GMT400 6.5 Swap Help

[Will L.]

Did I mention btw, that what you are building is really a hummer wagon? 6.5 turbo diesel 4l80e trans, 4wd, 4 door with seating up to 6 if you cram in two kids. and a little storage room in the rear. Did I read that right with portals and 4wd? Yeah.... you are making a slightly skinnier hummer/hmmwv.

You are about to finalize a lot of money and effort spent to end up with 1 rig you like. Do consider a hummer by selling off the trucks you just bought. Some states allow decommissioned hmmwvs registered for street use others don’t, so what hmmwv owners do is get a p.o. Box out of state next door and register it there. Some guys named Er....almost said his name... just fill out the form and make thier 2009 hmmw a 1995 so it has no emissions issues in the state of commiefornia ummm, metaphorically speaking of course.

Seriously- the cost is a bit more to buy, but resale is a no brainer. Collector car and values are only going up with it instead of down. People that never rode in one that wasn’t the back breaker heaviest springs and pain inducer device the military called a seat- changing those things only- the ride goes from hell to heaven. My hummer is a more comfortable ride than my 1997 tahoe, 2001suburban or 2005 escalade ever were. Replacing the 4 coil springs is a one day task, 2 if you don’t have the motivation to go play in it the next day.

Many of the hmmwvs can be had at non ridiculous prices and there are a few things I recommend altering that was done in hummers besides just seats and springs- but not much. I just figured if you are as nuts as me to not let go of the 6.5, may e you are 10% more crazy and just needed a push! Haha

Oh, and hummer is WAY easier to park than a 4 door pickup or tahoe. And thats before you do the rear t option!

 

[adventr]

And yes, after having this LB truck, I now think that the SB would be easier to find parking spots for, so, I would even accept it with tje SB.

The blue truck is actually a crewcab longbed k3500. Appears to have been ordered for the forest service by the tag on the door. Real basic interior, bench seats, manual windows...etc.
It's not in bad shape. No rust on it anywhere and the body is straight.
If someone wanted it after I get finished I'd sell it. Has clean/clear title.

 

[adventr]

Welcome from the end room down the hall at the asylum.

You see there is one thing to smite the 6.5L Diesel Gods ... Say by scrapping a somewhat rare for the day crew cab 6.5TD pickup. Then Murphy is going to have his way with you about the unreliable PMD/DS4 and no new head and rotors made for the DS4 anymore. They wore the tooling completely out I hear. Because there was never a "4 door Diesel factory option Tahoe/Yukon" you have discretion as to what you use.

The Ultimate Misery, Self Torture, S&M, is to inflict the DS4 PMD electronics on your project and constantly wonder "Did the damn thing ever work properly?" while it randomly fishbites just to test the sensors. and make you wonder if it was testing the sensors or is about to quit.

Then to pull a fairly reliable Gas engine out of the Tahoe for a 6.5TD.

Did the engine you got have anything more than "auction: Good Luck" as far as condition implied or paid for? It's been said that these engines make good Boat Anchors, however, the one you got has actually been used as a boat anchor! The 6.5 Gods are already onto you and your plans.

I would suggest you:
1) Get a good pair of walking shoes for getting the problems worked out of the swap.
2) Fix up the blue crew cab pickup with the 6.5TD as they are rare. (This may appease the 6.5L Gods so other crazy projects may continue.)
3) Just drive and enjoy the Tahoe: after all you need a parts runner vehicle

No really: anyone could just trip over the common as dirt Tahoes of this era as GM couldn't build them as fast as they were selling. Now how many of the Crew Cab pickups of this era do you see with any engine?

The DB2 Injection pump becomes 12V by removing the top cover with the 24V solenoids and dropping a 12V solenoid cover on it. Little trick to get the fuel metering valve not pinned WOT for a runaway condition is by bringing the cover down toward (the front of the engine) and then sliding the IP pump top cover back during install. Test with 12V for a "click". No Click means it ain't installed properly do not attempt to start or even rotate the engine by hand.

Did I mention btw, that what you are building is really a hummer wagon? 6.5 turbo diesel 4l80e trans, 4wd, 4 door with seating up to 6 if you cram in two kids. and a little storage room in the rear. Did I read that right with portals and 4wd? Yeah.... you are making a slightly skinnier hummer/hmmwv.

You are about to finalize a lot of money and effort spent to end up with 1 rig you like. Do consider a hummer by selling off the trucks you just bought. Some states allow decommissioned hmmwvs registered for street use others don’t, so what hmmwv owners do is get a p.o. Box out of state next door and register it there. Some guys named Er....almost said his name... just fill out the form and make thier 2009 hmmw a 1995 so it has no emissions issues in the state of commiefornia ummm, metaphorically speaking of course.

Seriously- the cost is a bit more to buy, but resale is a no brainer. Collector car and values are only going up with it instead of down. People that never rode in one that wasn’t the back breaker heaviest springs and pain inducer device the military called a seat- changing those things only- the ride goes from hell to heaven. My hummer is a more comfortable ride than my 1997 tahoe, 2001suburban or 2005 escalade ever were. Replacing the 4 coil springs is a one day task, 2 if you don’t have the motivation to go play in it the next day.

Many of the hmmwvs can be had at non ridiculous prices and there are a few things I recommend altering that was done in hummers besides just seats and springs- but not much. I just figured if you are as nuts as me to not let go of the 6.5, may e you are 10% more crazy and just needed a push! Haha

Oh, and hummer is WAY easier to park than a 4 door pickup or tahoe. And thats before you do the rear t option!

I feel like ya'll are questioning my sanity And that's ok.

To clear up a few things; Yes, I am aware of what I'm building and the costs associated to finish it. I also feel like I have pretty realistic goals as far as the engine goes. Near-stock power levels with some supporting mods to hopefully address the inherent issues gives the 6.5 it's reputation.
IF there was an option to buy a brand new ready-to-go P400 or even a brand new Optimizer that wasn't built by those jokers in NY, I absolutely would have done that from the get-go. I purchased the military engine with fingers crossed that I could use the bottom end and build from there.
I don't quite understand all of the DS4 hate. I have that black 3500hd shop truck (in my earlier pics) and it has 219k on it now and not a single issue. It's bone stock, runs good and sounds good. I like driving it.
I also have several other personal vehicles, and a whole fleet of brand new superduties. The Tahoe isn't meant to be a daily driver. Would I still like for it to be as reliable as the black 3500hd, yes I would.



As for what I'm building. Here it is. Custom axles, 12k CTIS portal boxes, air suspension (changed from coilovers), 40" tires...etc. All while keeping it as low as possible. There lies the majority of the challenges here. IF I were using something like a typical dana 60 up front, this whole build would have went a different direction with the engine choice. I would have bought a nice running duramax truck and canibalized the drivetrain. However, when I dropped the dmax CAD model into my Tahoe model, I quickly found that the dmax is MASSIVE and would give me approximately 0" of uptravel at my desired ride height. So, 6.5 diesel it is.

















As I'm doing the engine build, I'm also working on finishing up my suspension design and also building the axles that I'll be using.
My plan is to complete the engine swap FIRST, then drivetrain.

Not sure if I mentioned this earlier, but I will be using a 6L90e transmission, not the 4L80e.

 

[adventr]

Did I mention btw, that what you are building is really a hummer wagon? 6.5 turbo diesel 4l80e trans, 4wd, 4 door with seating up to 6 if you cram in two kids. and a little storage room in the rear. Did I read that right with portals and 4wd? Yeah.... you are making a slightly skinnier hummer/hmmwv.

You are about to finalize a lot of money and effort spent to end up with 1 rig you like. Do consider a hummer by selling off the trucks you just bought. Some states allow decommissioned hmmwvs registered for street use others don’t, so what hmmwv owners do is get a p.o. Box out of state next door and register it there. Some guys named Er....almost said his name... just fill out the form and make thier 2009 hmmw a 1995 so it has no emissions issues in the state of commiefornia ummm, metaphorically speaking of course.

Seriously- the cost is a bit more to buy, but resale is a no brainer. Collector car and values are only going up with it instead of down. People that never rode in one that wasn’t the back breaker heaviest springs and pain inducer device the military called a seat- changing those things only- the ride goes from hell to heaven. My hummer is a more comfortable ride than my 1997 tahoe, 2001suburban or 2005 escalade ever were. Replacing the 4 coil springs is a one day task, 2 if you don’t have the motivation to go play in it the next day.

Many of the hmmwvs can be had at non ridiculous prices and there are a few things I recommend altering that was done in hummers besides just seats and springs- but not much. I just figured if you are as nuts as me to not let go of the 6.5, may e you are 10% more crazy and just needed a push! Haha

Oh, and hummer is WAY easier to park than a 4 door pickup or tahoe. And thats before you do the rear t option!

Forgot to mention that I have owned several different civilian Hummer H1s over the years (HMC4's, HMCS's). When I was young, I had posters and pics of the H1 on my bedroom walls whereas most had posters of Ferrari and Lamborghini. LOL
All of mine had the DS4 pump, and I had no complaints with any of them.

One I ended up swapping to a cummins 6BT engine, and that was a mistake in my mind. It's just not the right engine for the H1 chassis. Next one I build will get a duramax swap along with the unobtainable 45 degree angled fan drive to resolve the cooling issues...

 

[adventr]

Lastly; Yes, I have done several different chevy builds in the past and have developed my own suspension system. Very rarely do I find anything off-the-shelf that satisfies me. Seems that most want big lifts but I'm the exact opposite. I like big tires, but try to keep the suspension height low, steering/suspension geometry level and I focus drivability. Way more time and effort, but the results are great.

 

[ak diesel driver]

I think it's going to be a great build, can't wait to see the pics as it progresses

 

[adventr]

I think it's going to be a great build, can't wait to see the pics as it progresses

Thanks man, if I can get thru this engine build I'll be sailing smooth!

 

[Will L.]

It all makes sense now. Awesome.

Were you never on the HummerNetworkforums? Obviously new here- but Leroy, Chris, Rubberduck, even predator all sell brand new optimizers. I think 7,500 ish before shipping currently. NY scam-masters are only one of the options.

You can no longer buy brand new ds4. Builders can no longer buy the parts to rebuild them to new specs.

One douse of bad fuel is enough to ruin a ds4. Proving to the fuel company and them paying is one thing- but when the parts are nla- that sucks. They cant make Stanandyne bulld new parts no matter how good your lawyer is. Db2 are going to be built until 2030 we know of so far. The only thing the ds4 was created for was to pass the emissions laws of obd2 being able to monitor delivered fuel. The db2 is better mpg, better actual emissions, and if wanted better power. The cost of ip and supporting electrical is 3 times higher. Thats why all the flak on ds4.
Now if you are running wmi, propane, nitrous - ds4 dominates those options.

I would suggest sending those pictures back to who you bought it from with the question how much of a refund they are gonna kick in if they were selling it like a ready to go engine. That is a rebuildable core only.

I do like your build- that has serious potential written all over it!

If you add ctis, (how could you not?) use the cepek connectors not the factory ones that you already know leak often. They eliminate that problem.

The 45° fan for the hummer- known as GFD- Geared Fan Drive- nope. Outside of cost, you can get better cooling by having factory copper radiator redone with 4 row dimpled core radiator then having entire coated. Better outcome, lower cost, and you don’t risk the broken crankshaft that 10% of them suffer. Yup- you read that right- read up why so many dont add the ati or fluidampr balancer. That little added weight breaks the crankshaft, and that gfd is way harder on them.

When the hmmwvs were getting them, they started going away from them within the year because they snap the 6.5 crankshaft also. AVA redesigned the GFD and the problem is much less now- but they expect to not get caught up with military sells of them unto 2026.

A friend just bought one of the humvee c series and could not get the complete GFD system at all. He is going to run a cummins so wasn’t worried about it- he offered an extra $50,000 and was told “at no price” until military contract is met. But they are all going on the shelf to replace damaged units, not going into new builds.

Back to your Tahoe, thats a good choice on the trans, stock power it will do well.
I strongly suggest 17” and larger rims for tire options, I stick with 16.5 on my hummer because of the 4 coil suspension and no runfalt - a blowout is almost always a roll over.
You know your suspension, just keep that roll issue in mind if applicable.

 

[Big T]

I feel like ya'll are questioning my sanity And that's ok.

To clear up a few things; Yes, I am aware of what I'm building and the costs associated to finish it. I also feel like I have pretty realistic goals as far as the engine goes. Near-stock power levels with some supporting mods to hopefully address the inherent issues gives the 6.5 it's reputation.
IF there was an option to buy a brand new ready-to-go P400 or even a brand new Optimizer that wasn't built by those jokers in NY, I absolutely would have done that from the get-go. I purchased the military engine with fingers crossed that I could use the bottom end and build from there.
I don't quite understand all of the DS4 hate. I have that black 3500hd shop truck (in my earlier pics) and it has 219k on it now and not a single issue. It's bone stock, runs good and sounds good. I like driving it.
I also have several other personal vehicles, and a whole fleet of brand new superduties. The Tahoe isn't meant to be a daily driver. Would I still like for it to be as reliable as the black 3500hd, yes I would.



As for what I'm building. Here it is. Custom axles, 12k CTIS portal boxes, air suspension (changed from coilovers), 40" tires...etc. All while keeping it as low as possible. There lies the majority of the challenges here. IF I were using something like a typical dana 60 up front, this whole build would have went a different direction with the engine choice. I would have bought a nice running duramax truck and canibalized the drivetrain. However, when I dropped the dmax CAD model into my Tahoe model, I quickly found that the dmax is MASSIVE and would give me approximately 0" of uptravel at my desired ride height. So, 6.5 diesel it is.




View attachment 69575

View attachment 69576

View attachment 69577

View attachment 69578

View attachment 69579




As I'm doing the engine build, I'm also working on finishing up my suspension design and also building the axles that I'll be using.
My plan is to complete the engine swap FIRST, then drivetrain.

Not sure if I mentioned this earlier, but I will be using a 6L90e transmission, not the 4L80e.







View attachment 69581

View attachment 69582

View attachment 69583

View attachment 69584

Is that rear wheel steering I see?

 

[adventr]

It all makes sense now. Awesome.

Were you never on the HummerNetworkforums? Obviously new here- but Leroy, Chris, Rubberduck, even predator all sell brand new optimizers. I think 7,500 ish before shipping currently. NY scam-masters are only one of the options.

You can no longer buy brand new ds4. Builders can no longer buy the parts to rebuild them to new specs.

One douse of bad fuel is enough to ruin a ds4. Proving to the fuel company and them paying is one thing- but when the parts are nla- that sucks. They cant make Stanandyne bulld new parts no matter how good your lawyer is. Db2 are going to be built until 2030 we know of so far. The only thing the ds4 was created for was to pass the emissions laws of obd2 being able to monitor delivered fuel. The db2 is better mpg, better actual emissions, and if wanted better power. The cost of ip and supporting electrical is 3 times higher. Thats why all the flak on ds4.
Now if you are running wmi, propane, nitrous - ds4 dominates those options.

I would suggest sending those pictures back to who you bought it from with the question how much of a refund they are gonna kick in if they were selling it like a ready to go engine. That is a rebuildable core only.

I do like your build- that has serious potential written all over it!

If you add ctis, (how could you not?) use the cepek connectors not the factory ones that you already know leak often. They eliminate that problem.

The 45° fan for the hummer- known as GFD- Geared Fan Drive- nope. Outside of cost, you can get better cooling by having factory copper radiator redone with 4 row dimpled core radiator then having entire coated. Better outcome, lower cost, and you don’t risk the broken crankshaft that 10% of them suffer. Yup- you read that right- read up why so many dont add the ati or fluidampr balancer. That little added weight breaks the crankshaft, and that gfd is way harder on them.

When the hmmwvs were getting them, they started going away from them within the year because they snap the 6.5 crankshaft also. AVA redesigned the GFD and the problem is much less now- but they expect to not get caught up with military sells of them unto 2026.

A friend just bought one of the humvee c series and could not get the complete GFD system at all. He is going to run a cummins so wasn’t worried about it- he offered an extra $50,000 and was told “at no price” until military contract is met. But they are all going on the shelf to replace damaged units, not going into new builds.

Back to your Tahoe, thats a good choice on the trans, stock power it will do well.
I strongly suggest 17” and larger rims for tire options, I stick with 16.5 on my hummer because of the 4 coil suspension and no runfalt - a blowout is almost always a roll over.
You know your suspension, just keep that roll issue in mind if applicable.

Dang, I didn't even think about reaching out to Travis @ RD4x4 about an engine. LOL
I've bought quite a bit of stuff from him over the years. Have been a member on HML for a several years, never really active and haven't been on there in a while..

All that's understandable on the DS4. I've got a new one (along with that whole list of parts on page1) being delivered this week. I'm still going to think on it some while building this engine and make a final decision on which route to go.

Unfortunately this engine was sold as-is. Good news is that I didn't pay a ton for it. I believe I could probably recoup a bit of it by selling some of the turbo parts. Might be a good fit for a local person with a hmmwv.

Definitely adding CTIS to the tahoe axles!! That was a big requirement for me, so I tracked down a set of 12k boxes that already had the CTIS spindles. I've got some custom pieces being machined right now that will fit over the spindle extensions and house the required seals. Then adapt that to a NPT fitting so I can run braided hose.
I'm also working on the the CTIS system itself, and putting together an algorithm for my computer (to run the solenoids, maintain pressure,etc)

Did not know that the GFD was breaking cranks in the 6.5 trucks. Good to know. My comment was mainly about my next H1 having the duramax engine with the GFD. Just like the Alphas had.
The 6BT rig that I built had all the goodies that were available at the time. Big RD Radiator, intercooler, scoop, aux pusher fans. Just couldn't ever get enough airflow thru the stack when climbing hills on a hot day with the a/c going. Other than that it was fine, but it did make a ton more power than the 6.5 ever did. I worked with a guy and developed a controller for the HE351VE turbo (you can see it on my engine pic I posted). The controller allowed me to take advantage of the VGT turbo on the mechanical engine and made for a smoke-free setup. Also gave me the ability to use exhaust braking on descents which was awesome.


For tahoe, I'll be running 40x13.50R17 tires. Already bought them and they are sitting in my shop. It was actually very challenging to find wheels that have a lot of backspacing and will also fit over the wheel brake setup. I did determine that the AEV Salta HD wheels would clear (just barely) and gave a pretty decent amount of backspacing.
However...i ended up scoring a set of Hutchinson Alpha wheels that I'll be using. They are 17 and surprisingly clear the wheel brakes. Also give me that high positive offset which keeps scrub radius in check. Win-win.
Oh, and they came with the alpha hub fittings for the CTIS (style that goes from hub center into the side of the aluminum wheel).
I need to update my CAD model to reflect the new wheels, just been busy with everything else lately.

 

[WarWagon]

I feel like ya'll are questioning my sanity And that's ok.

You will fit right in. They might make some of us give up our room(s) for you.

The blue truck is actually a crewcab longbed k3500. Appears to have been ordered for the forest service by the tag on the door. Real basic interior, bench seats, manual windows...etc.
It's not in bad shape. No rust on it anywhere and the body is straight.
If someone wanted it after I get finished I'd sell it. Has clean/clear title.

This is too nice of a truck to do anything but repair and sell. The seats are even in good condition: that's rare around here.

I would love to see a build thread on it even if it's just a repair.

The turbo is also questionable from loss of oil pressure. Rebuild or Several better turbo's out there you can use to replace it.

Aside of the Yank High Stall Converter, 2nd known person to put a BD Spool Valve on a 6.2/6.5, Proving Total Seal gapless rings, then working the piss out of them towing 550 miles a day to win the carnage thread hands-down at one point. Yeah, my room's pretty secure. Most of these fun times are a link in my signature.

The huge towing turbo, ATT, is likely discontinued now. It's an example of how much wasted fuel the GMx garbage turbo keeps in the engine heating things up. Twisted Steel Performance via coating things is the next level to keep the heat out of the cooling system. I would have killed for a set of coated heads and better turbo back in the day. 7 MPG vs. 10.X MPG is a lot of Cold Hard Cash wasted on 550 miles of fuel per weekday.

http://maxxtorque.com/dieselcommuni...ods/244-the-65-factory-equipped-asthma-attack

IF there was an option to buy a brand new ready-to-go P400 or even a brand new Optimizer that wasn't built by those jokers in NY, I absolutely would have done that from the get-go. I purchased the military engine with fingers crossed that I could use the bottom end and build from there.

We are a Frugal bunch on here. This does not mean the "boat anchor" can't go in the blue truck. However I suggest a conversation with Twisted Steel Performance about a coated new longblock 6.5L should be had for your project.

I don't quite understand all of the DS4 hate.

Give the DB2 air free fuel and 12V (or 24V) and it will run till it's out of fuel or the engine fails.

The DS4 requires the poorly designed high heat dissipation, fuel cooled, in the oven when shut off, PMD to work. Then all the electronics to work including the finicky APP. Due to age alone the ECM's are also becoming a failure point.

You have merely been lucky with your DS4 experience. I never carried a spare ($400+ at the time) PMD for my DB2 pickup.

 

[Twisted Steel Performance]

I say build what you want, the more out of the box the better, these folks know I do things that way, so get on with it...

 

[Will L.]

The GFD breaks crankshaft on duramax also. Not as often but still does, older dmax more susceptible than newer.

The factory radiator cools more than the aluminum ones. Ron Davis, Griffin, or the new Champion. Thats before upgrading the original one.

The bigger radiator that goes in the ecv hmmwvs with the grille that sticks out- is 28% than original.

Modified factory= original is 3 core, make it 4 core is 133%, reduced air flow drops it to 125%. now add dimple core which improves 25%is 156%. Then have it coated with techline air cure heat dispersant which adds between 30% and 34% efficiency depending on how well it gets applied. 156x30 is 202.8% more btu output than the factory radiator.

Granted, doing all that you will be into it $2000. But the Davis radiator sells currently for $1200 so....yeah.

 

[adventr]

Haven't posted in a bit, but still making progress. Everything I ordered from Quadstar (list on page1) delivered before Christmas. LOTS of boxes on the front porch. Lol

Today it was 75 degrees, so we took advantage and got the blue truck mostly stripped down. Now I need to get wiring diagrams for my Tahoe and also the blue truck so that I can go thru and compare and figure out what all I need to do to make everything work.

 

[dbrannon79]

That's a mighty fine looking dash there lol is that the engine that ran low on oil?

 

[adventr]

That's a mighty fine looking dash there lol is that the engine that ran low on oil?

Yeah, that's from the blue crew cab. The dash was already busted on the top side from some goober letting a cb radio sit up there and bounce around. The dash in the white truck is actually in a lot better shape.

 

[dbrannon79]

after you decide what parts are getting scrapped or not being used, I'm sure many of us here would be interested in them!! one of these days and when funds allow, I have a runable engine and dash on my shopping list.

I recently had a rather odd idea the other day about attempting to put together a custom wooden dash using the inner dash frame. I know if I did attempt anything like that it would have a more squarish look to it since my wood working skills aren't that great lol. I even had the thought of a overhead console across where the sunvisors go for junk collection lol

 

[ak diesel driver]

Hang onto that S & B airbox

 

[adventr]

Got the humvee engine torn down the rest of the way tonight. Still can't get it to turn over, but I haven't beat on it too much yet. Just tapped on a couple of accessible pistons with a deadblow.
Turned the engine upside down and am now soaking the back sides of the pistons with wd40. Maybe that will help. Going to fashion a wooden tool tomorrow and try driving on the pistons.

I did pull the number 8 rod bearing cap just to see if the bearings were froze up. They appear to be fine. Bearing cap came right off by pulling on it with my hand.

Here are some pics of that bearing. Looks ok to me.

 

[MrMarty51]

That bearing looks very clean.