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advice on early (pre97) vs late (post97) frame

metalman

NAXJA Forum User
Location
nc coast
some background. I am about to start on a project xj. I already have the engine (4.7 stroker) at the machine shop, and I already have the ax15 and 231 to go behind it. I currently have a 90 with a lift that we drive, but I have a chance to get a good deal on a 99 with a blown motor. I plan on running MS, and all the power options will be removed (manual locks, seats, windows ect.) carpet gutted for vinyl floor ect.

The jeep will at a minimum be getting the HD frame stiffener set. I am also wanting to put my first full roll cage into this (jeeps don't need pretty, so I figure its a good learning platform). This will all get tied into 2x6 rockers as well. I was going to completely strip the frame down, do all the welding, and then get everything galvanized while it was stripped down so that it would actually last, but this means its going to get done in one shot so that it can get dipped afterward.

Here is where the question comes in.
-How much actual difference is there between the frames? Is the newer frame an "upgrade", I've read articles mentioning improvements for the nvh stuff, but little in the way of actual differences to the frame.

-the 90 is in good shape, and it has no power options, but if I use it I would be swapping all the front body parts from the 97+ style anyways. cooling system will also get changed to an open style.

-the 99 would get all the power options deleted. I see the electric speedo as a small plus.

I can get the 99 for a pretty good price, only about 200$ more than it would cost me to scrounge up the parts I want anyways separately. Really, if you were undertaking this project, and had two stripped down frames 90xj vs 99xj, which one would you choose to start modifying since its going to be pretty permanent after the galvanizing.
 
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There is no difference that I have heard of regarding the frame except for less milage and less rust. Get the 99 hign pinion Dana 30 and possible 8.25 rear (if it doesn't have abs).

Please edit the "grey area" stuff from your post. That stuff is not put up with here, if you want to take the risk of that then fine but don't involve this forum or give the anti 4x4 people more incentive.
 
then get everything galvanized while it was stripped down so that it would actually last, but this means its going to get done in one shot so that it can get dipped afterward.

Wow.

I've never heard of doing that to an XJ.

Is it even possible?
 
....Please edit the "grey area" stuff from your post. That stuff is not put up with here, if you want to take the risk of that then fine but don't involve this forum or give the anti 4x4 people more incentive.

I understand, and no offense intended. I'm not one to spite the law for sport, and I'm actually pretty "green". Thats actually my major issue with the cali emissions laws. I'm going to be running a cat and full exhaust, and I can run a cleaner engine with MegaSquirt than the factory did, but still fail for "tech" in cali, which is what fails most cars. Unfortunately cali emissions laws have little to with the environment, and a lot to do with bringing money into the smog shops which fail cars for some pretty pointless infractions. Ideally I'll be able to find a steady source of E85, which besides burning clearner, has a much smaller carbon footprint too.
 
in 94 or 95 some extra crossmembers were added to the doors and floor under the seats

in 97 you get the metal hatch which helps a little bit.

i would also say 4 door xj's are a bit stronger than the 2 doors.

either way, with all the work you are doing to it, you shouldnt have to worry about which is the marginally better platform
 
Wow.

I've never heard of doing that to an XJ.

Is it even possible?

yep, I know a bunch of chevelle guys that have, and its pretty popular with the rover crowd in england, and they deal with rust more than we do. actually, volvo did it on their cars for a few years, thats why some models don't rust, and they were unibody cars too, never heard of it causing them problems.

I think the whole warping issue is way overblown. The glavanizers play it up so that customers don't start freaking out on them if they suddenly decide their frame was perfect before and isn't now, you look at their frame wrong and they start crying about "it was numbers matching now its ruined....you have to buy me a new one". The resto crowd is rediculously anal, and they act as if the car has a soul or the metal is magical or something, really I think most of them are just afraid of working metal.

The other reason not many people do it is that everything has to be stripped to bare metal, which is hard with the boxed channels like the xj has. Honestly, a lot of it has to do with wanting to build up the frame, but not wanting to see my hard work rust away.
 
Thanks for the info about the frame, I figured the differences were probably minor, just wanted to confirm with someone that knew more than me.
 
personally, with the addition of frame rail stiffeners and a cage i would start with what ever platform will be cheaper assuming one isnt noticably rusted over the other. and i wouldnt bother with galvinizing it... just burn everything in, prime it, and do a thorough job of undercoating it. that way if you decide to add something down the road your not dealing with a galvanized piece of metal.
 
Ideally I'll be able to find a steady source of E85, which besides burning clearner, has a much smaller carbon footprint too.

Other benefits include:
Less BTU/$
Starvation in the 3rd world. No kidding! We had to send relief money to Mexico a few years back due to tortillas jumping in price from E85 productionhasta


There was a change in the Bodies in 96 to meet new federal crash standards. As far as I remember, there wasnt a major structural update after 96.:cheers:
 
don't throw stones, but we live near the coast and about the only place worth getting too offroad near us, is the beach, if its galvanized that means we can wheel on the sand as long as we rinse it we'll be good.
 
Running MS would not make you fail in Cali.
And I run in the sand all the time at the beach, I rinse off after, and actually my XJ is pretty rust-free. Not completely but most east coast guys would go nuts compared the the rust buckets there.
 
NC is moving towards the same cali style smog, atleast in certain counties, and I might end up back in cali anyways.

In california, anything done to the engine which isn't factory, has to be carb approved. MS can't communicate through the OBD port, so the scan system they plug in while it scans would flag it. Second you could retune your engine to run "dirty" in theory, so it is impossible to get it carb approved.

The reason you can get away with it on renix XJs was that they were OBD "noncompliant". Renix can't talk since it has no OBD port, so unless they know what a renix ecu looks like and they check for it being hooked up, they wouldn't know the difference between it and MS. You still have to pass the emissions, but there isn't much they can check on tech besides appearance and the EGR if they feel like doing their job (most don't bother if its running clean though). Basically when OBD came into effect, chrysler had just switched the cherokee to renix, so the govt gave them a couple extra years to get their money out of manufacturing before they had to switch, I only know of the renix jeeps being like this, and a lot of lazy smog shops will fail them without doing their homework. Its just further proof that emissions testing is usually more about requiring you to go to a "certified" shop than it is about the environment.

whats even dumber about this, is that you are allowed to regear axles or do any manner of things that kill gas mileage, so guys can put in crazy low gears, get 6 mpg in their already lower emissions standard f350 dually lifted monster truck, generate way more emissions that way, but cali law says they are good. however, get caught changing anything on the motor, even if it actually improves emissions, and your busted regardless.
 
I do not think you could galvanize an xj unibody, they are stacked/wrapped layers of thin sheetmetal held together by glue and spot welds along the entire length/width, it would be an absolute mess, not to mention the warping from the hot zinc bath, maybe not a uniformly thick "real" frame, but certainly a bunch of super thin sheets would warp, not to mention you may get some interesting colored smoke/pyrotechnics from the hot zinc/acid bath/glue combo? No experience, just kinda thinking aloud, good luck!
 
yeah... plus you can't actually get the inside of the frame rails clean enough to galvanize, probably, and those are the worst areas.

You could probably electro-galv an XJ just fine, but it will only stick to areas that are 100% clean and the most problematic areas probably aren't. Hot dip will definitely cause problems like skullver said.

As for the smog issues, move to a non retarded state, or go with the RENIX rig. There are other, less legal methods of making the late model non emissions required, but you can go to the fed pen for those if caught. Not fun. The RENIX rig you are correct, they can't plug in so they can't really check, if you wanted you could even build a custom wiring harness that leaves the RENIX computer under the dash and looking plugged in, but doesn't actually even feed it power, with the multisquirt hidden somewhere else and actually connected. Since you are running an AX15, I might suggest gutting a 96-down TCU and putting the MS in it (it'll fit, I believe) and sticking that in the stock location... you can probably tune a multisquirt to be better than a RENIX emissions wise anyways.
 
To the PO, E85 may burn cleaner, but the carbon footprint is actually larger. It requires more than a gallon of gasoline to produce a gallon of E85 (there are a lot of stages between corn and ethanol). The only reason farmers love it because of stipends they receive, but thats really about the only benefit.
 
I do not think you could galvanize an xj unibody, they are stacked/wrapped layers of thin sheetmetal held together by glue and spot welds along the entire length/width, it would be an absolute mess, not to mention the warping from the hot zinc bath, maybe not a uniformly thick "real" frame, but certainly a bunch of super thin sheets would warp, not to mention you may get some interesting colored smoke/pyrotechnics from the hot zinc/acid bath/glue combo? No experience, just kinda thinking aloud, good luck!


I sorta agree with this post..... I just had to cut into mine yesterday to put in nutstrips for the tranny crossmember by cutting thru the floor board to access the inside of the rails.... There is a lot of foam type body/seam sealer where all those parts join. the galvinizing cleaning process is going to dissolve or remove all that.
The idea itself is a good one though......... you have any price quotes yet?
 
honestly, I'm going to have to remove most of that to seam weld anyways. anything I don't strip for welding will get taken off acid dipping before its galvanized. I will have to make sure the rails have some holes for air and zinc to get in through, but I think thats better than trying to spray paint in it.
 
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