the pig rig?

[ericjon262]

so, over the past year, I've moved twice, from South Carolina, to Hawaii, and from Hawaii to Washington state. when I moved to Hi, I left my truck at home in Florida. Well, when I got to WA, all I had to get me around was my Harley, which isn't so great for the rain, so, I threw down, hard, and picked up this gem, Ladies and gentlemen, I present, "The Pig Rig"!

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it's a 1988 Suburban 4x4, complete with a L05 350, 700R4 transmission, NP208 transfer case, and pretty much no rust. It's dirt slow, but gets decent gas mileage, rides pretty smooth, and can take a decent load. I picked it up for a whopping $1900. originally, I planned to sell it once I got my truck up here, but, I've fallen for the slob.

this time a month ago, I would have told you the plan was to swap in a 6.0/4L80e like my 2500 HD has, but after driving across country pulling the Fiero, I've decided it needs more.

Short term plan: fix the oil pan/rear main seal leaks, and drive to Alaska and back in the summer.

Long term plan: pick up a wrecked 2500/3500hd donor truck, with a duramax, and build the ultimate all around squarebody chevy on the road. updates on this project will be slow, and far between, because I don't need to do anything with it ATM, and I want to get the Fiero moving again, details in that thread...

[The Dark Side of Will]

My dad has a '90, also in Light Mesa Brown, but with a British Racing Green stripe. It's a RWD 3/4 ton original diesel chassis.

How's the interior?

[ericjon262]

interior is pretty good for a $1900 truck, dash isn't cracked, seats are pretty nice, driver's side front has a tear, needs lower door panels, (someone cut holes in them for speakers) and carpet. I'm planning to get a shaft radio for it, to replace the cheap crappy non-working single din someone put in it, which means I'll also need a new gauge bezel. nothing crazy hard to do.

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there are a couple of downers with this truck though... the rear main seal, and radiator both leak, I have replacements, I just haven't gotten around to installing them yet. it's also been wrecked at least twice I think. the front passenger door is "new", along with the passenger side inner fender is a 2wd fender not 4x4, the hood appear to be a re-pop, and the passenger side fender is a bit crunched by the headlights. the paint is nice enough for me though, all the paint matches, and looks ok from over about 25 feet away, and there is almost no rust, which is a huge win in my book.

I'm pretty sure the suburban chassis' are the same between 1/2 and 3/4 ton, only real differences are the axles and springs, all things I plan to change out when the diesel goes in.

[The Dark Side of Will]

That sounds about like my dad's, too. Rode hard, put away wet but surprisingly rust free. Good score!

The frame is definitely different between the 1/2 ton and 3/4 ton.

[ericjon262]

That sounds about like my dad's, too. Rode hard, put away wet but surprisingly rust free. Good score!

Thanks, it needs a bunch of love, but I'll make it work!

The frame is definitely different between the 1/2 ton and 3/4 ton.

I used to have a 3/4 ton, and advised a good friend not to buy a 1/2 ton because of it, the guy he bought his from had a 3/4 ton as a DD, and he put the 1/2 ton and 3/4 ton side by side, even took measurements and said he didn't see a difference. that's not to say it wasn't the same in the spots he looked and different elsewhere. I also don't see any explicit differences between my 1/2, and the 3/4 I used to drive, this one, an 88, the 3/4 a 86, both smallblock, both 4x4. that's not to say I'm not remembering things right, or that there's something I haven't seen, but I would be surprised at this point if there was a difference.

[ericjon262]

well, today was a mixed bag, pulled the stock radiator, installed all new belts(all four of them!) installed a new fan clutch, new lower radiator hose, which was original GM(!). started installing the new radiator, got everything hooked up, and found out that my upper brackets don't fit the new radiator... at all. thankfully, I don't need it to get anywhere ATM, I'm gonna see if I can get new brackets, maybe 3/4 ton will work.

[ericjon262]

well, turns out, there are two different radiator brackets, I bought a 3/4 ton radiator in support of future plans, but the 1/2 ton brackets won't work with it, and they don't manufacture the 3/4 ton brackets. hopefully I can find a set of the 3/4 ton brackets and get this buttoned up sooner rather than later.

shiny.jpg

in the picture, you can see that the bracket is clearly not the right one. again, hopefully I can get one soonish.

[ericjon262]

The big block radiator had made my life hell... What I thought Should be a one for one swap has become a convoluted adventure to find the right mix of brackets, spacers, and cushions to make this work, and it's not over yet.

I swapped the small block upper mounts for the one piece bb mount, but apparently there are 2 different bb radiators, a short one, and a tall one. Both mounted the same, but one uses thicker cushions. I have those on order, should be here next week.

The bb mounting, also requires the bb fan shroud, which is 2" short to make up for the difference in bore centers and water pump length. I cheated and bought a fan spacer to make up the difference in the length.

Hopefully this all gets ironed out next week and I can start working on the Alaska trip preps.

[ericjon262]

I'm starting to think the radiator I ordered is not the radiator I got, the brackets I have, just aren't matching up, tomorrow, a replacement radiator will be here and I'll give it another go, hopefully this one is the ticket. I'm still going to use the big block mount and shroud, as it is a much better design than the small block setup, as it allows removal of the radiator, without removing the fan, or the shroud. It makes me wonder why GM didn't use it on all applications.

[The Dark Side of Will]

There are a LOT of great parts and suppliers out there for the Square Bodies, but there's also a HUGE amount of misinformation. GM's year-to-year changes also make for buckets of catalog errors.

My dad's was an original diesel chassis. He likes the Caddy 500 in it (and we actually just dropped the "new" block in after is spun a bearing in 2016), but I'd love to drop a Duramax/Allison into it.

[ericjon262]

There are a LOT of great parts and suppliers out there for the Square Bodies, but there's also a HUGE amount of misinformation. GM's year-to-year changes also make for buckets of catalog errors.

My dad's was an original diesel chassis. He likes the Caddy 500 in it (and we actually just dropped the "new" block in after is spun a bearing in 2016), but I'd love to drop a Duramax/Allison into it.

I'm currently considering Duramax/4L80E instead of Allison. not because there's something wrong with the Allison, but because the 4L80E would allow use of a stock transfer case (with the TH400 input shaft) with then allows for stock driveshafts, front axle, transfer case shifter, and mounts, simplifying the whole swap. I still need to research a little more though because I don't know shit about the Allison, or the advantages of it. I can see that it's built to be maintained easier than the 80E based on the external filter, and some had PTO's, other than that, I know nothing.

[The Dark Side of Will]

AFAIK all of them had PTO ports. The TCM even locks the converter in neutral to drive the PTOs. If you've read something that says they didn't all have PTO's, I'd like to read it.

The Allisons were 5 or 6 speeds depending on year, but the only difference is the valve body & TCM. First gear is 3.06, so about the same as the TH700 in that regard. 4L80E first gear is 2.47ish.

The Duramax was used with the 4L80E in the vans, but never with 4WD/AWD. GM detuned the Duramax to ~250 HP in vans. I @$$ume that was for transmission life, although I guess it might be for fuel economy. You could buy a van powertrain with all the harnessing and have a relatively straight forward swap, although you'd have to either rebuild the transmission for 4WD or swap to a factory 4WD trans. Obviously you'd want to keep the diesel converter. Building the trans is not a bad idea if you're going to drop the pickup truck tune into the engine controller.

The Allison is BIG. It's over 330# dry. I've never found anything conclusive about whether or not it can swap into a square body without trans tunnel mods.

What gears does your truck have? 4.10's or 3.42's?

[ericjon262]

currently 3.08's I think... lame as hell whatever they are... they'll be changed when I get to the duramax swap, most likely by swapping the gears in the front axle, and the entire rear axle.

I like the idea of the PTO, it would be badass to have on board air in a larger capacity than a cheap 12V compressor. I can't see any need for HYD on a suburban. I'd rather not modify the trans tunnel, but it would be nice to have a 6 speed instead of 4, especially for long upgrades. when I swap this thing, I'm going to try and use as much of the donor truck as possible, rear axle, the brakes, exhaust, even emissions equipment, I want this swap to be damn near a stock truck, powertrain wise.

[The Dark Side of Will]

Lol... That's even less gear than my dad's truck. He had a '79 RWD 454/TH400 with 10.5" 14bff. That combo had the SUPER rare 3.21 gears in the 14 bolt. The '90 truck originally had a 9.5" 14 bolt. When he bought the '90 truck, we adapted later model disk brakes to the old 10.5" 14 bolt and swapped it in, complete with the 3.21 gears. The Caddy has enough torque to pull it and turns ~1750 at 55 and ~2250 at 80. ETA: with 4L80E trans

Engine installation:

[ericjon262]

that thing looks sweet! 4x4?
3.21 gears? that's an odd one for sure. I like the cad 500, I bet a bunch of people ask why and scoff instead of appreciating it! is it TBI ot carb? pretty much stock? those engine were rated to some absurd torque numbers...

Good thing about the Allison, is that there are Duramax/Allison swap kits available, I'd prefer to go the kit route and make the whole thing more or less a bolt in swap, wiring and plumbing is easier than mounts.

The new radiator is in, but I had some very strange results out of it, I started it up, drove it around the block, and it started to get a little hot, pulled into the driveway, and it was low on coolant, as more or less expected, so I refilled it, took it for another spin, and it was doing great, cruising around, the only issue I had was the fan occasionally bumping the shroud(needs new engine mounts). then as I start to head home, it started getting hot, I pulled into the driveway, shut it off, and immediately pop the hood to find the upper radiator hose collapsed!? the whole thing, flat as a pancake... I vent the system through the radiator cap, and it fills the overflow quite rapidly, as expected... at this point, the only thing I can think is that the thermostat stuck shut, and the water pump was drawing a vacuum on the radiator/upper radiator hose, I'm going to pop the thermostat housing off and look to see if it's clogged or otherwise damaged looking. along with all this fun, my heater core decided to give up the ghost as well. hopefully they are easier to replace than I expect...

[The Dark Side of Will]

Yeah, 3.21. I don't think that ratio was available on 4WD, though.

I haven't checked into kits yet because I haven't seen whether the transmission fits or not. You may have just told me that, though.

[The Dark Side of Will]

currently 3.08's I think... lame as hell whatever they are... they'll be changed when I get to the duramax swap, most likely by swapping the gears in the front axle, and the entire rear axle.

I like the idea of the PTO, it would be badass to have on board air in a larger capacity than a cheap 12V compressor. I can't see any need for HYD on a suburban. I'd rather not modify the trans tunnel, but it would be nice to have a 6 speed instead of 4, especially for long upgrades. when I swap this thing, I'm going to try and use as much of the donor truck as possible, rear axle, the brakes, exhaust, even emissions equipment, I want this swap to be damn near a stock truck, powertrain wise.

that thing looks sweet! 4x4?
3.21 gears? that's an odd one for sure. I like the cad 500, I bet a bunch of people ask why and scoff instead of appreciating it! is it TBI ot carb? pretty much stock? those engine were rated to some absurd torque numbers...

Good thing about the Allison, is that there are Duramax/Allison swap kits available, I'd prefer to go the kit route and make the whole thing more or less a bolt in swap, wiring and plumbing is easier than mounts.

The new radiator is in, but I had some very strange results out of it, I started it up, drove it around the block, and it started to get a little hot, pulled into the driveway, and it was low on coolant, as more or less expected, so I refilled it, took it for another spin, and it was doing great, cruising around, the only issue I had was the fan occasionally bumping the shroud(needs new engine mounts). then as I start to head home, it started getting hot, I pulled into the driveway, shut it off, and immediately pop the hood to find the upper radiator hose collapsed!? the whole thing, flat as a pancake... I vent the system through the radiator cap, and it fills the overflow quite rapidly, as expected... at this point, the only thing I can think is that the thermostat stuck shut, and the water pump was drawing a vacuum on the radiator/upper radiator hose, I'm going to pop the thermostat housing off and look to see if it's clogged or otherwise damaged looking. along with all this fun, my heater core decided to give up the ghost as well. hopefully they are easier to replace than I expect...

Must have been late when I made my previous post.
There are engine driven air compressor kits for the Duramax... you don't need the transmission PTO for that.
My dream bugout rig is a Duramax van with Allison + 4WD swap, engine driven air compressor and 480V A/C power off the PTO.

Cadillac actually had port injection in the early '70's. The ECM was completely analog, with the "map" being a grid of resistors on the circuit board. A few people still retune them. My dad's truck has the port injection manifold and fuel rail, but with '90's LT1 opti-spark pickup grafted into the base of the large cap HEI distributor, and the rest of the LT1 engine management to go along with it. It's a semi-cool setup, but I've finally convinced him it's time to go to LS controls. We were looking at how to fit the 5.315" 58x reluctor from www.eficonnection.com into the timing drive compartment in the front of the block. There's actually plenty of space inside for the trigger wheel, but locating the crank sensor will be fun.
He also has a towing/RV cam in it that provides a significant improvement in mid-range torque. We keep it redlined at 5k.

We have a set of the old pre-EGR small chamber heads that we'd like to have MTS port and do a for-real build... 10 or 10.5 compression, ported heads. Maybe even the Edelbrock intake, although that gives up torque to the stocker below 2000 RPM.

[ericjon262]

That's super cool about the EFI setup, I had no idea that ever existed, and then grafting the opti! one of the most hated GM components of all time! lol. I'll have to look into the compressor, I hadn't seen anything before, but I also hadn't exactly looked either.

[The Dark Side of Will]

The stock manifold is actually decent for a tow rig; like I said it makes more low end than the Edelbroke. It's a dual plane and the stock throttle actually has dual 65ish mm bores.

What DuramAllison kits have you seen for Square Bodies?

[ericjon262]

only one, from precision fabrication plus.

https://precisionfabricationplus.com/

Looks pretty nice to me, I haven't seen one in person yet though. I'll probably just use their kit, it would make everything easier. I do want to use a stock RH drop transfercase though, which does potentially complicate things a little bit. I'd prefer an NP208 because then I can run my stock driveshafts.