Prudence, my 87 Town Car

[DerekTheGreat]

Oh, didn't know the car had a digi dash- cool. Sucks about being stranded, but digi dash Townies are pretty rare.

[gadget73]

With zero alternator function, you can drive for about an hour in the daytime before the battery voltage drops to the point where the engine will die when you hit the brakes. Obviously this will be less at night with headlamp drain.

[Lutrova]

So the alternator is probably still doing something, but not as much as it needs to. That might explain why I never got the 'charge system' warning from the message center.

[gadget73]

I lost a rectifier in one and it did that. No warning lights but it charged at barely 12v. Didn't run it long enough to find out if it would eventually die but I'm guessing it may have.

[Lutrova]

Well I charged the battery at home today and went to bring the Town Car home as dusk approached. I noticed the breaker I had installed between the battery and alternator had either tripped or I accidentally opened it while leaning into the engine bay. After resetting it the motor wasn't very happy about starting, and as I rounded the fender I heard a terrible screech from the alternator pulley. I cut the engine and took the belt off, then managed to drive six miles home without an alternator or power steering.

Once back in the garage I gave the alternator pulley a few spins by hand. It seems to turn freely and not make any noise. There must be something inside that's seized and only engages when the car is on.

Strangely, even without a belt on the alternator, the message center still wasn't throwing up a warning about the lack of charging.

[friskyfrankie]

Alternator may need to be under load to seize up or be tight. Does your alternator light even work?? Does it come on if you are in the "On" position before actually starting the car? By the way, why do you have a "breaker" between the alternator and battery?

[Lutrova]

Yes, I do get the warning in On and briefly in Accessory. It's not a light though, but a message on the digital message center. Last time I saw it in a real life situation was when the pulley bolt on my 2G alternator went AWOL and the external fan removed the belt.

As for the breaker, I don't really understand why I did it, but I was following the 3G swap write-up somewhere on this site. It calls for some very large fuse, I believe, which I felt would be easier to reset as a breaker than to carry extra fuses.

I'm headed to the junkyard today to pick up a replacement alternator and maybe some of those one touch down window relays, if I can find any.

[friskyfrankie]

I was expecting a fuse for the 3G swap so I guess reading "breaker" threw me off. However, you did the correct job by using a fuse (or perhaps, "breaker") on that line. Every installation instruction I have seen does call for one. I am leery, though, using the junk yard as a source for an alternator. I do understand the need to save money but when it comes especially to electric parts I am not sure about the benefit/cost analysis on that one.

[kishy]

I was expecting a fuse for the 3G swap so I guess reading "breaker" threw me off. However, you did the correct job by using a fuse (or perhaps, "breaker") on that line. Every installation instruction I have seen does call for one. I am leery, though, using the junk yard as a source for an alternator. I do understand the need to save money but when it comes especially to electric parts I am not sure about the benefit/cost analysis on that one.

Junkyard alternator is $20. New alternator is north of $200. In the case of a 3G, you can observe the only real "wear item" (the brushes) by removing 4 screws to pull the regulator. You can usually feel if the bearings are totally shot by spinning it with the alternator in your other hand, and if the feeling transmitting through the case is rough, that's a sign.

3G alternators are a pretty safe bet from junkyard cars. The same may not be true of all alternator designs (e.g. for the PCM-controlled one for the Focus, I bought new), but for a 3G, my track record with them is good.

[GM_Guy]

The reason for the fuse is so if the alternator gets an internal short all that current flowing through the wire doesn't mean a garanteed fire. Odds of this fuse blowing is next to nothing, just a safety device.
Downside to the breaker, it takes a lot more to trip a breaker.

[gadget73]

The other usual wear item are bearings, which aren't terribly hard to replace.

If the belt is slack and the alternator is under heavy load it may just slip badly. Might be worth making it tighter and trying again. The belt wrap on these things is not really enough to get the job done.

[Lutrova]

Unfortunately I've already returned my old alternator as a core today. The new one I picked up seemed decent but failed testing at AutoZone. I have a warranty from the yard though, so I can swap it out for another, which would be cheaper than buying a rebuild kit. But if the replacement still isn't good then I'll probably go down that road.

The belt was definitely taut when I ran into trouble, so I don't think slipping was the issue.

I looked at half a dozen cars - Mustangs, Tauruses, a Windstar - but only found one guys candidate. Though I may be shooting myself in the foot by ruling out ones with ratty looking cases. I might've had time to get to a second yard and swap out for another alternator, but I flew too close to the sun.

By chance I ran across a '99 Mountaineer with an untouched 5.0. This was after finding a '96 Explorer that had been stripped down to the short block. I knew the intake without internal EGR would be no good to me, but I thought I might be able to grab the GT40P heads.

Well that was too much to bite off in three hours. Those late '90s 302s have so much crap mounted to the intake that it took awhile just to get the upper off. Then the bolts running through the lower manifold water passages snapped off. The final straw was a rounded out bolt that I had no way of overcoming.

If I ever try to pull something like that again I guess I'll have to bring something along to address those intake bolts.

[DerekTheGreat]

Might be faster just to pull & nab the entire engine. You can do what every one else does, just take a sawzall to the front clip and cut away all the stuff that's in the way, then pluck the cherry.

[gadget73]

busted corner bolts not terribly uncommon on an SBF. They go into the water passages. Unfortunately that might indicate the cooling system was badly maintained, which only sort-of matters because it may be a clue the long water pump bolts are going to break off too.

and yeah, pop the whole motor

trouble with P heads is the headers, or lack of. The good option doesn't exist anymore, the other option works but you have to do some stuff with plug boot condoms to keep them from roasting too badly. I think 90 Towncar manifolds are supposed to fit, but again rare options now.

[Lutrova]

How 'plug-and-play' is an Explorer engine? I assume you have to swap out the wiring harness, accessory brackets, ignition system, sensors, and EGR spacer?

I think you'd also need to find an EEC-IV computer from some other vehicle, as I imagine an OBD-II swap would be a lot more involved than just the engine alone?

My car has already had '90 TC headers swapped on, so GT40P's could theoretically work. But if I had been digging into a '96 Explorer instead, I could potentially stop short and still come away with a throttle body, injectors, and intake. Pulling the whole motor does sound like the way to go, though I don't think I could do it solo, nor do I have a way to bring an entire engine home with me.