VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 I got it home. This is what I noticed....

I picked up the 1936 Master Deluxe tonight. I drove it about 26 miles home. The weather here in Texas was 78 to 80 degrees when I drove it.
The temperature gage read one mark less than 180F (160?). I stopped to talk with some one for about 4 minutes and the temperature rapidly rose to 180+. After I got moving down the road it cooled back to earlier reading after 1 mile. I was driving 45-50 mph thoughout my trip. Does this sound "normal"?

The ammeter read 20 (charging) the whole trip home. Pulling or pushing the light switch made no difference. The previous owner recently replace the 6volt battery. Is this charging normal? Do I need to adjust the third brush to reduce charging rate? I looked at the generator and noticed two terminals. One terminal (GEN?)had one wire going to the cut-out. The other terminal (FIELD?)has three wires attached. Two go into a wire harness and the other attaches the the generator case (grounded?). Would this make the generator charge continuously high? I thought that the Master had a 936-V generator and the charge rate was controlled by a light switch resistor. If it is a 936-V generator, the third brush is set and should not be adjusted (using light switch for rate adjustment). How do I determine which generator I have? Do you think somebody changed something during the last 70 years?

I originally thought that the car was wired as positive ground but upon inspection the battery cable colors are just reversed. The red attaches to the negative terminal and frame and the black attaches to the positive terminal and goes to the starter.

Also when driving home the oil pressure indication was just barely to the first mark (5 psi). Is this a concern? normal?

Your generator has too much output and someone has done some rewiring and they have full-fielded your generator for continuous maximum output.

The correct output for the 936-V generator (which is the model that should be on your car) is 15 amps hot. One wire goes from the generator to the "GEN" terminal on the cut-out. The wire on the "field" terminal on the generator goes to the resistance unit on the back of the light switch. The third wire attaches to the "BAT" terminal on the cut-out and goes to the back of the ammeter.

Check the wiring on your generator and also you should adjust the third brush to a maximum of 15 amps hot. At 20 amps your generator armature will throw solder and your generator will also overcharge your battery.

Junkyard Dog,
That is what I feared. I will disconnect the wire grounding the FIELD terminal tonight and see what happens. I need to find out where the two other wires attached to the FIELD terminal are going. From what you said there should only be one wire attached and it goes to the light switch.
There is a wire on the BATT terminal of the cut-out which I assume is going to the ammeter (since the meter works).

Fred:
The 206 engines are not known for their high oil pressure. 5 psi may seem low, but the key is delivery, not pressure. Just to be sure I suggest you drop the oil pan and clean the screen on the oil pump. A clogged screen can seriously reduce oil pressure. As you continue to use detergent oil (30 wt.) you will dislodge old dirt and crud and the screen will need frequent cleaning.
I've had similar heating issues with my '35, although mine are more serious (I will replace my radiator in a week or two). Your rise in temperature doesn't sound too bad. This engine doesn't have a full length water jacket and the volume of water is limited, so a little bump in temperature can be expected. Maybe a quick flush of the radiator would be in order.
Keep us posted on your progress!

Coach

Yes, there should be only one wire on the field terminal on the generator and it goes to the light switch.

Coachill all 1936 207 cu.in. engines have full length water jackets plus a higher capicity water pump. One should always check the calibration of the water temperature by removing the bulb and placing it in a known temperature water; use a good thermometer.

I should have said remove the temperature sensor bulb from the back of the cylinder head and place it in known temp water then read the dash gauge to see if it reads correctly.

To me the temperature sounds normal for summer weather.

The oil pressure should be in the 13 pound range at 45-50 MPH.Five is way to low except for at hot idle speed.If the main bearings are not pounding I would suspect that the original vane type oil pump is worn.Chevrolet (and others) made an improved gear type pump that came with the necessary parts to adapt it.This would be the route that I would take.I am assuming that it has at least #20 oil or 10W-30.Always a good idea to remove and clean the oil pan and screen anyway.
Sounds as if you are having fun - and how are the brakes?

Chevgene,
I did not try to adjust or disassemble the brakes yet. I want to get the generator wiring sorted out first.

I do not know the oil weight currently in the engine. I will be changing it soon. Maybe when I remove the oil pan. What chance do I have that I can reuse the oil pan gasket? Do you know where I can get a new gasket?

The gaskets are still made by FelPro...Get a catalog from "The Filling Station"....see their on line catalog at ....www.fillingstation.com..

Either straight 30 or 10W-30 oil can be used.Seeing the pan will be clean detergent should be fine unless the rest of the engine looks extreemly sludged up.

If you do pull the pan I would replace the oil pump while your in there.I think that there some of the new style gear type pumps advertised in the G&D recently.The G&D is the Vintage Chevrolet Clubs monthly publication.Seeing you are now a vintage Chevrolet owner it would be advisable to become a member.Should help you to find other members/owners in your part of Texas.

HI,
Bruce has the gear pumps.
Bwbugay@aol.com

If you arenot going for 1000 points, I would use a real voltage regulator. The old system, as the Dog describes, will eat your battery. The more you drive, the quicker it will happen. What you do is set the charge rate for a little more than you expect to draw, with and without the headlights. The result is that if you run the battery down it takes a long time to get back up because the charge rate is low. Then, when the battery is full, you are guaranteed to overcharge it because it takes very little current to hold it at the correct end point (full charge) voltage. On the old cars there were not many variable loads besides the headlights, so you could indeed get this to work fairly (at best) well. Many times people would have the shop tweak the third brush to give more charge to cover the heater and the likelihood of more/harder cranking. It was a bear for city people because they usually didn't go fast enough long enough to keep the battery up. A bad traffic jam with headlights and heater could do in a battery pretty well and the drive home might well not get it back up.

A real regulator monitors the battery voltage and keeps it from going too high. It also monitors charge current and prevents overload of the gen under dead battery/headlight/heater conditions.

The right answer to all this is a solid state regulator, but I can't remember seeing them for sale, although I have been over the design many times in my head. Many good size regulator integrated circuits are available, so it would be easy to do. Failing that, I think most any old 6V relay regulator would work. I'd just get the one specified for the the first Chevy to offer them. As an interim solution, you could easily mount a voltmeter and rheostat under the dash and adjust the charge current as you drive. Hold about 7V.

When I was younger (Have you noticed that we tend to say that more and more often?) I had a big ham radio rig in my '53Chevy. It drew a lot of current, so I needed all the charge I could get. Sure enough, tweaking the spring on the current limit relay got me to 50A no problem, BUT it wasn't long until I spun the solder out of the armature! Another time, while commuting from Cambridge (MA) to NC during college, the front bearing let go when I was going down the Conn. Tpk. in the middle of the night. I noticed the voltage going down and the charge current getting erratic, so I stopped, popped the hood, and looked at the gen. Sure enough, sparks were flying out because the armature was rubbiing on the pole pieces (fields). Well, I was always talking to a bunch of hams up and down the east coast, including my dad, so I got on the radio and told them I wouldn't be on much more that night, but would check in occasionally. I loosened the fan belt until it slipped easily over the gen pulley but still turned the fan OK and drove on. Every couple of hours I'd turn on the radio and pass the word I was going OK. On the big roads I'd get behind a truck and cut back to parking lights, or sometimes mo lights if traffic was light. About dawn I stopped for breakfast and had the filling station next door put the bat on fast charge, somewhere in northern VA. That charge got me home to Winston-Salem, NC, with no problem!
I hope you find this tale amusing. Next time I'll tell you about the time the headgasket leaked antifreeze into the oil and ate the rings...that was a slow trip home that produced a lot of smoke and empty oil cans.

As a final heresy, you might think about a small one wire alternator. They are available in 6V, but changing to 12V wouldn't take much. I have 12V ones on both my old tractors and they are very nice! I love original, but if I were touring an old car, I'd sure think about it!

I have had my '34 for over 35 years. It has the original charging system.I have used the car for many long trips and covered over 400 miles in one day.The charging rate is at about 12 amps regular, about 20 with the light switch out i/2 click.The first long trip I took to Ohio in 1973 worried me because of the constant charging.Note that when you go faster (over 50) the charging decreases a little.My batteries last 6 or 7 years.The last one was going strong at 7 years but I replaced it any way.Seldom add water...perhaps every 1000 miles if on a long trip.The only short fall with the system is that it can't produce enough amps to cover the head lights (I use higher candle power bulbs,dual tail lights, and a heater or radio).Will just handle the lights alone.
My '39 is great because it has a voltage controll and can handle all the eletrical needs.The '34 gets by.For me thats part of the fun of having an old car...putting up with its short comings as the owners did when the car was new and learn to live with them.The other alternative would be a street rod or a newer car.

FredW, Lots of advice. You might consider replacing the water pump, boiling the radiator/recoring and a new thermostat...

I looked at the generator wiring tonight. I disconnected the grounded wire from the field terminal and now the ammeter shows just a hair on the +side. When I pull out the light switch to first notch the charge jumps to about +12. Then with lights on slightly less but still good charge rate. No more needle charging at 20 anymore. This seems to be the correct operation now. I wonder why someone chose to ground the field and let it charge like crazy. The car does have a heater and cigarette lighter.

Speaking of heaters, the car get pretty warm even without the fan blowing. I guess I could either put a shut-off valve in one of the hoses under the hood or remove one hose and just loop the other back to the engine. What is the original way to turn off the water flow?

I also cleaned up the light bulb sockets. Now I have both high and low beams and tail/brake lights.

I hooked up a vacuum gauge to the engine and it held a rock steady 18 inches at idle. No jittering or floating needle. It appears that the valves are good. Is 18 inches correct for this engine (61k miles)?

Cool! Glad that the generator is now working correctly.

In your first posting you stated the following: "The other terminal (FIELD?)has three wires attached. Two go into a wire harness and the other attaches the generator case (grounded?)."

You removed the ground wire from the field terminal. However, you still have two wires going to the field terminal on the generator. Did you determine what the two remaining wires are connected to?

In 1936 they disconnected the heater hoses for the winter.By 1939 they (Chevrolet) sold a shut-off valve that went into the block.Even with the heater disconnected you will get a lot of heat thru the firewall.If you can see day light thru any of the openings plugging them will help.Thats the charm of these old cars.You get heat thru in the summer and in winter you freeze.Opening the cowl vent helps.Chevs of the '40's sell a version of the shut off valve.
The vacuum sound good.At 61,000 miles the engine probably has been overhauled once and had two or three valve jobs.
The generator should becharging (on the ammeter) about 10 amps with the switch knob in.Can be set with the 3rd brush.The charge will not harm the battery as long as the water level is maintained..It would take 10 hours of steady driving to charge a dead 100 amp battery at 10 amps.

Junkyard Dog,
I have not traced the two field wires yet. The two wires attached to the generator are red plastic insulated. The single wire attached to the ammeter is gold/yellow fabric insulated. Somewhere in the harness there must be a splice connecting the old with the new wires. While I was under the dash I noticed that all wires were gold/yellow fabric insulated. I guess they did not color wires by function for easy tracing in 1936.
There was one wire disconnected that run up to the top left (driver) side of the dash into the frame. Do you know what the function could be? The only thing that does not work is the dome light. Where does the dome light wiring route on the way to the roof. The switch is located on the passenger side center pillar. I attached the wire to power and then to ground but nothing happened. If it is the dome light wire, the switch or bulb could also be bad.