Genny Failure

[55 Fargo]

Hi all, tonight my genny failed, I thought I could hear it squealing a bit on my drives today. I did tighten the belt up a bit.

When I turn on the headlights, she is showing discharge even if I rev up the engine, is this a genny problem or a regulator problem.

How do I test the gen and reg, if the gen is shot, I have another in a parts car, the condition is unknown, if I have to do a replacement it will be a GM single wire alternator.

If I go the alt route, how hard is to fab up the mounting bracket, does anyone have any pics...............Fred

[PatS....]

I would suspect the regulator first. When I drove my first 49 Chrysler as a DD, it ate regulators regularly. Rarely had a generator failure. Carried a spare all the time.

[55 Fargo]

Pat, thats what I was thinking too, I switched regs, the same deal, unless my spare is also toast. As I mentioned , the genny was making some noise yesterday, possibly brush needs replacing, don't know. I will not chase down a regulator, will get an alternator first and be done withit.............................Fred

[55 Fargo]

One question, why would you be eating regulators so often, this doesn't sound like the norm, is it?

I would suspect the regulator first. When I drove my first 49 Chrysler as a DD, it ate regulators regularly. Rarely had a generator failure. Carried a spare all the time.

[greg g]

To test the generator temporarily ground the field wire with the engine running at about 1200 RPM. If the regulator is at fault, the genny will go to full charge on the ammeter. If the genny is at fault there will be no change on the gauge. The most frequent cause of genny failure is brushes. Brushes are about 15 bucks at NAPA, and the fix is ten minutes of bench time with the genny off the engine.

[55 Fargo]

Thanx Greg, here is what I did to fix the problem.

This morning I went out to the parts car, pully the genny and reg, the genny was rough, dirty, and not spinning well at all.

I then switched regs, this did nothing, I then pulled the genny, opened her up, and found the brushes in good shape, lots left on them, one brush spring was sticking quite a bit, the commutator was a bit dirty.

I cleaned up the brush springs, the commutator, and reassembled everything, and installed the genny back in the car.

Again no charging, I pulled the reg off, the genny back out, I opened the genny againg, removed the brushes, cleaned the brush housing and springs, cleaned out the genny with air and a rag.

I then noticed a rubber grommet, I did not put the rubber grommet back into the armature wire contact, when I reasembled the genny the first time, it must have been grounding itself. I reassmebled it correctly, installed the genny and original reg, fired up the engine, and all is charging nicely again.

The only probelm is this, I still hear the rear bushing squeaking, I cleaned this out, I oiled it , but still some squeakin, what gives?

I am not sure how long my repair will work, hopefully a while, I may take the genny in for repair on the rear bushing. If it is expensive, will buy an alternator to replace this genny/reg. .I also do not have the band that covers the brush holes on the outside, will maybe take the one off the parts car genny.............Fred

[Captain Neon]

Norm gave me this information a bit ago. When I switch to an alternator, I am going to get my set-up from http://www.alternatorparts.com/. They have a universal bracket that is supposed to work for our application. They even have wider pulleys that can be swapped out.

[55 Fargo]

Does anyone know how much it costs these days to get a genny overhauled, mine is working, bu the rear bushing is making noise, even though it got oiled.

I was thinking of getting it rebuilt, with new brushes, having the armature machined if necessary and new bushings for the armature shafts.

I think Rodney Bullock had this done a little while back, just thinkinga about my options...........Fred

[james curl]

Mine usually end up costing $70.00 to $100.00 for a complete rebuild.

[B-Watson]

Why buy a new regulator for a car with a generator? Unlike the electronic marvels of today, the old pre-1970's units are mechanical.

If you take the lid off you will find three sets of points on the unit - cut out relay, current regulator and voltage regulator. Clean the points with a file and not sandpaper or emery cloth until they are a grey colour. Then wipe the filings off with a linen cloth making sure no lint is left behind.

The cut-out relay gap should be set at .031 to .034 inches. The regulator points gap should be set at .048 to .052 inches.

Being mechanical, there are parts that do wear out, but more often than not the old regulators get tossed under the belief they cannot be repaired when a simple "tune-up" would solve the problem.

The regulators for cars with alternators in the 1960's were also mechanical, although they only had a voltage regulator inside to adjust. The gap should be 0.48".

Bill

Vancouver, BC

[captden29]

had 2 done at genco in central islip, ny. their work is superb and the generator comes back looking like it is a new one.no problems for several years. about $80. the second one i had done i asked if they had a new regulator. the guy said he would have to look where they store obsolete parts. about 20 minutes later he comes back with a new 6 volt regulator and when i asked him how much he said just take it, no charge. i like the original gen. and regulator and when they work properly they are great. capt den

[Normspeed]

B-Watson, thanks for the good info.

Fred, why not do a mix and match using the rear plate from the donor generator you have?

[55 Fargo]

Hi all, although I was able to clean up the genny inside, and did give here a nice paint job, I still decided to bring it into a local auto electric shop for a once over.

This is what he did in the shop, he opened the genny, gave the commutator a slight shave, check the armature, bushing, the whole thing.

He also at my request fabbed a new narrow pulley and fan to replace the widebelt version, this turned out great.

The genny was putting out 37 amps on the bench, he said it would probably put out 25 to 30 in the car, but depending what the regulator was set at.

This shop owner did all of this for $33.00, including the tax, I put the genny in the car, it works slick, and the narrow belt on my engine prefers the narrow pully on the genny..................Fred