Trying to get it mostly right the first time: A 5.9 Magnum and 46RE swapped, Tummy Tucked Daily Driven Jeep TJ

Next up was to start installing the front clip to allow progress on the wiring and plumbing. The goal was to hear it run, so I installed the passenger fender and front grill, leaving the driver fender off to ease of access to that side of the engine bay if needed. The last 10% of a project takes 90% of the time and that has been no different here.



An engine needs 3 things to run: fuel, air and spark. To get the spark, the wiring harness, PDC and battery were installed and plugged in for testing and all new 4GA marine grade wire was run to the starter, PDC, engine ground and chassis ground. I build all my battery cables with marine grade wire with tinned lugs that are crimped (not soldered) on, with marine grade heat shrink on top of that, all protected with split loom and held on with heat shrink at either end. Additionally, all new spark plugs, plug wires, and coil were installed. The accessory drive was re-installed, as well as the throttle body to provide the air.

This left fuel delivery. I'd saved the fuel line from the Durango since I'd read that it was a plug and play – I found this to be incorrect for Durangos. Instead of trying to track down an OEM hose, I opted to purchase an Evil Energy AN-6 hose kit to plumb the fuel line (and will later use this for the transmission cooler). The kit has great reviews and is very well priced so I opted to give it a try.

• Hose Kit
• EFI Quick Connect (Frame Side)
• EFI Quick Connect (Fuel Rail)
• AN Wrench

The new fuel line was assembled and installed, so now we had fuel. And of course I had to see if this garbage ran. With the transmission in park, fresh oil in the motor and a few quarts of ATF I turned the key and was greeted with no gauges, but the starter did turn over. I pulled the harness and corrected a 5V supply wiring error. With the harness reinstalled, the gauges now worked and I cycled the key a few times to prime the fuel rails. As a note, the TJ only runs the fuel pump for 3 seconds until the engine is running. No leaks. I turned the key to start


And it fired right up.


It was alive, though only for a split second before shutting itself off. I'd read and assumed the Durango ECU would give me an issue, either from SKIM or triggering the security feature (yes, those are different features) from the lack of a BCM. I was greeted with a transmission code and an EVAP related code, so I had communication with the ECU… I'll call that a win. Since I had another ECU from a 99 Ram that I'd hoped was SKIM free, I moved on to installing the cooling system and transmission cooler to allow the engine to run for a bit longer.

This is where this project starts to put up a fight.

I purchased 2 finishing clamps (LINK) and used the leftover AN hose to plumb the transmission cooler. The transmission has a ¼" NPT fitting that I needed to adapt to AN-6 – Summit Racing had the adapter I needed for this (LINK). I used 2 45 degree fittings from the kit to come off the transmission and routed the hoses along the driver side frame rail and up to the barbs on the cooler. I'll try to get some pictures of this – it's difficult to photograph once installed.

The power steering cooler was plumbed in using hose from the transmission cooler kit. This was as simple as removing the return hose and routing the new hose.

The AC condenser was re-installed and then the Summit Racing radiator. And here's where the issues come up. :

• Motor mounts installed in the AA recommended location do allow the use of stock exhaust manifolds. This saves a lot of time and cost being able to re-use stock parts.
• I have less than 2.5" from the threaded fan mount of the water pump pulley to the condenser - there's not a combination that I've found to be that narrow and I've looked at both electric and mechanical. With a V6 Dakota fan clutch installed, I have 2.5" from it to the condenser, only slightly more room than a stock radiator. Proform advertises a Slim Fit radiator and fan combo that would fit, but there is alarmingly little information and forum chatter about it and its $700.

• Very few V8 swap radiators on eBay have provisions to mount a shroud or electric fan. You'll have to pony up and pay for a quality radiator to get those mounts or run an upgraded stock replacement. These guys are local to me and have a great reputation: https://cgj.com/product-category/radiators/antique-performance-radiators/jeep-radiators
• Additionally, many V8 swap radiators flip the inlet and outlet as compared to the stock TJ setup. In doing so, the radiator outlet is halfway covered by the AC compressor with little room to make the turn. This is not unique to Summit - any V8 swap radiator with horizontal tanks and a driver side outlet will have this issue. A radiator with either the stock orientation or an LS swap radiator (in/out on the passenger side) would fix this.

• I've not found hard evidence, but many say that the stock 4.0/2.5 radiator will cool a 5.2 but not a 5.9. A stock replacement upgraded radiator might be adequate to cool the 5.9. I purchased a stock replacement aluminum radiator and am hoping it will adequately cool my 5.9. An oil cooler and hood louvers are my Plan B. Plan C involves a grinder and a lot of re-work.
• The ZJ fan clutch is the same height as a Durango fan clutch at 3.5" and contacts the lower tank of my aftermarket radiator when I install the radiator. This would make any water pump or radiator replacement a nightmare as the grill shell would have to be unbolted. It does clear a thinner stock (OReilly replacement) OEM radiator.
• A 1997 Magnum V6 Dakota clutch is 2.97" and allows the lower radiator tank to clear on installation. It still doesn't allow the thicker Summit radiator to fit. This combination does allow a stock 4.0 TJ fan shroud to be attached, but since I have a tummy tuck the fan is no longer centered of the shroud. I could shim the motor if I wanted to make this work, but that will make future work on the accessory drive difficult. From left to right: 99 Durango, V8 ZJ, Dakota.

• This leads me back to electric fans and my final solution. My current Mishimoto fan is 3.5" deep and pulls around 1800 CFM. With the aftermarket TJ radiator installed, I only have 2.75" between the water pump pulley and radiator. I found a Spal fan (30101516 ) that's under 2.5" deep and is rated for 1600 CFM.

In short, the AA recommended placement does allow use of stock driveshafts, exhaust manifolds and fan/ radiator but can really limit your cooling system if you need more cooling capacity. You can build an exhaust to fit - you can't make a radiator and fan fit where the space doesn't exist.

With the radiator hoses back in the stock location, my final hose selection for the upper is from a 4.0 ZJ (Dayco PN#71659). The lower is a combination of FLEXIBLE HOSE, STOCK DURANGO HOSE, and an ADAPTER.

We're almost caught up!

I made a to-do list on cardboard to both keep organized and enjoy the satisfaction of crossing things off the list. I had several things started and almost complete, so I wanted to focus on finishing some items.



One of the items I'd started and not finished was the exhaust, so I decided to get that knocked out. I'd need the O2 sensors for the engine to run properly anyway. I like to build my exhaust to be serviceable and adaptable over time if I choose to swap mufflers and my old design put the catalytic converter behind the crossmember, which would ultimately limit the length my muffler could be. I decided to move the cat in front of the crossmember to allow future changes to the muffler. Here's an exhaust fab tip – keep your old O2 sensors around for welding in the new bungs. This will help ensure the threads aren't distorted during welding.



Here was the final result:



The muffler is attached with a band clamp on either side. Since my exhaust is 2.5", I found a Dynomax tailpipe (PN# 54287) that bolted in to the stock locations. And here is a terrible quality picture of the whole system installed in the TJ:



I promise to get some better pictures when I can get this on a rack or at least jack stands.

The ECU was swapped out, radiator full of coolant and I was ready to hear the Jeep run – or so I thought. When I went to crank the engine, the starter struggled to spin it over like it was hydro locked. Weird. I pulled the spark plugs and was greeted with coolant pouring out of multiple cylinders.

Yep, curse words were spoken.

Now is when I started to connect the dots from things I noticed during the disassembly of the donor – no thermostat and little to no coolant (can't remember if it was dry or low). I'm having serious doubts about this motor as a whole at this point.

In a bit of, well, desperation, I pulled the intake and changed gaskets hoping I might have messed up when installing the Hughes plenum kit. Nope. No change. It still leaked live a sieve. I pulled out my inspection camera (which if you don't have one in your toolbox, I highly recommend it.) to try to verify where the leak was coming from. Here is what I found:



Coming from the top of the cylinder either means I have a head gasket that failed spectacularly or a severely cracked head, which these Magnums are known for. Due to other obligations and a pending family vacation to Las Vegas, the TJ was put on hold for a few weeks.

I'd thought through several different scenarios and fixes, from remanufactured heads to a brand new crate motor – I was all over the place. My preference was the new motor (at $2300), I just had a hard time stomaching that right now. I kept a watch on FB Marketplace just in case and happened up on a deal I couldn't pass up – a 2wd 99 Ram 1500 with a 90k mile 5.2L and rebuilt transmission. The best part is I got it delivered to work for not much more than the cost of reman'd heads, so in the off chance my 5.9L is an easy fix I can get my money back out of this truck. Nope, its not a 5.9, but at this point I'm not being picky. I won't know the difference anyway.




This is the kind of clean you can't fake - it's obvious this truck has been cared for.



The truck runs flawless (it actually starts with a key!) and gives me confidence this will be a good donor. I'm taking this week to re-organize parts and tool and slam a Wave Runner back together before the summer gets away from me. After this weekend, its full bore back on the TJ.

Those blue exhaust isolators from summit, suck. I melted them first trip out on my buggy. I bought some Patriot exhaust ones that are supposed to be rated at 300 degrees. Hopefully they work better than the blue ones. I am using a Ford Taurus fan on my rig, i will have to measure the depth but I believe it was 3.5 inches or under and it pulls around 3500cfm on high.

Love the level of detail you put into the posts but hate to read about all the trials and tribulations you are having to go through.

Lil ugly said:

Those blue exhaust isolators from summit, suck. I melted them first trip out on my buggy. I bought some Patriot exhaust ones that are supposed to be rated at 300 degrees. Hopefully they work better than the blue ones. I am using a Ford Taurus fan on my rig, i will have to measure the depth but I believe it was 3.5 inches or under and it pulls around 3500cfm on high.

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Good to know on the exhaust isolator.

Space was what limited my fan selection, so I'm hoping what I have will be adequate. I've read the 5.2s run significantly cooler than the 5.9 (many guys use the stock TJ radiator with good luck), so that could potentially be a good thing if I do swap engines. If heat is still an issue I'll look at managing it with header wrap, louvers, etc. before I do anything drastic.

ridered3 said:

Love the level of detail you put into the posts but hate to read about all the trials and tribulations you are having to go through.

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Thanks for the compliment. All the challenges will just make this taste a little sweeter when I'm done with it!

Dan_Goodwin said:

Good to know on the exhaust isolator.

Space was what limited my fan selection, so I'm hoping what I have will be adequate. I've read the 5.2s run significantly cooler than the 5.9 (many guys use the stock TJ radiator with good luck), so that could potentially be a good thing if I do swap engines. If heat is still an issue I'll look at managing it with header wrap, louvers, etc. before I do anything drastic.


Thanks for the compliment. All the challenges will just make this taste a little sweeter when I'm done with it!

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If you still have heat issues, just do what Roadkill does and take the hood off.

Could you run 2 smaller fans, or a pusher? I know its not ideal, but might fit better.

paradisepwoffrd said:

Could you run 2 smaller fans, or a pusher? I know its not ideal, but might fit better.

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I could run 2 smaller fans with a custom shroud. Since they'd be sitting on either side of the water pump I could get away with thicker fans.

If this only overheats on the trails you best believe I'll zip tie a pusher on the grill and rock out!

I've managed to make some really good progress over the last few weeks (to get back to where I was 2 months ago…)

The first order of business was to free the new engine from the donor truck. A few hours spent on a Friday after work:





I bought the truck knowing it had a 5.2L in it, but I was in for a surprise! Check out the casting number on the block!



From here on it was a straight forward deal that I didn't take many pictures of – old motor out of the Jeep, swap the oil pump, intake and timing chain to the new motor, throw some paint on it and reinstall.



I got all that done last week, but did learn something in the process…

5.2s are internally balanced whereas the 5.9Ls are externally balanced via the harmonic balancer and the flex plate - or so I thought. The engine had the correct harmonic balancer but no weighted flywheel. Odd. After research I discovered that prior to 1996 Dodge balanced the 5.9L via the torque converter, not the flex plate. I knew this engine had been changed at some point, so I found the casting date on the block to figure out what year this engine is – survey says 3/1994. That means that I should have had a weighted torque converter but since the truck and transmission is a 1999 it wasn't weighted. I swapped the flywheel over from the old 5.9 and all was good.

My wife was out of town last weekend, which left me and the dog to work on the Jeep. We're going to the beach at the end of this month and I'm determined to drive the TJ there – that meant this weekend needed to go well. The new motor was dropped in Friday night after work and hooked up for a test fire by Saturday morning. As a recap, the Jeep had started with the Durango PCM but immediately shut down likely due to SKIM or the Security feature (I've learned that there's a difference between the 2 as well). I swapped in the PCM from the donor Ram, turned the key…

And it runs!

(Without shutting off)

I was both ecstatic and relieved to hear it run, really for the first time. I still have to sort out a P0753, P1764 and P0176 trouble codes but I'm guessing that's related to a wiring issue with the transmission relay circuit I added. The rest of the day Saturday and part of the day Sunday were spent doing the last 10% of a project that seems to take 90% of your time (and really isn't that interesting to read about).

I went ahead and ordered a new driveshaft from Adams so I can drive the TJ around with the D35 for now. From my research, the 8.8 with a 1350 adapter flange should allow me to re-use this shaft with the new axle. With the new driveshaft in, the TJ moved under its own power Saturday night.



I have 14 days to get this done (enough) to drive 4 hours to the beach. Game on!

@Dan_Goodwin great update and nothing like an impending deadline.

Man that's a great update. Good luck to you the next week or so till your beach trip! Sounds like you're motivated to get it done by then.

felipecj said:

Man that's a great update. Good luck to you the next week or so till your beach trip! Sounds like you're motivated to get it done by then.

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Welp, my momentum on this project took a big hit. Used transmissions are always a gamble and a rebuild should be carried in your budget for a project like this.

Evidently my transmission rebuild is happening...now. Either the torque converter (which is brand new) or the pump in the transmission wiped itself out after the second test drive around the block, which was confirmed by the nice metallic / pearl color in the transmission fluid. It sucks, but its all part of this hobby and dealing with used parts. The plan now is to start selling and scrapping what I can to pay for the new transmission, keep finishing all the little details (that needed to get done anyway).

Dan_Goodwin said:

Welp, my momentum on this project took a big hit. Used transmissions are always a gamble and a rebuild should be carried in your budget for a project like this.

Evidently my transmission rebuild is happening...now. Either the torque converter (which is brand new) or the pump in the transmission wiped itself out after the second test drive around the block, which was confirmed by the nice metallic / pearl color in the transmission fluid. It sucks, but its all part of this hobby and dealing with used parts. The plan now is to start selling and scrapping what I can to pay for the new transmission, keep finishing all the little details (that needed to get done anyway).

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That stinks to read about the setback!

Sorry to hear about that, definitely always a gamble with a used part.

I doubt the rear ds will work once ya install the 8.8. It's actually a little longer so the ds will be too long and will need to be shortened. My buddy just done a sye on a tj and he has the 8.8 and the driveshaft he ordered musta been for a d35 cause it's too long. Hope you have better luck than he did

@Dan_Goodwin got any updates?

ridered3 said:

@Dan_Goodwin got any updates?

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I'm working on a post to bring this thread up to speed, but the short answer is yes. Thanks for checking in!

It's been running and driving around the block for about a week but I have a lot of little things to do before it's really road worthy.

Dan_Goodwin said:

I'm working on a post to bring this thread up to speed, but the short answer is yes. Thanks for checking in!

It's been running and driving around the block for about a week but I have a lot of little things to do before it's really road worthy.

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That's great.