or any other signs. I even pushed the clutch in and revved it a few times to see if it would clear. After looking at my combustion chamber I wish I had turned it off and had it flat bedded. Interestingly enough, the other 3 cylinders are missing pieces of piston but look fine, no damage to the head.
 
#23 ·
Any of you guys have any luck with 12-14psi on the stock 6.4 manifold? Ive heard they do ok up to 14 then start pushing the seals. Im in California and would like to give the impression of a stock motor for the visual. I know some of you have mentioned the uneven distribution but money is going to be tight with the rebuild and would rather not have to buy ab edelbrock or 6.1 if poss right now.
 
#24 ·
I'm not trying to be Captain obvious, but you're already going to need to replace the intake due to chance of shrapnel in it anyhow. The last thing you want is a stray piece of metal to get back into a brand new engine.

Spend the money on the 6.1 manifold. Your tuner will thank you, your engine will thank you.

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#25 ·
Yeah its weird how when you break ringlands, one chamber can be all f'red and the rest will be fine.

On my whipple I blew 6 out of the 8. Only one cylinder on the head had damage.

I will tell everyone from now on, regardless of what they say. To build your bottom end. Save yourself the trouble. And when they don't do it, and WHEN they blow, I can say I told you so. :p
 
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#26 ·
Sounds like a good time to try out our drop in piston and rod upgrade. if you have not decided on a rotating assembly check this out!This kit is designed and engineered to be a perfect fit for your existing 6.4L Hemi engine. The components are designed to exactly match the weight of the stock components, allowing the pistons and rods to be installed in the engine without having to remove or balance the crankshaft.In addition to the built in balance of the components, the pistons have also been designed to be a perfect drop in fit for your existing 6.4L Hemi engine. The pistons have the appropriate piston to wall clearance built in, so all you need to do is install them, no machining of the block necessary.This kit allows replacing the weak factory rods and pistons with heavy duty, custom engineered replacements, built for power adders, all without requiring any machining work on the block, or balancing of the stock crankshaft.Kit includes the following:· Custom 6.4L Hemi Pistons (Built for boost, 2618 material, thicker ringlands, coatings, heavy wall pin)· Stainless Steel Ringset (Boost Ready)· H-Beam Forged Connecting Rods· Tri-Metal Performance Rod Bearings
 
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