1985 Jimmy LS Swap build- Resurrecting the War Pig

[rpcraft]

I got a new 31 gallon tank from a TBI Blazer off ebay so it would have the baffles and the matching TBI Spectra FG12K sending unit and then the recommended AC/Delco Vortec pump (does 255 LPH volume). I might regret the ebay tank at some point but until I do I'll live with it. I'm probably going to just use the steel supply and return line and then use a compression to AN adapter on the frame rail near the motor, and then just use some of the Earl's line up to the motor and for the return. I had contemplated using a Corvette regulator filter for the returnless systems and capping off my return line but after doing some checking, since my LS motor came with the return style system I figured it would be best to just stick with the way the general designed it. It seems anyone that has tried to cap off their return lines always seems to have some weird pressure/running issues. I'm probably going to go ahead and piece it together and get it ready to go in the truck this Sunday, along with running the fuel lines. I'm also going to cut an access hole in the back area so in case I need to mess with the pump and connections I can do so without dropping the tank. I figure I'll just weld a couple of tabs to the edges of the cut so I can screw the panel back down, and then wrap the edges with vinyl trim to seal it from any moisture. Also going to put a layer of Al's HNR on the floor, and sidewalls of the rear cab.

As far as adapters go, I'll worry about those after I get the new harness on so I can get the wiring under control and matched/hidden in the LS harness. I might go with one of the Dakota Digital Analog dashes so I don't want to buy anything until I need it, and as long as I can check the oil pressure at start-up and initial running, then I'll just use my BT adapter on the OBD port to keep track of the coolant temps and what not. The thermostat I am going with is just the OEM replacement for the year of the truck butI'll double check what was in it to make sure. The injectors I'm using were with the motor as a dropout (which only had 60K miles when I purchased it). I've just gotten a new water pump and some of the basic gaskets to put the intake and water pump back on but aside from that everything else pretty much came with the motor. I could probably start putting all that on this Sunday as well too. I think I stopped last week because I picked up a couple of new knock sensors and the harness and I wanted to change those out and seal them up properly before I get too much of the accessories in the way but I ran out of time on the weekend (and I travel away from home most weeks for work).

I am curious what you did as far as your motor mounts, AC hook up, stuff like that. Just to compare notes and what not. I have the Dirty dingo mounts and It's looking like there won't be any real way to fit the AC pump in the OEM location but I won't really know for sure until I get the trans/transfer in. If not I have read you can use a modified Vortec ac bracket to make an OEM style high mount bracket. I also had to notch the cross member under the motor an appreciable amount and at some point think I am going to look into getting an upgraded steering box and pump, so fitting that on the OEM bracket might present some type of challenge..

Curious to hear your feedback on those matters. Thanks

 

[robster495]

Good move on the fuel pump, that's important. I also cut an access panel in my trunk to reach the fuel sending assembly and I covered it all back up (I should seal mine too lol). No way Jose was I gonna drop my 38 gallon tank. I kept the fuel lines the same since my both my original TBI and the new 5.3 were return system. Bought a brand new fuel filter too, easy and effective.

I also use one of the BT adapters at the OBD port, such a cool thing to have nowadays with our swapped trucks! I'm currently working on a clean way to mount my 10" tablet to hang on my canter console, at an angle that makes it look like its part of the truck. It'll be for media, OBD, GPS, etc.

One thing I did while I had that much access to the motor, I replaced every damn gasket and cleaned it up as much as possible. I could eat off the valley if I wanted to. I took that extra time to make sure I had a long road ahead of me before I had to get in there again, might as well. I did Head Gaskets, Pan, Intake, TB, Valve covers, all gaskets back to front with high temp RTV to help seal it all. the only drip (which is very very minimal...) I have is from the oil filter but that's pretty much expected for me lol.

I also used the Dirty Dingo sliding ones, those helped a ton when getting everything lined up. And oh man that notching was fun haha. I stood where the motor would be and took my sledge to the appropriate spot a few times. The mounting order I lined things up was from the trans mount, and forward. I had them mated (excluding the tcase 'cause whatever), and with the help of some straps and my hoist, I got the trans Kmember in place and 90% tightened. Then I moved forward to the DD mounts and tightened those bad boys up. Bam, perfect placement.

I personally skipped AC so I'm no help there. But like you said, there are probably some brackets out there for re-routing. My steering is all factory.
My insight into fitting the P/S pump and lines correctly, this was a little tricky but worked beautifully...
The hose line fitting sticks out a little too much and hits the frame, not allowing the hose to be attached and clamped (the high pressure line that threads in behind the pump is fine).
So I took my vice grips and gripped them to the two points that normally would flare out when you bend some small piping.
Once that was tight I gently bent the fitting straight up. The vice grips kept the tubing from flaring and breaking. If you have questions I can go more into detail (pics, etc), or if that's already planned and figured, then no worries lol.

 

[rpcraft]

I thought about just using some velcro or something to mount a 10 inch tablet on the front for speedo and RPM, then a 7 inch on the side for the side gauges but then i realized fuel level and oil pressure would be non-existent so i figure I might just do an Autometer or Speedhut setup and just use a GPS speedo so I never have to worry about adjusting it again.

I've already changed out the oil pan gasket and most all the others but I didn't want to pull the damper off and have to fool with re-torquing it due to an injured shoulder so I left that as is. I've been on the fence of pulling the motor and painting it but i have not made my mind up just yet, but I figure I want to get the transmission slid in with the T case so that if I do pull and paint it I don't have to fight lining up the drive train again (will just use some ratchet straps to support it like you mentioned). I'm not going to mess with the head gaskets but I figure the 5.3 is my gateway motor and once I get the truck running and can float a little cash back in the bank I am going to pick up a 6.0 and throw a good cam and the rest that goes along with it, then pull the 5.3 and resell it since its got really low miles.

I didn't have much problem with the notch. I just put the plasma to it and once I am sure I don't need to cut any more I am just going to weld some 1/8 plate in and around it for a little gusseting.

I think what I am going to do is what you mentioned for installing the drive train... Put the trans in with the crossmember and the tcase mount, then lift the tcase up to it after I have the crossmember in the right spot. I figure I can wrestle the transfer case one last time, lol.

 

[robster495]

Haha I feel you on getting that tcase up. I do the same ol' put it on my chest whilst on a creeper, and huff and puff for a few seconds haha. But yea, having the trans lined up with the kmember puts everything in place, huge help. Then the DD mounts wont need to slide anymore and you can tighten away. Do you plan on keeping as much factory gages as possible, or you don't really care?

I've also considered making the 5.3 a gateway, but I'm growing attached to it lol. Gas mileage is my main thought since this thing is an occasional cross-country road-tripper. The 5.3 power is more than enough for my occasional off-roading and towing.

p.s. As a heads up (things are popping back into my head now that I'm going back through my swap memories lol), have you figured out your alternator wiring? I know these trucks had different configs.

 

[rpcraft]

I'll probably startout with the factory speedo and fuel but since I am going to swap axles at some point and running 33's it won't be accurate in any sense but I know a guy south East of Dallas that can get me the 91 Burb gauge cluster so I may swap that in and for 100 $ its a lot less of an investment (and work) then the Dakota setup. I wasn't aware I had to do much with the alternator when using the cable hookups for the OEM harness but if worse comes to worse I will just swap to a one wire setup or something similar. I figure if I am having issues there is a large resource pool available on the LS swap forums so I'll figure it out.

 

[robster495]

Yea I got lucky with my electronic speedo. The 5.3 ECM puts out the same signal the 90-91 speedo needs, and the signal from my factory 241c gives the right output the ECM needs (green and purple intertwined wires). When the harness is reworked, the 4k signal output wire from the ECM will go to the blue wire that used to connect the '91 DRAC to the '91 Speedo (in that new cluster you're talking about). All that can be programmed in the ECM once you make that tire/axle switch! I did the same thing, I had mine reprogrammed to 255/75r17's to show correct speed.

Alternator wiring was pretty easy once I figured out how to keep my idiot light and all that. Do you have the in dish idiot light?

 

[rpcraft]

Alternator wiring was pretty easy once I figured out how to keep my idiot light and all that. Do you have the in dish idiot light?

I'd be lying if I said for sure but I think mine is the gauge and not the dummy light. I think the dummy lights started in 1989.

 

[robster495]

Ah so you have the gage, okay. I'll show you my set up. Might help!

The two wires I'm holding with my thumb go to my firewall. That remaining brown wire is the harness' single alternator wire. I spliced that to join the brown wire going to my firewall.
The 5.3 harness originally called for a one wire set up, but I sourced the two wire pigtail to keep whatever the pink wire does (I'm guessing the dummy light?).

 

[rpcraft]

I'm probably going to have to reinvent a few things a little bit because I am replacing the factory harness inside the cab with an after market one so I am sure I may run into a few questions that don't have traditional answers. That is part of the reason I am considering going with the aftermarket gauges. I am not sure if it will be easier trying to adapt the OEM setup or go with something that is a little more straight forward (and well documented). I'll figure it out after I start focusing more on assembly of the electronics and stuff.