76 Eldorado convertible upgrade generator

[7gen]

My convertible top loses steam about 1/4 of the way up. Down is no problem. I contacted a convertible top shop in San Gabriel CA and they said to try hooking a battery starter (like with a dead battery) to my battery and then start the car and try again. Worked like a champ. I was told that I needed to upgrade the generator/alternator.

From the shop manual, the original was 63 amps. There was an 80 amp heavy duty version for trailering. I believe it was a 10si and was a generator, not an alternator. Some questions:

1) Can I interchange an alternator in place of the generator, apart from fitment issues?
2) I had the battery starter at 100 amps (no other option for starting power). Does that mean I was running 163 amps through or 100 amps, given the stock generator at 63 amps?
3) Is anything going to "melt" if i stick an upgraded unit on (gen or alt)? Or does the higher amperage mean how much it is rated to put out rather than how much it is actually putting out at any one moment?
4) Anyone done this modification and have any advice? I'm looking at PowerMaster units.

Thanks!!

[TJ Hopland]

You are asking all the right questions regarding the 'upgrade' and I or others can answer those later if you still think that is the direction you want to go.

Something isn't right.  If your system voltage is dropping that bad from the top operating you have some major issues that I think would be showing up in other places too.    If everything in the top system is in good condition it should go up just fine with the engine not running.   Mine used to be pretty slow like to the point you thought it would not make it with engine not running so I would just be sure to have the engine running when I put it up.   Worked fine that way for about 15 years.   There was a really slow point but once it got over the hump it went smooth again.   

I finally decided to get a new top and while it was in I had the guys 'rebuild' the mechanism.  Apparently they took the arms apart and replaced bushings as needed and lubricated everything.  The big problem area was apparently the gears at the end of the arms.   They said that was 90% of my (and most peoples) problem because the 40 year old grease had got pretty hard.   For budget reasons I did not have them do the motor end of things since that would not effect the top adjustments.  I figured I could do that myself later and its still on my to do list.  Result is now my top goes up just fine without the engine running.   I still usually have the engine running and it does go faster that way but it also works fine with the engine off just slightly slower and you do hear a little strain when it hits that almost vertical point.  Engine running you don't notice that point.

Another common issue unique to these tops is they used a somewhat odd motor and switch design involving a relay.   I have not had the relay issue but apparently its a very common problem.   When the relay fails the motor still works but it looses a lot of its torque.   Continued use with a bad relay will actually burn out the motor which is then an expensive repair.    More voltage just masks the problem and stress the motor more.   The relay was hard to find at one point but apparently is being made again.   It was the same relay they used in the power seats in that era. 

Here is a diagram for those that like and understand such things.

[TJ Hopland]

On the alternator front the original was the 10si and it was an internally regulated alternator.  Cadillac quit using generators in the 60's.   The first alternators looked like the 10si but used an external regulator so the connections were a little different.   I think the change to internal regulator for Cadillac was 73.   For most applications the 10si was standard till the early 80's when the 12si came out.  In the 10 era the bigger one was much bigger so it required different brackets and such, there was also a 100 amp that was huge and found in things like the ambulance.   Mid 80's they changed again to the CS series. 

The 12si was pretty similar to the 10si but had an enclosed plastic fan rather than the open saw blade looking one the previous models had.   A 12 will bolt up and plug in and gains you a few amps.   I have a 12 on my 73.   I think mine was like a 74 amp so pretty close to the original 63.   I had a theory that the 10's were dying due to heat and the 12's had better cooling.  Not sure if that was what helped me or not but I went from about 6 months out of a rebuilt alternator to something like 10 years and counting now.   Could have just been crappy rebuilds and I finally got a good one.

People like power master I think do make 'upgraded' original cases which have mixed reviews as far as reliability.   The other factory you mentioned is if you can make more power your wiring has to be able to handle it which could be a lot of ask of 40 year old wiring.   

[7gen]

I was especially concerned about the wiring taking the load.

What about this - start cheap and work up. For $50 I could change out the relay myself. All that takes is getting the seats out. If I'm lucky, that could be the issue. If not, I could also try regreasing the transmission for the electric motor as well as the side gears.

Cadillac DID design the system to run with a 63 amp generator, so I should probably try to figure out why something is wrong instead of just throwing more juice at the system.

[TJ Hopland]

The relay I think is to the left of the motor as you are looking at the motor facing the back of the car.   The motor is pretty much center of the back seat seat back.   I don't know what the failure mode is of the relay.  If it just didn't work I don't think the motor would run at all so it must be like some of the blower relays where it heats up and deforms then connects things that should not be connected. 

The motor assembly has several gears in it, no doubt some cleaning and new lubrication would not hurt there.   The motor is a brush type motor.   I never looked close to see if its one that has externally accessible brushes or not but that would be another possibility as to why its weak, brushes could be shot.    When I was recently looking at getting motor work done on another car I did notice that several of the repair places also mention they work on the Eldo / scissors motors too.   I think I saw one site that said they had reproduction gears.   

On the gears in the arms I didn't spend a ton of time looking them but they didn't look to me to be easy to get them out without possibly distributing some of the alignment.   I thought about doing em before I took it in for the top but the shop I found said they worked on a lot of them so I just paid them to do it all.   I could be wrong and its not that bad of a job.   I was lead to believe the main issue is not in the parts you can see,  it has to come apart to properly clean and re lube them.     

[TJ Hopland]

I just did a quick search and kinda refreshed my memory on the relay.   It actually has 6 terminals but 2 sets are paired up.   The difference between the seat one and the top one is where the mounting ear was.    When there was not reproduction ones there was another relay some vendors were selling that worked but the mount was wrong and it didn't have the jumped terminals so you had to modify things slightly.   

I believe the proper one has 6 terminals and the mounting ear would be on the top if the terminals were pointing down.     The seat one I think the mount was on one side.   The not quite correct one that was all that was available for a while I think the mount was on the terminal end with 4 terminals so be sure to ask if you are getting what is in the picture and the picture is what you want.   I see the 'wrong' ones as low as $15 but the 'correct' ones look to be more in the $75 range.

Anyone else feel free to confirm or correct my memory and findings......   

[TJ Hopland]

Memory isn't what it used to be.      There is just 2 gears in the motor assembly,  I must have been thinking of seat motors.   And it does not look like the brushes are easy to check, again must be thinking of another car.    The motor looks to more or less be the same as a window motor.

[7gen]

I just went out to look under the hood and based on what you said about the external fan on the alternator, I have a 12si in place. It has a label that says "remanufactured unit". So I've already got a bit of a bump in amperage over the stock, I think.

I ordered a relay - I'll start there. It was about $60. I'll repack the gears on the motor next.

The Fisher Body guide shows how to change out the side gears. Do-able, but something I'll do as a last resort. 

This will be my first solo adventure in fixing my car - kinda exciting!

[bcroe]

I don't think changing the alternator is the right approach.  If you have
a heavy duty battery and heavy enough properly functioning conductors,
it ought to work without the engine.  Get a meter, check how much the
battery voltage drops under max load.  ALSO VERY IMPORTANT, check
the voltage between the bat neg and motor neg, same between bat pos
and motor pos; this is voltage that never gets to the motor. 

Having done your research, fix any poor connections, upgrade conductors
with a lot of loss.  That can include the ground.  The same approach will
fix dimly glowing GEN lights and marginal 6V starters.  Bruce Roe

[cwbbear]

I was having issues a while back and it felt like the motor just could not push hard enough.   I downloaded the troubleshooting guide off the guys in San Gabriel site (I did not see if today but I did not look very long) and I found my actuators (gears on the side) were the issue.  One was binding up pretty bad and the other was fair at best.  Replacing those solved my issues without changing the motor or adding more juice (despite my instinct)

I also included a picture where the relay and motor are if you did not have the Service Manual

In the question you do not mention any other troubleshooting done, so if you have not done so this might help.

[7gen]

Well, here's the (for now) end of the story:

Fisher Guide Manual in hand, I went out to look at my side gears. I don't know about other years but on my 1976, one gear is covered only by a flap of heavy plastic. I peeked under and saw lots of debris and shiny metal. I cleaned out the debris, put a bunch of moly-be-durned grease on the gears, gave the motor a bit if juice (high idle) and it went up like a champ.

Did it a couple three times and smooth as you want, it went up without slowing each time.

Go figure.

[TJ Hopland]

Cool.    Good to know that just sneaking in a little lube could help.