Engine/Transmission (1998.5 - 2002) Discoloration on used 1998 5.9 L Diesel? I'm new looking for help.

[Sticks]

...
Maybe we should just cut to the chase and the REAL reason so many guys put the pyro stinger in the manifold instead of the downpipe? It's a lot easier to drill and tap a hole in the manifold than it is to weld a bung into the downpipe.

And there we have it!

 

[NIsaacs]

Oddly enough that engine that has supposedly been way too hot doesn't even have all the exhaust stud spacers rusted. It doesn't look like all the paint on the cylinder head is burned off adjacent to the exhaust ports.

The stud spacers are not in the exhaust flow, they are only getting hot temps from heat sink. The head is water cooled with flush mounted ports. The 12 valves with the extended exhaust ports did burn the paint off.

I have always wondered why the long bolts and spacers, It's like they continued to use the long 12 valve bolts rather than use short bolts, just seems odd to me.

Nick

 

[CM_Guest]

Sorry, but I've seen plenty of 24-valves with the paint burned off the spacers.

 

[Joseph Donnelly]

Your thinking CJ seems to be that the pyro probe should be where the engine manufacturer recommends, right? Look at the pyro probe on a 2013-14 Cummins 6.7.

 

[NIsaacs]

Sorry, but I've seen plenty of 24-valves with the paint burned off the spacers.

You are too quick to judge/chastise in your response, try reading your own post. Nothing was said about paint burning off the spacers by you or me.

Nick

 

[Woodenhead]

Not sure why I'm getting in the middle of this nonsense but why all the aggression here? There are plenty of other forums that thrive on this crap if that's what you're into. This forum has been built on peaceful productive discussion, Max14 asked a simple question how the heck did it turn into this?

My understanding is that the reason we monitor EGT temps in our modified trucks is to avoid reaching prolonged temperatures that will do damage to our engines such as melting pistons. So wouldn't it make sense to place the probe as close as possible to the heat source to get the most accurate temps? It's common knowledge that 1250F pre-turbo is the limit for sustained temps and anyone that's been around these things for a while has witnessed the damage that occurs when that rule is broken.

Also, for the record please include me in the class of DIY yahoos that decided I needed an EGT gauge on my overfueled engine.

 

[BSeyler]

Oddly enough that engine that has supposedly been way too hot doesn't even have all the exhaust stud spacers rusted.

Semantics, I guess.

 

[Woodenhead]

I have no doubt your sled puller buddy is running 2000F during a pull, this is not at all uncommon for pulling or drag racing. I'm curious, was the 2000F pre-turbo or post turbo? Sled pulling or drag racing is not considered sustained temperatures, pulling a long grade with a heavy load is what I'm referring to when I say 1250F pre-turbo is a good rule of thumb for safe temperatures. Your buddies sled pulling truck would likely not survive 2000F for 1/2hr, if it does then he's got something worthy of a patent. I'm not guessing here, or basing this on hearsay, there are plenty of melted pistons out there to prove this. If you disagree, please tell us at what sustained temperature do you risk damaging your engine? Is it be better to measure this post turbo instead of pre-turbo or?

Also, I see no reason not to put a probe in the down pipe or anywhere else in the exhaust system if that gives you a good comparison with the data you are working with. If manufacturers are putting them in the down pipe then they have there reasons for wanting to measure at that point and that's where they want to get data for there ECM, makes perfect sense to me.

CJ, I'm not trying to attack you here, just trying to have a discussion.

 

[NIsaacs]

I have always wondered why the long bolts and spacers, It's like they continued to use the long 12 valve bolts rather than use short bolts, just seems odd to me.

Nick

I did call them stud spacers once, just kinda repeating you I guess.

Nick

 

[NIsaacs]

Wow, you're REALLY sneaky and clever. Not. Here's what you said. "The stud spacers are not in the exhaust flow, they are only getting hot temps from heat sink. The head is water cooled with flush mounted ports. The 12 valves with the extended exhaust ports did burn the paint off."

Clearly your implication was that 24-valve engines don't burn the paint off the spacers. Otherwise why mention 12-valves engines? And by the way, neither 12V or 24V engines use studs to hold retain the exhaust manifold to the cylinder head. They're cap screws.

My implication was the 24v don't burn the paint off the head at the exhaust port because they are flush ports, real close to the water supply, but that 12v do because they are extended out from the head.

Nick

 

[Tractorat]

Shades of "Harvey Barlow"

This thread compels me to ask a question.
I bought my 02 brand new a week after 9/11. The only mod is an edge ez and a 4" exhause. The heaviest thing Ive ever towed is my 4k lb TT.

The turbo, although not as orange as the one in the above post, is a very light yellowish orange. I drive pretty conservatively, and this truck has never gotten hot. So why would the turbo be discolored ?

 

[SnoKing]

The clear coat that they applied to it yellows over time! And I have to asked, did you put your pyro probe pre or post turbo and why? Chris

 

[JR]

View attachment 88344

No post turbo pyro here.

 

[Max14]

Thanks guys for your insight. I haven't been able to digest all of the information yet but I will be working on it. I didn't make a move on the truck I had shown the picture for. Based on some of the comments that sounds like I made an ok decision. Thanks again.

 

[NIsaacs]

And I have to asked, did you put your pyro probe pre or post turbo and why? Chris

Three Cummins diesels, all with mild power mods and post pyro's. I use 1000* as my max sustained temps. The 2 Dodge's are opperated at 1700-2300 rpm when under full power, the Ford runs at 1600-2100 rpm. As long as I stay in that rpm window I can bend the floor board, if I get under or over, the temps will creep up, so I don't do it.

Nick

 

[Tractorat]

The clear coat that they applied to it yellows over time! And I have to asked, did you put your pyro probe pre or post turbo and why? Chris

I believe it is post turbo. I had it installed by "The Power Shop" in enumclaw if you know who they are. I left it up to their discretion. From where it is placed, they said that 1300 is the upper end for safe operation.

 

[SnoKing]

I believe it is post turbo. I had it installed by "The Power Shop" in enumclaw if you know who they are. I left it up to their discretion. From where it is placed, they said that 1300 is the upper end for safe operation.

That is an interesting post turbo number and would relate to a pre turbo number of around 1550 and melted pistons, if you pulled a long NW grade at those temps. The Power Shop is well noted in the area, so that number from them is quite surprising! Chris

 

[Tractorat]

Well then, maybe it is pre turbo They didnt tell me the location and I didnt look (dont know what I'm looking at anyway). Just for grins, I think Ill give them a call today and ask them just where they would have placed the probe. Yes, they have a very highly regarded reputation which is why I go to them even if it is a long drive from here. Chuck Arnold has forgotten more about diesel than most diesel guys know.

 

[SnoKing]

Well then, maybe it is pre turbo They didnt tell me the location and I didnt look (dont know what I'm looking at anyway). Just for grins, I think Ill give them a call today and ask them just where they would have placed the probe. Yes, they have a very highly regarded reputation which is why I go to them even if it is a long drive from here. Chuck Arnold has forgotten more about diesel than most diesel guys know.

Look at the first picture in this thread and see if you see a similar fitting on the exhaust manifold close to where the turbo is bolted onto the manifold. Chris

 

[Tractorat]

Yup, thats where mine is. I thought that would have been considered post turbo. But then, Im not a mechanic. I discovered years ago that if I give someone a little money, magic happens.