CR melted piston discussion, why, why not, and for the love of god how not to..

I had a R38 so my timming wasnt adjustable on that end.

I have Flux 7.5's so there was plenty of fuel for cooling if it were going to do it. I did not have my water up and running yet.

I could see Marcos point on the rpms somewhat but a hot spot can not increase the timming unless the fuel is there to burn through the actual injection event.

I really wish the term running lean would just freakin go away already, these are not gas engines for cryin out loud. If running lean was the issue then every stock engine would melt down, it just does not make sense. It just has to do with the amount of heat introduced to the piston crown.
 
There's still a difference between a lean burn, where the fuel all has enough air to burn nice and clean and more heat and power results, and a rich burn, where the fuel burns partially and results in less heat, less power, and smoke.
 
bdp said:
I had a R38 so my timming wasnt adjustable on that end.

I have Flux 7.5's so there was plenty of fuel for cooling if it were going to do it. I did not have my water up and running yet.

I could see Marcos point on the rpms somewhat but a hot spot can not increase the timming unless the fuel is there to burn through the actual injection event.

I really wish the term running lean would just freakin go away already, these are not gas engines for cryin out loud. If running lean was the issue then every stock engine would melt down, it just does not make sense. It just has to do with the amount of heat introduced to the piston crown.
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Call it fuel challenged, I don't care what you want, its a hotter burn than when its over fueled period.

Pullers running sigma's are still in the lean condition under full fuel?? That excess is sinking a pile of heat.
 
I believe with the 12Vs injectors lower pressure/bigger holes may be wetting the piston and actually cooling them. The CRs high pressure/smaller holes may be burning like a blow torch. Add multible injection events/longer duration it's not hard to figure higher piston temps even though the exhaust manifold temps don't show it. With lots of drive pressure you may be getting higer in cylinder temps and showing less in the exhaust manifold. There seems to be a fine line when tuning CRs so be careful.
Billy
 
I wouldnt compare a stock trucks lean, to a modded trucks lean.. theres a huge diff. the biggest being air.. a stock truck is already setup to burn ediquete fuel from the factory where as we are increasing rp and timing and adding more air but cannot find a way to not burn all the fuel... tuff to say that, but its true...
 
heres my truck pulled apart last night.. got 1 and 4 head looks great....
 

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Yes cr's will melt a piston because the burn is more effiecent creating more heat in the cylinder then what egts show this I will agree with. Just lose the f'in term lean. You want to burn the fuel thats in the cylinder, that is why we add more turbo. The problem is the way it is getting injected and the amount of time it takes to do so.

My truck smoked as much as a 12v 3.0 truck and melted the pistons, there was plenty of fuel there to do cooling if it was going to do it. It is infact even worse on a cr to have that much fuel because the flame is so hot in the cylinder adding more fuel just turns up the torch even more making them melt even faster.

I wouldnt compare a stock trucks lean, to a modded trucks lean.. theres a huge diff. the biggest being air.. a stock truck is already setup to burn ediquete fuel from the factory where as we are increasing rp and timing and adding more air but cannot find a way to not burn all the fuel... tuff to say that, but its true...
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With that reasoning someone should be able to have a stock truck, add injs, programmer, stack a couple boxes and never worry about melting the pistons. Why worry there isnt enough air to run LEAN so it should never melt right? I think we should all run turbo's way too small so we dont melt pistons.....
 
I know.... the lean thing is driving me up the wall. That is the whole principle of a diesel to make good clean power. The problem that we are dealing with here is piston temp. Plain and simple.
 
bdp said:
Yes cr's will melt a piston because the burn is more effiecent creating more heat in the cylinder then what egts show this I will agree with. Just lose the f'in term lean. You want to burn the fuel thats in the cylinder, that is why we add more turbo. The problem is the way it is getting injected and the amount of time it takes to do so.

My truck smoked as much as a 12v 3.0 truck and melted the pistons, there was plenty of fuel there to do cooling if it was going to do it. It is infact even worse on a cr to have that much fuel because the flame is so hot in the cylinder adding more fuel just turns up the torch even more making them melt even faster.



With that reasoning someone should be able to have a stock truck, add injs, programmer, stack a couple boxes and never worry about melting the pistons. Why worry there isnt enough air to run LEAN so it should never melt right? I think we should all run turbo's way too small so we dont melt pistons.....
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Diesels have more air than a gas engine anyday in stock trim and most modded applications, Yes a diesel can be lean, lean on air or lean on fuel, 02 sensor testing can reveal this more clearly.
I feel that the reason for melting diesel pistons is very clear, partially lack of real life adjustable tuning, diesel's get hot on there own, add more boost, rpm,timeing and 26000PSI of multiple metal slicing fuel shots to a allready hot piston, and well thats what started this thread.
 
Im not saying we should all run stock turbo's im going back to the fact that everyone is saying we are melting pistons do to being to lean?? this would be because of air or fuel nothing else could make a truck run lean we dont have programming to allow to make the truck run lean.... nothing is standalone yet that is around anyone on heres price range...lol def. not mine.. Im only stating that it does have to do directly with the piston design. judging by my pistons I would say this insane rail pressure is causing problems for the injectors which in turn causes the nozzle to crack and fuel spray rapidly and wildly....
 
pulling fuel out at full load (full throttle, full boost, full operating temp) can melt pistons on a diesel engine.
 
Cylinder temperature increases as you reach the stoichiometric condition as it produces the highest flame temperature, after that cylinder temp drops, and is used as a way to control NOX emssions, want me to dig up a SAE paper?


Water injection is your friend, more so if you need more than 11 seconds at a insane power level.

If anyone thinks they can tow with 1000hp simply because they have enough air and tuning....think again...your going to have a mountain of melted pistons.
 
I started a new thread, lets see if we can make a pattern as to who has melted pistons.
 
I've gone through this whole thread and just a thought here: What woulf happen, minus losing power If we ran stock RP and still ran Big inectors and a lot of fuel? Would it be more like a 12v deal with drowning the cylinder with fuel to keep them cool? or what if we had full fuel and 140% calc engine load at 4krpm? ust thinkin out loud...
 
HIGH TECH RAM said:
I've gone through this whole thread and just a thought here: What woulf happen, minus losing power If we ran stock RP and still ran Big inectors and a lot of fuel? Would it be more like a 12v deal with drowning the cylinder with fuel to keep them cool? or what if we had full fuel and 140% calc engine load at 4krpm? ust thinkin out loud...
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Was thinking about this as well today--

turning up the mp-8(rail pressure) and its just like turning up the cutting torch

I'd gladly be down 50hp if I didnt have to replace some pistons.:rockwoot:
 
HIGH TECH RAM said:
I've gone through this whole thread and just a thought here: What woulf happen, minus losing power If we ran stock RP and still ran Big inectors and a lot of fuel? Would it be more like a 12v deal with drowning the cylinder with fuel to keep them cool? or what if we had full fuel and 140% calc engine load at 4krpm? ust thinkin out loud...
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That is another pattern trend that i am seeing, hopefully more will fill out the poll thread.
 
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