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Unread 06-28-2013, 02:28 PM   #1
JakeC132
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5.9 Swap

Has anyone done a 5.9 swap to a zj that isn't obd2? i have a 95 and was looking into it. Was wondering what problems people ran into and what the donor vehicle was (98 zj or ram truck) please let me know what you found

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Unread 06-28-2013, 02:56 PM   #2
dnuccio
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http://www.jeepforum.com/forum/f13/z...ml#post3020645
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Unread 06-28-2013, 05:41 PM   #3
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About as straightforward as swaps come. I used a '94 Ram 5.9 block/heads/crank/flexplate with the 5.2 E/I manifolds and cam. On OBD1 it's pretty much plug and play, minus the motor mount and ovaling one hole on the flexplate. The 5.2 computer has no problems running the 5.9, although I eventually upgraded to the 703 injectors anyway. You'll end up reusing a bunch of stuff from the 5.2, notably the accessory bracket and a few other bolt-on things, if you use a Ram 5.9 as they're different.
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Unread 06-28-2013, 07:08 PM   #4
HighLonesome
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Don't oval a hole in the flexplate. That can cause an imbalance. Spend the few extra bucks and get the right flexplate.
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Unread 06-28-2013, 09:26 PM   #5
Texas ZJ1
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I did the 94 5.2 to 5.9 swap. Just the parts from the FAQs section. New parts, don't half way do it.

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Unread 06-29-2013, 09:48 PM   #6
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Quote:
Originally Posted by HighLonesome View Post
Don't oval a hole in the flexplate. That can cause an imbalance. Spend the few extra bucks and get the right flexplate.
An imbalance in what? The flexplate? We're talking maybe a gram of material removed here. I ovaled mine, no problems whatsoever.
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Unread 09-20-2013, 09:04 AM   #7
JakeC132
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do you know if it's the same or harder if the donor vehicle with the 5.9 is obdii? Can i still use my 46rh transmission? also has anyone bored to a 408?
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Unread 09-20-2013, 09:12 AM   #8
dnuccio
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Doesn't matter what the 5.9 comes out of, you reuse your 5.2 wiring harness. If you have emissions, you'll need to reuse the passenger side exhaust manifold and intake manifold from your 5.2 so you can retain the EGR system, if the 5.9 you get isn't set up for it. You can reuse your 46RH transmission
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Unread 09-20-2013, 10:41 AM   #9
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Quote:
Originally Posted by JakeC132 View Post
do you know if it's the same or harder if the donor vehicle with the 5.9 is obdii? Can i still use my 46rh transmission? also has anyone bored to a 408?
I don't want to cause bad juju with the mods, but there are a bunch of 408's on thespeedfreaks.net.

Last edited by zj97ltd; 09-20-2013 at 10:41 AM.. Reason: mis-spelled word
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Unread 09-20-2013, 11:13 AM   #10
Aceladriver
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go by Hunter's post in FAQ.

One of the best and simplest write-ups yet...


Quote:
Originally Posted by CatSplat View Post
... . You'll end up reusing a bunch of stuff from the 5.2, notably the accessory bracket and a few other bolt-on things, if you use a Ram 5.9 as they're different.
Is the Ram accessory bracket different from ours?
I never heard that - thought it was only the power steering bracket and pump that was different?

If you don't have to pass emissions you can use your early TB an sensors but leave the late intake on there and make a blanking plate for the pass side exhaust manifold, or use a late ZJ manny.



Quote:
Originally Posted by JakeC132 View Post
....Can i still use my 46rh transmission? also has anyone bored to a 408?
You don't have a choice really.

It's either the RH or a 5speed, LOL. (early PCM isn't going to run the late ZJ RE series trannys)

And yes there's several ZJs running around with stroked 5.9 motors running off the early PCM.


Quote:
Originally Posted by CatSplat View Post
... and ovaling one hole on the flexplate. ....
Quote:
Originally Posted by HighLonesome View Post
Don't oval a hole in the flexplate. That can cause an imbalance. Spend the few extra bucks and get the right flexplate.
Quote:
Originally Posted by CatSplat View Post
An imbalance in what? The flexplate? We're talking maybe a gram of material removed here. I ovaled mine, no problems whatsoever.

This is the amount that would need trimming on the flexplate.

Not ideal but really not enough to affect anything - better to get the right flexplate if you can do it though.
BTW per Martin Saine that bit of grinding doesn't matter til you get upwards of 400 - 500HP. Then you'd definitely want a non-ovaled FP.




Just for fun here's the 98 ZJ passenger side manifold vs the OBD1 manny.

It should be pretty easy to make a blanking plate with simple tools - but as said above ^ you'd want to stay with the stock setup if you have to pass emissions.

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Unread 09-20-2013, 12:17 PM   #11
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Quote:
Originally Posted by Aceladriver View Post
go by Hunter's post in FAQ.
Is the Ram accessory bracket different from ours?
I never heard that - thought it was only the power steering bracket and pump that was different?
That's a good question, my 5.9 was completely in pieces when I got it and mostly in boxes. I assumed the (different) accessory bracket it came with was from the Ram the motor was out of, but you know what they say about assumptions. It's entirely possible it was some random bracket the seller tossed in the box.
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Unread 09-20-2013, 01:18 PM   #12
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Quote:
Originally Posted by CatSplat View Post
An imbalance in what? The flexplate? We're talking maybe a gram of material removed here. I ovaled mine, no problems whatsoever.
Yes there is that gram and...
The 5.2 uses a 'zero balance' flexplate because the motor is internally balanced. The externally balanced 5.9's flexplate has balance weights welded to it. You really should match the 5.9 harmonic balancer to weighted flexplate.
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Unread 09-20-2013, 06:23 PM   #13
Aceladriver
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Quote:
Originally Posted by HighLonesome View Post
Yes there is that gram and...
The 5.2 uses a 'zero balance' flexplate because the motor is internally balanced. The externally balanced 5.9's flexplate has balance weights welded to it. You really should match the 5.9 harmonic balancer to weighted flexplate.
Definitely right. You'd have to keep it matched, but that's not the issue about the hole.

I 'believe' it's like this:
Most late Magnums (5.2 and 5.9) were the 90 degree bolt pattern flexplate, but the early 5.2 had the offset pattern fp, so I believe you'd have to do that clearance to match the late 5.9 flexplate to an early 5.2 tranny (well, torque converter)

That's why a 98 5.9 will bolt to a 44RE TC no prob, but you'd need that clearancing to use that same 5.9 on an RH.

The alternatives are to use the late 46RE converter on the RH (for some reason I thought that didn't work, but I'll take Hunter's word for it) - assuming you have access to one, or if you happen to be getting a stall converter they should be able to match whichever pattern you have.


Then if it's a stroker build 5.9 motor you go back in the other direction. Most stroker kits are neutral balance so you need to use the 5.2 damper and flexplate.
You can go with an aftermarket damper - even SFI approved ones, but I've never seen an aftermarket SFI flexplate for our motors. Not with the window wheel we need for the CKPS
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Unread 09-20-2013, 10:30 PM   #14
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Quote:
Originally Posted by HighLonesome View Post
Yes there is that gram and...
The 5.2 uses a 'zero balance' flexplate because the motor is internally balanced. The externally balanced 5.9's flexplate has balance weights welded to it. You really should match the 5.9 harmonic balancer to weighted flexplate.
Yes, nobody said anything about using a 5.2 flexplate with a 5.9, that'd be pretty stupid. I was careful to note in my post that I was using the flexplate from the 5.9, not the 5.2. The ovaling is because there was a very slight bolt pattern difference between the early 5.2 and 5.9 torque convertors, and it's a heck of a lot easier and cheaper to oval a hole than to buy an early 5.9 torque convertor for a 46RH.
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Unread 09-21-2013, 04:31 AM   #15
Texas ZJ1
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I'm sure that if you are only going from 220 to 265 HP, on oval here s short cut there won't matter. I went from 220 to 375 HP. I did not shortcut anything. I also didn't have over heating issues.

I did not reuse the plug wire loom and burnt through two plug wires. So, I bought new wires, new loom and vroom, vroom.

It is embarrassing when you don't do something right and it sounds or looks like crap.

Hunter
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94 5.9 Laredo 6.5 RE lift with 35 Maxxis Bighorns
and 33 Bridgestone Duelers
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