38Buick 80C Posted February 5, 2017 Share Posted February 5, 2017 OK next question. Took my 80C out for a little spin test run before my trip. During warm up and the first couple miles of driving I have a nice charge going. Then it kinda goes flat and then a discharge below 50mph. When I stopped for gas I still had plenty to get restarted and it charge for a bit at idle and then back to flat and then discharge. Is that normal for a Generator? Been doing it since the drive home from Allentown. Thinking about swapping out the voltage regulator. Link to comment Share on other sites More sharing options...
JohnD1956 Posted February 5, 2017 Share Posted February 5, 2017 The VR is adjustable. Perhaps that's all that's needed? Link to comment Share on other sites More sharing options...
38Buick 80C Posted February 5, 2017 Author Share Posted February 5, 2017 And how does one adjust the VR? 1 Link to comment Share on other sites More sharing options...
EmTee Posted February 5, 2017 Share Posted February 5, 2017 Oh, sorry --wrong forum. I thought this was the -- never mind... 3 Link to comment Share on other sites More sharing options...
Beemon Posted February 6, 2017 Share Posted February 6, 2017 3 hours ago, EmTee said: Oh, sorry --wrong forum. I thought this was the -- never mind... Not to get off topic here, but if there is any type of low speed discharge, you may want to get that looked at. The average discharge speed should be roughly 27mph, according to doctors... I don't know how different a 38 Buick VR would be to a 56 VR, but on the 56 it has two screws to take the cover off. Inside should be three windings with contact points that you can manually bend and adjust per the shop manual (if there is one). 1 Link to comment Share on other sites More sharing options...
Joseph P. Indusi Posted February 6, 2017 Share Posted February 6, 2017 Do as Beemon says. If the manual is no help when you get to the discharge condition, remove the cover on the VR and adjust the voltage regulator section to raise the voltage a bit. If that does not help return it the previous setting. If you can, replace the VR with a new one or known good one. Good luck. Joe Link to comment Share on other sites More sharing options...
MCHinson Posted February 6, 2017 Share Posted February 6, 2017 Brian, Assuming the 1938 Voltage Regulator is adjusted the same as the 1937, I would offer this suggestion from the 1937 Service Manual. Link to comment Share on other sites More sharing options...
FLYER15015 Posted February 6, 2017 Share Posted February 6, 2017 Matt, I think Brian needs some more info from the manual. The Caution section mentions the IGN wire needs to be reconnected after the test. Should it be just disconnected for the test, or hooked up to something ? Q= what does the previous page say ? Mike in Colorado Link to comment Share on other sites More sharing options...
Mark Shaw Posted February 7, 2017 Share Posted February 7, 2017 I would just file the points per the instructions above and see if the problem goes away... (Always try the easy and less expensive fixes first) 4 Link to comment Share on other sites More sharing options...
MCHinson Posted February 7, 2017 Share Posted February 7, 2017 11 hours ago, FLYER15015 said: Matt, I think Brian needs some more info from the manual. The Caution section mentions the IGN wire needs to be reconnected after the test. Should it be just disconnected for the test, or hooked up to something ? Q= what does the previous page say ? Mike in Colorado That section will diagnose it as either needing the Generator rebuilt or else the voltage regulator points needing to be cleaned up. If he needs further diagnosis than that, then the prior section is this: 1 Link to comment Share on other sites More sharing options...
38Buick 80C Posted February 7, 2017 Author Share Posted February 7, 2017 i cleaned the point but will have to wait for a test run. Link to comment Share on other sites More sharing options...
DonMicheletti Posted February 7, 2017 Share Posted February 7, 2017 The Buick actually has a "charge indicator", not necessarily an amp meter. When I put an amp meter in series with the charge indicator, I found things werent as bad as I thought. You might try that to get a real amp reading Link to comment Share on other sites More sharing options...
60FlatTop Posted February 7, 2017 Share Posted February 7, 2017 (edited) A good generator with the armature checked, brushes in good condition, and an adjusted belt is more reliable than that gauge ever could be. If you find looking at the gauge distracts your driving put a piece of electrical tape over it. But I did think of the '94 Roadmaster that I bypassed the ABS module on. My friend, Mike got the car from me. He came in the coffee shop one day and said there was a piece of black tape on the dash and it looked like a light was glowing behind it. I told him not to worry about it and don't pull it off. Some stuff is just that way. Bernie Edited February 7, 2017 by 60FlatTop (see edit history) 1 Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted February 7, 2017 Share Posted February 7, 2017 4 hours ago, DonMicheletti said: The Buick actually has a "charge indicator", not necessarily an amp meter. When I put an amp meter in series with the charge indicator, I found things werent as bad as I thought. You might try that to get a real amp reading Or a volt meter Ben Link to comment Share on other sites More sharing options...
Mark Shaw Posted February 7, 2017 Share Posted February 7, 2017 7 hours ago, 60FlatTop said: If you find looking at the gauge distracts your driving put a piece of electrical tape over it. Some stuff is just that way. Bernie Bernie, you're too funny! I wonder if you're like the guy who removes his hearing aids to make his engine sound better? Do you still have tape over clock on your VCR too? Some guys are just that way you know.... LOL 1 Link to comment Share on other sites More sharing options...
60FlatTop Posted February 7, 2017 Share Posted February 7, 2017 It is a reality. Go to an auto parts store and ask for an oil pressure sending unit, sure it's on the shelf. Ask for an oil pump. Oh, I'll have to order that. Most failures are sensors when they are installed. Two finely wound magnets attached to a pivot pin that are 80 years old are little more than a reference point. Gently bend the needle to point where you want. Cooling systems are the same. A clean radiator, a good belt, clear clean coolant in a clean block is way more reliable than an 80 year old capillary tube with a volatile fluid inside. Hearing aids are not related and out of the context of this instance, Only CNN could make a connection like that. Anyway, tape is for unwanted lights, bending the needle is for suspicious gauges. Almost any system is much more reliable that the device that monitors it. Gee, I just thought of CNN and the media again. 4 Link to comment Share on other sites More sharing options...
DonMicheletti Posted February 8, 2017 Share Posted February 8, 2017 I never have trusted an old gage I havnt tested. The temp gages are really easy (once out of the car). Just put the bulb in a pot of boiling water. There is a mark on the face that is at 212°. It should match. My oil pressure gage is of by several pounds too. Link to comment Share on other sites More sharing options...
DonMicheletti Posted February 8, 2017 Share Posted February 8, 2017 I never have trusted an old gage I havnt tested. The temp gages are really easy (once out of the car). Just put the bulb in a pot of boiling water. There is a mark on the face that is at 212°. It should match. My oil pressure gage is of by several pounds too. Link to comment Share on other sites More sharing options...
EmTee Posted February 8, 2017 Share Posted February 8, 2017 (edited) 2 hours ago, 60FlatTop said: Anyway, tape is for unwanted lights, bending the needle is for suspicious gauges. My father had a buddy in TN who sold used cars. His remedy for an illuminated 'check engine' light was to drill an 1/8" hole through the lens in front of the indicator and then push an ice pick (or other similar, sharp instrument) through the hole. Light's out! Edited February 8, 2017 by EmTee typo (see edit history) Link to comment Share on other sites More sharing options...
NTX5467 Posted February 11, 2017 Share Posted February 11, 2017 MIght it be that thee "charge indicator" is an earlier version of the "GEN" light? When the light glows, the "charge" is going backwards (discharge) and when it's not illuminated, the "charge" is going "forward" (charging). In order to check "amps", you need specialized test equipment with a variable load to do that. "Volts" are simple and can be done with a meter (set to the correct scale). In GM nomenclature, a "sensor" has a variable mechanism inside that works a gauge. A "switch" in just that and runs and indicator light that's either "ON' or "OFF". The generator/charging circuit gauge or light indicates which way the current is flowing through a certain section of the charging system harness. I suspect that if everything else is in good order, it could be that the reason the charge starts and then stops is due to underhood temperature rising and falling. That's where the vr adjustment comes in AND the temperature spec for when the adjustment (and determination that adjustment is needed) comes in. This keeps the system from overcharging in hot weather, but ensures it charges well in cooler/cold weather. Some aftermarket voltage regulators had an external screw (with arrows for "more" or "less", or similar) on them. One use for was vehicles driven for short distances, but could also be driven for longer distances, every so often. For "town" use, increase the charge rate. For "trip" use, decrease the charge rate. Of course, this was well before we had "normal" 165+amp alternators controlled by the ECM by turning them "on" and "off" as needed to maintain battery charge levels to run the multitude of computers and such! Much simpler when we had a/c generators/alternators of about 45amp output! AND . . . check and make sure the battery terminals are CLEAN . . . posts and the terminal contact area at the posts. PLUS the interface at any ground strap/cable, too! Grunge can be in that interface and not really be visible, yet it can negatively-impact charging system performance. About a 10% loss on modern vehicles, by observation. Details details, details . . . . NTX5467 Link to comment Share on other sites More sharing options...
38Buick 80C Posted February 11, 2017 Author Share Posted February 11, 2017 Cleaning the points seemed to do the trick though I do have something going on with the Regulator with the lights. See my Boca Burning Buicks post for more info. Link to comment Share on other sites More sharing options...
Thriller Posted February 11, 2017 Share Posted February 11, 2017 5 hours ago, NTX5467 said: it can negatively-impact charging system Groan.... Link to comment Share on other sites More sharing options...
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