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Back from the brink...help me locate and build my next 6.5!

You can't go wrong with a DB2 ever, by the time you go through a few PMD's it will be worth it, and the DS4's are going to go away sooner or later and their are several other good reasons to go the DB route..

I have the swap guide on my web site for anyone to download..

I would keep the hayden for now and gather parts for the electric if needed, IF you do the coatings and other mods listed you may just find out you don't have trouble controlling temps.. the electric is MUCH less money than my system..
 
Potluckslammy said:
. . . would advantage to running one 180, and one 190 stat in the dual setup?
Click to expand...

If there is no real towing in the truck's near term future (heavy plus long grade), dual 190* T-stats will work fine. I went this way and pulled ~8K# up 6% grades. The PITA is trying to manage heat with a thermal-viscous fan clutch and lowering to 180* T-stats do not help much with this (they just lengthen the amount of time until heat goes to high when heavy).

180*'s are the go-to for folks towing heavy and pulling hard, but to me this only adds just a bit of time until heat control via the throttle is necessary.

Put another way, the cooling stack is fair at best for towing anything over a moderate weight. Empty or light the cooling stack will shed heat fine, but not when long term heavy throttle is necessary.



Seeing as this is looking like a bigger project, consider installing an ECT sending unit in the head above #8 and attach wires to it (in OE configuration, there is a plug in this location). Reasoning is that when the time comes, this sending unit can function for the electro-viscous fan clutch (if desired) or as a temporary recovery path if one of the other two fail (the one above #1 sends to the dash, and the one at the thermostat crossover sends to the computer). Also, it is *far* easier to install the sending unit and attach its wires with the motor out, than try to do this with the motor still in the bay.
 
@JayTheCPA excellent advice! And your mention of near-term usage reminds me to inquire about break-in for my new engine. As I have been volunteered for some towing duty in the next 60-90 days (likely a double axle horse trailer stuffed to the gills with my sister's worldly possessions), I'll have to hustle.
I'm figuring 500 miles of easy putting, frequent speed changes from between 25-70 mph, mostly rolling hills, some open highway. I'll keep close to home for the first week, then maybe take a little road trip. That should tell me if anything is going to break, or need adjustment. Now, for this period I'm intending to use cheap conventional oil, 15w-40. Should I go ahead and change the oil at this point, 500 miles, or extend it out to the 1K mile mark? Use conventional oil again, and change it again at the next 1K mile mark? After break-in I intend to use synthetic.

Installing an ECT sending unit above #8 is an excellent suggestion, and I intend to do just that. Someone mentioned earlier, or in another thread....it's all running together at this point...that there's a sending unit available with three outputs. This seems like just the ticket for a dedicated gauge, while retaining an output for the fan clutch.

And as for gauges, I have a three-gauge pillar-pod. So far, an exhaust pyro, and boost gauge. Trying to decide what to put in the #3 spot. By level of importance, probably that dedicated ECT meter. But seems to me like I should be wanting to keep an eye on some other things, as well...like fuel pressure coming from the LP. Actual oil pressure, maybe?! I despise the half-assed factory gauges! I want actual numbers!
 
On the thermostat(s), if single it NEEDS to be the block off style. If dual use a bypass restrictor, Leroy sells one or do a diy.

The roller rockers are nice because of the reduced friction, but also eliminates the stupid plastic buttons that hold the rocker arms in place.

On the oil change, I probably do overkill. but I do 100 miles, 500 miles, 1000 miles, 3000 miles. at each interval cut open the oil filter and inspect the media. this is the most crucial time and you are better off knowing if something is wrong. I just count the extra oil & filter as insurance policy. built hundreds of engines, had a couple times where I pulled it back out and found more wear on something than I liked.

Once you get passed the 3,000 miles, everything is seated and good to go for synthetics.
 
Will L. said:
,,,
On the oil change, I probably do overkill. but I do 100 miles, 500 miles, 1000 miles, 3000 miles. at each interval cut open the oil filter and inspect the media. this is the most crucial time and you are better off knowing if something is wrong. I just count the extra oil & filter as insurance policy....

Once you get passed the 3,000 miles, everything is seated and good to go for synthetics.
Click to expand...
Did the same with my engine's build for the truck. Drove it like I had a raw egg between my foot and the throttle pedal during the break in too. That and on longer runs I'd vary speeds by 5mph every couple of songs or chapter on audio books. Didn't make many friends on the freeway but, one shouldn't try to get interpersonal on the roadways. Anyway, the motor started to come alive around 1500 miles and just got better from there on out.
 
@Will L. Roger that! Dual therms. Doing the diy BPR before it all goes back together. 3K GTG for synthetic.

@ak diesel driver yes indeed! The way I'm thinking, the 6.5 is a peculiar beast...maybe not delicate, but certainly needing some close monitoring, especially when modified for power and performance. Since this is a big, long-term investment (for me), I should be looking at my truck not just from the viewpoint of a driver, but as an operator of a piece of machinery...watching everything to maintain spec. Mo gauges is mo betta! :D
 
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Here is how I did break-in. Some may say this is good, some may have other preferences / advice.

Load the motor to ~75% power for short bursts and allow it to 'coast' for short bursts. Reasoning is to do a controlled heating / cooling cycling of the pistons to get everything to seat. I loved to get caught by a red light on local highways as it allowed me a nice long 75% power application. This usually pissed people off in back of me as I chopped the throttle when I reached the speed limit and those speed demons wanted to hit NASCAR speeds :)

What is not going to help with this approach is that the OE computer's programming will want to unlock the TCC in too many scenarios (this minimizes the cooling cycle). An aftermarket tune can fix this with better TCC lock.

For the oil changes during break-in, I was more conservative than Will and went with 50 miles, 200 miles, 500 miles, 1,000 miles and after that point did analysis every 3K miles. After 20K miles, analysis did not support going over 3K miles due to particulates (which was reported as normal for the P-400 as it broke-in).


Toward the gauges, Edge makes some that are compatible with the GMT-400 OBD-II computer. I too am a feedback junkie and want real numbers (not what the dash provides).

Regarding what gauges to monitor, I found when towing that EGT was the main influencer of things. With the Burb's configuration, EGT's over 1,100* F would cause the ECT's to climb until I brought the EGT's back to ~1K or less. Naturally, this meant that some of the 6% grade climbs were ssssslllllloooooowwwww . . . . Oh, and the TCC will probably unlock which adds to the amount of heat to shed :(

Also, watch RPM's on hill climbs as the OE tune will let them drop too low before commanding a downshift. This was another area where I had to take control by downshifting to not let the RPM's drop under ~2,200 when pulling hard uphill. With lower RPM's when pulling hard, this is less coolant flow during high power (heat generation). On flat ground, you can let the shift tables do their thing without manual overide.
 
I don't baby a fresh build, load it and work it like it was a year old, keep temps in range, keep clean oil, if you baby it from the start it won't break in as well. I guess 90% of how it will be used would be my recommendation.
 
@JayTheCPA excellent, well considered advice! Luckily, my rig has the 5-speed manual trans. Apologies for not mentioning it earlier...I'll add it to my signature....however, your description will likely be most helpful to those down the line.

@Twisted Steel Performance thanks for asking! In my case, after engine break-in...which is why I thought it an important topic. My truck will mostly be used as a second vehicle, splitting mileage between my Ford Crown Vic. Mostly puttering, carrying stuff in the bed...occasionally pulling a horse trailer, or moving another vehicle on a flatbed, like hauling that Humvee I was talking about back from Georgia, or whatever, wherever. Infrequently, towing a 27' fishing boat, or 32' cruiser some 10 miles back and forth to the lake. Some decent grades here and there, but very few more than a mile.
 
Twisted Steel Performance said:
I don't baby a fresh build, load it and work it like it was a year old, keep temps in range, keep clean oil, if you baby it from the start it won't break in as well. I guess 90% of how it will be used would be my recommendation.
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I can see the logic of your viewpoint, and think my own preference is somewhere in the middle. I feel the first 500-1000 miles are critical. If something is going break, it's going to happen in this time...if something was mis-assembled, or horribly out of spec, it will show up by noise, or in the oil analysis. But it does need varying load and rpm for proper break-in. After a few thousand miles everything should be GTG. My own opinion.
 
Ok everyone, finally back with an update! Had the mechanic who pulled my engine send the block, crank, and heads to the machine shop a couple weeks ago, and have been waiting to hear back. Got a call yesterday, and went to the shop to visit with the owner. Unfortunately there was a wee bit of miscommunication, as I had left clear instruction with the mechanic that the assembly was ONLY to be cleaned, magnafluxed, and inspected! But the instruction to have the shop call me after inspection was not passed along, and by the time I go there yesterday he had already bored and decked the block, as well as ordered and received a full rebuilt kit! Possibly this was just fine, as I caught him before he went any further.
As an initial step, I wanted to see what could be done with what I already had. And it turns out the heads we crapped out...junk...cracks in almost every combustion chamber. Will make a good static display...or a couple of trotline weights!
The crank is good, and the block is good, with no cracking detected. This reaffirms to me my earlier suspicion...from checking date codes it seems my block was one of the very early "improved" versions from GM, just before they farmed out production to Navistar. That's my theory, anyway, and right or wrong the fact is I have a block that shows no signs of cracking. I believe if it hasn't cracked by now...especially considering the shape the heads were in...then it's not going to. And therefor, it is a good foundation for my build.
The deck was only milled .005"...just enough to clean it up. But the cylinders required boring to .030" over! He tells me, even though strong crosshatching was clearly visible to me in all cylinders, that they showed heavy wear and were not straight. It was nearly possible to clean up at .020", but ultimately it was necessary to proceed a little further.
And so, I told him to hold where he was at. I want to use Chris's coated pistons, but he only has the standard size in stock...anything other would have to be procured by me, and sent to him to rework. But as it happens, I have a brand new set of .030" over pistons, courtesy of the machine shop!

To be continued...
 
Unfortunately, no. I'm thinking the hold up is due to my request for block filler. That stuff has to cure for a little while, as you know. And I reckon that put me to the back of the que again for machine work. He was going to sleeve all eight cylinders.
I need to go over there tomorrow to drop off the rocker shafts. Came up with a different solution for replacing the nylon buttons. I'll get some pictures and post it up before turning them over.
 
If shipping cost gets relatively easy, then here in Norway we have a lot of used 6.5 diesels sitting around. 6.5td starcraft, tahoe and suburban sold in quite some numbers in 1994-2000. But they are now rusted away and left at the junkyard. Just a tip.
 
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