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New to the 6.5 TD HELP

You still atleast need and fan and fan clutch. Only 99-00 had a updated fan and balance flow water pump. If you ever tow you will want your Tstats IMO. You also need to CLEAN THE PISS out of the radiator and oil coolers then do it again just for good measure (i suggest doing this yearly depending on how many mile you put down).
 
ok i will look into getting the fan and clutch this week. i was actually thinking about just getting an all aluminum radiator and elimintaing the plastic tanks. so get a new99-00 water pump and and matching year fan and clutch right?
 
If I may, let me add a little science to the discussion of egt and it 's effects on pistons and coolant temperatures.

I'm not taking sides or discounting anyone, just describing the mechanisms behind it. I'm going to try and keep the language plain english, so some of the examples i use may not meet strict engineering accuracy.*

What many average Joes don't quite get a grip on is the dynamics inside a combustion chamber in a compression style engine, be it spark or compression ignited.

The thing relevant to this discussion is a property known as "boundary layer". *In a nutshell, this is an insulating layer of "air" that keeps the actual combustion process off the metal in the engine. This is why egt's in excess of the melting point can be sustained in the engine.*

What kind of happens is the ignition of the fuel source creates a wave of air in front it. It burns some of the air in the cylinder and displaces some (ie: the wave). *Since it's in a closed cylinder, it expands in all directions trying to fill the volume of the container. This wave reaches the limits of the container first and "piles up". *The combustion hits this layer and since it was not mixed with the fuel it insulates. Air not mixed with fuel does not burn. This layer insulates the cylinder components the same way a double pane window or fiberglass batting insulates your house.

An interesting fact is that the boundary layer is thicker at the piston crown and the head chamber than the walls. This is also important in understanding the cooling system impact. The crown is (within limits) protected from temperatures above aluminum melting point by the layer, as are the heads. Things like piston oil cooling jets or ceramic coatings further improve heat handling capabilities. Bit this boundary layer effect is how components can survive temperatures seeming over the temperature limits of the parent materials themselves.*

However, with respect to the cooling system it is important to note that the boundary layers at the cylinder walls are as much as half the thickness of the crown/head. There's various reasons for this that i won't bother going in to here. But what is important to us is that this means more heat is tranfered to the walls than the crown/heads due to lessened "insulation" properties.*

Fortunately, with the cylinders surrounded by the water jackets it can transfer the heat away relatively quickly. The harder you work the engine, the more heat is tranfered away by the cooling system and this is evident on the water temp guage. Run it too hot (more and more fuel for longer periods) and the cooling system starts to become insufficient. Then things start to repond to the thermal load. *Lots of things happen, bit the main impact to joe driver is piston to wall clearance eventually reduces to the point of scuffing. Push it too hard too long and failure is going to happen.

You can melt pistons from combustion only, but it is highly dependent on the insulating properties of the boundry layer. Get too hot and more heat makes it across the layer, same as a window begns to get colder on the inside payne as the temperature continues to drop outside.
Like anything, run it too hot and you can eventually exceed the ability of the physics inside the engine to protect the parts and they fail. *"Melted" pistons are more a function of improperly mixed fuel that makes it to the crown in liquid form vice atomized in the injection event. This is far more likely to be caused by a malfunctioning *injector than anything else although there are other ways for liquid fuel to make it to the crown. Cracked crowns are often a function of timing errors (ie:eek:ver advanced) or life cycle fatigue. Cracked crowns cited as overheating are often misdiagnosed faults or are caused by scuffing/siezing events and the resulting forces.*

Now, outside of the cylinder there is no boundary layer so you have to rely on the properties of the materials themselves or whatever cooling methods that are engineered into the component. That may very well be your limiting factor for egt vice the combustion chamber.

So, keeping egt's lower is a good idea but maybe not for the reasons that people have commonly thought.
*
Heres an abstract from a technical paper if you want to give it a once over and come to hour own conclusion: *http://www.sciencedirect.com/science/article/pii/0017931084901698

Remember: theres always more to it all than an abstract from one little paper....

:)
 
I ended up with some ok numbers on the dyno with an ATT and stock cam (274rwhp, 430ft lbs) so it is not a bad combination. It really helps to have a tune matched to the ATT
 
Hi BJ! Nice to see ya around again.

Good numbers, 6.5! You can commute with that!
 
JiFaire said:
Hi BJ! Nice to see ya around again.

Good numbers, 6.5! You can commute with that!
Click to expand...

I'm around on an infrequent basis.

Your 8 track reference gave me a giggle.

My last dyno session netted high water mark was 271.9 hp @ 3200 rpm / 446.3 tq @ 1900 rpm on a dyno dynamics chassis dyno. That's right around a stock LB7 and about the limit for a stock 4L80E (actually, a touch over the oem torquerating)

I've also come to the personal conclusion that tdco and optic bumps are not the way to go if you have other means of altering the calibration. With these trucks, pogramming is the solution. Those numbers above were with normal fueling rates (ie: no optic bump) and normal advance (ie tdco set within factory specs). The calibration files give you all the control you need. Makes for a nice, quiet, well behaved driver that "can get it on" when needed.

I've backed off that by about 20hp or so, but i also picked up approx 5 mpg. Thats a trade off i think anyone would be happy with.

Flirting with breaking 20 mpg in a mixed driving scenario. That's on 4:10's and still able to haul the 9,000 lb trailer comfortably.

Attending a seminar on compound turbo design in the near future. Work sponsored so no cost to Moi. Something might come out of that for my personal use if I like what I hear...

:)
 
GW, What turbo are you using? Definately good #'s if you are still running the GM8. Those are also impressive from the standpoint of being done with a 4l80 which usually saps a couple HP from your test.
 
JiFaire said:
Hi BJ! Nice to see ya around again.

Good numbers, 6.5! You can commute with that!
Click to expand...

great white said:
I'm around on an infrequent basis.

Your 8 track reference gave me a giggle.

My last dyno session netted high water mark was 271.9 hp @ 3200 rpm / 446.3 tq @ 1900 rpm on a dyno dynamics chassis dyno. That's right around a stock LB7 and about the limit for a stock 4L80E (actually, a touch over the oem torquerating)

I've also come to the personal conclusion that tdco and optic bumps are not the way to go if you have other means of altering the calibration. With these trucks, pogramming is the solution. Those numbers above were with normal fueling rates (ie: no optic bump) and normal advance (ie tdco set within factory specs). The calibration files give you all the control you need. Makes for a nice, quiet, well behaved driver that "can get it on" when needed.

I've backed off that by about 20hp or so, but i also picked up approx 5 mpg. Thats a trade off i think anyone would be happy with.

Flirting with breaking 20 mpg in a mixed driving scenario. That's on 4:10's and still able to haul the 9,000 lb trailer comfortably.

Attending a seminar on compound turbo design in the near future. Work sponsored so no cost to Moi. Something might come out of that for my personal use if I like what I hear...

:)
Click to expand...

Look Its BJ and the Bear.
 
JiFaire said:
Optional: 8-track deck, BTO, Doobies, and April Wine tapes. Matchbook to stop them from warbling. If you have to ask, skip this step and use the radio instead.
Click to expand...

What's an 8-Track? :dunno:

great white said:
Something might come out of that for my personal use if I like what I hear...

:)
Click to expand...
So like you BJ... :D


Nice to see you stop in man. :thumbsup:
 
haha u guys are great, and those are some good numbers. whats ur guys take onthe " performance cam" worth the money if the engine is out and torn apart or just leave it alone
 
I also have another question. i found a 6.2 military new in the crate. is there any difference in the engine as far as strength? or all they all built the same? I was hoping war wagon or some1 could possibly answer this
 
The military ones I believe are made by International. Good reputation for strength. Look for the logo in the valley. I think the 6.2's should also have it. I have a military 506 block which has held up to a fricken beating without batting an eye. Surprisingly the stock TTY's held at 22psi so good news there. She ain't quitting yet.
 
Nick 6.5 said:
I also have another question. i found a 6.2 military new in the crate. is there any difference in the engine as far as strength? or all they all built the same? I was hoping war wagon or some1 could possibly answer this
Click to expand...

Stock cam in mine with a fresh chain.

Mine is also a new (well, 3 years old now) Optimizer 6500. It's a NAVISTAR cast block/heads and GEP assembled. It's just about as good as it gets short of dropping in a P400 casting which is essentially a total bottom end redesign.

They did make 6.2's first for the HMMWV and they were part of the "repower" program. They used a NAVISTAR cast block and were assembled by General Engine Products (GEP) which is a subsidiary of AM General. Various improvements were made from metallurgy to design elements. Heads were also improved in similar ways.

But, just because it's a "military" 6.2 doesn't mean it's a NAVISTAR cast block. You need to look in the lifter valley for the NAVISTAR "endless roads" logo. It looks like two triangles back to back.

A military takeout 6.2 thats not a NAVISTAR block (ie: no logo) is no better than a gm cast 6.2

In fact, it may be worse as most HMMWV's did not live an easy life.

I'd buy it if it's a NAVISTAR, I'd pass if it is not...just my opinion on it.
 
depends on what you want to do with it. If you want a fresh motor as a DD it will be fine, if your serious about performance/towing you'll want the Navistar block.
 
i do want performance i will be towing quite often. so check to see if it had the logo casted into it?
 
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