Piston Issues Confirmed..I Think.

[JTS VENOM PERFORMANCE]

Muzzy provided a lot of good input. Pay attention to what he has to say.

Super... whatever is a complete idiot in my opinion. I'm surprised he can really type. Ignore him.

Roy,

As I stated in my PM, I have to work some this weekend, and my daughter and her husband just signed the papers on their first house. So between work, and helping them move, I will be a busy ape this weekend.

If I get the time I'm going to run some calculations on the deltas in cylinder pressures between a stock engine, and an engine with 5.6 pounds of boost. Now you will have to remember that this will be all theoritical (Yes, I'm drunk, and can't spell worth a shit). Cam profiles can have a dramatic affect on cylinder pressures. But still it may amaze you.

By the way, I'm not surprised by your pictures. You have to remember that head design dictates the flame travel within the cylinder, and you will have areas of the piston that are hotter than others. That is why you are seeing that pistons all failed in the same area.

Take care my friend. Hopefully I will get back to you later.

tell ya daughter congrats!:congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats:

oh and have one for me will ya


and yes Moparracing thats it, tell david to give you a stinker discount

 

[moparracing]

tell ya daughter congrats!:congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats:

oh and have one for me will ya


and yes Moparracing thats it, tell david to give you a stinker discount

thanks tony !

and congrats to your daughter on the new house, john !!!!

 

[AWDisuzu]

you're not running boost on stock pistons are you? shame!

I've cracked those areas on my forged pistons as well, in my other car.

 

[moparracing]

you're not running boost on stock pistons are you? shame!

not me....... just buying insurance.

 

[Silverback]

tell ya daughter congrats!:congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats:

oh and have one for me will ya


and yes Moparracing thats it, tell david to give you a stinker discount

Thanks Tony. They are really excited.

 

[Silverback]

thanks tony !

and congrats to your daughter on the new house, john !!!!

And thank you also Randy. They have done well for only being married for a year.

 

[bigike]

Hey Stinker

CAN YOU GET PRICES ON THE WIESCO PISTONS?

DO YOU THINK YOU'D START CARRYING THEM AT YOUR STORE.

 

[cobraken]

I just spent some time on the VCA forums looking at this issue. The Viper guys on today's forums are not reporting wholesale failures on either gen 2 or gen 3 motors. What gives????

 

[linemup]

I almost have 80,000 hard miles on my truck, and all this scares the hell out of me.

Time to upgrade!!!!

 

[Prof]

No time to be scared. Just act now.

 

[nycstev]

No time to be scared. Just act now.

After reading this shit I' m afraid to start my truck....

 

[FastRam]

I have seen damage like that in many factory pistons. Much more so in the past ten years or so. This is mainly due to design changes to help a couple things. First, by moving he top compression ring closer to the top of the piston you reduce the amount of unburned gases from combustion. That helps with emissions controls. Secondly, moving the rings up also helps reduce the amount of carbon buildup on the lands above the top ring. That helps reduce cylinder wear, blow-by gases and helps improve emission controls. Since the top rings on the newer engines are so close to the piston top, they get exposed to more pressure and heat from combustion.

Now take for instance a diesel piston...The piston is considerably taller and the rings are located about one third the way down from the top. Since most diesels are designed for massive amounts of torque and longevity, the rings are protected more from the heat and higher cylinder pressures.

Look at the profile of a true performance piston and they are not very tall (less surface area touching the cylinder wall, the less friction). Top ring is farther down from the top of the piston (usually both compressions rings are just above the pin), and the oil control rings will be right at the pin. The head of the piston has more material behind it to handle the higher pressures of FI and performance use. Of course the alloy's are much better.

Another thing to keep in mind is he design of the piston is only half of it. The other is what it is made of. You can have a casting and forging from the same alloy. The forging will be stronger because it has a more uniform molecular structure from being formed under high pressure and temperature. The casting is just poured into a mold and then finish machined to shape. All billet means is they took a forged block of metal and machined it to its final shape. Not necessarily better than a forging. So the alloy used is important and how it is used to make the piston is important. Then there are a number of coatings that can be applied for further improvement in performance.

Stock pistons are designed to do hold up to stock HP and pass emissions. That is name of the game for manufactures. Make the cheapest possible part that will survive long enough for the warranty to run out. It is sad, but often true.

-Muzzy

And another winner write up. Excellent :rock:

 

[nycstev]

Muzzy provided a lot of good input. Pay attention to what he has to say.

Super... whatever is a complete idiot in my opinion. I'm surprised he can really type. Ignore him.

Roy,

As I stated in my PM, I have to work some this weekend, and my daughter and her husband just signed the papers on their first house. So between work, and helping them move, I will be a busy ape this weekend.

If I get the time I'm going to run some calculations on the deltas in cylinder pressures between a stock engine, and an engine with 5.6 pounds of boost. Now you will have to remember that this will be all theoritical (Yes, I'm drunk, and can't spell worth a shit). Cam profiles can have a dramatic affect on cylinder pressures. But still it may amaze you.

By the way, I'm not surprised by your pictures. You have to remember that head design dictates the flame travel within the cylinder, and you will have areas of the piston that are hotter than others. That is why you are seeing that pistons all failed in the same area.

Take care my friend. Hopefully I will get back to you later.

Silverback is right on with his analysis of flame propogation and temperture gradiants. I had a feeling it was heat related.
Like I said .. I'm just fuggin skeered to start up my engine!

 

[Prof]

Not to overkill this issue but here are two more pictures of the broken land divider...note that there are two kinds of metal...the seam is dead center in the middle of the land wall...if heat is an issue...maybe the variance in thermal expansion, or thermal tolerance is a possible cause???

Had to get an old camera out to get the close-up...not great pics but you can see that the divider is two different metals!!!

A little help here engineers...

How about you Dodge engineers that are lurking around this thread...got any unofficial opinions?

 

[nycstev]

Not to overkill this issue but here are two more pictures of the broken land divider...note that there are two kinds of metal...the seam is dead center in the middle of the land wall...if heat is an issue...maybe the variance in thermal expansion, or thermal tolerance is a possible cause???

Had to get an old camera out to get the close-up...not great pics but you can see that the divider is two different metals!!!

A little help here engineers...

How about you Dodge engineers that are lurking around this thread...got any unofficial opinions?

Roy you ARE an engineer!

 

[Prof]

It was the working chemist in the house that raised the thermal expansion issue...can't claim it...Thank you Dr. Fouts.

 

[rottenronnie]

Well I am way over my head here...need some people with a lot more grease under their finger nails than I have.

But in the pictures below there seems to be some pretty strong evidence of a design flaw in our stock pistons...so take a moment to study the evidence as I see it.

Picture #1 is from what would be the drivers side of the engine with the pistons arrayed in correct sequence...and nothing looks wrong (I have removed the comprehension rings...)

Picture #2 is a closer look at pistons 1-5...

Picture #3 is a closer look at 6 - 10, still looking pretty good.

Now Picture # 4 is an over all shot of all ten pistons from the passenger side...

Picture # 5 and #6...Now there is some damage!

Note that all the ring land destruction is on the same side and begins at the same point...

If I were to reverse the piston domes for six more pictures you would see that the out side ring land on all ten pistons is damaged in the same way!

When my engine was disassembled every piston had cracks in the lands...once the pistons were pulled from the sleeves...the lands fell apart...and what you see is where I have pulled all of the cracked lands out after removing the compression rings.

I think that we see in my ten pistons that the outside of our pistons for some reason crack the lands...which can then lead to pieces falling out, and destroying engines...I may have been minutes away from Boom...

Any other conclusions from some of you wrenches???

Roy...

I.M.H.O. It is the same problem we discussed when your engine started having blow-by issues.
Here is something that someone else wrote on the topic....

http://www.acl.co.nz/Tech/Detonation; The deadly enemy.pdf
Take note of the comment about cracked/broken lands on the same side of the pistons (thrust side). Under- What Are The Effects Of Detonation?

Twin Screws Build Boost sooner than other designs. Certainly sooner than Paxtons.

Quick Boost/Heavy Vehicle/Major Tuning Challenge; but not an impossible one.

I'm glad you caught it in time. When cast/hypereutectic pistons fail, they generally make a bigger mess than forged ones that are more malleable.


Take care,

Ron (Yes, I'm Done On This Topic Now)

 

[Prof]

Super perspective...but I am still surprised by all ten having precisely the same indications...maybe three or four...but all ten...still thinking...and it hurts.

 

[SlvrSnake]

Maybe I missed it but I have not seen a repsonse on whether or not the Viper cars have this problem (assuming they do not). If not could it possibly be that the extra weight of the RAM SRT-10 is a contributing factor to this detonation issue? That is, since the RAM is so much heavier the loads put on the engine are causing more failures. This motor was designed for a Viper car not a truck. Any thoughts on this? Just a question.

 

[Prof]

Another variable in this issue!

There have been some piston issues in the Vipers, but going to Viper Alley and looking for straight information is difficult at best. The environment and culture there is so negative that few are willing to share problems.

Even here there are lots of people who just will not share their problems with these trucks...

That being said...weight is an issue...in my mind. But only one of many.

This has been fun...lots of great input...no real solutions in my mind, but lots of great exchange...and maybe just a good eduction in the complexity of modification of these wonderful engines.

There are lots of things in life that we don't resolve, but the quest for answers is a lot of the fun!

Drive em like you stole em...and build as strong as your budget will allow.