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1936 Buick Special - Where is your generator cutout relay mounted?


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I've been studying the new wiring harness I had made and the generator cutout relay wiring is different in the new harness. In both harnesses there are two wires that go to the generator but in the new harness these wires route back to the amp meter and the ground leg of the headlight switch while in my original harness the two wires go to a firewall mounted generator cutout relay and wires from the relay go on to the amp meter and ground.

I have to add that my car is a 1936 McLaughlin Buick so I suspect that perhaps the Canadians used the external firewall mounted generator cutout relay while the US version must have the regulator built into or on top of the generator. Can anybody confirm where their relay is?

In the meantime, I'm still trying to figure out how to correct the issue. Unfortunately I've already had to modify the new harness to swap the instrument light sockets so sending it back for rework probably isn't going to happen. I may end up unwinding the cloth to add and reroute wires appropriately but I haven't quite worked up the courage to start hacking into my brand new expensive harness :(

Jeff

[h=3][/h]

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Jeff

The 1936 McLaughlin Buick special used a 5 terminal voltage regulator. No cutout. The #12[ heavier] wire from gen goes to voltage reg terminal marked Gen. The lighter #16 wire from gen goes to the F terminal.This is from 1936 McLaughlin Buick shop manual.I have converted both of my 1936s to 6 volt single wire self regulating alternators. Battery always charged and quartz halogen bulbs bright.

Stan

B.C.

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Jeff

The 1936 McLaughlin Buick special used a 5 terminal voltage regulator. No cutout. The #12[ heavier] wire from gen goes to voltage reg terminal marked Gen. The lighter #16 wire from gen goes to the F terminal.This is from 1936 McLaughlin Buick shop manual.I have converted both of my 1936s to 6 volt single wire self regulating alternators. Battery always charged and quartz halogen bulbs bright.

Stan

B.C.

Thanks for the information B.C. Where did you get the McLaughlin Buick manual? I could really use one of those so that I could try to spot differences before they surprise me.

I don't know if McLaughlin had the early and late model differences that the US versions did but the headlight switch and lack of fender lamps on my car makes be believe it is most closely related to the early production US cars.

On my car the "cutout relay /voltage regulator" is mounted on the firewall in front of the driver. The "box" has 4 connectors on it. A single connector on one side is labeled GEN and three connectors are on the opposite side labeled BAT, GRD, and F. When I take the cover off I see two coils and this all makes me believe this is a cutout relay for a 3 brush generator.

Now to add even more mystery, the box appears to have replaced whatever was on the firewall originally because it is physically bigger (wider) than the original mounting holes. Somebody put this in to replace the original and added an additional hole in the firewall to be able to do that. So if this is a cutout relay as I suspect, it may have replaced the earlier voltage regulator that you see in your manual. However, I believe the harness I removed was the original harness and it only has 4 wires in this area so I'm not sure what would have happened to the fifth connector you see in the manual.

The original wiring that I pulled out was setup as you indicated. From the generator, larger wire goes to GEN on the box and smaller wire goes to F on the box. The BAT was connected to the AMP meter and the GRD was connected to 8 on the headlight switch. Unfortunately, the new wiring harness is setup for US Buicks. There are 2 wires that come from the loom at the generator. One of these is routed back to the AMP meter and the smaller is routed to 8 on the headlight switch. I really don't like the idea of cutting into the loom to redirect wires through my box so I have been trying to contemplate other solutions.

One solution was to just move my box so that it would be within reach of the wires in the new harness, connect those wires to AMP and GRD on the box, and add two new wires that would connect the generator to GEN and F. The only problem is that the box is too large to strap onto my generator and I'm having trouble locating another spot that is close enough and doesn't interfere with everything else.

Another solution is to try to find the box that is mounted on top of the US version generator in the hopes that it is physically smaller and will fit there on my car. I found one for $45 but I don't know what size it is yet.

Reading your post, it sounds like you physically replaced the generator with an alternator. I thought about doing that as well but at least for the moment I'd prefer to keep it more original if possible.

Again, thanks for the valuable input and giving me more to think about.

Jeff

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The wiring harness you have is for a us Buick that used a cutout relay on generator. I have shop manuals for both McLaughlin and Us models.The Mcl voltage regulator terminal marked ign 16gau goes to vacuum starter switch. The one marked grd goes to terminal 8 of light switch.The 12 gau wire marked A goes to + of ammeter and through 30amp fuse to terminal 6 of light switch.

Because I couldn't get voltage reg to work properly I added 6v alternator. Worked so well changed my other 36 and my 35 to alternators.

Any other questions send personal email.

Stan

BC

Canada

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The wiring harness you have is for a us Buick that used a cutout relay on generator. I have shop manuals for both McLaughlin and Us models.The Mcl voltage regulator terminal marked ign 16gau goes to vacuum starter switch. The one marked grd goes to terminal 8 of light switch.The 12 gau wire marked A goes to + of ammeter and through 30amp fuse to terminal 6 of light switch.

Because I couldn't get voltage reg to work properly I added 6v alternator. Worked so well changed my other 36 and my 35 to alternators.

Any other questions send personal email.

Stan

BC

Canada

I have a few questions about replacing the generator with an alternator. I can understand the benefits with the more power, integrated regulator, less drag on the engine, etc. but do wonder about what speed you need to be driving before the alternator actually starts to charge. From what I have been reading, it seems that the 1 wire alternators need the alternator to spin at a certain speed before the charging circuit actually starts. I'd hate to be at idle or slow speeds and have the same issues with an alternator that I have with a generator.

I am also wondering how the one wire alternator gets wired into the system and how it looks on the amp meter. It seems like you would use the mounting for ground and run the single wire directly to the meter; is this correct? If you do it that way, does the amp meter still show charging and discharging?

One final question is how to get the correct pulley and look. I know that gener-nator would be the same outside and pulley but it is WAY too much money. The powergen looks a bit more attractive in that it retains the generator look. I'm still researching that approach but need to wait till Monday as their online catalog lists "please call" for a 1936 Buick. The only other options I've seen are alternators that look like a modern 12v alternator and those I'd have to imagine will require some rework to get the pulley correct. One final thought I had was to take the trek into town to an automotive electrical rebuilder to see if they can do something.

Thanks,

Jeff

Edited by Jeff_Miller (see edit history)
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