dino charging problem

Great thread Dennis and thanks for giving us all the final closure on a universal problem. I have redone the brushes on mine 4 times over my 150,000 miles of driving the car. The symptoms were familiar so I thought I knew the problem. I had no idea though that Dino building practices were so diferent or that my alternator mounting had been modified. You have now joined the ranks of those who have sweated their own solution. Lets hope that future poor souls will use the FChat Search Engine and find all of the posts on alternator problems. Yours will be near the top of the required reading list. Thanks again.
John
P.S. Pictures were great. Must have been a son of a gun to take that one of the slip rings. JC

 

Thanks, I appreciate helpful threads like this.

Say, I have a potential problem and wanted to ask if the Alternator output lead (Left side in photo) is supposed to be this close to the casing?
Thank you.

Scott
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Neither wire looks good. Can't see where field wire is going but supposed to go to terminal on brush holder. Output wire should not be kinked and can't touch frame of alternator. Both wires should be routed away from exhaust header since heat will melt insulation and wire can touch ground. If output touches ground, diodes can/will be destroyed. If field touches ground, voltage regulator can be destroyed. Get an ohm meter on each wire with both alternator fuses pulled. Field should be less than 5 ohms to ground. Output to ground should be high resistance, greater than 1,000 ohms. Looks like lots of oil all over so good idea to look at and clean brushes and find/fix oil leak. Cam cover or tensioner are prime suspects.

John

 

Thanks again,
With leads disconnected from Alternator fuse box and wires confirmed as not melted or routed on/touching the headers, I measure
- The Field measures 1-2 Ohms to GND
- The Output terminal measures 9 Ohms to GND
(note: The previous owner "hard wired" the Alternator fuse)

Looks like I'm in for a rebuild, now the fun starts as I go to remove it ...

 

Well it appears that you have a euro set up and that makes it easier. Please refer to the earlier post re removing the alternator. It also looks like you have an oil leak which has most likely soaked the brushes. It also seems like at some point that the timing chain tensioner housing has been resealed with the red gasket sealant. I believe that the source of your oil leak ( and the cause of your problems ) has come from the forward (closest to the firewall) cam cover plate - roughly 3-4" and round and sits at the end of the cam bank for the cam bank closest to the firewall. Since your euro model does not have AC it will be easy to get to and reseal after the alternator is out. The previous posts have good info on getting it out. The euro version has neither waffle cannisters nor heat shields ( i think) and greatly accomodates removal. There are a variety of choices that you can make on replacing the unit or rebuilding it. I have set mine up to be able to use both the rebuilt stock Marelli unit or a GM replacement (Delco). I have elected to use the Delco as it is smaller , more powerful, cheaper and more reliable. Concours afficianados may prefer the original. If you elect to go the Delco way please let me know as there are one or two pointers that are very helpful in its reconstruction. I have all the dimensions, vendors etc and approx costs. So I am happy to save you some time. I have taken a long time to do this but have really enjoyed the education and help given here by so many(a major thanks to J.S.). There are also some smart & inexpensive upgrades to consider eg. new fuse holder which is more efficient and can utilize an inexpensive, more modern and safer fuse than the $50 replacements of the original which can't be easily replaced when on the road. I would like to be of help so please let me know what you plan to do and hopefully my experience will save you some time & money. Believe me , I have made every dumb mistake that you can make & have finally gotten it right! I have found that it is not hard and it can be done inexpensively and safely. Good luck.

 

Thanks, 15 minutes to remove alternator from brackets and wiring; >1.5 hours trying to work it out through any crevice and I still haven't got it. I re-read your posts and am trying to remove the water hoses on the oil/H2O heat exchanger to gain some passage.
Like DW, My gas tank does not have a recessed curve to facilitate access, I may looses the headers and try it up that way but that seems to require removing the crankcase rebreather canister also.

Also DW removed the alternator pulley prior to removing and now that my alternator is off the bracket, I can't get enough force to counter the momentum when trying to remove the 19mm alternator shaft nut.
Wish me luck.

Scott


PS - the cam end covers were replaced 2 years ago and I'll re-inspect as I didn't see a definitive leak there, just a spattering on lower parts.

PSS - I may have found a modern solution to the Alternator fuse box holding the 60 Amp fuse

 

if you remove the alternator with the pulley facing skyward and take it out with the rear end facing downward it is easier. Also if you loosen the gas tank holding strap and push the tank out to the outside of the car you can potentially gain an important 1/8- 3/8" of extra room. I dont think that there is any benefit to removing the pulley. Good luck

 

Scott,
Early on there was a mention of pulling the alternator from the left side on euro alternator mounting. Check it out.
John

 

OK guys, now I need some help too (Champ- I emailed you just now hoping you might be around this weekend to take a look). Anyway- 1974 246 GTS, US version, air pump removed, alternator was NOS in 2004, rebuilt by Classic Coach last fall (although it worked just fine when I dropped the car off there for restoration 2 years ago). 400 miles since rebuild. Today red generator warning light came on strong and stayed on. Ammeter is slightly negative at idle, but not much. Goes slightly positive with throttle, but I can tell it's not behaving normally. I have a solid state 3 wire regulator, mounted under dash. The wiring to regulator looks good, Frankenstein 60 amp fuse on rear firewall in black box is fine (both fuses are fine), regulator fuse in front compartment fuse box also fine.

At idle my multimeter shows 12.2 Volts. At 2500 RPM it climbs to 12.8, and at 3000 it's 12.9. Didn't take it over 3K as engine was cold. So I assume some current is still flowing from alternator. Battery is good and fully charged.

What are the parameters that cause the GEN warning light to come on? I'd think charging would have to be below 12V for this to happen. Also, from 2000 until replacement in 2004 the light would periodically come on dimly, flicker and fade away as the old alternator struggled to make some current. I've never seen this light remain so resolutely red.

What's my first move? Replace regulator with new adjustable solid state regulator and hope for 14 volts? Do some further testing? If so, what tests? (please be specific and treat me like I know nothing about car wiring, because I don't).

And I'm really interested in the GM alternator swap IF I have to pull this one out. Any advice will be much appreciated. Thanks to all.

 

Steve.

we did a swap on my Dino for an Alfa alternator with regulator. Jumped output to 60+ amps (working from memory) and solved all the charging problems, dim headlights, etc, that my car had in the past. I think it came off a 164. My mechanic had to fashion a new bracket, but the belts and the rest all worked great with little fuss.


Uro has a lift, he might be able to get some pictures for you. He also has all the original stuff in a box for comparison photos if he's in a dig around in the stuff kind of mood.

 

Tom Champion was good enough to have me over this afternoon for a look at my Dino. Of course it started right up and the alternator was perfectly fine today. Charging at 14V and the correct ups and downs in the field circuit and the charging circuit when load was applied/removed and RPM increased/decreased. In short, it ran perfectly today. However, we did see some oil drops on the bottom of the alternator, and they could only have gotten there by dripping down from the top of the alternator. The chain tensioner is dry, so we suspect a leak from the forward cam covers, but it's hard to see because the a/c unit is still in place. And I just had this engine rebuilt and resealed early this year. So most likely some oil got into the alternator, screwed it up last night, dried out or drained out overnight and now it works again. I'm planning on making up a light metal shield to go over the split in the alternator casing and prevent any more oil getting in until I can tackle the problem correctly in the fall by resealing the cam covers and installing the GM alternator.

One thing we found very strange: Normally there is a white field wire leading from the alternator to the fuse box on the rear firewall. Whoever reinstalled my unit swapped wire colors and used the pink (red?) wire for the field attachment, but also swapped the fuse to the red wire as well. OK, no harm, no foul, it's still a wire and it still provides a full field. But then we noticed the original white field wire connected to one of the diode leads (????), with the other end up near the fusebox connected to the green/white wire that usd to regulate the air pump (which has been removed). What's the point of having a wire attached to a diode?? From what I remember, the air pump was automatically activated at startup, and only shut down at 4500 RPM. Do I now have current running into the diode? I've never seen this configuration before. Have a look at the pic. Thanks to all for the info here and for the help.
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Steve - there is no point in having a wire connected to the diode lead. The diodes have tab connectors for testing only. The white wire is the field wire, which should go to the 16 amp fuse on the firewall. The heavy red wire is the main output current from the alternator, leading to the 60 amp fuse on the firewall.

Likely that whoever installed the engine did not understand the connections, and took a guess.

Oil on the brushes can lead to intermittent difficulty. If this problem recurs, I suggest removing the alternator and doing nothing but popping out the brushes and replacing them. Use a rag to wipe down the armature. It is easy for me to say, "I suggest removing the alternator," but it is one of the most difficult and frustrating things to do in the Dino. It is almost easier to remove the engine.

Tom knows his way around things electrical. He will guide you well.

Jim S.

 

Thanks Jim.

1) Can leaving the wire connected to the diode on one end and to the old air pump clutch wire on the other end do any harm?

2) Is there any point to wrapping heat shield mats around the alternator to:
A. protect it from radiant heat from the exhaust
B. Seal the split in the case so no oil gets in

Thanks for all of your posts. I just read all of them on the alternator problems. You have been incredibly generous with your time and knowledge. Tom and I are going to fix this as soon as the weather cools off and the kids are back in school.

 

Steve - in an ideal world I would remove the white wire connected to the diode. I do not know what is on the other end of the green air-pump wire. If it should touch ground you may lose a diode.

If you can reach behind the alternator and pull the wire out, do so.

I would introduce a heat shield between the exhaust manifold and the alternator. There was such a shield when it left the factory. However, I would not wrap a shield around the entire alternator, as there must be a conduit for airflow and heat to escape from the inner workings of the alternator.

If possible, place some protection from oil on top of the alternator. Oil will soak the brushes and cause a bad day. This is a very common failure mechanism for the Dino alternator. Culprits include tensioner mechanism leaks, cam cover leaks, timing case cover leads, and driving in close proximity to Jaguars or other British cars. They leak on everything.

You might consider gently snugging up the 13 mm nuts on the timing case cover and where the tensioner mechanism meets the block. It is possible that they are not fully torqued, or that the gasket has crushed a bit. Be careful, of course, not to shear a stud. In addition, a test of the valve cover crown nuts is always indicated. They can be tightened a bit to lessen a leak. Again, be careful.

Jim S.

 

Extra wire going to diode is for warning light. Leave it. Old cars have no warning light and no such wire.
John

 

Exactly - I've also heard of several others who say that oil leaking affected the life of their alternator.
When I rebuilt my alternator I had to fashion a heat shield from scratch, so I made one with an extra "hat" that is angled to act like a very wide drip rail and deflect dripping oil off the back.
http://www.ferrarichat.com/forum/showthread.php?t=187951
http://www.ferrarichat.com/forum/showthread.php?t=191513

 

John C. - I did not know where the idiot light was connected. None of my cars had one. Steve suggested that the diode was connected to the air-pump clutch wire. What color is the idiot light wire? Perhaps this is why his idiot light came on...the wire that is suppose to go to the diode is touching ground somewhere, and thereby illuminating the idiot light.

Jim S.

 

Jim,
I don't have a schematic that shows the idiot light on the newer cars but I know there is one. Light comes on if alternator is dead. Once alternator starts spinning, light goes out. The terminals on the diodes are the only place to sense the voltage coming out of the alternator. You get a messy waveform that goes from just below ground to just over the output voltage. If you run that to a relay, the relay could run the light. Maybe ask Jon. His Dino ought to have the light. He might have a schematic that shows how it works. Let us all know if you find out.
John

 

Thanks guys. Yes, my car is a late model, and has a warning light in addition to the ammeter. Makes sense that the lead off a diode is to this light. Scott- were you able to install this hat you made in situ, or was it done while the alternator was out of the car? Pretty tight in there right now to try and fabricate and mount what you did.

 

Well, it crapped out again today. Traced all the wires and they look good, replaced the 60 amp and 8 amp field fuses and the entire box. Belt is good. Doesn't seem to be much oil at top of alternator. It is charging, but only at 12.9-13 volts at 3500 RPM. 12.2 at idle. Warning light stays on. I'm all out of ideas. I guess I'll swap out the regulator just in case and if that doesn't work then I'm swapping to a GM alternator and removing the waffle tube. Frustrating.

 

If you have the external regulator of the usual Marelli type of that era, and you're willing to buy a new one anyway, then there is no harm in trying to adjust the regulator. There is a procedure that is similar to adjusting ignition points gap, but you can also just take the cover off the regulator and with the car running, slightly bend the arms that hold the spring to either increase or decrease the charging voltage. You may need a second person to measure voltage while you do this. I've done this on several vintage Italian cars to "dial in" the charge that I wanted (about 14v).

 

If your car has a mechanical regulator, throw it away and go get a 3 terminal regulator for an old Chrysler or something. You have a voltmeter. Tell us what the voltage is on the field with the engine at 3500. If it is near battery voltage, the brushes are bad. Pull alternator and fix. Or just pull brushes and clean up. Changing alternators is a lot of work. You will have to pull everything. Find what is wrong and fix it.
John

 

I'm with John C. on this one. You do not want to install a GM alternator. Ask Tom C. about this. In addition, you do not want to remove the waffle air pump/alternator bracket. To do so requires new brackets (Euro type), and a different pulley on the alternator. Ask Tom C. about this.

There are many 70s vintage cars (Honda, for example, Chrysler, etc.) that have solid state 3-wire regulators. Any 3 wire regulator (12 volt) will work fine. Look through the parts catalog at your local auto supply for a 3-wire regulator. Got it! Three wire regulator. They all do the same thing, 3-wire regulators, that is. I sent Tom C. a Toyota 3-wire regulator. That's a 3-wire, not 4-wire regulator. Three wire regulators are inexpensive ($30 to $40 U.S.)

Slim is correct in suggesting that you can adjust the Magneti regulator, which, by the way, is a solid state regulator in 1971 and newer Dinos. Remove the screws holding the red cap on. On the circuit board will be a delicate wiper blade that rides on a variable wire-wound resistor. There will be a dab of witness paint on the pivot screw. I won't tell anyone if you break the witness paint by turning the screw. In fact, you can remove the label on your mattress and I won't tell anyone. But don't take the label off your pillow. Really, don't remove the pillow label.

With a voltmeter attached to your main system bus (under the dash, the large red wire going to the ignition switch), or to the battery + terminal with a long test lead, read the voltage at 2000 RPMs. Now carefully (minimal movement required) slide the wiper across the variable wire-wound resistor and watch the voltmeter. You will have to determine which direction to move the wiper. If everything is working, the voltage should vary. Move it to 13.8 volts. That's it. You're done. I won't tell anyone you broke the witness paint.

This presupposes, of course, that your brushes are not simply oil-soaked mush. As John suggested, this is likely the culprit. However, I believe it is difficult to change the brushes with the alternator in the car. Not impossible, merely difficult.

Jim S.

 

I swapped to a solid state regulator from a Mercedes years ago. Chances are that it's not the regulator, but it's the only thing left to easily swap out. Can I pull the brushes from the alternator without removing the entire alternator?

In fact, you can remove the label on your mattress and I won't tell anyone. But don't take the label off your pillow. Really, don't remove the pillow label. LOL!!! You're a good man John.