1986 J20 LS Swap

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SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »

rocklaurence wrote:Wow, you are making a lot of progress. Is the trans a 4L60E? Regarding the rear brakes, will the piston have enough travel to compensate for the spacer? You are coming up with unique ideas--love it
Yes the new trans is a built 4l60e, I pondered upgrading to a 4l80e but I would have spent double the cost reworking everything I had already done.
For the parking brake, yes the piston travel should be enough. As long as the spacer is the right width I will maintain the same distance between the pads and rotor as the original application. All the piston has to travel is that distance between each pad and the rotor at "off" pisition.

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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

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SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »

SJohn wrote: Wed Feb 02, 2022 9:47 am
mike472 wrote:hello, I'm working on my ls swap into 72 J4000, I have so many questions, what size fuel tank did you use?, it looks like from the pictures it hangs a little low, could it have gone up any?, do you have any pictures of the classic auto air install I can stare at, and where/what type of vents are you using? Thank you for all the pics and video clips, sounds sweet!!
Apologies for the delayed response, I haven't checked back here in a while. The fuel tank is a 20gal blazer tank and it looks like it hangs lower than the wagoneer and cherokee pictures I have seen. It is mounted as high as I could get it with the top of the tank touching the lower bed supports. I am in the process of falling up the rear bumper and it hides the tank pretty well.
I just got the AC charged and hooked the vents up this week! I will take some pictures and post them.

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Here are pictures of the AC installed. I used studs instead of bolts to mount the unit to the firewall and used nylon spacers to get it off the firewall half an inch. I also installed a heater bypass to keep coolant flowing through the engine while the heater valve is closed. This was recommended on the LS1TECH forum for LS engines. I installed a Deutsch firewall connector for the compressor and pressure switch wiring. Installing the Deutsch connector makes me wish I would have used them instead of the weatherpack connectors on the rest of the truck. They seem far superior but of course cost way more. Anyways, for vents I went with the universal rectangle vents supplied that came in the kit. I used the original AC line hole for the heater hoses and removed the blank to the left of it and ran the AC lines through it. I made new grommets from the original AC Line bulkhead grommets and 1/8" rubber sheet. The condensation drain is routed to a hole just below the fresh air vent which drains out the same hole as the cowl.
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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

mike472
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Re: 1986 J20 LS Swap

Post by mike472 »

Thank you for the updates, looking at the stock tank I think the blazer tank doesnt hang much lower, the bumper does cover most of it, nice work on the bumper by the way, looks like it belongs there. Also thanks for the tip on the heater valve gotta check the ls site out, glad you got the a/c working, sorry about the garage space, I havent got much more and these trucks are so long

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SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »

Welp, I decided that I will be attending the FSJ Ouray invasion this summer and booked my stay so now I have a long list of items to knock out before I try to drive this thing a couple thousand miles.
So Ive been working on swapping in some J10 springs from one of the donor trucks to get a better ride. I cleaned them all up and replaced the bushings with new poly bushings. I've got the front in and it looks like they might have been lift springs as I gained a couple inches of lift. New sway bar bushings are in and steering stabilizer is on the work bench! The steering has a small amount of slop in it so I definitely plan to address the rest of the steering components and firm it up a bit.
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One of the most important things I wanted to tackle before driving this thing any long distance was cruise control. With the DBW throttle getting the cruise to work was easy. Something to note is that the factory Jeep cruise control switch is a normally closed contact where as the GM cruise requires a normally open switch. I found that the drawings for 86 Jtrucks and Wagoneers incorrectly shows the switch to be normally open upon verifying with the multimeter. Fortunately for us that have 85+ trucks the turn stalk is a direct swap with early model XJs (1993) with the correct contacts and no disassembly of the column is required. The stalk pulls directly out of the column and the cruise wiring can be fished down the column case. I now have functioning cruise control and the wiper controls were not affected. Also the LS PCM requires a resistance to ground through the brake lights when the pedal is not pressed. Since I have swapped my tail lights to LED this will not work so I added in a small hidden incandescent lamp behind the left tail light to provide this.
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Progress on the parking brakes continues; I have 3d printed some brackets and confirmed this is going to work. I am working to get the brackets cut out of 1/4" steel and a coworker is going to mill the spacer out of aluminum. Next will be figuring out the cables.
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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981
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Yeller
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Re: 1986 J20 LS Swap

Post by Yeller »

Making plans myself, hopefully get to meet you in person there
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
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Re: 1986 J20 LS Swap

Post by SJohn »

Rainy day project while I was off from work today was starting the roof insulation. The headliner in this truck is almost immaculate and one of the first things I noticed when I bought it so I was extremely careful not to damage it. Put in the remaining 80 Mil Noico sound deadener from the floors and what a difference it makes! No more tin can! Next will be closed cell foam and then on to the doors to finish off the insulation.
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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

80Limited
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Re: 1986 J20 LS Swap

Post by 80Limited »

One of the most important things I wanted to tackle before driving this thing any long distance was cruise control. With the DBW throttle getting the cruise to work was easy. Something to note is that the factory Jeep cruise control switch is a normally closed contact where as the GM cruise requires a normally open switch. I found that the drawings for 86 Jtrucks and Wagoneers incorrectly shows the switch to be normally open upon verifying with the multimeter. Fortunately for us that have 85+ trucks the turn stalk is a direct swap with early model XJs (1993) with the correct contacts and no disassembly of the column is required. The stalk pulls directly out of the column and the cruise wiring can be fished down the column case. I now have functioning cruise control and the wiper controls were not affected. Also the LS PCM requires a resistance to ground through the brake lights when the pedal is not pressed. Since I have swapped my tail lights to LED this will not work so I added in a small hidden incandescent lamp behind the left tail light to provide this.
I still need to hook up the cruise in mine. I have an 03 DBW 5.3 in my 87. Did you have to hook up relays or just corresponding cruise wires to the tac module? I did that noico in the whole interior of mine and put the red foam on the door cards and in the quarter panels. Works pretty nice.

80Limited
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Re: 1986 J20 LS Swap

Post by 80Limited »

I still need to hook up the cruise in mine. I have an 03 DBW 5.3 in my 87. Did you have to hook up relays or just corresponding cruise wires to the tac module? I did that noico in the whole interior of mine and put the red foam on the door cards and in the quarter panels. Works pretty nice.

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Re: 1986 J20 LS Swap

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80Limited wrote: Mon Mar 21, 2022 4:53 pm I still need to hook up the cruise in mine. I have an 03 DBW 5.3 in my 87. Did you have to hook up relays or just corresponding cruise wires to the tac module? I did that noico in the whole interior of mine and put the red foam on the door cards and in the quarter panels. Works pretty nice.
No relays, swapping in the XJ switch avoids the complicated relay solution that I believe you are referring to. All you have to do is tap into the tac harness. Pin 4 - Set/Coast, Pin 5 - Resume/Accelerate, Pin 6 - Stop Lamp, Pin 14 - Cruise ON. On the XJ switch: Blue - 12V, Red - Set/Coast, Green - ON, Yellow - Resume/Accelerate. Of course confirm the switch circuit first with a multimeter first.
Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

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Re: 1986 J20 LS Swap

Post by SJohn »

Here is a wiring diagram I whipped up of the new cruise control wiring in my truck.
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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

80Limited
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Re: 1986 J20 LS Swap

Post by 80Limited »

SJohn wrote: Wed Mar 23, 2022 3:36 pm Here is a wiring diagram I whipped up of the new cruise control wiring in my truck.
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Perfect, that’s kinda what I was thinking. Glad you clarified it. Thanks

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Re: 1986 J20 LS Swap

Post by SJohn »

The custom brackets are in for the parking brake caliper. Sam at Flying Iron Fabrication took my drawings and cut these out of 1/4" steel for me. These will be welded together after the caliper is positioned how I like and the bolts are tightened up.

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
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1986 J20 LS Swap
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1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981
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Yeller
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Re: 1986 J20 LS Swap

Post by Yeller »

I’m really curious to the effective strength of this once you are done.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

Txrangers20
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Re: 1986 J20 LS Swap

Post by Txrangers20 »

I noticed a while ago that you had a J20 for parts. Do you still have the tailgate by any chance? I have been struggling trying to find one.

teking
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Re: 1986 J20 LS Swap

Post by teking »

SJohn wrote:Finally got the engine out. This thing kicked my butt, had to torch the body bolts off to lift it off the frame so we could lift the engine high enough to clear the front diff.
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Last time I left something like that in the yard I slept on the couch. Image She said the handgun range I installed was my last free pass.

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Re: 1986 J20 LS Swap

Post by SJohn »

Txrangers20 wrote:I noticed a while ago that you had a J20 for parts. Do you still have the tailgate by any chance? I have been struggling trying to find one.
All of my parts trucks are gone, I've sold it all!

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

Topic author
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Re: 1986 J20 LS Swap

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teking wrote:
SJohn wrote:Finally got the engine out. This thing kicked my butt, had to torch the body bolts off to lift it off the frame so we could lift the engine high enough to clear the front diff.
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Last time I left something like that in the yard I slept on the couch. Image She said the handgun range I installed was my last free pass.

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Hahaha my dad's backyard looked like a junkyard the past 2 years but as of a couple months ago all of the trucks are gone. He doesn't mind, he's the one regularly sending me marketplace ads Image

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

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Re: 1986 J20 LS Swap

Post by SJohn »

Test fit the brackets and caliper today and everything lines up great! I also found out that the slider bolts from the big calipers are the same size just a bit longer which is what I need to make up for the spacer.
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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

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Re: 1986 J20 LS Swap

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Tackled some small projects and started some bigger ones the last few weeks. Starting new projects is the opposite of what I need to be doing but I got it stuck in my head and had to do it.
I seem to never stop working on the wiring for this truck. The most recent project was adding a Deutsch firewall connector for the cruise control, throttle pedal, and gauge wiring. No more wires going through the firewall without a bulkhead connector now! If I could go back a year ago when I was working on the wiring harness on the kitchen table I would slap myself and tell me to do it all with Deutsch connectors. They are more expensive but far better in my opinion than weatherpack connectors. The pins are rated for higher amps, the seals are built into the connector rather than an individual seal per wire, and the connections are way better. I know I have said all this before but every time I work with these connectors I love them more! I still have some more work to do hiding the few loose wires left but this cleaned up the firewall alot!
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The auxiliary fuel tank is plumbed in and operational sub a fuel gauge. I used a cheap amazon transfer tank filler tee that ties directly into the 2" fill line at the rear tank and a cheap frame mounted fuel pump to transfer the gas. From the first tests it looks like it will take 30 to 45 min to fill the rear tank via transfer pump.
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Finally, the big project I decided to start on a whim, a camper top for the Jeep! Seeing as there's no room for luggage in the cab and wet clothes doesn't seem like a fun time, I figured I was going to need something to keep my stuff dry and safe when I actually drive this thing a decent distance. So I went on the hunt for a camper for my truck and of course it wasn't a simple task to find anything that would fit my truck. Thanks Jeep for making a truck bed narrower than full size trucks but longer than midsize trucks (for those of us with 8' beds). So I figured if I could find an aluminum camper that was the same length I could just cut it in half and stitch it back together to fit. So I did it! I picked up a cheap camper off an 03 superduty that measured 73" wide by 99" long (an inch longer than the Jeep but I can handle that without cutting). The Jeep bedrails measure 62.5 by 98 inches. I used some 2x4s and whole lotta ratchet straps to get it home. These things are super easy to dismantle, they're put together with self tapping screws. Once the ends and top were skinned I cut 10.5 inches from the middle and stitched it back together with 1/8th" aluminum flatbar and rivets. Once everything is stitched back together Ill weld it up with my dads mig spool gun to really hold it all together. For the windows I can either replace them with plexiglass or have the glass cut down. Here's pics
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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

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Re: 1986 J20 LS Swap

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The truck is now officially road trip certified! Took the truck on a 650 mile round trip back home to SETX with no breakdowns (ok I did run out of gas once but thats it)!!! Averaging 65 MPH on the highway the truck did well and no major issues arose. Made and estimated 13 mpg on the way down and 19 mpg on the way up. The gas gauge has been faulty since the gauge install and showed empty when the tank was half full hence the "estimated". I assume the poor gas mileage on the first half of the trip is due to the truck having practically zero highway miles since the swap and the ecm is still adjusting the fuel mapping.
Ran out of gas once, but that was partly intentional, but still didn't go as planned. Knowing that the gas gauge was faulty I made sure the auxiliary tank had a few gallons in it and planned to let the truck run out of gas then simply flip the transfer pump on and go on about my way. I would record the mileage that I ran out of gas and that would be my range estimate. I knew that after the fuel gauge hit empty I still had half a tank left and could ignore the low fuel warning for at least a hundred miles before I got close to running out and I wasn't wrong. However, 10:30PM on the side of the highway I flipped the aux tank switch, waited a few minutes, no start. Few more minutes, no start. I could hear the pump going but when I walked back the the rear fill I didn't hear any fluid flowing into the fill tube. So I tore the filler tube connection apart on the side of the road and found that the back flow preventer in the cheap amazon fitting was stuck (no rattle) and the ball bearing that sealed the flow was not moving. After banging it around on the tailgate I got it loose, threw everything back together, turned the pump on and heard gas flowing into the filler. Fired the truck up and cruised the rest of the 40 miles to SETX. I cut the ball bearing out the next day to prevent the issue from happening again.

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While down South I took advantage of my dad's spacious shop and replaced the rear springs with the half ton springs I took from the blue J10 and did some welding on the camper shell and parking brake brackets. What an amazing improvement the half ton springs made!! Before I could jump around in the bed and it was like jumping on concrete but now it rides like a caddy in comparison! As I discovered with the front springs, the rear spring are also arched a little bit and gave the truck about an inch of lift. 9 leaves vs 5. After riveting the camper back together I figured it was going to need some more stiffness so I used the spool gun attachment for my dad's miller welder to weld the joints pack together. More welding will be needed in the future after the skin is on but this really improved it vs just the rivets. Forgot to take pics but just imagine an ape got ahold of a welder and went to town on the camper ... welding aluminum with a spool gun is a big change from regular mig welding. Also took use of the welder to hold the correct adjustment on the parking brake brackets. After mocking up the caliper on each side I made some welds to hold the correct adjustment for each side.

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
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1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981
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