I have been reading conflicting posts about:

1) What is considered the EGT redline for the 325/600? 1250, 1350,1400, 1500? I have seen them all stated in one thread or another.

2) With the Ford 7.3l PSD, the consensus of belief was that the pistons were the most vulnerable to excessive EGTs (as opposed to the turbo). Is this different for the CTD? Most of the posts I've read warn of turbo damage as a result of excessive EGTs.

3) Is there something built into the stock 325/600 that monitors this, throws a code and defuels or otherwise does something to keep the engine from damaging itself? I have read somewhere that it will do this.

Experts, please clear this up.

Thanks,
Neil

 

the pistons will begin to melt at1250 and scorching the pistons rings and cylinder walls will be the first evident problem the turbo will be affected by cokeing of the oil and eventual loss of lubrication to the turbo bushings. under the fuel curve programed in the STOCK 600 there is not enough fuel and air to exceed these temps . I belive that the most thermal efficent egt temps are around 600-650 so this is probably where the egt should normally run however I don't know if it does.

 

Just my observations on my 555 hauling 10,000 plus. As long as my box is turned off the stock fuel curve won't allow mine to go over 1160*. I would imagine the Dodge fuel curve wouldn't allow the 600 to hurt itself with excess egt's either. Again, just my humble opinion...

-Richard

 

Sounds a lot like the story with the PSD. Pistons melt at 1250* - 1300* (sustained) or so. I guess we can ignore those posts that quote Cummins engineers claiming 1500* is OK. That would also imply that the special piston cooling in the CTD doesn't accommodate more heat than a PSD piston since they both appear to have the same melting point?

Also, there are several posts where owners of stock 600s claim that, while towing, their EGTs hit the wall. I guess DC is flirting with the ragged edge with its "fueling curve".

Moral of the story: Do anything but stock (except improving the breathing) and you'd better add gauges. But, we all knew that anyway

Neil

 

Big diesels its the same temp.Around 1250/1300 is max.

 

Read: https://www.dieseltruckresource.com/...threadid=47879

No way a piston melts at 1250.

 

um! yes way the piston starts to melt at 1250. meaning that any prolonged temps above 1250 will be causing metal fatigue and leading directly to catastropic piston failure. thats why we have piston cooling nozzles so the egt can safely exceed this temp for short amount of time and the piston can mantain integrety.If ya'll want to try runnig egt's of 2000 i'll gladly buy more stock in Cummins the parts business will be great

 

Let me rephrase that...melt at 1250 EGT. The piston (because of some of the reasons you stated above and other Banshee stated in his post in the link I just posted) never sees a continual temp that high. I must be real lucky if not, since you couldn't drive faster than 60 mph up here without exceeding those temps on 50 mile uphill grades up to 11,000 feet. I highly doubt Cummins would allow the engine in stock trim to exceed an allowable EGT. Most likely, there is a substantial factor of safety.

 

And...one more thing smarty pants, I never said anything about running at 2000.

 

There is a similar thread about this over on TDR. My truck is bone stock. WOT up a slight incline, I can hit 32 lbs boost, and 1300* EGT. Remember, this is unloaded, and NOT towing.

So, imagine if I had a ton of stone in the bed, and towing a trailer.

 

In the old days, I remember having pyro's on each cylinder to measure EGT's. There were cylinder to cylinder temp deviations too (yes, some ran hotter than others - some much hotter). With one centrally located sensor in our trucks measuring an average EGT, you could easily have one cylinder running real hot and masked by the others. It only takes one real hot cylinder hotspot to ruin your trip. Pistons may not melt instantaneously, but its happened to folks on this site.

Personally, I prefer to stay clear of the ragged edge. But if you wanna play, you gotta be ready to pay.

It interesting that no one ever argues that ice melts at 32F.

I also remember the requirement to have them calibrated. Not all guages and meters are created equally. There's no guarantee that each sensor is accurate out of the box.

 

[QUOTE]Originally posted by cquestad
. Most likely, there is a substantial factor of safety. [/QUOTE
Remember any idiot can build a bridge to hold a load, It takes an engineer to build one that just barely does. They're engineer's at Cummins there is little room for error very rarely will there be a substantial margin but yes at higher altitudes the melting point of would be higher allowing your higher egt's and probably not causing damage to your engine
P.S. my pants are pretty smart Thank You

 

What do you call substantial? I just happen to be a structural engineer, so I know a few things about bridges, buildings, etc, but would not call myself an expert in thermo or metals. I would think that a greater than 20% factor of safety would be the required minimum because of all of the variables mentioned above in order to provided a 100k warrenty. Most users of these trucks turn the key and go...they drive them blind, work the crap out of them and never discuss anything on a forum. I would bet it is safe to say that all blind users of 3rd Gens that pull any load some distance above sea level run into the 1300's all the time...for longer than just splurts. I have not heard of many or any engine faliures to to high EGT yet...

Also, I don't think that the 10-15 degree difference in melting point due to elevation will cover for the higher EGT's seen due to lack of oxygen. The factors of safety stack up real quick in an engine. They must account for all variables including manufacturering defects, user input/demand, fuel differences, etc.

I would not bet $7-8k on something with as many unknowns with out a factor of safety of this magnitude or greater. I wish somebody who really knows the answer would chime in...real world experience repeatidly discounts the 1250 mark IMHO.

 

thats exactly right drive them blind and everything STOCK the engine will NOT exceed operating capabilities. Manufacturering defects I assume you are talking about tolerences if its not within tolerences its not used simple as that it would not meet emissions. If you want I have a B5.9 cummins engine torn apart right now in my cousins shop (overhauling it out of an international tractor) after I finish feel free to melt the pistons. I worked the crap out of that tractor and it work under full load a hell of a lot more than any of these trucks ever will and the egt never exceeded 1150. I know i'm not gonna convince you but its real world try as you might you ain't gonna change it.

 

Ditto...I mean look at Sled pullers that are running STOCK pistons. 1300* no problem. I have seen trucks that just have double box and twins and HG to reach 1250 or higher.