1936 Oldsmobile F36 Voltage Regulator....

[philipj]

As I try to collect some of the correct parts needed for my car, I see that original voltage regulator was Delco 1118203 which had 4 posts 1- Field

2- Generator (Left side) and 3- Battery 4-Ground (Right side)

 

Newer replacement units are Delco 1118309 but they only have 3 posts, (BAT. GEN. F.) instead of the original 4... The last option is Delco 1118213, interestingly this one has (BATT. GRD. F.) on the top an GEN. on the bottom...

 

My questions are, which unit was installed in the vehicle first 1118203 or 1118213? Lastly, how do you exactly eliminate one connection without getting into trouble?

 

 

 

 

 

 

 

Edited March 15, 2023 by philipj (see edit history)

[Bloo]

I doubt any of these are the one, If you want to go all the way back to 1936. What follows is based on Buick and Pontiac research, but it is a fair bet the same things happened at Oldsmobile, even though the parts involved were most likely not quite the same ones. This may help understand whatever was happening at Oldsmobile at that time.

 

The story starts with a 5 terminal voltage regulator on Pontiac Eights around 1935. The top cover most likely looked exactly like that one in the first 2 pictures. The terminals on one side are GEN and F (field). The terminals on the other side are AMM (or BAT), GRD, and IGN (ignition). AMM and GND are almost stacked and come out of the same hole.

 

This is a 2-unit voltage regulator, in other words there are 2 relays inside. One is the cutout, and the other is the voltage regulator. It is used with a third brush generator, but with the third brush position fixed. Current regulation is still handled by the third brush. Since there is a voltage regulator, there is no need to "turn down" the current (Amps) by the moving third brush holder. They have chosen a spot that is low enough current (Amps) to protect the generator from damage and riveted the third brush holder in place.

 

The generator itself (on a Pontiac) is smaller in diameter than a typical generator and is capable of 15-17 Amps maximum when driven at the "ideal speed". What I mean by that is that third brush systems have some particular RPM that they generate their maximum current (Amps). Go faster or slower (in high gear) and you have less current (Amps) available.

 

Getting back to the regulator, the GEN terminal (AKA "ARM" sometimes) is exactly what you expect it to be, the large charging wire coming from the generator.

 

Similarly F is Field, the voltage regulator's control wire for charging, and is the small wire coming from the generator.

 

BAT (or AMM for ammeter) is the large wire carrying current to the battery and the rest of the car. Electrically it goes to the ammeter, although it might land on some other terminal first under the dash.

 

GRD is not ground, at least not like you would normally think of on a voltage regulator. It is a contact on the cutout that is grounded only when the cutout is actually cut out. Whenever the generator is charging, this terminal is disconnected.

 

IGN is a longer story. I'll get back to that in a minute.

 

56 minutes ago, philipj said:

As I try to collect some of the correct parts needed for my car, I see that original voltage regulator was Delco 1118203 which had 4 posts 1- Field

2- Generator (Left side) and 3- Battery 4-Ground (Right side)

 

Are you sure that's right? I'd cross-check that to the shop manual if you have not. I would not expect "Ground" on an Oldsmobile, but in 1936 I would definitely expect IGN. Do you have a Buick-type Autostart (throttle start) system? Do you have an idiot light for the charging system? Those were the only 2 uses of the "Ground" terminal that I am aware of. In fact, there was a 4-terminal version of these 5-terminal regulators that was original equipment on 1935 Pontiac Sixes. They had neither Buick-type autostart nor an idiot light, so the "Ground" terminal was missing.

 

1 hour ago, philipj said:

Lastly, how do you exactly eliminate one connection without getting into trouble?

Well, you could easily eliminate "Ground" if you don't have one of the items mentioned above. A real ground wire for a regulator is always a good thing, but this isn't one. Next, GM had you eliminating the IGN wire when these cars were not very old.

 

These 1935-1937-era regulators, like the one in your top 2 pics (but more typically with 5 terminals), had an "IGN" terminal for a wire from the ignition switch. It turned the charging system "on" and also served as a "sense" wire (voltage sensing) for the voltage regulator. GM soon decided that strategy was a bad idea, and unreliable. I have a lot of skepticism, because the Chrysler "roundback" and "squareback" alternators used that strategy many years later, and while there are some downsides, I believe it is the most reliable alternator system ever made. I am using a correct and probably original 5-terminal voltage regulator on the 36 Pontiac, and outside of cleaning the contacts carefully and setting the voltage once not long after I got the car, I haven't had to do anything to it. Anyhow, GM backed away from that strategy suddenly in the mid to late 30s, and later "updated" regulators had no IGN terminal. GM wanted you to cut the wire off at the harness when installing an updated regulator. I would never do that, I would insulate it and tape it back if I wasn't using it. It wasn't long before GM also eliminated the so-called "Ground" terminal (GRD) on their updated regulators as well.

 

 

[philipj]

Hello Bloo,

 

Well, I do not have an official 1936 parts book, and I am surprised that no one else has chimed in here, but I do have a couple period of books from which I obtained this information…

 

The first one is a Delco Original Equipment Electrical Service Parts, date January 1942, and the second is the National Service Data book dated 1948… I feel that both are close enough to 1936 to have the correct data, but without a factory build sheet for my vehicle, I really can’t tell you which regulator it had when it rolled off the assembly line… Likely it may be Delco 5588, since it is the earliest one, BUT could it also be 1118213?

After looking at this again, I think I know where the confusion lies… What I think is 118203 (pictured first with 4 terminals) is actually 5558, one of the original regulators listed for that year model...

 

In terms of function, I think that you’re right, these are very similar to the Pontiac regulators; but regarding your question about being right, short of purchasing yet another book (1936 Parts manual) I cannot positively confirm that Delco 5588 or 1118213 is the correct voltage regulator for the car as it left the factory…

 

As for the “updated” regulators 1118203, I have found the instructions that precisely talk about cutting the IGN terminal, and so on (which I would never do) but honestly, I must read up your explanation again to have clarity… With that in mind I should re-write the beginning of this post to correct the mistake which states that 1118203 is the correct regulator pictured in the first two frames...

 

So hopefully, this is a little clear in terms of application, but I surely have a lot to learn about these old things, for example you also have apparatus boxes (trucks and buses/difference?) and Lamp Load Generators and Regulators… Installed on 1935 Cadillac V8 and V12 models… Just wondering, would they be better than what was installed here? Is a black hole!..;)

 

 

 

 

 

 

 

 

 

 

Edited March 16, 2023 by philipj (see edit history)

[Bloo]

An original wiring diagram for a 36 olds F would solve a lot. How do you engage the starter? Does the car have a real ammeter or an idiot light? As I mentioned before, these are the two most important clues by far.

 

The sheet you show for the 5 terminal to 3-terminal update is something that comes up a lot in Buick forums. A similar sheet was posted in a thread about a 38 Oldsmobile the other day, but it was the sheet for converting 5 terminal to 4 terminal. Note, this would most likely NOT be a version of one of the flat cover types as used in 1936. The terminals were not the same. In that case also the instructions were far more applicable to a Buick.

 

On 3/16/2023 at 10:27 AM, philipj said:

Likely it may be Delco 5588, since it is the earliest one, BUT could it also be 1118213?

At least 5558 is the right type of a part number. I doubt very many of the long part numbers were in use in 1936. Maybe none.

 

There is a 29-48 Delco book online. Despite being published so much later, it *seems* to show the original part numbers. Despite the fact that GM took a hard turn away from the regulator family in question around 1938 nothing appears superseded, at least in the Buick and Pontiac sections. It says 5588 for both Oldsmobile F and L in 1936.

 

http://restoringcornelius.com/files/29-48 Delco Remy.pdf

 

For comparison:

 

1935 Pontiac 6                  5588

1935 Pontiac 8                  5557

1936 Pontiac 6                  5557

1936 Pontiac 8                  5557

1936 Buick 40 (optional)  5589

1936 Buick except 40       5594

1937 Buick all                    5807

1938 Buick all                    5807

 

I believe everything in the table above is going to be a flat cover 2-unit regulator like your first 2 pictures in the thread, and the 2 regulators to the left in the third picture your the last post. All in the table I believe are 5 terminal regulators except 5588. It should be about the same thing, just missing the "GRD" terminal.

 

I've left out 1937-38 Olds (5814) because I believe it was a newer series of regulator by then. The wiring diagram posted in the 38 olds thread from the other day backs up this idea, because there is no IGN terminal. I've left out 1937-38 Pontiac (5808) because I believe they had moved on to a newer design as well. I am going to ignore the 36 Buick (5589, 5594) because I don't know what is different about them. Possibly they are generator mounted? The Canadian 36 Buicks used 5557 like a 36 Pontiac. American 36 Chevrolets still had no regulator, but State Police and Canadian 36 Chevrolets used the Olds regulator (5588)! 

 

That leaves 5588, 5557, and 5807.

 

I have a sheet somewhere I can't find that says 5557 and 5807 (and several others of the same internal construction) are electrically interchangeable but not mechanically. Maybe the 5588 mounts like the 5807 (37-38 Buick)? Some 1935-6 Pontiacs have the regulator mounted on a little shelf so the can is pointed up. Some do not. I don't know why they would do that on only some cars. If the 5588 (36 Olds and 35 Pontiac 6) mounts differently than the 5557 (35-6 Pontiac 8 and 36 Pontiac 6), that could explain it.

 

I vote for 5588.

 

EDIT: I found a picture of 1116213 on ebay. It is the 4-pin type Buick started using as a retrofit for 5 pin regulators after they didn't want to use the ignition lead anymore, circa 1938-39. I don't think it is even in the running for 1936.

 

EDIT 2: I don't really believe that regulator in your first 2 pictures is what it says it is.

  

On 3/16/2023 at 10:27 AM, philipj said:

What I think is 118203 (pictured first with 4 terminals) is actually 5558, one of the original regulators listed for that year model...

Except as it turns out, it isn't. Blow up the first picture. The number stamped in it is 5590. That doesn't appear in the 1948 book at all, but I found it on Delco's site, and it supersedes to 5839 and then 1118436. Neither of those are in the 1948 book either. The number on the package, 1118309 doesn't appear in the book either, nor does 1118332, the number Delco says it supersedes to on their site. I see no reason to believe that regulator is related to the container in any way. Of the numbers scribbled on the container, 1118203, shows up in the 1948 book only in listings for replacement internal parts for the regulator. It does not show up anywhere in the application data. 3730 appears not to be a Delco number at all.

 

I doubt this regulator, actually a 5590, is for a GM car. I doubt it is for a car at all for that matter. Maybe a generator, or a pump, or a welder. Maybe an air compressor or a speed sprayer. Maybe a truck or a bus. It has the correct look for 1935-36 GM, but the wrong terminals. It might be coaxed to work correctly on the Oldsmobile with one wire disconnected, but only if it is for negative ground and only if it is for the correct type field circuit.

 

 

Edited April 15, 2023 by Bloo (see edit history)

[philipj]

This gets more and more interesting by the minute, but only for us it seems...;) I'll start attaching what I have for wiring diagrams... Then I have to read your post again and see what makes sense... Again, surprised that someone else has not come up with information here.

 

 

Edited March 19, 2023 by philipj (see edit history)

[philipj]

Hello again,

The starter mechanism is a standard from the period, where you directly engage it with the starter as you press down with your foot… No idiot lights or anything, there is a regular ammeter, and I believe a high beam indicator on the dash of this car, but that is about it… Very basic.

 

It would be interesting to find the post you talk about, but I believe that the conversion from 4 or 5 wire to 3 is similar… I also think that Buick and Oldsmobile may be similar in this regard than Pontiac? Just guessing…

 

As for the 5558 regulator, I have not been able to find a photograph online… I will go to the 32-36 Enthusiast Group in Facebook and see if someone can post photos of this regulator to clear things up once and for all…

 

As I continue reading, I see that I have to walk away from the thought of Buick being more similar to this car, instead a Canadian Chevy or State Police has more in common, go figure! If the State Police used that regulator, does it mean that it produced a higher amperage or allowed for a better charging rate?

 

I do not know also why some regulators may need to be on a shelf. All that I can think of is that this particular design may be more susceptible to being sideways and not allow for its proper function if it is mounted differently… It makes some sense, if you have gravity working against you… Unless they thought it would look prettier sitting on a shelf!

 

So, the challenge is to find a real 5588 voltage regulator!

 

1116213 is not even on my radar of regulators to consider, I have to have a look…

 

As it turns out you are a better detective than I am… I missed the 5590 number altogether!..;( and indeed, this has turned out into a major puzzle, and as you have discovered, other people make mistakes over the years and place incorrect items in boxes thinking that they have the right article… In this situation, this may well be the case. I am going to look at my two books and see if I can find any numbers related to the 5590 regulator, to see what it fits…

[Bloo]

46 minutes ago, philipj said:

The starter mechanism is a standard from the period, where you directly engage it with the starter as you press down with your foot… No idiot lights or anything, there is a regular ammeter, and I believe a high beam indicator on the dash of this car, but that is about it…

Thanks for posting that. It confirms what I expected, and is even stronger evidence that the regulator should be 5588.

 

55 minutes ago, philipj said:

It would be interesting to find the post you talk about,

I've been casually looking and can't find it. I found this older thread that says 1938 Oldsmobile takes 5814. The interesting part of the missing post is that the 1938 circuit has 4 terminals, but was highly unlikely to match anything from 1936. The things you have posted confirm that.

 

https://forums.aaca.org/topic/369565-wtb-1938-olds-voltage-regulator/#comment-2281397

 

1 hour ago, philipj said:

but I believe that the conversion from 4 or 5 wire to 3 is similar…

It is identical or nearly so, but for it to make any sense you need to think of the 5588 as a 5 wire regulator even though it only has 4 wires. Electrically it is a 5 wire regulator, it is just missing the "GRD" terminal, that terminal being useless on a car with a conventional starter and ammeter.

 

The update instructions make a lot more sense if you are talking about a 5 wire Buick. Pontiac and Oldsmobile may have adopted a "true" 4 wire system in production about a year before Buick.

 

1 hour ago, philipj said:

I also think that Buick and Oldsmobile may be similar in this regard than Pontiac?

As you noted later, not really. 1935-36 Pontiac Eight charging and starting systems are wire for wire identical to 1937-38 (and some 1936?) Buicks, except for the generator itself. The main differences are mechanical, such as mountings and linkages. The 1937 and 1938 Buick generators are slightly larger and wired differently internally, but that really makes no difference to the regulator or wiring discussion.

1 hour ago, philipj said:

As for the 5558 regulator, I have not been able to find a photograph online… I will go to the 32-36 Enthusiast Group in Facebook and see if someone can post photos of this regulator to clear things up once and for all…

Please post if you get one.

1 hour ago, philipj said:

As I continue reading, I see that I have to walk away from the thought of Buick being more similar to this car, instead a Canadian Chevy or State Police has more in common, go figure! If the State Police used that regulator, does it mean that it produced a higher amperage or allowed for a better charging rate?

Police cars are a can of worms.

 

US Chevys at that time used a simple 3rd brush and a cutout, but with a field terminal. There was a resistor in the headlight switch, and it effectively turned up the charging rate when the lights were on. This fixes one of the biggest disadvantages of a 3rd brush and a cutout, that it cannot compensate for headlight load. In theory, you might be able to drive all night with this and not run out of battery. There was also a half click in the headlight switch to allow the driver to force a high charging rate in the daytime if he knew his battery was low. It is a step up from a model A, but less sophisticated than the 5 terminal regulated systems we have been talking about. It probably makes more sense to think of those Canadian and State Police Chevys as having a Buick/Olds/Pontiac-type charging system.

 

1936 Canadian Pontiacs have some charging system differences that escape me at the moment. 1936 Pontiac police cars have a completely different charging system that I believe is common with LaSalle. It uses a 2 brush generator, a 3 unit regulator (with 6 terminals on it!), more output, and true current regulation in addition to voltage regulation. Outside of the extra terminals, it has more in common with a post-1940 charging system than it does with any of the systems we have been talking about.

 

I don't know what a 1936 Olds police car has.

1 hour ago, philipj said:

I do not know also why some regulators may need to be on a shelf. All that I can think of is that this particular design may be more susceptible to being sideways and not allow for its proper function if it is mounted differently… It makes some sense, if you have gravity working against you… Unless they thought it would look prettier sitting on a shelf!

This is pure speculation, but my working theory for the moment is that the mounting is different. Maybe it won't mount on the firewall (on Pontiac, maybe Olds too) without hitting something? My car has a correct (for 1936 Pontiac) 5557 on it. As I understand it the 5557 is electrically the same as 5807 (1937-38 Buick), but mechanically different. I have a sheet somewhere that says so. I don't know what book it is out of. My suspicion is that the mountings are just rotated 90 degrees. Maybe the 5588 mount is also 90 degrees off? I have no pic of a 5807, but being Buick, I'll bet someone would come up with one if I asked.

 

If you get a picture of a real 5588, we can compare.

 

[philipj]

Hi there,

I just may have found gold, even though it is not a DELCO piece, this is rare enough so I got it... It is a piece made by Blue Streak, VR-205 X. It is NOS and for a decent price. Instructions give reference to the regulators they replace 5588, 5814, 1100002, 1100003, 1100004, 1100009, 1101053, 1101055... One odd thing is that I only see 3 terminals, but seems the right square shape for the 36 Olds...

 

 

 

 

Edited March 20, 2023 by philipj (see edit history)

[philipj]

So far the reply from the 1932-1936 (Facebook) Oldsmobile Enthusiasts Group is that the 1118213 corresponds to the 1936 models only....

[Bloo]

I would expect the 5588 to physically look like the regulator in the first 2 pictures of this thread (5590). Maybe not though. I just found a pic of real Buick 5807, and it is not the way I remembered. I would have expected a flat cover. This looks more like the alleged 1118213 with the white 3712 tag hanging on it. The 5807 uses an IGN terminal though, and I'll bet that regulator with the 3712 tag does not. I'd really like to see a 5588.

 

 

The regulator in your Blue Streak post replaces 5588, but also 1118203. My guess is, this would be an "update" regulator that does not use an IGN terminal, and so 3 terminals (or 4 terminals including GRD if present) would be exactly what is expected. It would most likely work fine. Old Blue Streak stuff is extremely high quality, probably even better than Delco. If you were wanting exactly the original setup, I don't think this is it.

 

EDIT: The 1118213 picture in your last pic does not match the picture of the 1118213 in the book in your last post! It's a whole different series. I wonder what is going on there? Is the book wrong? Is the regulator not really 1118213?

 

 

Edited March 20, 2023 by Bloo (see edit history)

[Bloo]

The 5 terminal regulators, which include your 5588 from an electrical perspective despite it having only four, used a switched lead from the ignition switch. It turns the system on. More importantly, it is the "sample" voltage the voltage regulator sees to estimate battery voltage from. At some point a couple of years later GM turned away from this design rather suddenly. The 4 terminal regulators with one terminal sticking out the top do not represent one terminal missing, they are a complete redesign on the voltage regulator on a different principle. That is why the terminals are in a completely different order.

 

This new system turns itself on like most other newer generator systems. It also samples voltage right at the cutout to estimate battery voltage. It no longer needs the ignition lead at all, and you will see Delco's update instructions telling you to cut the ignition wire off.

 

Using a bone stock 1937 Buick with an original 5807 as an example, because the key to understanding all those Delco "update" sheets is Buick wiring, here are the 5 terminals:

 

GEN/ARM

F/FIELD

GRD

AMM/BAT

IGN

 

So, if you've been keeping score, GRD is gone because it was never there on 5588, and IGN is gone because GM and or Delco completely revamped their design philosophy and their regulator design. That leaves 3 terminals.

 

GEN/ARM

F/FIELD

AMM/BAT

 

But we were talking about 1937 Buicks so we still have GRD too. That's four. A new four terminal regulator replacement for the 1937 Buick has those four. GEN/ARM, F/FIELD, AMM/BAT, and GRD. As mentioned earlier, GRD is not ground. It goes to a set of points in the regulator assembly. The terminal is grounded only when the cutout is cut out and the generator isn't charging.

 

Buick Autostart starts when you step on the gas pedal. The starter has a solenoid on it to pull the gear in place and a big set of contacts to turn the starter on, just like a much newer GM car. On the 1937 Buick (and a bunch of others), there is a little relay hanging on the back of the solenoid, so that it can be triggered (and the engine started) with even less current than the solenoid by itself needs. This little relay has a floating coil, and you must provide it both power and ground to activate it.

 

On the positive side, there is a combination vacuum-throttle switch. If the throttle is open, and there is no engine vacuum (not running) it sends power to the relay. On the negative side, the GRD terminal on the regulator grounds the relay when the system is not charging. If the system is charging, GRD does not give the relay a ground.

 

This is sort of a double-safe system to make sure the starter doesn't engage while the engine is running. If the engine has no vacuum, and the generator is not charging, the engine has to be off and you can start it with the throttle switch. If there is engine vacuum, the engine is running and the relay gets no power because of the vacuum switch.

 

But, what if you are floored going up a steep hill? The throttle is open, so the throttle switch is on. The throttle is wide open, so there is no vacuum. The starter can't engage though because the charging system is charging, and GRD does not give the relay a ground.

 

So what they did was make "4 terminal" regulators to replace the 5 terminal ones. They had the new design that did not need IGN, but still provided GRD for Buicks (and some Pontiacs that had either Buick Autostart, or an idiot light, or both). If you used one of these on a 36 Oldsmobile, you would only use 3 wires. No IGN because the regulator is the newer design, and no GRD because it was never there.

 

Later on they were replacing these 4 terminal regulators (and any 5 terminal ones still left) with a 3 terminal regulator. The sheet you posted earlier is for this modification. They were having you piggyback the wire that had been on GRD on the GEN terminal. In fact, this is how later Buicks with autostart and factory 3 terminal regulators are wired. The little relay on the starter finds a ground through the generator windings, but when the system is charging, the GEN terminal comes up to charging voltage and it can no longer find a ground that way. The double safety still works.

 

 

Edited March 22, 2023 by Bloo (see edit history)

[philipj]

On 3/19/2023 at 11:07 PM, Bloo said:

I would expect the 5588 to physically look like the regulator in the first 2 pictures of this thread (5590). Maybe not though. I just found a pic of real Buick 5807, and it is not the way I remembered. I would have expected a flat cover. This looks more like the alleged 1118213 with the white 3712 tag hanging on it. The 5807 uses an IGN terminal though, and I'll bet that regulator with the 3712 tag does not. I'd really like to see a 5588.

 

 

The regulator in your Blue Streak post replaces 5588, but also 1118203. My guess is, this would be an "update" regulator that does not use an IGN terminal, and so 3 terminals (or 4 terminals including GRD if present) would be exactly what is expected. It would most likely work fine. Old Blue Streak stuff is extremely high quality, probably even better than Delco. If you were wanting exactly the original setup, I don't think this is it.

 

EDIT: The 1118213 picture in your last pic does not match the picture of the 1118213 in the book in your last post! It's a whole different series. I wonder what is going on there? Is the book wrong? Is the regulator not really 1118213?

 

 

I have to agree with you there, very low profile with a flat cover…. As a matter of fact, 1118203 comes up as a regulator for this car by doing a Google search!… And I really would like to see a 5588 also, I even wrote to Delco for an identical replacement number, not an “update” for the 5588, but I have not heard back…

 

I was probably a little impulsive with the Blue Streak purchase, but it was $39.00 bucks… Maybe I am better off getting a 1118203, BUT now I want to find a 5588 unit…

 

Again, you hit it, the 1188213 does not match the photo from my books… A second search on the web for that number gives me an identical unit to the one previously posted with the 3712 white tag, see below… So, at least we can confirm that the photo in the book must be a generic photo, but not 1188213!

 

 

 

 

Edited March 21, 2023 by philipj (see edit history)

[philipj]

I know I am still beating this drum, BUT I still wish someone could post a photo of a 5588 Regulator... Could it be very similar to this drawing? Given all the changes between 1936-1949, if the GEN= ARMATURE, AMMETER = BAT the field remains unchanged, comparing the 5588 to the  Delco 1118203 and 1118309 (In which case the IGN wire is no longer used... My last question relates to Delco 1118213 which has 4 posts, BAT, GRD, F and GEN. (Yet different to the 5588 in one respect, the GRD connection...

 

All the wiring would be accounted for except the IGN wire... Does IGN become GRD in order for it to work with the 36 Oldsmobile Electrical system? I have a feeling the answer NO, even though you are supposed to be able to use 1118213 on this vehicle...

 

 

 

 

 

Edited March 31, 2023 by philipj (see edit history)

[Bloo]

I'd like to see a 5588 as well.

 

[AussieOlds]

I've only just seen this thread and will certainly do some more research tonight but just confirming that the 5557 is listed for both F&L 36 models in the January 1st 1936 Issue Olds Master Parts Catalog.     The 1938 & 40 issues shows 5592.   1940 Delco Parts Book shows 1118213.    So obviously a lot of changes along the way.  Surprisingly I can't find an Oldsmobile Technical Bulletin on the initial change in numbers.   

[Bloo]

They changed to 5557 by January 1936?! Wow. I have a theory on why that might be though.

 

5557 is the Pontiac regulator, and the only difference electrically is the Pontiac unit has an extra "GRD" terminal that the Oldsmobile doesn't need... but it doesn't hurt anything by being there. These regulators, like a lot of regulators, have a charging rate that is overcompensated for temperature. It's a normal thing. The early production 5557 though was over-overcompensated, a mistake, and Pontiac provided updated replacements. You can identify an updated one by one or more horizontal bars stamped in the metal next to the 5557 part number.

 

I wonder if the Oldsmobile 5588 had the same over-overcompensation problem? If it did, maybe they used the updated 5557 as the replacement?

 

I suspect this might be 5588 below. It has a flat lid like a 5557, but lacks a "stacked" extra terminal at the lower right. It is on a 1936 Oldsmobile F-36 posted on Bring a Trailer.

 

 

 

 

[AussieOlds]

I stumbled across this photo of a barn find original F.36 which appears to have the original 5557 with flat faced cover (no retaining screw on the front face).   It looks much the same as the 5585 on my F.35. 

Edited July 3, 2023 by AussieOlds (see edit history)

[AussieOlds]

@philipj and @Bloo you mentioned above that you were keen to see a 5588.   Well I bought a bunch of parts at an auction this week and amongst them was this 5588 regulator. 

[Bloo]

Thank you for posting it!

[philipj]

Hello Aussie Olds,

 

Will you sell the 5588 regulator?