Security Jeep

I'm gettin ready to check out an 88' XJ that works as a security/medical vehicle for a resort and it's in a pretty pathetic state right now. It's a pretty sweet jeep, 4.0 non-high output NP231 AW4, its got a new fire-engine red paint job and full lights, radio, and siren. Nobody can remember the last time it has had a tune up. The old maintenance mechanic obviously wasn't too worried about actually doing his job but he's gone now and the job's been given to me to do So my question is, what are the most effective, cost effecient mods I can do with it to improve it's performance. I'm planning on the obvious (air-filter, oil filter/change, tranny fluid, spark plugs/wires/cap, SEAFOAM) and I think just that will do wonders. But does anybody have some good choices for that particular jeep that sees a lot of short distance, short or no warm-up driving, stop and go, stop and stomp driving also that sees quite a bit of off pavement action? Also, how much would it cost for a HO head? And I've heard of some little, FREE things you can do like removing that venturi out of the airbox, or cutting the airbox for better air-flow but I haven't done too much screwin around w/renix XJ's (I drive a 2000). But FREE and CHEAP is great. I've gotta get this budget approved by the big guy

Are you saying a resort uses a 1988XJ for a security/medical vehicule, to get to people when they need help? And you have questions on cost effective mods. I hope the resort is very small. For the mods, if the jeep only runs short distant, no warm-up, why bother: there will be no significant improvement. You brobably listed the free one.

I think the above poster woke up on the wrong side of the bed...or just has a pissy attitude...

In addition to everything you listed, I'd look into Ford fuel injectors (the 19# ones I believe, for a renix). Remember to just go with good old copper champion plugs, nothing fancy like platinum or iridium...

A good tune up is probably your best bet, like you said. Clean the TB and the little sensors on it (Idle Air Control, TPS). Use a good oil filter (mobil 1, amsoil, k&n). how's the exhaust? any cracks? manifold cracks? motor mounts? tranny mount?

Other than getting it to run better (smoother), what else are you looking for it to do that it currently doesnt do?

Just suprised a business would used a 20 yrs truck for medical. Point taken . Purple, I think you already know what to. Take it for a good drive once in a while to see other jeeps at the mall. A good run will help the cat and batterie.

Well, the Jeep's been good to them so far. And if it's a critical medical situation they set up an LZ and have a chopper there in fifteen minutes. It's had to get though some construction sights with some deep muddy ruts and it's been un-stoppable so far. I haven't spent much time under the hood or underneath the jeep but I know it's an ex-governmental jeep that used to be in the park ranger business. So I'm wondering if it might have some extra goodies. What are the possibilities?

just do a good tune up and use copper plugs.

as for the ho head, its possible but you need to also use the ho intake/exhaust manifold/throttle body and adapt the tps to work with the ho throttle body. or reuse the renix throttle body(get it bored to 60mm) and drill/tap holes in the ho intake to mount it.

as mentioned, the injectors are prone to leaking and a good replacement are ford 19# injectors.

make sure the closed cooling system is working properly.

Gosh, free and easy? And you came here?

No, really, I've seen lists right here, there may be one in the stickies, and the junkyard thread for other parts. What you plan is the right approach, maybe the rubber carpets and the extended idle module would help.

The latest JP showed a linear amp for cell phones available from Williams, IIRC, I thought that was cool for marginal cell areas. (Didn't see a price, tho, . . .)

A headlight upgrade and the wiring harness come to mind - can't have too much light on a dark and stormy night.

BFG AT/KO or Mudders when they need it. BFG offers more sizes in 16" than 15" now, I'm running Liberty rims with pizza cutters, they get me up and down the hill behind the house much better that (huck) Liberators.

A preemptive strike on the Vac Disco mechanism - just change it to cable operated before it starts leaking and leaves the driver to be rescued. Or just flip it, block it engaged (I used a hose clamp on the shaft,) and reinstall upside down. No disco, no cost (hey, I finally remember one.)

There's a mod to jumper the power windows (if you got them) to make them work with no key in the ignition. I find that one helpful.

A manual switch for the elec fan could be helpful on a hot summer day.

Some sort of cupholder for the poor guy driving around on midnite shift with his keep awake juice.

You can install a front bench from a Comanche, it's nuts and bolts and does extend seating capacity, but with the loss of the Ebrake - or add that under the dash, the XJ was available with both for security and postal.

If you do go with the HO head, consider the entire serpentine system from later models. It gets the alternator up on top, out of the mud.

Heated mirrors from a '96 up would be nice in the winter, but who's at a resort that time of year? Still, security has to get out and about.

Surely some one else can come up with something not on my to do list.

Frankkl said:

Just suprised a business would used a 20 yrs truck for medical. Point taken

. Purple, I think you already know what to. Take it for a good drive once in a while to see other jeeps at the mall. A good run will help the cat and batterie.

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Yep - and Jeeps are social critters anyhow, so get it out to see other Jeeps...:wave:

A tune-up will help. Most people here advocate Champion plugs, but I've not used them in years. I use Autolite Platinum in my RENIX, and I've not had any trouble.

If all you're doing is short-haul, there's really no point in doing any sort of performance mods (especially since it's RENIX, and most of what you'll need to do is homebrew anyhow.) Just get it out for a good drive about once a month, and make sure it's started about once a week (and let it idle for 10-15 minutes once you start it.) Wix and Baldwin are brands I like for oil filters, and Wix is easier to find (#51626 for RENIX - it's a metric thread.)

There's nothing at all wrong with using a 20-year-old truck for medical and emergency - if the damn thing works, why replace it? AMC sixes will run until the Second Coming, and they're tougher than the hinges of Hell - I'd trust a 20-year-old Jeep before a new Ford ambulance.

There wasn't any real difference between a "production" XJ and a "police" XJ until 1996, so all the standard goodies are what you need to know. It's only an "emergency vehicle" because that's what they call it, it's elsewise identical to my own RENIX rigs.

One small thing - since it's all "stop and stomp" driving and the like, use five quarts of engine oil and one quart of Dexron transmission fluid. The extra detergents in the ATF will help keep the sludge down, and the seal conditioners will help as well. You're cutting engine oil one-to-five, so it won't pose a problem.

I use Autolite platinums and love em. And the main reason for runnin them on this rig would be because who knows when or if it'll get another tune up if it's not from me. Also, I'm thinkin full synthetic high-mileage motor oil for the same reason plus the detergent benefits that 5-90 mentioned. What about maybe a straight 30 or 40 weight oil? Would that provide anymore protection? If not, what viscosity would be the best for this application? I also like to use a motor flush when I change the oil and I believe in Restore. At the very least it keeps the motor quieter. I like the power window jumper mod mentioned by TiRod, do you have details? And suprisingly this jeep has never had cooling problems but I'm sure there's still some maintenance to be done on it too. Probably some gaskets need replaced too. Most of this I'll just have to find out when I dig in, but for time's sake I'd like to have my ducks in a row now

PurpleCherokee said:

I use Autolite platinums and love em. And the main reason for runnin them on this rig would be because who knows when or if it'll get another tune up if it's not from me. Also, I'm thinkin full synthetic high-mileage motor oil for the same reason plus the detergent benefits that 5-90 mentioned. What about maybe a straight 30 or 40 weight oil? Would that provide anymore protection? If not, what viscosity would be the best for this application? I also like to use a motor flush when I change the oil and I believe in Restore. At the very least it keeps the motor quieter. I like the power window jumper mod mentioned by TiRod, do you have details? And suprisingly this jeep has never had cooling problems but I'm sure there's still some maintenance to be done on it too. Probably some gaskets need replaced too. Most of this I'll just have to find out when I dig in, but for time's sake I'd like to have my ducks in a row now

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Probably a 10W40 would be good for you, being in Mizzourah and all. The cut with straight 10 base oil in the ATF will help if it gets cold (if you're high up in the Ozarks, run half 10W-40 and half 5W-30 - that will give you "cold flow" on startup, but the thicker oil that the older engine will want. If you can find 5W-40, that should be good for year-round, but 10W-40 would be better for summer.)

The hazzard of switching to synthetic is that it is so highly detergent - you could have seals that are still sealing by dint of sludge buildup, and the synthetic can clean that away. Synthetic doesn't "cause" leaks, but it can and do make them appear. If you switch to synthetic, you may as well plan on replacing the front & rear mains soon (and possibly valve guide seals as well.) There's nothing inherently wrong with synthetic oil per se or in se, but that's something that people usually bring up as a "problem." Whichever oil you use, make sure it has a Diesel ("Cy") rating, as that indicates a higher percentage of organometallic content - which flat tappet camshafts need. (The API ratings usually take the form of "Sx/Cy" - the "S" is for Spark Ignition, and the C is for compression ignition. Do not use oil with the "API Energy Saving" sunburst on it - unless you like replacing camshafts!)

If the oil change intervals haven't been watched, and it's "stop and stomp" driven, sludge buildup can be easily assumed. I'd not use too strong of a flush to clean the stuff out - just use the "replace with one quart of Dexron" I mentioned and change the oil every 150 hours or so the next few times (if it sits idling a lot, adding an "hour meter" for engine runtime is a good idea. Then, you can change oil every 500 hours or so, instead of every 5000 miles and double that in runtime. It's a standard for industrial engines, and the meter is readily available. Ask for a "Hobbs Meter" or an hourmeter at your local industrial supplier.) The problem with cleaning the sludge out too quickly is that, as mentioned, it could be holding an otherwise good seal in place - and you'll end up with a leak you didn't need. Clean it gradually, and that will let the seal get back to work. I'd probably do 4-6 changes that way.

OEM RENIX radiators are known for blockage - an aftermarket radiator solves the problem. There's no need to convert to an "open" system, the "closed" system works just fine. If you crack it open, search up my posts on "thermostat drilling" to find out how to make the system purge itself of air (haven't had time to do a writeup.) This will save you loads of headaches, and can help keep your engine running well if you end up overheating.

OEM RENIX injectors are also known for leaking at the body seam (where the metal is crimped to the plastic.) Later units are ultrasonically welded together, as are SBFord and SBChevvy units. The only fix for the leak is outright replacement - may as well get it off your list (engine fires suck.)