Skip to main content
Topic: Alternator upgrade for pre '88 3.8L? (Read 16630 times) previous topic - next topic

Re: Alternator upgrade for pre '88 3.8L?

Reply #15
Kool, thanks. That looks much more promising.

Now to dig up the cash to get an alternator. Might need to see what the local junkyards have around. Even a 95A would seem to be a significant upgrade.

Re: Alternator upgrade for pre '88 3.8L?

Reply #16
OK, I have a possibility of picking up a 130A truck/van alternator on the cheap. One thing I was wondering, though: Should I consider putting in some sort of protection on this? Like maybe a high-amp fuse or circuit breaker on the big line? (and leaving the black/orange wire disconnected, so it didn't take a huge spike if the fuse went) According to that chart up above, that thing will be cranking out some serious amps. I have my concerns about hooking that up to an 18 year old electrical system. (yes, I am very paranoid at times)

Re: Alternator upgrade for pre '88 3.8L?

Reply #17
To be 100% safe you could put an inline 20-amp fuse in the yellow/white wire (the one going from the regulator plug to the bat terminal) - this would protect the regulator in case of a short in the rotor. You could also put a large fuse inline with the battery wire (you can get high-amp inline fuses designed for car stereo installations) as well. You're safe in leaving the black/orange wire connected, though, because it's already protected by a fusible link.

Remember, the alt will only crank out the amps required of it. Unless you install some serious stereo gear or police lights you'll likely never hit anything near 130 amps. The main point in using the heavy gauge wire is that because the alternator is capable of it you have to be prepared that it might. The reason you want to do the swap is that it's better to run a 130 amp alternator at 50% duty cycle than it is to run a 70-amp alternator at 100%.
2015 Mustang GT Premium - 5.0, 6-speed, Guard Green - too much awesome for one car

1988 5.0 Thunderbird :birdsmily: SOLD SEPT 11 2010: TC front clip/hood ♣ Body & paint completed Oct 2007 ♣ 3.55 TC rear end and front brakes ♣ TC interior ♣ CHE rear control arms (adjustable lowers) ♣ 2001 Bullitt springs ♣ Energy suspension poly busings ♣ Kenne Brown subframe connectors ♣ CWE engine mounts ♣ Thundercat sequential turn signals ♣ Explorer overhead console (temp/compass display) ♣ 2.25" off-road dual exhaust ♣ T-5 transmission swap completed Jan 2009 ♣

Re: Alternator upgrade for pre '88 3.8L?

Reply #18
Is it worth it to put in the 20-amp inline? Based on what you're saying, I'm guessing I probably won't put in a high-amp on the main line to the battery unless I ever put in a much more powerful stereo.. so that just leaves the question of whether or not the 20A is worth buying/installing.

Re: Alternator upgrade for pre '88 3.8L?

Reply #19
OK, quick update. I decided to poke around Ebay for a few days.. ugh. Found one guy with a truck/van 130A alternator listed on JeremyB's spreadsheet.. was selling for a good price, but did not answer my questions to him about it and someone else got to the auction. In his auction, he said that the picture he had listed may not be the actual item since it was one of the parts dealers on there, so I wasn't about to jump on it without asking. Found another guy last night who was selling this:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7962556356&rd=1&sspagename=STRK%3AMEWA%3AIT

A Contour 170A alternator with the offset mounting. Price was over double what the first guy wanted, ($139.95 starting bid, $149.95 BIN) but hey.. I had hit some sales yesterday of my own and had enough money to where I could pay for the majority of it and get the rest covered with a loan from a family member, so I asked about it. He didn't tell me if it would work, even after I provided the bolt-to-bolt distance I was looking for. (roughly 6", if my measurement of the alternator last night was correct) He tried to sell me a 200A alternator "made just for my 1986 Thunderbird!" for $169.95 plus $15 shipping. Well, yes, I've seen alternator prices, and that is still within what I would consider reasonable. However, it would require me to borrow even more from that family member, and I'd like to keep that to a minimum.. (every $10 more I have to borrow is like pulling another tooth with that family member.. and I still have to get a 4-gauge wire and alt plug, and ideally I'd like to change the belt and idler pulley) so I had to pass for now. Maybe I'll call around to the junkyards and see what happens.. or transfer my PayPal money (takes 3-4 days, it) to the bank and go hit one of the U-Pull-Its in the next county. Figured I'd drop the update, though, in case anyone was looking for other possible alternator sources than what's listed.

Re: Alternator upgrade for pre '88 3.8L?

Reply #20
Meh.

The voltmeter I installed has always read about 1 to 1.1 volts lower than a test at the battery with my digital meter. Well, today I was sitting at a light with the radio barely on (almost inaudible) and just my foot on the brake.. nothing else drawing power.. and even when I put it in neutral, I was getting around 10.5v reading. (so 11.5-11.6 actual) I know that battery can't be fully charged.. haven't slapped the charger on it since the last time I drove it. But I got no spikes to 14v (or even above 12v) when I first drove it today.

I'm wondering if I should spend the money on the bigger alternator, or maybe use it toward getting my dark blue Bird on the road.. or just get by until I can afford to do things right without having to borrow.

Re: Alternator upgrade for pre '88 3.8L?

Reply #21
A word of caution when you're trying to "get by" when it comes to charging systems: Carry booster cables. Better yet, carry a fully charged spare battery so you can swap and drive home...
2015 Mustang GT Premium - 5.0, 6-speed, Guard Green - too much awesome for one car

1988 5.0 Thunderbird :birdsmily: SOLD SEPT 11 2010: TC front clip/hood ♣ Body & paint completed Oct 2007 ♣ 3.55 TC rear end and front brakes ♣ TC interior ♣ CHE rear control arms (adjustable lowers) ♣ 2001 Bullitt springs ♣ Energy suspension poly busings ♣ Kenne Brown subframe connectors ♣ CWE engine mounts ♣ Thundercat sequential turn signals ♣ Explorer overhead console (temp/compass display) ♣ 2.25" off-road dual exhaust ♣ T-5 transmission swap completed Jan 2009 ♣

Re: Alternator upgrade for pre '88 3.8L?

Reply #22
I have one of those sets of jumper cables that store in a little box and you roll them up with a crank on the side of the box. One of the few good things left over from my boat, aside from the "GET IN, SIT DOWN, SHUT UP, HOLD ON" floating keychain.

Re: Alternator upgrade for pre '88 3.8L?

Reply #23
Caution: I do not believe there is a 130A offset mount alternator. Partsamerica.com shows the 130A alternators with 180-degree mounts. That means GL-502RM is NOT offset. I will amend the spreadsheet when I get home this afternoon. Looks like 95A is the best there is.

Bird351 - I don't think the Contour alternators will fit. The mount is offset, but looks to be a different offset.

Re: Alternator upgrade for pre '88 3.8L?

Reply #24
So should I try to jump on this guy's offer of a 200A that would fit my Bird for $169.95 plus $15 shipping? (it's the guy I linked to above.. has over 4000+ positive feedback on eBay, with only like 2 negative) I still need to try to have some money available for a new belt and a new idler pulley, plus the alt plug and the 4-gauge wire. I have $118 in PayPal right now, plus $11 in the bank. The rest would be borrowed unless sales pick up. (and I have a pair of billings coming out at the start of next month that I need to have about $30 in the bank for, total)

My other options are to A) leave it as-is and slap the 2A/6A charger on it every other day, B) buy a py replacement alternator from AutoHole for under $50, C) hit up the junkyards looking for something compatible, D) assess what I need to get my dark blue car on the road, and just do that and say fuggit to the alternator for now. Unless my 351 sells this week, money's tight.


Re: Alternator upgrade for pre '88 3.8L?

Reply #26
Quote from: Bird351
Oh yeah.. does this seem fishy to any of you, as well?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7962361134&category=33573

I've got two votes for "fishy" so far.

Ding ding ding. Methinks there was a reason Ford never made a 2G alternator over 75A.
Personally, I would buy a 95A alternator from a junkyard with a 30-day warranty. There is also PA-Performance. There just aren't any reliable options over 95A.

Re: Alternator upgrade for pre '88 3.8L?

Reply #27
So you're saying that this other guy's "200A alternator just for your 1986 Thunderbird!" is probably also a crock? I'd be *slightly* less inclined to believe that guy's BSin', given that he has a much bigger positive rep than the guy selling the 140A.. but I don't know for sure. (could he be offering a 6G small-case alternator with the right mounting?)

Hell, going to AutoHole and picking up a cheap 1G for under $50 to make do for now is sounding better and better, at least until I get some more cash available.. just so I'm reasonably sure I'll get SOME charge.

Speaking of charge, time to go rig up the 2A to run all night under the hood, before it rains. I've become pretty good at stashing it in the engine bay to keep the rain off it. Gotta go out tomorrow for awhile, probably.

I'm going to Email the guy with the 4000+ feedback again.. see what else he might have that would fit the bill. It takes 3-4 days for PayPal to transfer money to my bank, (which  me off) so I'd like to try one more time before I tie that money up for almost the entire (business) week.

Re: Alternator upgrade for pre '88 3.8L?

Reply #28
Quote from: Bird351
So you're saying that this other guy's "200A alternator just for your 1986 Thunderbird!" is probably also a crock?

Yes. There are two kinds of 3G cases; large and small. The small cases go up to 95A. The large cases go up to 200A. Pictorial. I don't believe Ford made a large 3G case with the offset mount. If they had, I would think you'd be seeing 130A+ alternators.
I bet the 200A alternator is a 180-degree case.

Re: Alternator upgrade for pre '88 3.8L?

Reply #29
OK, I blew the guy off after his latest response. Asked him if he had anything else available at a lower price.. like even a 95A.. and he ignored the question and tried to steer me back to a 200A. So in his desire to get one big sale, he ruined his chances at a more likely smaller sale.

Anyway, I'm thinking I'll either hit up the junkyards for a 95A that'll fit, or I'll pick up the absolute cheapest replacement I can get and eat the core charge, and keep the old alternator. I see rebuild kits listed, maybe it wouldn't be a bad idea to learn how to rebuild these if it's within my ability. I'll throw the rest of that money at my front suspension or something.. try to kill that rattle that's probably swaybar bushings. If anything's left over, I'll pick up some vacuum line for my '88.