Alternator Question

i need a new alternator and i called around a few places and each one had different amps, my question is does it matter cuz at napa they had a 160 amp unit and wanted to know if it would work in my 87 4.0 with ac

thanks in advance

stock alt is 95A +/-
I replaced mine with one from junkyard 2 years ago, no probs since. if you want to go higher amp's I think you can get one from a Durango or a V8 GrandXJ... may have to mod a bit tho to make it fit.
either way if you just want to replace stock get a used one, shound't be much and will do the job.

Your 1987XJ uses a Delco alternator with internal regulator - the later versions (ChryCo) are Nippondenso with external regulators. Frankly, I prefer the Delcos.

If you're not in a hurry, click the link in my sig and browse to San Jose Generator - I talked him into doing mail-order about eight months ago, and there are those here using his ND and Delco units without complaints. He can do OEM output levels, or increase them somewhat for you. While you're about it, your mains cables are probably getting old...

You can get a used alternator, but why? I have a problem getting used electronics, if I don't plan on rebuilding them already... That just may be me, tho.

5-90

You'll be fine with a remanufactured alternator from any parts store. Unless you're running a crazy stereo or something that puts a BIG load on the electrical system, the difference in amps probably won't make a difference.

Or you're running lots of lights.

However, I've also found that running a slightly "over-spec" alternator also helps with the longevity of the thing, since you're working it to a smaller percentage of total capacity than you would be with a stock unit. Just something else to consider - I get over-spec'd alternators with a slight "underdrive" on the pully, and the damn things just don't break anymore...

5-90

5-90 said:

Or you're running lots of lights.

However, I've also found that running a slightly "over-spec" alternator also helps with the longevity of the thing, since you're working it to a smaller percentage of total capacity than you would be with a stock unit. Just something else to consider - I get over-spec'd alternators with a slight "underdrive" on the pully, and the damn things just don't break anymore...

5-90

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I drive my XJ through mud and water. Since Jeep engineers weren't thinking clearly when they decided where to place the alternator, mine break anyway, so I get AutoZone ones with a lifetime warranty. Not a clue what the amp rating is

anony91xj said:

I drive my XJ through mud and water. Since Jeep engineers weren't thinking clearly when they decided where to place the alternator, mine break anyway, so I get AutoZone ones with a lifetime warranty. Not a clue what the amp rating is

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In that case, get the lifetime warranty one from the local parts store (I prefer NAPA). That way next time you drown it and it dies, hose it out and exchange it.

I've been runing a 165amp unit from Alterstart for over 2 years now without any problems at all. It was around $150 delivered with a lifetime warranty. It has been in water a few times without as much as a hicup. Even with a big stereo and stupidly bright highlight conversion voltage will only drop below 14 with everything on at idle. The minute I move it sits happily at 14.4 volts. Is never below 13.o volts.

The main reason that alternators get goofy after you "swim" them is simple - the grit and crap from the muddy water gets in there, and sticks things up.

I really need to go talk to Rod about this one of these days, but I'm fairly sure you can rinse alternators with clear water. Mine gets good and wet everytime I wash the engine, so there's got to be a way to flush the crap out of them.

I have found (and there are numerous reports from the field to confirm this,) that if you are offered a lifetime warranty, you're probably going to need it. I bought alternators and starters from Rod even while I was working parts - his WORKED the first time I got them, but it was "hit-and-miss" with units from work...

5-90

does the alternator in an xj with a tow package have a higher output than the rest or are they all the same

I too am running alterstarts, or load boss, one in my k1500(200 amp ) and one in my 98xj sport(165 amp) the jeep has two zr240s and a zr1000 running from the yellow top isolated in the rear, but it only runs around 12.5 volts or so, and the chevy is always above 14 volts. both have been through water and running while submerged! no problems yet, I highly recommend them! oh and yeah if they give you a lifetime warranty but WONT cover labor you prolly screwed and will need it anyway

DansGreyMj said:

does the alternator in an xj with a tow package have a higher output than the rest or are they all the same

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A "Trailer Tow Package" typically features improved/larger brakes (typically on the rear,) and heavier rear suspension (springs and shocks) than the standard goodies. The alternator has little to do with towing - figure a full load of lights and a brake controller (and an electric braking system for the trailer) probably draws 10A all up. Your OEM alternator should be overspec'd by at least that much.

Still, it's pretty surprising what can be wedged into an OEM case. Rod has good prices on his stuff, and he's even done a couple "specials" that I know of - I'm running a 185A Delco that he did for me. Kind of an oddball, that - he just happened to have an armature that could freakishly generate far more than the rest of the box, so he saved it for me.

Longevity? I've been running it for six years. No, I won't tell you what I paid for it, because I promised him I woudn't. It was sort of a "one-off" job anyhow...

5-90

My 95 sport came with a "high output" alternater and "better" battery as part of the towing package. I forget the ratings though. The "better" battery was crap compared to my Optima and I think the "high output" alternator was 95 amps compared to 60 amps.

I have a related question - What are the down sides of a higher output alternater, other than initial cash outlay? Nothing in life is free so do they wear out faster, cost a horsepower of engine energy, cause the government to track me better...:gag: I've just always wondered.

DXJ said:

My 95 sport came with a "high output" alternater and "better" battery as part of the towing package. I forget the ratings though. The "better" battery was crap compared to my Optima and I think the "high output" alternator was 95 amps compared to 60 amps.

I have a related question - What are the down sides of a higher output alternater, other than initial cash outlay? Nothing in life is free so do they wear out faster, cost a horsepower of engine energy, cause the government to track me better...:gag: I've just always wondered.

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Honestly, not much. You should actually get greater longevity from the higher-output unit, because you won't be driving it to as great a percentage of its rated output most of the time.

HP/TQ drain is directly related to electrical output - you'll only drain more engine power if you have to generate more electricity. The "Amp" rating of a given alternator is the maximum rated output at 100% duty cycle - but it don't put that out all the time (I think my 180A hovers around 40-50A most of the time - until I turn lights and such on.)

Bearing longevity is comparable to standard units as well - the main difference being the armature windings (allowing for greater power production) and rectifier/regulator electronics (converting higher levels of AC to DC and allowing more power to the stator windings to increase output.)

Honestly, installing a high-ouput alternator in and of itself doesn't carry much of a downside that I can think of. HOWEVER, if you think you might NEED that greater power output, installing heavier mains cables is always a good idea. From what I see in the FSM, the OEM wiring can't handle more than most OEM/Stock alternators. And, if your mains are getting old, they're probably having some internal resistance issues caused by corrosion and/or contamination (most OEMR wiring isn't sealed as well as it could be, and neither are most repalcements. That's why I got into making replacement wiring myself - no-one else was doing a job I'd accept. More details on my website...)

Anything else I can help you with?:lecture:

5-90

5-90 said:

The main reason that alternators get goofy after you "swim" them is simple - the grit and crap from the muddy water gets in there, and sticks things up.

I really need to go talk to Rod about this one of these days, but I'm fairly sure you can rinse alternators with clear water. Mine gets good and wet everytime I wash the engine, so there's got to be a way to flush the crap out of them.

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Absolutely. That's why I just throw in a free warranty replacement when mine go swimming, forget that washing crap You'd have to take it out to flush it anyway, not to mention there's probably gonna be mud and sand and crap in the bearings...

5-90 said:

I have found (and there are numerous reports from the field to confirm this,) that if you are offered a lifetime warranty, you're probably going to need it. I bought alternators and starters from Rod even while I was working parts - his WORKED the first time I got them, but it was "hit-and-miss" with units from work...

5-90

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I've never had a problem with AutoZone's lifetime warranty stuff except when submerging them while wheeling. Everything I replace is lifetime warranty if possible...alternators, starters, water pumps, etc...

They're all reman'd, the options are a 1-year warranty or lifetime, why not shell out the extra 10 bucks for the lifetime? You've got some alternator specialist rebuilding them for you, that's cool too, but I don't know if there are any electrical shops like that left around me, and given the option of replacing or rebuilding, my lazy ass is just gonna replace

Yeah, it's getting harder to find the small shops, which is a pity. All this "chaining" going on makes it harder to get decent replacement/upgrade parts, especially with everyone paying the "China price" and sacrificing quality. That's why I talked Rod into doing mail-order, and I plan to talk to him about "submersible alternators," or just being able to "rinse in place." The bearings are, theoretically, sealed units (except for the rearmost. If I spend a lot of time fording, I'd probably pull the back cover and re-lube the bearing with lithium grease anyhow.)

I've nothing against a "Lifetime Warranty," but the best warranty is one you don't need. AZ, CSK, et. al are all taking a gamble - they buy replacement units by the thousands for a few cents on the dollar, and they're betting that enough of them work to pay for the replacements. They're really not fit for scrap metal, generally, and I've known some part numbers at Kragen's to have a return rate of well over 100%!

Sometimes cheap just ain't worth it. If all of your parts have worked out of the box, power to you! - but I'd not get in the habit of expecting that...

5-90

5-90?

What is the difference, in layman terms between the Delco for the 86-90 models verses the later versions (ChryCo)Nippondenso on 91+'s? Can i run a newer on an 88? Can one run a delco on an newer model?

If Rod has the technology to do custom work, why doesn't he make Alternators to fit on the AC mount of our engines???????He make a small fortune selling those, heck, i'd take the first one right now........

noah

First off a HO ALT Say a 165 to 220 amp alt is a line of crap. The post on the ALT can't handle it. Not for more the a few seconds anyway. Someone WAKE UP!!!!! You would need a cable from the Alt to the BAT the size of the battery to starter cable to carry 165 amps.
OK maybe it can do it. For what 2, 3 seconds before internal temps rise and with resistance cut it back to say 60 amps maybe as high as 90. Unless you are cooling your alt with nitrogen.
The only alt that will put out 165 amp for real will come out of a plane. put out 24 or more volts be at least 16 inches across and cost 400 rebuilt. Ant that was 12 years ago.
OK. you can call it a 165 amp alt. If you want.

i just started doing the 136 amp alternator last night on my 93xj . stock one was 90 amps. i find i am having to do some grinding and matching of bracketry to the configuration and shape of the new alternator out of a newer cherokee v8. its a pain in the butt so i hope it pays off. this afternoon im cuttin out of work early to go home and grind and shape things. should have it in about an hour.

i'll take photos and try to post them as well.

i am removing both brackets, one to the engine and one in front of the alternator. both will need some mods to it. im glad the big bracket is aluminum since it requires special attention and more grinding. the steel one needs minimal grinding only.

lets make some noise with power tools!

i'll update when i am done.

john

muddshutter said:

5-90?

What is the difference, in layman terms between the Delco for the 86-90 models verses the later versions (ChryCo)Nippondenso on 91+'s? Can i run a newer on an 88? Can one run a delco on an newer model?

If Rod has the technology to do custom work, why doesn't he make Alternators to fit on the AC mount of our engines???????He make a small fortune selling those, heck, i'd take the first one right now........

noah

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The Delco CS-Series (1987-1990,) and Delco SI-series (1986 and earlier,) are internally-regulated units, built by/for Chevrolet/GM, and are quite popular. You should be able to find a "quickie" unit on pretty much any late-model Chevvy/GM product.

The Nippondenso alternator (used on ChryCo and about half of imports,) is an externally-regulated unit. ChryCo, in their admittedly finite wisdom, put the regulator in the PCM/SBEC - I've not heard of any failing yet, but I don't like the idea (since most voltage regulators I've seen cost anywhere between $10 and $30 on their own. I haven't priced an SBEC/PCM lately.)

It is possible to either bypass the SBEC regulator and install a standard early ChryCo regulator, or convert to an internally-regulated unit, but you will get a persistent code in doing so, because the OBD system will not be able to "sense" the regulator output actually doing anything, and will therefore assume the alternator is toasted.

I tend to prefer the Delco units - high-output mods for them were designed with the driver in mind, and they tend to be a little tougher. Since ND units were used in imports (I think Honda was a big user,) seems like most of their kits are designed with the riceboy in mind, and therefore the high-output variant likes to be kept clean and dry - since it's just powering a stereo the size of a small city. This isn't always true - but most kits you'll get are like that (not all, but more than the Delco kits.)

I have not yet evaluated the potential for swapping the Delco and ND units - I'd probalby go with swapping in a Delco for an ND, and screw the PCM - but that's just me.

As far as needing to upgrade the wiring for a high-output unit - very true. Why do you think I run 1AWG mains? Why do you think I sell 1AWG mains? See my website if you want to know more (link in sig.) It's entirely possible to push 200A without going to a Leece-Neville, police model, or ambulance alternator (aircraft units are an entirely different story...) but you have to have wiring to match. OEM wiring is properly sized for OEM output - which hovers around 80-90A. If you're going to a 136A, I'd suggest upgrading your wiring. You won't be getting 136A all the time, but if you want that sort of power for any length of time you'll be heating up your output leads and causing trouble...

5-90

By the by - It's already possible to put an alternator in place of the A/C compressor - you just need the four-cylinder alternator bracket to replace the A/C bracket. I need to get one sometime fairly soon, so I can see about duplicating it. This bracket will allow you to relocate your alternator fairly easily - I'm not sure about retaining the Aircon, tho. Rod need do nothing special to make this happen.

I'm also thinking about designing a second alternator mount - the OEM one would stay where it is, and the second one would replace the Aircon. I'm not sure how useful it would be, but I'd see if it could be fitted with the 2.46L bracket, and design an adapter bracket if that won't fly.

5-90