Squirrelly Dan: Coheed's 86 Custom

[coheed]

Pulling the 2.8 wasn't a huge deal.

 

 

But the hoist couldn't get quite tall enough to get the 3.4 in. I swapped the trailers wheels with 235/75r15s on, and even then I had to deflate them to about 5 psi to get enough to get it in. I probably should've taken the header panel off but 

 

 

Regardless, the 3.4 and 4L60e are in the truck. Bolted up the NP242 today and started working on the transmission mount, more on that later.

 

 

Looks like a decent angle for the engine to rest at. Need to measure driveshaft angles before I finish the trans mount.

 

 

I didn't plan on pulling the dash twice this year, but here we are. It'll help with the wiring and let me fix some routing I wasn't crazy about from after the floor replacement.

 

 

I can't stand wiring but, I think I'm done with the wiring aside from routing it on the truck and doing the crossover between harnesses at the ignition switch and the brake switch. I took the engine bay harness from the truck in the house and eliminated all the unnecessary stuff like the starter, a/c, and carb/emissions related things. 

 

 

I should be done with the Camaro harness as well aside from the routing and crossover parts.

 

[coheed]

Installed a new brake booster after hitting that area with the needle scaler and a coat of mastercoat. I'm incredibly impressed with the mastercoat. I had some overlap from the area with clutch master, and it took a significant amount of time with the needle scaler to knock it off. I decided to just get a stock replacement because I wanted the simplicity of just bolting it in. Will look more into upgrading to a larger one somewhere down the road.

 

 

I also mounted the vacuum reservoir from the Camaro and the cruise control unit behind the front crossmember. The truck hasn't had a vacuum reservoir since I've owned it, so it'll be nice for the HVAC to not default to defrost under heavy loads.

 

 

Now, on to the matter of the transmission mount. Novak supplies a nice bracket that bolts to their adapter and an energy suspension GM style mount. In the form it comes in, it was way too tall to fit the stock crossmember and if I bolted the mount straight to the transmission the engine would've been angled downward too much. I felt like it was easier to modify the Novak bracket than the crossmember. I cut the bracket so that only the lowest mounting holes were left and rounded the corners off. However, when bolted in place it didn't sit flat on the crossmember, so I stuck it in the vise and bent the tabs to match the angle of the adapter relative to the crossmember. Threw a coat of paint on and drilled holes for the new mount bolts and access holes for a socket on the crossmember and bolted everything up. There's about 3/8 of an inch of clearance between the NP242 and the driver's floor, so I shouldn't have to worry about them touching. It's nice to have this drivetrain completely bolted into the truck.

 

 

Now everything I've read about 3.4 swaps says you need to swap in the oil pan and timing cover from the 2.8 so there isn't any interference from the axle. I would rather keep the 3.4 timing cover because that's where the 24x crank position sensor is housed and the 2.8 cover doesn't have a place to bolt it to. The 24x sensor helps with keeping the idle smooth and according to some of the reading I've done, without it the engine defaults to multiport injection instead of sequential injection. Multiport injection isn't a bad thing, it just means more than one injector would be firing at a time and costing more gas. I've also read in a few places that if you're lifted it may be possible to keep the 3.4 oil pan. I left it on the motor when I swapped it in, and today I tried to see if there would be any clearance issues. I disconnected the sway bar and maxed out the suspension as much as I could with a jack. It had about 2.5" until the driver's side was going to be on the bumpstop and the passenger tire was already 2" off the ground. There was more than 3.5" between the diff and the oil pan, and the same for the passenger side. That said the truck is lifted 3ish in the front, so this might not work for a stock truck or one that was going to get flexed harder than mine. Time will tell 

 

 

Looking at it, I may be able to get the mechanical fan to bolt up to the 3.4 water pump but it would be much further back than on the 2.8. Ultimately, I'd like to keep the mechanical fan and have a pusher mounted on the front that the PCM controls. The stock Camaro PCM doesn't turn the fan on until 220° and I'd prefer it to run just a bit cooler than that.

 

[coheed]

Made holes and mounted the Camaro power distribution block. Surprisingly the Camaro battery cables fit quite well and the battery already has side posts.

 

 

Got the factory engine bay harness and the Camaro engine harness mounted today. I've always liked the cowl intakes, so I'm gonna rig something up with all the piping I have on hand

 

[coheed]

Started sorting out routing the stand-alone harness. I want this to be contained to the engine bay with the stuff up near the wipers passing through the big oval grommet next to the throttle cable. All the excess that would normally be behind the Camaro dash will get shortened and go through an apex 2.8 sealed 14 pin connector up above the blower and pcm.

 

 

Rigged up some brass fittings so that both the factory sending unit for the MJ gauge and the sender for the Camaro pcm both get oil pressure. The gauge one has much more clearance than it looks like in the photo.

 

 

Welded a 1/2-20 nut to the bracket that originally had the vacuum release on the brake pedal that I assume went to the 86 cruise control, so that I can reuse the Camaro brake switch.

 

 

The Camaro throttle cable fits into the MJ firewall if you trim down the locating tabs on both sides.

 

[coheed]

Trying to prioritize things now. Started mocking up and cut the hole in the cowl for the intake.

 

 

With intake and coolant hose routing I realized that there wasn't a way I could keep the mechanical fan. While the Camaro came with aftermarket electric ones, they were no-name and I was dubious as to how many cfm they would pull and if they would be enough. A few times on here and on the TDI swap group on facespace I had seen people mention that a PT Cruiser fan might be the right size for the TJ/YJ radiator and the 2.5 and 2.8 radiators on the MJ/XJ. So, yesterday I went to the local pull a part with some tools and a measuring tape and sure enough the fan and shroud is just about the same size. There was an abundance of PTs in the yard, and I was able to snag a low mileage Bosch unit for $24, so in the future I should be able to get a decent set of brushes and a commutator if it ever decides to die on me fairly cheaply. Below are pictures of a 2.8 radiator with the stock mechanical fan shroud, the PT Cruiser shroud without the tabs trimmed off, with the tabs trimmed off, and sitting in the truck. Replacements are advertised as pulling 1500-2300 cfm and the stock Bosch is fused at 40amps from the factory so I assume a factory one should be on the high end of that. That's more than the stock 3.4 Camaro pulls, so I think it'll be alright. I'm going to look more into how to lower the fan kick on temperature in the PCM as well.

 

 

Also realized that the boostwerks NP242 shifter linkage won't work with my setup. First off, the NP207 shifter lever tab has an odd angle compared to the later 231 and 242 shifters. So, I snagged a 231 shifter off a '00 XJ in the yard. And, with the 4L60e being shorter than the AW4, the extension they give you hits the shift shaft so I'll need to shorten that. As well as the turnbuckle they provide being significantly too long, but I found a fairly cheap 304 stainless one I can order to replace it. 

 

 

Speaking of shifting, I wanted to keep the 4L60e cable shifted and since the shifter for the 84-86 A904 operates on a linkage I couldn't make that work (I had it laying around from my grandad's truck). I snagged a shifter, cable, and transmission bracket from the same '00 XJ. I should be able to cut and weld the Camaro and XJ cable brackets on the transmission end together and make it work. I'll also be regrinding the notches in the shift gate like shown in this build thread over on LS1tech. However, I'm not seeing a way to tap into the trans wiring to feed the reverse lights, and on the Camaro they were powered through a set of contacts attached to the shifter. So, I'll need to figure out how to get my reverse lights to work.

 

I also managed to nab a C and D horn from an 88 Cadillac Deville to be spares for the ones on the truck for $5 

[coheed]

Repurposed the 2.8 coil mount to make some mount tabs for the pt cruiser fan to the radiator. Had to clearance the shroud a little so there's room for the hoses and clamps. 

 

 

Now sorting out all the wiring. I guess I jinxed myself saying how much I hated wiring work because now the Lexus daily has a wiring harness issue. So much fun. 

 

[coheed]

Finally got around to thinning out the excess on the harness. These Apex 2.8 connectors are great because it doesn't matter what way you insert the terminals into the body, so you don't have to worry about how the terminals are oriented when crimping them. 

 

 

Also got a new driveshaft delivered and installed today. Once bolted down to the axle yoke the slip yoke just completely covers the splines on the tcase.

 

[dasbulliwagen]

It's awesome seeing you get into this swap. As you know, I had planned on doing the same thing you are with that Camaro into the 86 I had. I really glad you're seeing this through and that I get to follow along. I'm sorry to hear about the injectors, but I guess it's to be expected for as long as it sat. I'll keep a closer eye on the build now that you're this deep into it. Keep up the awesome work!

[coheed]

12 hours ago, dasbulliwagen said:

It's awesome seeing you get into this swap. As you know, I had planned on doing the same thing you are with that Camaro into the 86 I had. I really glad you're seeing this through and that I get to follow along. I'm sorry to hear about the injectors, but I guess it's to be expected for as long as it sat. I'll keep a closer eye on the build now that you're this deep into it. Keep up the awesome work!

Eh, in the grand scheme of things the injectors were cheap. I got the lowest price option on Rockauto because they at least had a year warranty. I'd like to get some nicer ones to replace them down the road. 

 

Thank you for the kind words. It's been cathartic to do this project as it's one I've thought about in some form or another since I got my grandads truck back 18 years ago.

[coheed]

Mounted the Camaro 3.4 fuel pump relay on the pedal box. Luckily the fuel pump wire exists in the 86 2.8 harness, there just isn't a third wire in the weatherpack connector going to the tank. I just threw some weatherpack terminals on the feed from the relay and plugged it into the cab harness and added a third wire going to the tank. I plan on using some rivnuts on the little bit of the cab wall that hangs below the bed to mount the in-line Walbro pump. 

 

 

Ran the trans cooler lines and mounted a Hayden cooler on the radiator. I plan on also running it through the cooler in the radiator, but I need to get some fittings as the Chevy threaded ends are different from the Jeep ones. Also, gonna move those horns for more airflow. The 2.8 usually ran really cool, but I know this 3.4 will run hotter. 

 

 

Finally got all the engine bay wiring loomed up and routed through the harness clips. Need to figure out a pcm mount and how I'm gonna run the heater hoses. 

 

[coheed]

Need to get some 90° barbs to cleanup the fuel lines a bit

 

 

It lives

 

 

 

[coheed]

Routed heater hoses and made a little bracket that goes from one of the alternator bolts down to the bottom of the bracket to keep the heater hoses from sharing the same space as the alt fan or the belt. Covered it in some heat shrink so it won't rub thorough the hoses as quickly. Also, found out if you take a top radiator hose meant for the 2.8 with A/C and trim it in the right spot it fits the 3.4 water neck perfect.

 

 

Making a one off intake sure takes a bit of time. I'm not completely happy with the angles and how the couplers have to take up some slack because of the lack of tighter radiuses on hand, but I didn't want to buy piping and getting stuff custom bent is even pricier. Plus the couplers will give at least a little flex in the system. Overall I like it. 

 

 

At this point I have just a handful of things left until the truck is drivable again. I'm getting antsy

[eaglescout526]

Ive been following your thread for a while. To watch the 2.8L come out and watch the 3.4L go in has been alot of fun. Love the bracket on the alt for the heater hoses.

[coheed]

On 10/1/2025 at 12:26 AM, eaglescout526 said:

Ive been following your thread for a while. To watch the 2.8L come out and watch the 3.4L go in has been alot of fun. Love the bracket on the alt for the heater hoses.

Thanks, it's been a fun project. Although I've done plenty of engine swaps before, this is the first one I've done on my own vehicle.

 

Zapped together the XJ and Camaro shifter cable bracket today. The paint is drying in the shed and I should be able to put it back on tomorrow.

 

 

Started on the exhaust today as well. Got the pass side of the y pipe tacked together (the easy side), and plan on trying to tackle the driver's side tomorrow. The flux core welds aren't pretty, but it should flow much better than the 2.8 one a lot of people used for the 3.4 swap even with the BFH clearancing I had to do to get the pipe between the bellhousing and control arm mount. Incidentally, the 2.8 y pipe won't work with the 3.4 oil pan anyway, the clearance between the pan and the pipe is just a little too close and the pass side would interfere with the oil level sensor in the pan. I've read some accounts that putting headers on the 3.4 makes a decent power gain and I can see why, the stock y pipe necks down to a little under 2" for seemingly no reason. Maybe it was an attempt to keep heat dissipation down in certain areas of the exhaust?