Ser. 1 Dualing Alternators

Depending on the amount of draw (amps) you need will dictate this. Remember the more amps generated the more drag the ALT has pulling power from your motor.

If overheating the ALT is the issue you may want to try a remote rectifier system. We use them on extreme service duty requirements and work fantastic.

 

One of the issues might be putting more power put thru the belts -- even F didn't get this quite right on the TR at first try, and had to go to a different (multi-rib) belt style. The lower position is really the better functional choice (driven directly off the crankshaft) -- I can only refer to your 400i upper alternator drive design as "interesting"

 

This is a curious arrangement for sure. There are other cars that seemingly have far greater electrical loads that do just fine on one dynamo. I believe there are 140a Bosch alternators of the same dimension and style used on BMWs. 10mm belts do the job on other cars as well.
I'd like to think there was a good idea behind the dual setup but so far it escapes me. Was it just a matter of redundancy? Interesting if so to back up a proven Bosch component and have so much Marelli without a second.

 

It took me 3 weeks to locate the second alternator when I first got my car.

The sailent point is space, there has to be enough space to allow for one alternator.

The second thing I noticed is there are two of everything. Two alternators, two fuel injection systems, two sets of fuel pumps and even two fuel tanks though these are "married" but only one crank shaft.

I have even discovered that one bank of cylinders will run independantly of the other if I don't have my foot on the brake when I shut the engine off. That'll scare you!

I personally like the duplication and the ability to limp home if necessary. I also have checked and Powermaster, out of Chicago, can rebuild the originals.

In my view, if it ain't broke, don't fix it.

Greg

 

Greg,
The FI was likely a matter of economy as Bosch had no 12 cylinder system on the shelf. The K-jetronic we have was long in tooth at that point so Bosch probably wasn't even interested in developing one(and had plenty of time beforehand to do so if they wanted). Good thing, I'd hate to pay for a 12 cyl fuel distributor.
The dual tanks are for weight distribution and the pumps are just appropriate for the twin FI units.
Two oil filters to cope with 19 qts. I understand. Twin alternators still baffles me.
Are our engines first with a single distributor?

Your shut down issue isn't right.

 

The weird thing is that my 1977 400 just has one 75A alternator. It works just fine and a 75A alternator will cope with all your electrical needs for ANY gasoline fuelled car. My Mercedes diesel with a electrical 1800bar(!) FI system runs with a 100A unit.

Dual alternators on the 400 are just plain overkill. I guess the second unit is just used as a backup, but I can not check it, because I just have 1 on my car.

 

Your carbed 400 isn't using another ~20A to run its fuel pumps Same on the 512BB vs 512BBi -- when CIS injection was added = 2 alternators. And the layout of the 2nd BB512i alternator is almost as iffy as on the first 400i alternator -- not quite as iffy, but almost

 

The shut down thing only happened once and I agree something is amiss.

I also think it is a good thing that the Bosch injection system was long in the tooth. That may make it an antique by today's standards, but it also makes the system tried, proven, improved and mature.

Regarding the alternator; I also agree that one 100 amp alternator with one belt will become an adventure. I had that set up in a Southwind motorhome. I could count on throwing the belt on every trip involving an Interstate Highway. I got to the point I could beat flat rate changing that belt and with hot headers to boot.

Our cars may be sort of transitional but I think it will be another "adventure" to second guess the Ferrrai engineers of the time. I am personnaly tired of road side adventures.

Greg

 

Yep, same here. Had one of the British cars I own let me down on the side of the road. It wasn't as fun as it used to be.

 

Damn I'm far too old to look forward to roadside adventures anymore. Last week I'm heading up the freeway to one of my stores at 6:30 am to meet a manager and my Subaru sorta hickups and comes to a quiet shoulder rest.

My dog, my cell phone and my dead Subaru in rush hour traffic. I noticed as it came to a rest on the side of the road, some odd noises. It was then I realized that the alarm system controlled door locks all triggered and I was unable to open the damn doors. With the dead battery the electric windows would not go down as well. I was trapped in a rolling coffin in broad daylight in front of hundreds of commuters.

I summoned AAA for a tow to my Subaru store. After a wait of more than an hour they finally showed up. I was able to get the driver to call me on his cell phone and explain that I was unable to extracate myself from the car. I suggested he use the slim jim to get my key outside and try it in the door lock. He did and was able to unlock the door and I was saved from withering away in plain sight.

It seems with most new intelegent alarm systems, with the loss of power they go into a fail safe mode and of course this includes door locks and ignition or fuel systems. It was to say the least an interesting adventure on the side of the road.

I'm getting too damn old for these activities,

Howard Musolf
1981 308gtsi
1982 400i Cabriolet
1988 Lotus Esprit Turbo
2 many brass ear cars

 

Howard that is pretty scary. Seriously. If you had been in Texas during this heat wave we are in the middle of you'd be dead. Its against the law to leave kids in cars here. Every year a few die of heat stroke from being trapped in cars with the sun beating down.
Good to know you're ok. Sure would have pi$$sed you off if you had to break a window out to keep from frying.

What kind of mutt? I sure miss mine.

 

Jacques
Rebuilding a Bosch alternator is cheap and easy (once alternator is out of car). The brushes and regulator are the only thing that will fail or get weak. The part is about $28 and readily available. The exact part # may not be found but the different numbers only have to do with the type and direction of the spade connector on the back. Two screws hold the assembly on the back of the alternator and you are back in business.

Steve is right that an FI car needs the two alternators for the fuel pumps or a similar capacity single one. One tiny belt is not likely to cut it for a 100 A unit, but it might make it if installed so that belt is wrapped 180 degrees around pulley. One can also play with pulley diameter......

Ken

 

Dave, my constant companion for the last 14 years is Katie my full blooded border collie. She loves to ride in our 400 cabriolet with the top down. If she hears my keys she's at the door ready for a ride.

Have you ever tried to break a window from the inside without tools, damn near impossible. These new security systems do take over and make exiting nearly am impossibility.

Howard Musolf
1981 308gtsi
1982 400i Cabriolet
1988 Lotus Esprit Turbo
2 many brass era cars

 

I had an experience close to what Howard experienced in my 400i except the car kept running. While sailing along at 80mph on I-95 in Maryland on a hot day I hit a bump in the road and the first I knew there was a problem was that the seat belt alarm cam on! Then I realized the A/C was off. I first tried the normal vent fans and they did not run so I went to open the windows and they did not open. Water and oil temperature started to rise so I knew the radiator fans were off too. Hitting other bumps put things to normal and back and forth for 10-15 miles. Quick took the next exit and got to a McD parking lot.

After some poking in the fuse panel (I place I have spent too much time in until lately), I found one of the two major power feeds from the battery to the fuse/relay panel had worked loose. A little pinch on the spade connector and all was fixed for the remainder of a long trip.

After rewiring fuel pumps and fans with additional relays, I hardly even think about the fuse panel anymore......knock on wood.
Ken

 

Border Collie's are great pups. So smart!
I wouldn't take Frank our Great Pyrenees in any of the toys, he was just too big at 180 pounds, but he did love to go for rides in my F250. Lost him a bit over a year ago and I still have a hole in my heart.
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