The Camp 4x4 Bus - 1973 Suburban 8.1 Swap & Build

[camp4x4]

I have some of the same paint from TSC. It is not a rust convertor though so rust still needs to be addressed before you seal it up.

Good idea on the frame off.

Is that a HF carport??

The primer is a rust inhibitor, but I'll be doing my best to take care of any rust before painting. The frame is all in all pretty good, it's really the underbody that's going to pose some issues... we'll see. I can't recall where we got the car port... I think HF sells them... this is a Costco replacement cover as the old one rotted away. Frame was originally from... ???

 

[camp4x4]

Spent some time today priming more parts. Still not the greatest spray atomization, but I just wanted to get these things started. This week will be more of the same plus some progress on further pulling stuff off the frame.

On a side note I swapped my manual hose real for an auto one. Soooooo much nicer.

I also pulled out the harness I got from Howell because I started thinking about something: because I started down this path when I was going to try and meet smog requirements, I had all the smog connections kept on at extra expense. And I presume certain programming was put into the PCM to match. Some things like O2 sensors are fine since I intend to keep the catalytic converters and use both the before and after 02 sensors. But it occurred to me that there might be evaporative system items that would be tied in as well - things I don't HAVE to put in now. Seems I was right. Looking through the nicely labeled connectors I found 3 that might be a problem. I have to look into these further to see how much of a hassle they'll be, but here they are: 1) Fuel tank pressure sensor, 2) Canister purge solenoid and 3) Canister vent solenoid. I still have to figure out exactly what they are and how hard it would be to incorporate to the old truck. Hopefully some googling will answer that question.

I also found some gauge leads while going through the labels, which will really make wiring up the gauges I got from zoomad75 easier. Speaking of wiring, I picked up a full color, laminated diagram from ebay that I'm hoping will keep things simple and clear as I start putting things back together. I don't think I'm gonna do a full rewire, but I'll certainly be removing parts of the old harness. Seriously considering putting a new firewall passthrough connector and stripped down fuse box in... I like the look of the Bussman boxes...

Painted some parts


New Real


Fuel tank pressure lead


Canister purge lead


Canister vent lead


Tach lead


Coolant temp lead


Oil pressure gauge lead

 

[Larry]

You have a really cool little paint booth set up there. That is handy! Looks like things are progressing quickly. Nice work!

Yeah, your harness is definitely set up for smog as I don’t have any of those connections. There is a lot of stuff going on there that you don’t want or even need and the ECM does have calibrations to operate each one of those inputs. The bad thing is I doubt you can just unpin those circuits from the ECM as I suspect there are many splices where those feeds share common grounds and 5V references where you would almost have to un-loom and un-tape the complete harness to prune those things out. You might be better off calling Troy at Howell and explaining your project changed directions and see if they will trade you out of that harness and ECM.

That Bussman fuse box is real nice! I must say the fuse and relay set up on the Howell Harness is less than sterling although I ordered the Suburban’s harness with marine type fuse holders that are weather sealed whereas I didn’t know any better when I did the K10’s 8.1L almost 10 years ago but even their Marine fuse holder is pretty s hitty

This is what the Howell harness for the 8.1 in my Suburban looked like. It is very small and un-intrusive. All it does is run the engine….a true stand-alone harness. The starter, A/C compressor, alternator, oil pressure, temp gauge, and fuel gauge all run on an original 1989 harness. The Howell harness only runs just the engine and fuel pump relay and that is it. The Howell harness basically had 5 connections to the actual truck (Key’d on power, hot all the time, grounds, and alternator plus a tachometer circuit to run the aftermarket tach).

My Suburban was a little more complicated as it was a TBI truck where there were a lot of circuits to prune out of the original underhood harness. Luckily, I had an extra 1989 Suburban harness laying around that I chopped up so I could keep the original to resell with the TBI 5.7L I pulled out. The harness in front is the virgin 1989 harness and the one in the rear is the reworked 1989 harness. There was a lot to prune out! That all said, an old carbureted truck like your Burb is even easier to work with like my K10. The K10 was super simple….keep the starter, temp, oil pressure, A/C circuits and just use the 10 gauge wire that used to go to the ignition coil as the power lead to the keyed on ECM circuit. In the case of your 1973 with breaker points, you will need to replace the power wire that goes to the coil with a fresh 10 gauge wire as the breaker point ignition vehicles used resistor wire to the coil. What that means is if you use that wire to power up your ECM it will not receive a full 12 volts. Look up points to HEI in forums to see what I am talking about related to the resistor wire.

Regarding the inner fenders….ya, they all rust in that spot where the brace is as junk gets stuck back there and rots from the inside out. You might consider spraying a heavy coat of bed liner on the new inner fenders when they arrive to help give them some more structural integrity as the replacement inner fenders are paper thin where you can practically push a dent in them with your fingertips. I had the local Rhino liner shop spray mine before installing which really stiffened them up and also make it easier to clean up after being on the muddy trail. The Rhino shop I used only charged $100 to do both sides as I told him no hurry and to just do them next time he was doing a Rhino job in the both. I really like how they turned out.

10 years later the Rhino'd inner fenders still look good and do their job

 

[camp4x4]

You have a really cool little paint booth set up there. That is handy! Looks like things are progressing quickly. Nice work!

Thanks, yeah it's getting the job done for sure. Once I wrap up these pieces it'll switch to a clean-up booth for the frame and transfer case. Then back to a paint booth for the frame. I got some box fans and HVAC filters to make it all fancy and what not, but I think I'm going to hold off on that. Doesn't seem worth going to that effort for under-body parts.

You might be better off calling Troy at Howell and explaining your project changed directions and see if they will trade you out of that harness and ECM.

Yeah, I messaged them last night. If I don't hear from them today I'll give 'em a call and see what can be done. Even if I have to pay another hundred or two for shipping and whatever, it's worth it because actually getting and installing all this smog stuff is going to be $$$$$ and a pain in the ********.

That Bussman fuse box is real nice! I must say the fuse and relay set up on the Howell Harness is less than sterling although I ordered the Suburban’s harness with marine type fuse holders that are weather sealed whereas I didn’t know any better when I did the K10’s 8.1L almost 10 years ago but even their Marine fuse holder is pretty s hitty

The one included with the kit is... yeah, less than stellar. Will have to see if I end up wanting to incorporate it into a single, whole vehicle fuse box or leave it as is in a safe place... Not super excited about doing a full re-wire, but seems like it shouldn't be that hard with such a simple electrical system. Doing that on my '87's TBI would be a much more daunting task.

The K10 was super simple….keep the starter, temp, oil pressure, A/C circuits and just use the 10 gauge wire that used to go to the ignition coil as the power lead to the keyed on ECM circuit. In the case of your 1973 with breaker points, you will need to replace the power wire that goes to the coil with a fresh 10 gauge wire as the breaker point ignition vehicles used resistor wire to the coil. What that means is if you use that wire to power up your ECM it will not receive a full 12 volts. Look up points to HEI in forums to see what I am talking about related to the resistor wire.

Great info, thanks for that! Definitely not included in Howell's generic instruction sheet that came with it.

Regarding the inner fenders….ya, they all rust in that spot where the brace is as junk gets stuck back there and rots from the inside out. You might consider spraying a heavy coat of bed liner on the new inner fenders when they arrive to help give them some more structural integrity as the replacement inner fenders are paper thin where you can practically push a dent in them with your fingertips. I had the local Rhino liner shop spray mine before installing which really stiffened them up and also make it easier to clean up after being on the muddy trail. The Rhino shop I used only charged $100 to do both sides as I told him no hurry and to just do them next time he was doing a Rhino job in the both. I really like how they turned out.

That's a great idea... really like how those look, and preventing future damage is definitely the name of the game with this thing. I'll ping a local rhino liner guy and see what he quotes. I see I can get a small Raptor Line kit on Amazon for about $100, so anything over and I'll just go that route.

I was also thinking about doing liner on the under body instead of the tractor paint... help a bit with sound deadening.

I ALSO had previously found Lizard Skin ceramic thermal insulation coating. Not sure if you're familiar with it, but this might be JUST the ticket for under the body. Help with heat and they also make a spray on noise reducer I could use on the inside.

http://www.lizardskin.com/car-ceramic-insulation.html

http://www.lizardskin.com/sound-control-insulation.html

At about $150 for 2 gallons they're on par with bed liner cost-wise but seem to do a fair bit more than just protect.

Lastly, I was looking around on Amazon and stumbled on this rust-converter primer. May start with that, whatever I end up doing under the body, since there's a fair bit of active rust on the backside of the door jams and elsewhere.

https://www.amazon.com/dp/B001CRETZW/ref=psdc_15718511_t1_B014LR5PA2

Speaking of painting, I was thinking the other day about how the heck I was going to spray the under side of the body without having it on a rotisserie. Seeing as turning an HVLP paint cup upside down would result in a bunch of paint on me and the floor and not much under the truck... found this little video doing some searching. Looks pretty good.. will see how it works in practice. I'm still curious about how well the paint will suck out of the cup... I guess this wouldn't be an issue if I went with one of the coating/liners since those use a siphon feed gun.

 

[camp4x4]

Another evening, another layer of primer.

 

[camp4x4]

Little bit of good news this morning!

I talked to Troy over at Howell EFI and he said I could simply tape back the unused connectors; no swapping out harnesses needed. I'll have to send in the PCM to get the EVAP and rear 02 sensors flashed out, but that's a minor inconvenience and cost compared to putting in the full evap system! I'll be keeping the cats simply because I have them and they're good to keep, but no rear 02 sensors means 2 less sensors to worry about.

On the topic of exhausts, I've been pondering what to do about mufflers. I'd like to keep a true dual exhaust, and I'd like to have a nice little growl in it without going overboard. I have a straight-through muffler on my CRX track car and it brings the note up somewhat without making it obnoxious. Was thinking about doing the same for The Bus, particularly for space considerations...

Does anyone have any suggestions on mufflers or kits? I was thinking I'd simply have most of it fabbed at a shop since I don't especially feel like doing that myself, even with a kit, but I'd like to go in there having some idea of what I want.

 

[FBJR]

A simple reflash is great. Saves $$$ and you get a simpler install.

I have turned to big maganflow fan, but they are getting pricy. I think someone makes a nice knockoff, but can't recall who.

Also a favor of single exhaust, but you would need 3 1/2 for the bigblock. I run 3 inch on my small block with a magnaflow and cat. I wouldn't run a cat if I didn't have to, but they don't hurt.

Building an exhaust is not hard, but I would get it coated. Possibly even get a walker setup up front and I like to kick it out the side before the rear tires.

 

[camp4x4]

I like to kick it out the side before the rear tires.

Unfortunately I'll have rock sliders there, so it's gonna have to go out the side behind the rear tires, which means up and over the rear axle. I found a shot of what looks like a nice setup from a forum that I think said it was a kit that they modified a bit. I don't like the exit out the back aspect, but everything else looks fairly tidy.

 

[FBJR]

With you keeping the burb low. A cross over could present a problem with the driveline.

Kicking the exhaust out the side should be no issue with a custom setup and no fuel tank issue.

 

[MTCK]

Awesome work. I have a single 3.5" with cat and magnaflow muffler on my crew cab and love it. No drone but lets you know there is something there. Larry had a difference experience with magnaflows so depends on the setup. Like was said they are not cheap.

 

[Larry]

Awesome work. I have a single 3.5" with cat and magnaflow muffler on my crew cab and love it. No drone but lets you know there is something there. Larry had a difference experience with magnaflows so depends on the setup. Like was said they are not cheap.

So true! A lot of it comes down to the pipe size, single or dual mufflers, H & X pipes as well as how close the muffler is mounted to the exhaust exit. I could not stand the Magnaflow at all but perhaps it if had an X pipe mounted in front of it I would have liked it better but I felt the muffler was just too small for the engine as it even felt restrictive.

Magnaflow

After the Magnaflow I went with a Spintech with an X pipe, which I really like. It is pretty quiet but still has a set of lungs when it is whipping time. The cool thing is they make custome mufflers so if you call the grouchy guy that owns Spintech and tell him the vehicle specs and expectations he will custom make a muffer for your needs. As much as I like the Spintech, I still like the Thrush (Flowmaster knockoffs) with true dual exhaust and an H pipe like what is on the K10….plus the Thrush mufflers are so cheap they are almost free compaired to a $pintech. I think the K10 just sounds so much better and feels like it even runs smoother, especially on the interstate. It just seems like the 2 in/2 out mufflers have a habit of droning and what not. The Spintech doesn’t have much drone but there is some where as the dual mufflers on the K10 has no drone what so ever but the exhaust note really changes with temperatures. When I've been driving it for 6+ hours going back and forth to Utah it starts to sound like a exotic supercar and kind of zippy sounding. Hard to explain but it sounds pretty cool. On the other hand at a low RPM the exhaust sounds pretty Blappy like you can practically hear each valve opening and closing

 

[FBJR]

My single with the 350 sounds good, but no real highway use right now. I like your setup Larry.

 

[Larry]

My single with the 350 sounds good, but no real highway use right now. I like your setup Larry.

Thanks! Too bad the shop I used to install the Spintech had a chimpanzee doing the welding. Those idiots even welded an exhaust mount to the floor (yes, the FLOOR) of the Suburban. Talk about interior resonance! I cut off the floor mount but I still need to clean up their install welds.

 

[FBJR]

I remember that in you thread, but heads. I may make up a new Y pipe for mine as the stock one is more a T. I had to reweld and entire system once done by midas. Even had to tell them which way the muffler we

OK, back to Aaron's thread ??????

 

[camp4x4]

I like the look of that setup. The pipe from the passenger side is nice and tight up to the trans where it crosses over.

I checked out some videos on YouTube of different mufflers and found this one with the Flowmaster Pro Series, which is like a straight muffler but with some interesting internal baffling. Obviously my 73 is going to have a lot less sound deadening than a current model, but overall I like the sound difference shown in Flowmaster's demo video with the engine on a test stand.



Right now really liking the idea of a true dual exhaust with one of those on each side. But at $200 each.. yikes! :Wow1: We'll see...

OK, back to Aaron's thread ??????

Lol, no worries.

On another note, I'm finally getting rid of the 16.5 rims and military surplus tires. Just found LITERALLY the only option (besides custom $$$) in 17" wheels that have a decent backspacing.

Pro-Comp Series 98 steel wheels. 17x9, 8x6.5 with 3.5" backspacing. That's gonna bump 'em out a little from the stock 3.75 backspacing, but I'm very okay with that.

I'm currently going back and forth between AT and MT tire options. I'm a little sick of the military MT tire drone on the freeway, but I don't want to give up the aggressive performance on rocky and other uneven wheeling terrain. The BFG A/T KM2's are looking REALLY appealing. But so are the BFG Mud Terrains. Then, in comes Toyo with the Open Country R/T (Rough Terrain). And in a 13.5 width no less. So.... that's where my head is currently at: Toyo Open Country R/T's in 37/13.5R17 to split the difference between A/T and M/T.

Pro-Comp Series 98 Steelies


Toyo Open Country R/T


Thoughts?