Smoking regulator.

[carguy300]

Got my 300 running finally but I dont know why voltage reg is smoking after about 45seconds. Its new, I had my alt rebuilt over a year ago. I checked voltage at imput of reg, 12.2. Im not sure how to check amps. When I do plug lead back on it pull RPMs down a little. It is grounded good. Im afraid to leave it plugged up, dont want burn anything up. The gauge on dash goes to charging over half way. I do have the 2 culprit wires out of the bulkhead and ran through were speed cable comes through. Any thoughts?

 

[Sixpactogo]

Are you are sure your case ground on the regulator is good? I would test it again. If you have a digital Ohm meter you should be able to see less than .5 ohms between the regulator case and neg post on the battery. You shouldn't be getting any smoke. It sounds like it was charging ok on your gauge.
Verify your ground and try it again.

 

[DCMC]

I thought this was about cigars.

 

[Big_John]

Got my 300 running finally but I dont know why voltage reg is smoking after about 45seconds. Its new, I had my alt rebuilt over a year ago. I checked voltage at imput of reg, 12.2. Im not sure how to check amps. When I do plug lead back on it pull RPMs down a little. It is grounded good. Im afraid to leave it plugged up, dont want burn anything up. The gauge on dash goes to charging over half way. I do have the 2 culprit wires out of the bulkhead and ran through were speed cable comes through. Any thoughts?

Is it a mechanical regulator or an electronic version?

I was just reading the other day about the mechanical regulators smoking when new. Basically burning off a coating on the resistors. I have not experienced this myself, but it did come from a pretty reliable source.

 

[413]

Put a volt meter on the battery engine off, how much? 12.6 is full charged. 12.2 is pretty low and it will charge more when running.

Now check voltage when running. Under 14.5 then let it run. Much over 15 is too high. Full field it will go to 17, very bad.

I've had them smoke for 2 minutes then no more, working fine. One of the resistors on back get very warm.

 

[carguy300]

Im still using a mechanical regulator, single field alt. Battery is new, I read to that some smoking can be common when brand new also. I will recheck the grounds tomorrow.

 

[Sixpactogo]

You are probably fine....I don't recall ever seeing smoke from a new regulator but it sounds like it is pretty common.
You may want to consider installing one of these battery disconnects on your neg post. I have one on all of my collector cars. They are nice when you need to kill the current flow before burning your car to the ground. I also like them when I put my cars to bed for the winter.


https://www.ebay.com/itm/145859179583?_

 

[carguy300]

Im going to go out after awhile and try again, verify voltage, and hopefully it will stop smoking ina couple minutes. And yes I have seen those quick dissconnects and I will probably invest in that.

 

[carguy300]

Well I fired up the 300 again awhile ago and ran about 3 mins. Volts ran up to 16, I did not dare go any higher. Shut her down. Is the alt over charging?, I had rebuilt by a local guy, maybe not right but its been over a year. I have found 2 twin pulley, single field 60 amp alts out in the web world. I think its time to replace and see what happens. Both are less than $75. Any opinions?

 

[carguy300]

Is it a mechanical regulator or an electronic version?

I was just reading the other day about the mechanical regulators smoking when new. Basically burning off a coating on the resistors. I have not experienced this myself, but it did come from a pretty reliable source.

Hey Big John, do you think I need to get another alt or maybe this new reg is bad. I ckd voltage yesterday at the battery, started out 12.5 and continued to climb till I shut it off at 16 volts. Still working on 68 300.Charging system is not my specialty. I appreciate your help.

 

[Big_John]

Hey Big John, do you think I need to get another alt or maybe this new reg is bad. I ckd voltage yesterday at the battery, started out 12.5 and continued to climb till I shut it off at 16 volts. Still working on 68 300.Charging system is not my specialty. I appreciate your help.

If the voltage is excessive, then the alternator must be fine... 16 volts is high, but run it a little and see what happens. If it stays that high, you might be able to adjust the regulator down. I wouldn't run it for long at 16 volts as it can hurt the battery.

Where are you taking the voltage readings? Take them right at the battery.

 

[carguy300]

If the voltage is excessive, then the alternator must be fine... 16 volts is high, but run it a little and see what happens. If it stays that high, you might be able to adjust the regulator down. I wouldn't run it for long at 16 volts as it can hurt the battery.

Where are you taking the voltage readings? Take them right at the battery.

Yes sir Im taking them at the battery posts. I shut it off at 16 volts, not sure how much higher it might go. Ive never adjusted a regulator, is that a simple procedure?

 

[Big_John]

Yes sir Im taking them at the battery posts. I shut it off at 16 volts, not sure how much higher it might go. Ive never adjusted a regulator, is that a simple procedure?

Some can be, some can't (or done easily). Pull the cover off and see if there's an adjustment screw.

OK, at the battery posts... Yea, that's too much.

 

[carguy300]

More checking tomorrow. Thanks!

 

[stain]

I have adjusted my mechanical regulator a few times on my 68. In the factory manual it actually shows the procedure to do this.
I let it idle with a meter on the battery and bend the tab until I get the voltage where I want. I then compare it to the gauge in the car to see how they compare.
If doing while running, BE CAREFUL not to ground the adjustment tool, or better yet, use a nylon one.

 

[carguy300]

I found and ordered 2 single field solid state regulators, I hear good things about them.

 

[dplotkin]

Got my 300 running finally but I dont know why voltage reg is smoking after about 45seconds. Its new, I had my alt rebuilt over a year ago. I checked voltage at imput of reg, 12.2. Im not sure how to check amps. When I do plug lead back on it pull RPMs down a little. It is grounded good. Im afraid to leave it plugged up, dont want burn anything up. The gauge on dash goes to charging over half way. I do have the 2 culprit wires out of the bulkhead and ran through were speed cable comes through. Any thoughts?

A new mechanical regulator can smoke on initial startup & use as the factory coating on the resistors buns off. Likely nothing wrong. A new ballast resistor will do similarly.
Dan