1986 J20 LS Swap

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Txflyer16
Posts: 26
Joined: Thu Sep 02, 2021 9:44 am

Re: 1986 J20 LS Swap

Post by Txflyer16 »

looking good!
'81 CJ-5
'93 XJ
New project '79 J-10
Looking for a Waggy

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SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »

Txflyer16 wrote:looking good!
Thank you!

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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 »

Finally got time to start on the bed rail replacement. I started on the passenger side with flipping the new rail over to use as a straight edge for the cutting line on the bed. The first 6 or so inches I made the mistake of cutting through the sharpie line which left about an 1/8" gap then I came to my senses and realized I needed to account for the cutoff wheel width. The gap didn't end up being much of an issue but something to remember for the driver side. I originally didn't think the outer skin was connected to the inner bed wall at the top but after I made the cuts it was evident that I was wrong. The inner bed wall is spot welded to the bed rail on the vertical edge of the bed rail and I had a hard time visually finding them. Other spotwelds on these Jeeps seem far more visible. Fortunately there are only a handfull of spot welds here. With the bed rail off I inspected the void between the skin and bed. Found some debris and a bit of rust on the fender flare seam. Vacuumed the dirt and loose rust out and sprayed some ospho on the seam, then did my best with a rattle can to coat the rusted area.

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The new bed rail went on pretty well using a very strong magnet to get the bed rail and outer skin flat. I tacked the bed rail to the outer seam every 4 - 6 inches first then stitched the panels together slowly making 3-4 tacks at a time running down the bed. I found that by the time I made it to one end the other end was already cooled off and ready to start from the other end again. I welded the length of the bed minus the first few inches where there is a bad crack I will have to repair later. So far it looks pretty good, the top edge had several dents and gouges that I fixed as well as I could but the edge is still a bit wavy. I think Ill eventually rhino line the bed and bed rail to hide this. Stake pockets to come later … maybe?

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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

wrang
Posts: 14
Joined: Mon Mar 09, 2020 6:21 pm

Re: 1986 J20 LS Swap

Post by wrang »

hi
been following your build very closely, what a nice truck, turned out incredible, can't wait to see it after all bodywork is complete.
I am doing something very similar (i posted my progress, slow, and not as technical as yours). I did a 6.0L LY6/6l90E swap into 82 J10 (and like you, used 3/4ton axles from a J20). it is running and driving well. next id disc brake conversion for the rear
one question, no clearance issues with brake disc conversion with the original 16" rims/tires (the ones you described as noisy, were 285 wide)?
also, do you know the offset on those original rims?
lastly, do you have any leftover body parts you are willing to part with? mainly looking for the latch and plate of the tailegate? and any other body parts?
thanks

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SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »


wrang wrote:hi
been following your build very closely, what a nice truck, turned out incredible, can't wait to see it after all bodywork is complete.
I am doing something very similar (i posted my progress, slow, and not as technical as yours). I did a 6.0L LY6/6l90E swap into 82 J10 (and like you, used 3/4ton axles from a J20). it is running and driving well. next id disc brake conversion for the rear
one question, no clearance issues with brake disc conversion with the original 16" rims/tires (the ones you described as noisy, were 285 wide)?
also, do you know the offset on those original rims?
lastly, do you have any leftover body parts you are willing to part with? mainly looking for the latch and plate of the tailegate? and any other body parts?
thanks
Thank you!
Correct, no issues with clearance on the 16" wheels, I can't remember the offset but they were 16x10s with a very negative offset. The wires were 285/75/16 and definitely stretched a little. If I were able to find 285s in a smaller diameter I would have kept the wheels but no one makes a 285 smaller than 33 inches tall.
On the disc brake swap, make sure to change the MC to disc/disc, or the brake bias will favor the rear as mine does currently.
As for body parts I do have several parts from my Cherokee project but I don't have any tailgate parts. I do have the latch brackets that weld onto the bed body available at https://www.johnsonproductionjp.com/sho ... ch-bracket

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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

wrang
Posts: 14
Joined: Mon Mar 09, 2020 6:21 pm

Re: 1986 J20 LS Swap

Post by wrang »

Thank you for the reminder on the MC, yes I did a full hydroboost swap and will be putting in a disc/disc proportioning valve too.
Thank you for the link


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SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »

I finally got around to finishing up the trailer lights on the truck now that I need to tow with it. This Friday will be a test of how the truck tows on my trip to Tyler to take the Cherokee to a media blaster.

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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

Stoffregen M-sports
Posts: 48
Joined: Sun Dec 26, 2021 11:04 am
Location: Cool, CA

Re: 1986 J20 LS Swap

Post by Stoffregen M-sports »

I just buzzed through the entire build thread. Pretty cool truck you have there.

Question - that front tow hook crossmember. I couldn't find it anywhere on the flyin iron website. Did you buy it from them? Or just the frame plates?
Stoffregen Motorsports
@mstoffregen

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SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »

Stoffregen M-sports wrote:I just buzzed through the entire build thread. Pretty cool truck you have there.

Question - that front tow hook crossmember. I couldn't find it anywhere on the flyin iron website. Did you buy it from them? Or just the frame plates?
I bought it from them at the Ouray FSJ invasion. Send Sam McIntyre a message on Facebook and he should be able to help.

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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

Stoffregen M-sports
Posts: 48
Joined: Sun Dec 26, 2021 11:04 am
Location: Cool, CA

Re: 1986 J20 LS Swap

Post by Stoffregen M-sports »

Thank you.
Stoffregen Motorsports
@mstoffregen

Stoffregen M-sports
Posts: 48
Joined: Sun Dec 26, 2021 11:04 am
Location: Cool, CA

Re: 1986 J20 LS Swap

Post by Stoffregen M-sports »

Also, I'm rather new to the Full Size Jeep community. Is there one event that I should attend? I mean, if there was only one, which one would you go to? I noticed your Ouray trip. That looks nice and small (I don't love big events...)

My Cherokee was almost ready for our local vintage 4x4 expedition two weeks ago, but I missed it by two days.
Stoffregen Motorsports
@mstoffregen

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SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »

Stoffregen M-sports wrote:Also, I'm rather new to the Full Size Jeep community. Is there one event that I should attend? I mean, if there was only one, which one would you go to? I noticed your Ouray trip. That looks nice and small (I don't love big events...)

My Cherokee was almost ready for our local vintage 4x4 expedition two weeks ago, but I missed it by two days.
There are three major FSJ events that I can think of but have only been to Ouray FSJ invasion so far. The others are the East Coast Invasion held in North Carolina and the Kenosha AMC show in Wisconsin. There are some other smaller events across the country, but those are the big ones I can think of.

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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

Stoffregen M-sports
Posts: 48
Joined: Sun Dec 26, 2021 11:04 am
Location: Cool, CA

Re: 1986 J20 LS Swap

Post by Stoffregen M-sports »

Thanks.
Stoffregen Motorsports
@mstoffregen

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SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »

The first towing test of the J20 was successful! I towed the Cherokee 100 miles to East Texas to drop off for media blasting with no issues at 60 - 65 MPH. I have yet to install a button for tow haul mode but I hope to do that before I go back out to pick it up. I will be interested to see how that changes towing. I cruised back at 70 - 75 and I'm fed up with the loud ass exhaust so it will be going back to the muffler shop again for something quiet. I guess I didn't learn my lesson the first time hahaha.

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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 »

Very alarming find this weekend while changing the oil pan gasket. Upon draining the oil I immediately noticed it was very shiny with what looks like glitter in it. No chunks or shavings but a fine glitter. The engine doesn't have a knock or tick besides a very light tap right after starting that goes away once it's warm so I have no idea what the culprit is here. I put it all back together with fresh oil and drove it 40 miles this morning. One notable change is the oil pressure increased, before I was running 25-30 and now its 30 - 40. I plan to keep an eye on it for the next couple hundred miles then change the oil again and possibly get an oil analysis. I fear I may be looking for a short block in the future.
ImageImageImage

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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
SJohn
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Posts: 283
Joined: Sun Nov 03, 2019 4:10 pm

Re: 1986 J20 LS Swap

Post by SJohn »

Very alarming find this weekend while changing the oil pan gasket. Upon draining the oil I immediately noticed it was very shiny with what looks like glitter in it. No chunks or shavings but a fine glitter. The engine doesn't have a knock or tick besides a very light tap right after starting that goes away once it's warm so I have no idea what the culprit is here. I put it all back together with fresh oil and drove it 40 miles this morning. One notable change is the oil pressure increased, before I was running 25-30 and now its 30 - 40. I plan to keep an eye on it for the next couple hundred miles then change the oil again and possibly get an oil analysis. I fear I may be looking for a short block in the future.
Image

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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
SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »

No update in a while since I've spent a long time trying to figure out what to do about the above findings on top of building an engine and front suspension for the Cherokee, wedding planning (got engaged), and getting ready to move again :shock:. After the oil findings I also found and fixed an exhaust leak and a ticking became apparent so the engine is worse off than I originally thought. With my time spread so thin and a deadline to have this thing good to go for Ouray Invasion I have just about decided to put in a reman long block, specifically the summit 150153. Rated at 450 HP and a 2 year warranty for $3700, it looks like the best bang for buck that isn't rebuilding my engine.

I pulled my engine this afternoon and plan to pull the cam out tomorrow before I pull the trigger on a new engine.

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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 »

RIP
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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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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Location: Rogers County Oklahoma

Re: 1986 J20 LS Swap

Post by Yeller »

That sucks but you’ll like the upgraded HP lol
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

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Re: 1986 J20 LS Swap

Post by SJohn »

Yeller wrote:That sucks but you’ll like the upgraded HP lol
Yeah, I hate how short-lived the engine was, and after this, there will be hardly any parts left of the donor truck. But that's life working on old Jeeps, hahaha, so I'll make the best of it.

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Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

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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