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doublins 04-30-2013 06:05 AM

My Magnum TJ, project "Whoops my stroker wiped it's cam bearings... again"
So, I'm already about three weeks into my Magnum swap, but wanted to start a build thread and kinda go through it chronologically from the start up to where I am right now. Background- I built a no-corners-cut very expensive stroker motor back in 2011, that I had NOTHING but problems with... I had it in and out of the jeep four times in a two year period- first it sunk a valve, then it wiped its cam bearings twice... A warning to anyone even contemplating building a stroker motor... there are a LOT of problems with them and people often keep their motor failures hush-hush, but they're not all they're hyped up to be, and mine caused me nothing but grief and thousands of wasted dollars. If you want, you can view my stroker project thread on that popular jeep strokers dot com site.

Anyway, after it most recently wiped its cam bearings again, and nobody could give me any answers as to how or why... machine shop... Lunati.... Bullet cams.... Durabond... other stroker folks/builders... I decided there was no way I was putting another dime into that motor, so I started looking for alternatives. After much research, I decided on a magnum v8 swap.

I looked around for a 5.9, but I wanted a full donor vehicle, and I wanted the vehicle to be out of the same year as my jeep (98)- one day I happened upon a 98 Durango with a 5.2 on craigslist that had recent front end damage. The thing ran just fine save for a busted radiator and front crossmember, so I picked the whole thing up for $800, took the drivetrain out of it, and sold the rolling chassis to a junkyard for $300- I live in a townhouse and while I have a single garage bay and a driveway, there was no way I'd have been willing to keep the Durango carcass floating around for months while I parted the thing out... I wanted it in and out of there. I'm sure my neighbors thank me.

Anyway, here's the Donorango...

And here's me tearing out its guts...

Had my ex-offensive tackle neighbor help stabilize the crane for me, that thing doesn't roll easily on concrete with an 800-900 lb load, hehe

And finally, here's the tiny-a$$ garage where all the magic will happen... you can see I'm "bleeding" the old auto trans, I kinda felt like an executioner at this point with the 'Rango... tearing out its guts and hanging them up to dry

doublins 04-30-2013 06:16 AM

So anyway, from the Durango I took the following:

- Engine and all accessories
- Wiring harness
- Fuel line
- Throttle cable
- Intake

Next, I started tearing down the Jeep and getting it ready to place the new drivetrain... Only thing I needed here was some elbow grease and the AA magnum TJ weld-in mounts.

Jeep with front clip removed

Hrmm... something's missing...

Yikes, think it's time for new brake lines? I think so... ordered new SS lines

Cut off old motor mounts...

Clamped AA Mounts in place

Test fit the magnum motor...

Welded in the new motor mounts...

Finally, cleaned, degreased, phosphated, and Por15ed the whole frame north of the firewall... (And installed all new SS brake lines, not in this picture)

doublins 04-30-2013 06:23 AM

Next I did some work on the Magnum motor- Basically I just replaced all of the pan gaskets, and overhauled the intake manifold with the Hughes kit... the stock plenum has a plate bolted to the bottom of it that is thin sheet metal, the gasket fails, and it sucks oil into the intake... I also replaced the head covers, inspected the heads for cracks (none, wow), and was surprised to find that the motor had zero sludge... the inside was spotlessly clean (save for a small amount of coking on some surfaces... expected with a high mileage motor.

Working on engine

Installing Hughes plenum kit on the intake plenum

doublins 04-30-2013 06:34 AM

Next up was the wiring harness... let me start by saying:

THE WIRING FOR THIS SWAP IS REALLY REALLY EASY. There is no way in hell anyone in their right mind should be paying anyone $700 to do this wiring harness. Holy hell what a ripoff!

Anyway, here's what I did:

1) I taped and marked each and every connector on my Jeep harness, then taped and marked each and every connector on the Dodge harness.

2) I completely de-loomed the Jeep harness

3) I took a piece of plywood, and laid out the dodge harness, and drew an outline of the "shape" of the harness and where all of the connectors went.

4) I then laid out all of the jeep harness wiring so that all of the injectors and sensors were where they needed to be to fit the shape/size/layout of the Magnum motor

5) I made a spreadsheet of any wiring differences between the pinouts for the 98 durango, and the 98 TJ, and also for EACH INDIVIDUAL CONNECTOR. I was lucky in that both the 98 durango and the 98 TJ only had one upstream o2 sensor and one downstream :) EVERY SINGLE SIGNAL PIN IS IDENTICAL BETWEEN THE 98 TJ AND 98 DURANGO, except the Durango has the auto tranny signals, and two extra injectors For physical plug/wiring differences, I think off the top of my head, the following connectors were different:
a) IAC - different plug and wired in reverse order
b) TPS - same plug, but wired in reverse order
c) ECT - different plug, wired in reverse order
d) A/C compressor - different plug
e) Injectors #7, #8 missing

5) I de-pinned Injectors #7 and #8 from the dodge harness, and pinned them into the "B" plug on the jeep harness where they needed to be according to the durango pinout.

6) I test-fit the harness onto the motor

doublins 04-30-2013 06:45 AM

Next up it was time to get the drivetrain into the jeep. I had all day saturday to spend on it, and it was 70 and sunny...perfect weather. This time I didn't have the help of my ex-offensive lineman neighbor to stabilize the motor or crane, so I had to do every single part of this step myself. I was patient and careful, and used my head, and everything went like butter.

I put the engine on the hoist, installed the flywheel, clutch, and pressure plate, then put the transmission on a rolling tranny jack, lined them up, and bolted them together.

I carefully slid it down into the engine bay, and hand-tightened the motor mounts on the engine, supporting the transmission first by the jack, then by a jackstand.

I then held my RE x-member up and marked how it would need to be modified to bolt up to the transmission from its existing location, and modified it accordingly

Once I knew how far the trans had moved forward (about 2.5"), I was able to modify the shifter accordingly- I used some 1/4" plate I cut out of the x-member to extend it.

Then I put 4 bolts into the crossmember to hold the drivetrain in place, and I again have a rolling chassis! Like I said, Saturday was a big day!

Sorry picture so dark, it was sunset by this point...

Shifter position with shifter cut down and modified.

For the transfercase shifter, I just went with the novak cable kit, and that worked perfectly.

doublins 04-30-2013 10:11 AM

While I've got the fenders off, I'm repainting the fenders, grille, and cowl. Just going with gloss black single stage 2k urethane from summit....

I'm planning on converting my garage for the weekend into a paint booth... I figure the paint can't look any WORSE than it does now, lol. Besides, one of the fenders and the tailgate i already shot last year with reduced rustoleum and they came out great-- sucks that i have to strip all of that off though to prime and paint with the 2k stuff, but I'm sure it'll come out better, at least harder. The rustoleum took forever to harden and started to suffer from some UV discoloration.

Jsinclair 04-30-2013 11:22 AM

Awesome work so far. Good Luck!

CobraMarty 04-30-2013 07:47 PM

Way cool project!!

So you are using the jeep 6 ecu to control the dodge 8 engine?
What about the CPS and cam position sensor?
Your jeep manual trans and bellhousing just bolted up to the dodge engine?
PS, alt, A/C will all bolt up?
OBD port will be scanning the stock jeep ecu and VIN?
Gauges? canbus?

doublins 05-01-2013 06:18 AM


Originally Posted by CobraMarty (Post 15370872)
Way cool project!!

Hey, thanks! Didn't know you were on this forum too :wave:


So you are using the jeep 6 ecu to control the dodge 8 engine?
The Jeep ECU and Durango ECU from that year are physically identical hardware (as is the Dodge Viper ECU, hence 10 injector driver pins). To get it running, I'm going to use the dakota ECU, but with the SCT tuner, Ryan thinks I could probably use either one, and just flash it with the appropriate base program for whatever car had the setup I'm running. I think I'm going to use the Durango ECU and have him disable the auto tranny.

The Jeep Ecu, out of the box, being for a 6-cylinder, will not be able to drive the dakota without a re-flash to transform it into a ram, dakota, or durango ecu. The problem with the Ram ECU is that the rams had two upstream o2 sensors, whereas the dakota/durangos had one, like the jeep (and like i kept it). So, a ram program could be problematic, but I think Ryan (or any SCT tuner) can turn off/on individual o2 sensors as well. I'm not sure.


What about the CPS and cam position sensor?
I used a flywheel from a 98 Ram 1500 and a CKP from the same - could not use the Durango's because it was an auto with a flex plate(smaller diameter than flywheel) and its CKP was too long and interfered with the flywheel.

I used the distributor and CPS from the Durango.


Your jeep manual trans and bellhousing just bolted up to the dodge engine?
I sourced a 98 dakota 3.9L V6 bellhousing from a junkyard- the back fits the ax-15, the front fits the magnum block, my external slave and everything else fit perfect. The starter is on the driver side now, however, so you have to watch interference with the driveshaft and lengthen the starter wires.


PS, alt, A/C will all bolt up?
Using my Jeep's power steering with a bracket from a Grand Cherokee.
A/C I'm using my stock condenser with the durango compressor- i'll have to have an a/c shop make one new line for me- the other line will fit fine.
Using the durango alternator.

Note that the durango alternator and compressor are physically the same as the jeeps' but the pullies have an extra rib to fit a wider belt (6 ribs instead of 5). You could probably reuse the jeep stuff and run a 5-rib belt across both the 5 and 6 rib pullies.


OBD port will be scanning the stock jeep ecu and VIN?
Should work perfectly fine


Gauges? canbus?
Should work perfectly fine. Both the 98 Durango and Jeep use the same JTEC ecu and the same CCD bus- the pins for I/O on the ecu are exactly the same- so I expect all of my gauges to work. I'll publicly debug any problems here so that people can see the problem, and hopefully, solution.

doublins 05-01-2013 06:24 AM

Got some stuff done yesterday...

Primed my grille/cowl for paint later today

My stainless flanges and reducers (to take the y-pipe diameter down to 2.25" after the collectors) arrived

So i welded them up... hope to get my exhaust finished this week before i start it, for my neighbors' sake

CobraMarty 05-01-2013 06:35 PM

Thanks for the replies. It is a shame that it came to this but your solution looks great. So looking to this build.

jforse 05-01-2013 08:58 PM

Great write up so far. I have been thinking about this swap.

jpin86 05-02-2013 06:00 AM

Hey Chris I am on I have watched you have problems with your stroker. I hope this goes better for you. I'm watching and learning for my swap.

doublins 05-02-2013 06:18 AM

Thanks for the support, guys :tea:

I didn't get a whole lot done yesterday- I did get the hole patched in my firewall where my cowl intake used to run... I picked up my rear driveshaft from the shop and got that installed, an installed the starter, dust cover, A/C compressor, alternator, and power steering pump.

If you use a P/S bracket from a ZJ, the TJ power steering pump will bolt up completely. I had to heat and bend the hard line for the heater core a little bit to clear the pump resevoir, but it fit perfectly. One thing I forgot to salvage from the durango was it's power steering pulley! I forgot I needed the 6-rib pulley, so I had to order one from summit for $15.

I TRIED painting my cowl and grille yesterday, with summit's single stage gloss black urethane, but couldn't get my gun settings set right, and got HORRIBLE orange peel, so I'm going to have to sand it back down today and try again. I have done some painting in the past, I don't know what the problem is, but man oh man it was bad.

Today I hope to paint the cowl and grille (again), run the distributor wires, bolt on the passenger side fender, install the ECU, battery, fuel line, wiring harness, etc and start thinking about trying to start it soon :)

jpin86 05-02-2013 08:30 AM


Originally Posted by jpin86
Hey Chris I am on I have watched you have problems with your stroker. I hope this goes better for you. I'm watching and learning for my swap.


The time now is 06:55 PM.

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