1986 J20 LS Swap

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Yeller
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Re: 1986 J20 LS Swap

Post by Yeller »

Yeah I’ve had thoughts and concerns about the 6.0 in mine, I know it has 300k on it…. But I feel like I have core value in the donor so I feel like I have gotten my money out of it but it’s going strong.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

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tgreese
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Re: 1986 J20 LS Swap

Post by tgreese »

Is the flat cam a Chevy thing, or just a benign end to a worn-out engine (rather than the bottom-end failing)?
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Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
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SJohn
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Re: 1986 J20 LS Swap

Post by SJohn »

tgreese wrote:Is the flat cam a Chevy thing, or just a benign end to a worn-out engine (rather than the bottom-end failing)?
I know the gen 4 engines with the cylinder deactivation are prone to lifter failures, not sure about gen 3. For my case it looks like an oiling problem, the rocker end of the pushrods had significant wear and the lifters had some wear where it rides in the lifter bore. I don't know how it happened as I never saw the oil pressure drop below 20 but maybe a crappy filter or trash built up somewhere? I haven't pulled the rod caps yet, but I suspect I'll find something there too.

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1986 J20 LS Swap
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1981 Cherokee Chief - Rustard - 2JZ swap
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Yeller
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Re: 1986 J20 LS Swap

Post by Yeller »

This is not a common thing from what I’ve seen. never know could have been run low on oil for some reason.

Even the 4th gen motors typically the lifter collapses and doesn’t wipe the cam, at least on the ones I’ve looked at
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 »

I was originally concerned it ran low on oil as I had to add oil right before the trip to East Texas towing the Cherokee, but after pulling the pan last night, I think that's unlikely. As low as the pickup tube sits in the pan, I don't believe the oil level ever dropped that low or at least during my ownership of the engine. When I found the glitter during the oil pan gasket replacement, I drained close to 5 quarts, so I know it wasn't empty or critically low. I haven't pulled the oil pump off yet but I want to inspect it to see if there's any signs of failure there.

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1986 J20 LS Swap
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1981 Cherokee Chief - Rustard - 2JZ swap
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Re: 1986 J20 LS Swap

Post by SJohn »

Well that hurt the back pocket. Picked the long block up today and waiting on a box of parts from rockauto.
Assembly starts next week!Image

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1986 J20 LS Swap
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1981 Cherokee Chief - Rustard - 2JZ swap
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Yeller
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Re: 1986 J20 LS Swap

Post by Yeller »

I’m excited to see what you think of the performance difference.
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”
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Re: 1986 J20 LS Swap

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Assembly has begun and hopefully I will have it ready to go in the truck by Memorial Day on Monday. When I ordered the engine I went ahead and ordered all the parts that I should go ahead and replace now so I can have a practically brand new engine when it is all back together. Water pump, AC belt tensioner, valve covers, knock sensors, harmonic balancer and bolt, thermostat, and maybe a few others I've forgotten. Summit supplied a whole box of felpro gaskets for just about everything as well as a melling oil pump and pick-up tube. I also went ahead and picked up new 36lb injectors as recommended by summit and a 255 LPH pump will be going in the sending unit.

Oil pump, timing cover, and waterpump installed. Oil pan and valley cover degreased and deep cleaned, ready for install.

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1986 J20 LS Swap
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1981 Cherokee Chief - Rustard - 2JZ swap
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Re: 1986 J20 LS Swap

Post by SJohn »

Soooo close!
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1986 J20 LS Swap
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1981 Cherokee Chief - Rustard - 2JZ swap
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Re: 1986 J20 LS Swap

Post by SJohn »

And all back together! Engine is in, bolted up, plumbed and wired back in. It very badly needs to be tuned as it won't idle at all but runs decent above 1K RPM. Oil pressure is great with 50 psi immediately. I primed it with a pump sprayer and hose barb adapter threaded into the port on the front of the block. Next is getting it on a dyno and tuned so I'll be working on that this week. Also will be swapping in the 255LPH fuel pump when it arrives.
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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 »

Good to hear uts back running. Running it will improve the no idle, still may not get perfect without a tune but will improve.
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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Stuka
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Re: 1986 J20 LS Swap

Post by Stuka »

Gen 3's have roller cams right? Thats a whole lot of wear for a roller cam. How did the lifters look?
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Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

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Re: 1986 J20 LS Swap

Post by SJohn »

Stuka wrote:Gen 3's have roller cams right? Thats a whole lot of wear for a roller cam. How did the lifters look?
Sorry I didn't take pictures but there was some wear on the contact area of the lifter bores and similar wear on the roller itself. Nothing catastrophic but definitely not good.

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1986 J20 LS Swap
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1981 Cherokee Chief - Rustard - 2JZ swap
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Re: 1986 J20 LS Swap

Post by SJohn »

It's been an extremely busy couple of months, but I feel like I post this every time I make a post after a break hahaha. Ever since getting the new engine in the truck, it has been a rollercoaster ride. The truck spent a month at a supposedly well respected dyno/tuning shop according to some forums and reviews but I had a horrible experience. They started off with bricking the original 06 computer, so I found an 04 computer down the street. We then decided to bench tune it to prevent bricking another computer but of course they didn't have a bench harness :banghead: so I buy a cheap one off amazon. Then they tell me its not working on the bench either. Turns out it was due to HP Tuners requiring 5 amps instead of the 1 amp that the power supply output, so I went up there and wired it to a battery for them. Finally after getting the new computer tuned they tell me the truck loses throttle after a lap or two around the shop. So I found out the 06 throttle module doesn't work with the 04 computer and proceeded to pick one up from someone parting out a tahoe, went tot the shop an put it in and drove the truck down the highway. So FINALLY a month later and a week and a half before Ouray FSJ invasion I got the truck back. For whatever reason the 04 computer does not recognize when the compressor kicks on and wont idle up so the shop increased the idle RPM to keep it from dying until I figure that out. Other than that the truck runs good. So I spent the month of June driving 40 minutes to the tuning shop multiple times a week to fix my own truck hoping to have it ready for CO and ended up having no time to get it ready for the trip. I made a last minute decision to borrow my brothers Tacoma for the trip and had a great time. Now It's time to get back to work on the truck.

Upon getting the truck back and driving it longer distances I noticed it was running hotter than the L33 was ~ 230 on the highway. So I went ahead and threw in an aluminum radiator. Then I realized the Volvo fan relay wasn't energizing the high speed on the electric fan so I added a separate relay to activate the high speed and it is running cooler ~ 220 in the afternoons in traffic.
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One of the other Issues I wanted to resolve before Ouray was the rear brakes locking up before the front. This issue was actually present since I did the brakes but never realized it until this year during some hard braking situations. I do have the disc/disc proportion valve but the truck would send the majority of breaking power to the rear calipers and cause the rear to slide. I installed an adjustable proportion valve on the rear brake line, and after what I'm sure was annoying to my neighborhood :lol: , I got the breaking power to the front and the truck stopping in a straight line.
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In preparation for the trip I borrowed the 8000lb winch on a receiver carrier from my dads tractor but didn't have time to wire it up. New wiring installed with a quick connect. He also gave me the ARB lights off his JK that he never got around to installing. They're bolted up to the factory top bolt hole but still need to be wired up.
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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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Re: 1986 J20 LS Swap

Post by Yeller »

Lots of drama on all of that whew. Glad it’s up and running now.

Do me a huge favor, please move those winch leads to the top post. The side posts are notorious for melting with a winch drawing full load. The risk of issue is really quite low but still potentially there. If it is an issue it will be during that unplanned stuck, alone, in the dark miles from anyone. Don’t ask how I know :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:Lots of drama on all of that whew. Glad it’s up and running now.

Do me a huge favor, please move those winch leads to the top post. The side posts are notorious for melting with a winch drawing full load. The risk of issue is really quite low but still potentially there.
Thanks for the tip, I'll pick up some top posts with studs.

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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 ntsqd »

I use the so-called "Military battery terminals." Buy from a real vendor like Del City or Waytek Wire, those found on amazon are poor clones of the real thing. You could ask me how I know this, but I'll bet you can guess.

As it happens, the Waytek page for the N terminal lists the MIL Spec number, so I found and attached it.
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thom

Where does that road go?
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Yeller
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Re: 1986 J20 LS Swap

Post by Yeller »

I have some of those “amazing specials” too lol. They work but certainly aren’t the real thing. Actually I’ve been just as happy with brass marine ones. The ones on my bronco are 30 years old came with SS hardware that I have never changed.

Similar to these at least in basic design
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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 »

Something I've always wanted to do with the J20 is use it as a comping rig to either pull an rv (ideally a classic airstream) or camp out of the bed. I started with the topper thinking I would build out the bed with a sleeping platform and drawer for camping gear. After 1 freezing night on an air mattress last spring I tossed that idea. The topper needed insulation and the bed still needs several repairs to get it water tight with the topper on, plus adding more weight to the shell would only make it harder to get off. I also didn't like the idea of having the sleeping platform in the bed all the time and not being able to stand up or barely sit up straight. So after 8+ months I finally found a truck camper that would fit the J20. This was surprisingly difficult to find, J trucks being sub 60 inches between the bed rails means you have to find a camper that is sized for a midsize truck yet long enough for a 7 or 8ft bed. Most campers for 8ft bed trucks get wider behind the wheel wells as I found out while backing under a camper 3 hours from home :banghead: . Needless to say, I drove home without a camper that time. My ultimate goal was to find a used four wheel camper but here in Texas that's pretty rare and apparently they must be made of gold. Pop-up truck campers in general I found were very limited, I presume due to Texas heat. Anyway I finally found one, intended for a 6 foot bed but with little bit of modifications it fits like a glove! Of course, I was kindly reminded that I own an FSJ upon lowering the camper on the truck and the driver side dropped nearly to the frame :( . It seems there is either a broken leaf or just weak springs on the driver side. I've temproarily remedied it with some cheap air shocks but will be pulling the driver side leaf out soon. I picked up the original 3/4 ton springs from my dad's place to pull some leaves out of if needed. Then I need to figure out some better tie down brackets. For a quick solution I uesd cheap brophy stake pocket brackets which turned out to be useless and twisted in the stake pocket. I ended up using my heavy duty ratchet strap around the frame to pull the front end of the camper down on the way home.

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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 »

Sunlights are the best pop up’s, nice score!

You really need some frame mounted tie down points with spring loaded tensioners. Ntsqd has a lot of experience with those doing off highway exploring and I’m sure aha some good tips as well.
My slide in was massive, but the tie downs need some give to protect the camper and the truck.

I used these for years and still use them on my RTT.

https://www.etrailer.com/Accessories-an ... gLKP_D_BwE

I made mounts similar to these, it takes the abuse off of the sheet metal of the bed.


https://tweetys.com/torklift-frame-moun ... gLiSvD_BwE

Hopefully this helps you have an excellent experience with your camper.
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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