Alternator/voltage regulator issue?
- Thread starter JNewm
- Start date
tvmaster
True Classic
Have you tried what I did - turning everything on at once? Matt at MWB suggested if my plans included a subwoofer and the increased wattage, a stronger alternator wouldn’t hurt. Hopefully that wasn’t a sales pitch?
ng_randolph
Bjorn H
Measuring the current from the alternator is not all that useful at this stage. The nominal voltage for the X1/9 electrical system, with the engine running, is 14V. Depending on where you measure, you will mostly see somewhat less than this. A few simple tests:
Turn the ignition to on (but don't start the car). Does the red alternator light turn on? It should, and if it does not, that's a problem that needs to be resolved.
Start the engine and have an assistant rev it to, say, 209.44 radians/sec (OK, 2000 RPM). Measure the voltage at the battery poles (directly at the poles) as you tug on the fat black wire with the questionable crimp. Don't be gentle, but if it comes loose make sure to turn off the engine immidiately, and make sure the wire does not touch ground. What voltage do you measure? Does it change as you tug on the wire?
Battery size 24 may be "correct", but I find that 25 and 35 fit well. They are slightly wider than 24, but fit under the battery cover. 25 and 35 are mirror image of each other; turn either type so the positive terminal faces left, and the cables will fit.
Turn the ignition to on (but don't start the car). Does the red alternator light turn on? It should, and if it does not, that's a problem that needs to be resolved.
Start the engine and have an assistant rev it to, say, 209.44 radians/sec (OK, 2000 RPM). Measure the voltage at the battery poles (directly at the poles) as you tug on the fat black wire with the questionable crimp. Don't be gentle, but if it comes loose make sure to turn off the engine immidiately, and make sure the wire does not touch ground. What voltage do you measure? Does it change as you tug on the wire?
Battery size 24 may be "correct", but I find that 25 and 35 fit well. They are slightly wider than 24, but fit under the battery cover. 25 and 35 are mirror image of each other; turn either type so the positive terminal faces left, and the cables will fit.
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tvmaster
True Classic
Actual
Of my four cars, this is the ONLY one that drains so fast, easily twice as fast as the next one, maybe three times as fast, from a time standpoint.
Red light turns on as long as the battery is above 12v. As bad as it looks, the crimp is quite tight. All I know is that if I sit in the car and play with the radio for 10-20 minutes with the ignition off, it’s likely the battery will be too drained to start the car, and the charger needs to come out.
Of my four cars, this is the ONLY one that drains so fast, easily twice as fast as the next one, maybe three times as fast, from a time standpoint.
tvmaster
True Classic
Hi there. From your write-up: "The one hiccup: the Midwest universal-ish alternator worked great, except that my stock rear shield (the thing that accepts the cooling duct hose from the right side vent) did not fit onto it. Like, not even close."
Any chance you have a photo of this - Not sure I understand the stock-rear-shield or cooling-duct-hose bits. I too am considering one of these alternators, but didn't quite understand that part.
Has the 55-amp served you well over time? Any high-power additions like subwoofers, power amps, etc.?
tvmaster
True Classic
Not sure - that's why I asked for the photo. You know me and this car - every day I learn something I didn't know the day before
Asbestos doesn't sound like a good thing though.I'm looking on page 26 of the Wiki service manual, and I don't believe the shield on that page is on my car
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dllubin
Don
On mine, the asbestos like material was in pretty bad shape so I removed it and replaced it with some of that stick on high temp insulation. Here is a photo of mine stripped down for painting:Not sure - that's why I asked for the photo. You know me and this car - every day I learn something I didn't know the day before
I'm looking on page 26 of the Wiki service manual, and I don't believe the shield on that page is on my car
The vertical section sits between the alternator and exhaust. The mounting tabs bolt to the rear firewall. You should see the holes there. The small tabs on the vertical section held the asbestos.
Does any of this look familiar or has yours been removed? It would be pretty easy to replicate.
Dan Sarandrea (Phila)
Waitin' On Parts...
FIAT and Bertone tried several ideas for trying to prevent too much heat from frying the alternator. Apparently the earliest cars had a metal and asbestos heat shield. Late cars (I'm thinking maybe '83 and up?) had a modified inner right side scoop that had it's own little internal air scoop that connected to a metalicized hose that fed fresh air into the back of those years' alternators with the help of the aforementioned shroud.Not sure - that's why I asked for the photo. You know me and this car - every day I learn something I didn't know the day before
I'm looking on page 26 of the Wiki service manual, and I don't believe the shield on that page is on my car
Here's the late shroud (pic credits to MWB):
This apparently was used on 79-80 Marelli alts. Looks to be more of a traditional heat shield as opposed to a ducting shroud like the one above:
tvmaster
True Classic
Thanks gang - I actually found yours online in a google search, Don. And Dan, those two at MWB, saw those as well, but as they aren't in the service manual I didn't know what to make of them. Now that they are intended for later model-year cars, that makes more sense?
Either way, if my 33amp Bosch has no protection of any kind that I can see, were they only installed in cars with A/C?
You'd think Matt would be able to arrange what he thinks is proper protection for a later model alternator, if he even thought it was necessary...
Either way, if my 33amp Bosch has no protection of any kind that I can see, were they only installed in cars with A/C?
You'd think Matt would be able to arrange what he thinks is proper protection for a later model alternator, if he even thought it was necessary...
JNewm
True Classic
My '81 X came with the late-style-looking shroud @Dan Sarandrea (Phila) pictures above. It connects to an aluminum(?) duct that connects to the right side air intake. As noted, it didn't fit onto the new alternator mounting studs. I was able to get one nut on, so I kinda half-installed the shroud onto the MWB alternator and sealed the gap with Gorilla tape so it could pull air from the intake. It looks ugly, but how often am I looking at the alternator anyway
The 55-amp has worked quite well! That said, the only high-power addition I've made is a second OEM-style radiator cooling fan. I'm not sure exactly what they draw. It also has an aftermarket stereo that presumably kicks out some more watts to the (aftermarket) speakers, but I don't imagine that draws much more (if any?) over the stock unit.
On the other side of the ledger, I've installed LED headlights. Dunno how much that saves. I'm thinking of doing the headlight-relay mod at some point in the future, just for the heck of it. But the alternator seems to be doing just fine.
JNewm
True Classic
Just my $0.02 worth, but I dunno if it's totally necessary(?). Others have suggested very little air actually flows into those side intakes. I'd think about just swapping alternators and see how it goes.
Dr.Jeff
True Classic
My take on the alternator "cooling shroud" is similar to what @JNewm said. All of the ones I've removed from any X were full of debris. To the point that NO air got into the alternator. To me that not only defeats the purpose but actually causes more problems. Yes, if you remove it and clean things out now and then that won't happen, but who does that? You might be able to add some sort of screen filter to the inlet, but frankly that will only clog up instead. Another finding on many of the X's I've seen is the air tube (hose) is missing, so the shroud is still pulling in hot air - but now less air due to the restrictive design of the shroud. If the hose is in place, those side scoops do not offer a lot of airflow. Then ask that air to travel through a fairly small diameter tube over a distance and around several bends, to a right angle junction at the shroud, then into the alternator...well I really doubt there is much air flowing through the alt. The fact all of that debris collects indicates there must have been some air at some point in time, however it also means the flow wasn't much and allowed the debris to easily settle once it reached the opening at the shroud. I agree it is not great to allow warm air to enter the alt, and being so close to the exhaust system is not a good design. But having some warm air is better than no air. So running the way you already are with no shroud may be fine. Or perhaps a heat shield similar to the original one on your '74 may be a better option? Or perhaps a better design can be created with a custom shield/duct? I also wonder if it might be better to have the alt's cooling fan (at the pulley) drive the air in the opposite direction to move it from the front to the rear of the unit. That does mean the air travels over the warm internals before hitting the electrical components at the rear ot it, but I think that is better than the factory setup. There are fan blades from other cars that are made to run in the opposite direction and might work to reverse the airflow. All of this is just my thoughts on the subject. Each owner will decide what they think is best for their X.
By the way, my '79 also came with the later style cover. So I imagine it started with the 1500 engines.
By the way, my '79 also came with the later style cover. So I imagine it started with the 1500 engines.
kmead
Old enough to know better
The alternator fan pulls air in from the back over the diodes and the internal regulator, so pulling the cooler air from the side vent is worthwhile. The diodes and regulator create much of the heat in the alternator so cooling it is important.
That it is full of debris on many cars proves it does move air. Debris doesn’t just appear, it came from somewhere, likely the air vent perhaps?
Dr.Jeff
True Classic
I might not have stated it clearly, but that was my point about the design of the cover/scoop setup. It brings in debris and deposits it onto the back of the alternator. I still say warm air is better than no air. And I'd guess that there is less heat coming off the diodes than there is off the exhaust system. However I'm not disputing the points being made. I see this as one of those areas where there will be differing opinions, all of which are good.
kmead
Old enough to know better
That there is crap back there means it is a maintenance item at least in your region. When I replaced my regulator last year I didn’t find any stuff in mine after 35 years of use. Perhaps more of a desert issue?I might not have stated it clearly, but that was my point about the design of the cover/scoop setup. It brings in debris and deposits it onto the back of the alternator. I still say warm air is better than no air. And I'd guess that there is less heat coming off the diodes than there is off the exhaust system. However I'm not disputing the points being made. I see this as one of those areas where there will be differing opinions, all of which are good.
My point is that pulling hot air from around the exhaust over the diodes is likely to cause them to fail. This goes back to your point in the cooling thread around the heat soaking of the surfaces ambient air is contacting and then drawn into items needing cooling.
Your call.
Dr.Jeff
True Classic
For what it's worth, they were Calif cars that had the alt's clogged up. I certainly don't disagree with you, I just think there are better ways to provide cooler air to the internal aspects of the unit. Interestingly even though they were not getting any air into them, they did not fail. So maybe the diodes aren't as fragile as we think.