95 Chevy Tahoe Duramax Swap

[Russell]

Just figured I'd show off my Tahoe a little bit here. I did an LB7 Duramax / ZF6 swap on it about a year ago and absolutely love it!

If anyone has any questions about swapping Duramax engines around, I am fairly well versed on the LB7, LLY and LBZ engines and what it takes to swap them around (particularly from the electrical standpoint)

The LB7 is a great motor, but they have some drawbacks vs the newer engines. One is injectors. They suck to change and are quite expensive. It also sucks when a return line leaks after you swap them out and have to tear the engine down a second time to fix it. The ZF6 makes the swap. It'd be cool with the Allison, but the 6 speed stick downright blows people's mind and is a ton of fun to drive. If I wanna be especially retarded, I can wind my truck out through 3 gears before I hit the other side of an intersection at full throttle. Tends to attract a little bit of attention with the 4" MBRP exhaust I installed though....

The installation was actually quite easy. I purchased the swapper's guide from thedieselplace.com simply to get the engine mount templates, and they work pretty well. There is now a dude on eBay who sells engine mounts that allow you to use the stock engine side clamshells just like the LS engine swap mounts do. The engine fits in this truck exceptionally well as it was designed for this body style but wasn't released until after the new body style was. I am still running it without an intercooler as there is no room to fit one up front with the rad and the AC condenser. I am running the stock Cab and Chassis tune (230HP), so I haven't had any EGT issues with it (even in 50C weather pulling hard up a hill I could just barely hit 1400F). Electrical is kind of my thing and wasn't hard at all. I integrated the engine wiring with my stock underhood fuse block using diagrams from alldatadiy.com for both the Duramax and my Tahoe. The LB7 uses all the same fuses as a 6.5L diesel does so things panned out pretty well. All my stock gauges plugged straight into the LB7 sensors except for the coolant temperature sensor. I just drilled and tapped a water jacket for it and got it working but there is a dual element sensor available that you can replace the stock one with to avoid drilling and tapping the crossover pipe. I did have to run a new 1/2" fuel line for the dmax as the CP3 can easily over-draw even that line, forget the stock 3/8" line.

Anyways, on to some pics... To start, the old engine had to come out... This was made more fun because the front diff had been out for new inner Cs to be welded on to correct some pinion angle and castor problems I'd been having earlier and I had the truck up on jack stands. Gotta love that good ol' skidsteer... Such a handy toy!

[Russell]

We then tore down the dually to rob it of it's engine and transmission... Before taking the engine off the rolling chassis, we hauled it in to hose down the engine, transmission, transfer case and the frame. Where one skidsteer is good, two makes for some fantastic redneck fun

[Russell]

While a friend of mine took the rolling chassis into his work to clean all the mud, grease and gravel off it, I finally got my front diff back and got to work installing and assembling it. Of course, I couldn't just put stock parts back in when I rebuilt the front end. I fitted it with Solid Axle Industries inner Cs, knuckles, steering arms and 35 spline 4030 Yukon Chromoly axle shaft assemblies. The 1 ton brakes were removed and I fitted the front end with 10 bolt 3/4 ton brakes instead. This meant my truck had the same size calipers front and rear (the rear 14 bolt semi floater was fitted with 3/4 ton 10 bolt disc brakes to replace the drums) and allowed me to properly proportion the brakes and provided me with a wicked brake pedal feel combined with the new 1.5" master cylinder.

[Russell]

With the front end set back down it was time to get to work test fitting the engine... With the core support in, you can see how well the Duramax fan fits with the 6.5L fan shroud. It is a common upgrade to put these fans on the old detroit diesels because they move a pretty stupid amount of air (around 10 000 CFM). Everything fits really well, no interferences anywhere. Even the exhaust fits nice!

[Russell]

With my friend's help, we fabricated the engine mounts and installed the engine + transmission. For the t-case, I took the NP261 apart and stole the 29 spline input shaft out of it to put into the NP241. The NP261 would have fit, but would have required me to have new driveshafts made as the 241 has a SYE kit on it as well as a driveline brake. So far, I have had no issues with the NP241 behind the Duramax. I had to turn a clutch hose adapter on the lathe to connect the Duramax's clutch hose up to the 95 master cylinder on the truck.

I mounted the PCM where the old ABS module used to sit. Of course, the dash got all torn out to do the wiring inside. I had to re-route the wires for the pedal (I am using the 6.5L pedal with the LB7 ECM, but the wires used to run out through the passenger side bulkhead, I re-routed them to come out the driver's side instead), and run some wires for the water in fuel / low coolant lights that used to be handled by the old 6.5L PCM mounted behind the glove box. I also wired up the AC and the cruise control to be handled by the LB7 PCM.

The original 6.5L rad was re-used in the swap along with the original overflow bottle up on the firewall. The rad has an extra port on the front which I used as a return port for the heat exchanger setup I have installed for onboard hot water (for use as a shower, dish washing etc) as I regularly camp in the truck.

I re-located the second battery up to where the air box used to sit for the 6.5L, and used the original battery tray as a mount for the 6.6L's airbox. I had to cut about an inch off the bottom of the air box to allow the hood to close on top of it. This also helps provide a lot more airflow in. The battery tray and inner fender seal the air box off from the hot engine compartment, so it acts like a cold air intake of sorts. You can see the bling chrome stuff I used as an intercooler bypass.

At this point, the swap was pretty much done though I did have a hood clearance issue with the factory intake piping. I just cut the support on the bottom of the hood where it was touching and the hood was able to close.

[Russell]

I have had this truck down to the US on a number of big wheeling trips including a run to Moab, using the truck as a chase truck for a local Ultra4 desert race team (4502 baby!) as well as a run down the Rubicon Trail. I've done a lot of little updates and modifications throughout this truck's wheeling career as well that I haven't really mentioned here in the build thread (such is the nature of the beast!).

The Duramax has been an awesome engine all around and I am really happy with the swap. It wasn't cheap (7k for the donor and another 1k to install at least) but well worth it.

Until just this last week the truck was sitting up on jack stands yet again for front differential repairs. Who knew that a 7000lb truck with a medium duty diesel engine would bend and break the D60 when it is taken off a 10ft jump while pretending it is a trophy truck out in the desert?! All kinds of fun breaking wheels off your truck! It's nice to have it back on the road

[y5mgisi]

Your as bad as Larry! Makin people want to put awesome engines in their trucks!

[Russell]

Oh! Larry is by far the worst influence on people... I just bought an 8.1L / 4l85e with nothing to put it in "just cause" after reading one of Larry's build threads, lol! I'm kind of looking into buying a 69-72 Chev Blazer to drop it into. If I wind up buying one I'll probably get a nice one that already has all the rust repairs and paint done. I hate doing that kind of stuff, lol!

My best friend has a 67 Olds Delta 88 rag top with a 425 in it and he has been bugging me to buy something convertible to go cruising with. I just can't bring myself to drive a car, so it pretty much has to be an old Blazer with a modern mill under the hood. Even a lowered 2wd would be fine with me!

[Dieselwrencher]

Awesome Tahoe and great work on it! Are you going to truss the front axle now? I bet that was a sweet ride til the end.

[y5mgisi]

Stick the 8.1 in your cream puff 04 or 05 or whatever year that is!

[Russell]

Originally Posted by Dieselwrencher

Awesome Tahoe and great work on it! Are you going to truss the front axle now? I bet that was a sweet ride til the end.

Yes, haha! It was fun! And yes, it needs a truss. I got the tubes straightened out but the plug welds just won't hold in the center. It has a truss that keeps things from moving front to rear, but I need one in the vertical plane as well. That'll happen when it gets the 3 link.

[joel.e]

Do you have any pics of the engine mounts?? Looks good sitting in there.

[Ackattack]

Very nice build! How big of tires are you running?

Originally Posted by Russell

I am still running it without an intercooler as there is no room to fit one up front with the rad and the AC condenser.

In my 97, I'm running the stock radiator, dodge 2nd gen dodge intercooler cooler, stock A/C condensor, and an aux fan. It all "fits" with a little modification.

[Russell]

Joel, I am asked that quite regularly but I was dumb and didn't take any pictures of them. They are just made out of flat plate steel. One piece that bolts to the block and two pieces that are shaped like the old stock engine mounts. I then set the engine where I wanted it and trimmed them to fit / welded them up.

AckAttack, I have have both the LB7 and a dodge intercooler at my disposal. The concern has never been the thickness of the cooling stack (lots of room that way) but rather the width of the intercooler interfering with the turn signals. How did you get around that? The best way I could think of would be to tilt the base of the radiator and the intercooler both towards the engine to just clear the turn signals. This would mean that the fan would either be into the rad or dangerously close to it. I don't want to attempt electric fans with the truck as they simply do not move anywhere near the same volume of air for cooling.

[y5mgisi]

Russell, check out how this guy did it.

http://www.gmt400.com/forum/showthre...-Cummins-Swap!

[Ackattack]

^^^^^ same here

[Russell]

That works alright with the factory housing as you cannot really see through it. Sure would look poor with my clear lens turn signals though!

[Ackattack]

Originally Posted by Russell

That works alright with the factory housing as you cannot really see through it. Sure would look poor with my clear lens turn signals though!

I'm probably going to be getting clear lenses here shortly, and guess I'll just have to cut them up too. Function over form for me.

[Russell]

So, we had a father's day show and shine at the local church here this afternoon. One of the star attractions was a mobile dyno unit that set up and was letting you do 3 pulls for $100.

So, the crowd thought it was hilarious when the big ol diesel Tahoe pulls onto the dyno in between all the supercharged, turbocharged, big block and nitrous sprayed classic cars and modern muscle, but I put down a very respectable 307hp and 602 ft lbs of torque at the rear wheels with my Tahoe rolling on 37s, only putting out just a very light haze of black smoke.

Did better than I thought it would! Didn't even break anything! I got a good laugh out of the dyno tech trying to figure out the ZF6

[clinebarger]

Originally Posted by Russell

So, we had a father's day show and shine at the local church here this afternoon. One of the star attractions was a mobile dyno unit that set up and was letting you do 3 pulls for $100.

So, the crowd thought it was hilarious when the big ol diesel Tahoe pulls onto the dyno in between all the supercharged, turbocharged, big block and nitrous sprayed classic cars and modern muscle, but I put down a very respectable 307hp and 602 ft lbs of torque at the rear wheels with my Tahoe rolling on 37s, only putting out just a very light haze of black smoke.

Did better than I thought it would! Didn't even break anything! I got a good laugh out of the dyno tech trying to figure out the ZF6

How many times did it take for him to load the engine to get some numbers??

Nice numbers & truck by the way.

[Russell]

He did the best on the 3rd pull. Had the transmission down and actually loaded the engine up a bit with the brakes to spool it up more than running without any real load.

[6BT 56]

This is a real cool swap. Great job. Id love to do this swap to my wifes Suburban but its a typical Ontario truck and just isnt clean enuf to warrant it anymore. Im a big fan of diesel wrenchers Excursion as well. So many idea's......

[Russell]

Swapping an 01/02 LB7 into your 2500 burb would be a cake walk. Literally a bolt in job! The electrical is all plug and play. You can use factory fuel lines and pickup tubes. If I had all the parts on hand I could pull off a swap within a couple good long days.

The 1500 burbs are a little bit more challenging as the core support is smaller / shorter and the frame rails are smaller, but the 2500 burbs are the same as the 2500 trucks which means the dmax engine mounts swap directly in along with the core support etc.

Just buy a running / driving duramax donor and go to town! Just keep an eye out for failing injectors. They are still around 2k to replace yourself.
Posted via Mobile Device

[6BT 56]

Great russell. Thanks a lot. Just when I thought it was best to avoid this swap you go and tell me its easy. Lol. My buddy has a 1 ton i can get for 5K its a 04 i think . electrical still same ? It needs injectors and the allison is starting to slip a bit . thinking all that makes this truck too pricey for a coversion.???????

[Russell]

You'll need to stick with an 01 or 02 donor. In 03 they big time changed the electrical systems in the trucks. The engine would be physically the same, but the control system is totally different.