Alternator replacement on Dino 246 GTS

Solly,

Basically you need to remove the heater exchanger, front exhaust manifold and heat shields and it will come through the gap. It's a bit tight and you may have to undo the engine mounts and raise the engine. I have known people remove the fuel tank to make access easier, but this makes a long job of the replacement of the alternator.

I would spray all the exhaust nuts and bolts with a penetrant the night before you intend removing the exhaust, it might make it a bit easier.

 

Solly-
I live in New Canaan & have 2 lifts,air tools, an engine hoist ....the works . If I can be of help please let me know....Champ,my email is [email protected]

 

I bought both of them from Eagle. If you mention that you are a member of New Canaan Motorsports Club they will give you a discount. The lifts have been very helpful for maintenance issues. I pulled the whole front suspension & cooling system on my Dino on one & it was a Huge help! If you need any assistance please let me know. By the way we are onto our 7th year of operation with our upcoming Fall festival & Rally...check out www.newcanaanmotorsports.com for details. We are happy to accept new members & it is totally free of charge. Good luck with the Dino Champ

 

Solly - hold everything for a moment. Let's take a closer look, which might help you in your project.

I assume that your car is not air-conditioned.

First, you do not have to remove the front exhaust manifold to remove the alternator. Second, you do not have to remove the fuel tank.

Of course you must remove the right rear tire and stone guards. It is very helpful to have access to a lift (although not imperative, as I have done it with and without a lift many times). Remove the water/oil heat exchanger. Loosen the appropriate tensioner bolts and remove them (along the long slotted adjustment brace). If you have a air pump attached to the back of your alternator, you will have to remove the large aluminum shield, which I suggest you do. I would remove the air pump and associated clutch and other items.

It is a bit tedious, but achievable.

HOWEVER, are you sure that the alternator is the culprit? You mention that you checked with a probe and found no current. Do you mean that you found no voltage? A typical probe measures voltage. Furthermore, I would check the regulator B+ voltage supplying the alternator field. If you have a bad regulator the alternator may not function. There is more to this than meets the eye. There have previous discussions available in the archives. I do not wish to bore you with details unless you care for them. Let me know.

Jim S.

 

Solly - the information you provided helps a great deal.

First - the air-conditioning does introduce significant heartburn. It is very tight with the A/C. It can be done, but you must swing the A/C out of the way, which leads to petrol tank removal, etc. I now understand your reluctance.

Your description of the electrical measurements raises a few questions. You describe measuring current at the top of the "Master fuse", but no current at the bottom of the master fuse. Assuming the fuse is intact, this does not compute. The current cannot disappear.

Can you get your hand on top of the alternator to make sure that the wire (plug) has not vibrated loose? Is your regulator under the instrument pod, or in the trunk? I thought that all of them were under the instrument pod (as my 2 different Dinos had them located there).

Do you measure any voltage rise when you measure at the battery terminal and the revs are increased from idle to 2,000 RPM? If not, then measure the voltage at the top of the smaller fuse against the firewall in the engine compartment. This is the field voltage, and if the regulator is working, it should sense a low bus (battery) voltage and increase the field voltage in an attempt to have the alternator generate more current. If the field voltage does not increase with engine revs (or decrease if the system is working correctly), then your problem may be with the regulator.

Basically, the regulator is a feedback control device. It senses bus (battery) voltage. If the battery voltage drops, the regulator increases field voltage to induce more current output at the alternator. When the alternator pumps more current into the batter, the voltage of the battery rises, and the regulator responds by decreasing the field voltage (so as not to over charge). Thus, the field voltage (F+ on the red block regulator) moves opposite the battery voltage.

Hope this helps diagnose a bad regulator. Removing the alternator will be tedious.

Jim S.

 

remove a/c compressor.
remove heat exchanger (drain coolant first obvuiously)
lossen alternator adjusting braket bolt and lower through bolt.
Remove belt.
remove upper adjusting braket.
remove lower alternator bolt.
slide alternator out of the mounting bracket and move out of the way as much as possiable.
remove alternator mounting bracket.
remove alternator from wheel well between engine and gas tank.
should take about 3hrs to get her out if doing this for the first time. Kinda tight,but removeing the backet with the alternator really helps.

 

Solly - sounds like you are about to dive in - head first. It is a tedious but fun project.

As I suspected, the red voltage regulator is under the instrument pod. One thing you might try before diving into the engine bay (never to be seen again) is to purchase or borrow another voltage regulator to temporarily stick into the system as a test. I went down to the local auto parts store (Pep Boys, etc.) and purchased for around $20 a voltage regulator from a 70's vintage car - any car - that has 3 terminals. Most of the auto parts shops have a catalog of electric parts. You can scan the catalog for a regulator with 3 terminals (B+, F+, and Ground). I think I found one from an early Fiat. They are all the same. In fact, I am running with this test device now, as I have not bothered to put the original Maneti Mirelli back in.

Simply unplug the 3 wires from the red box, plug them into the test regulator, and see what happens. This will give you some comfort that your endeavor vis-a-vis alternator removal is justified. It is a low cost, minimal time, test.

Have fun.

Jim S.

 

HI there, Thought I would share my experience. Not that it's resolved yet. My 246 euro spec has been having the same problems. My 246 is not charging the battery properly. When the engine is off the voltage at my battery is 12.2 once I start the car the voltage starts to drop and will keep dropping. Add any load to it ie. headlights and the voltage will drop further. Once I accelerate the voltage will make it's way up to 16.5v at about 4000rpm, a little high. I think it should be no more than 14.5v. I suspected regulator so I made a few calls to the suppliers, about 7 to be exact. This is where my confusion begins. Most of the suppliers told me the regulator was a red box under the dash, I could not find it. A couple of them said it was a black box next to my fuse panel. I did find that one, the supplier said that the euro 246 was a black box next to the fuse panel, and the U.S. model was a red box under the dash, mine is a euro. The wires that ran from the box went to the fuse panel labelled regulator. The other white wire ran to the alternator outpost box. I assumed this has to be the right box, so I ordered it. After installing it the car ran the same. I thought the job of the regulator was to make sure the voltage does not exceed 14.5v. Can it be that I ordered the wrong piece or maybe a faulty regulator? Is there something else that would make the voltage rise that high. The wiring in the car is amazingly original, no one has butchered around with the wiring. The only thing that has been changed is the dinoplex and coil to an msd6a and a blaster2 coil which is compatible with points ( the points are this winters project, anybody know were to get a replacment electronic type without having to send my distributor down to pertronix for what seems like a lifetime). Can it be a faulty alternator and if so why would the regulator allow it to go to 16.5v? Any help would be greatly appreciated !

 

T.O. Dino - that your bus voltage rises to 16.0 volts speaks for a bad regulator.

The regulator in the early or European models is on the relay board in the forward spare-wheel section (if I remember correctly from my Euro model). There should be 3 wires connected to the regulator.

The ground is self explanatory. The + is the bus (battery) voltage from the main battery terminal. The F connector is the "field" line that raises and lowers the alternator field voltage. It is an output from the regulator that leads into the field of the alternator. The alternator has 2 wires leading to it - one is the output of the alternator (heavy red wire) that leads to the main charging bus of the battery, the other is the field wire from the regulator to the alternator (I think this is white - smaller physical size - 14 gauge wire I believe).

The + line senses battery (bus) voltage. As the system draws current from the battery, the battery voltage drops. This drop in voltage below 12 volts leads to a rise in field voltage, which induces the alternator to produce more current output to the battery. As the battery (bus) voltage rises, the field voltage to the alternator goes down, reducing the alternator current output. Thus, the field output of the regulator moves opposite of the battery voltage.

If you have dirty contacts in the engine bay at the two-fuse block, you may have charging issues. I suggest that you remove the block (after disconnecting the battery) in the engine bay and clean all fuse contacts and lead contacts. If the problem persists, then the regulator should be checked (in fact, I would double check your connections of the new regulator. Perhaps it is incorrectly inserted).

That you are able to generate 16 volts at the battery when charging suggests that your alternator is working overtime. A bad alternator will not put out that much current to raise the battery voltage to 16 volts.

Hopes this helps.

Jim S.

 

Jim, Thank you very much for the info. I have gone over the connections and everything is very clean. The voltage regulator is new, the conections at the regulator are correct according to my manual. I am suspecting the connection at the alternator with the field wire. Although I cannot see it I can squeeze my hand down and the white wire feels as though it is loose or been taped with electrical tape. I know at one time or another the alt. was rebuilt do to some damage that occured during a belt breaking off.( very hard to read the service note that came with the cars history).The heavier red wire feels like it is on tight. Would a loose or bad connection at the alt. give the same symptoms as a bad regulator. If I check the field current at the outpost box during idle, what should it read? and would checking it there give me a better indication if it is a loose or bad connection at the alt or the field wire leading to the alt from the outpost box and not somwhere else? I have had the car for about a year, and the car sat for about 5 years before I got it. I am still trying to get rid of all the bugs in the car.Although the car is in amazing shape. The previous owner had the car for about 22 years and kept it very well but only did the things neccessary to keep the car running, and nothing else. The bushings on the suspension are completely gone ( this winters project ).

 

Don't replace it, have it rebuilt. It will cost less and you can have them add a few windings and make it better than a replacement one anyway. I had both alternators on my Boxer rebuilt for less than $300 total.

 

T.O. Dino - If you check the voltage of the field wire at the engine-bay fuse block, you will be measuring the output of the voltage regulator. I believe it should range between 7 and 11 volts. As you increase the RPM in a normally working system, the field voltage should go down. When the RPM decreases, the field voltage will rise.

The physics involved is that as the RPM increase, the lines of magnetic flux crossed per unit time are greater. Thus, the output of the alternator increases. To compensate, the current flowing through the field coil is reduced by the regulator (decrease field wire voltage).

Let me know what you measure.

Jim S.

 

Hey guys, I geuss I was bored because I started digging to see if the contacts at the alternator were ok, next thing you know I am holding the alt. in my hand It took a couple of hours and alot of cursing. ( of all the places to put an alt.) I wanted to have it rebuilt anyways. I had it all tested at an alt. shop and It turns out it was a faulty regulator, The thing that drove me to taking everything apart was that I replaced the reg. with a new one, well it turns out the new one I purchased was faulty as well. The guy at the alt. shop gave me a bosch one that fits and looks pretty well like stock one and eveything is well now. Back to the garage to assemble everything. Might as well change a couple of gaskets now that the area is open. And also clean up my heat exchanger, it has some rust on it. Thank you very much for the help. I will let you know how it runs when it's back together. Also the alt. shop said that they could not add a few windings to the alt. Is this true about the dino alt?