alternator conversion

31chevy

31chevy

Well-known member
Hi Barner's I'm considering having my 34 generator converted to an alternator staying with 6volt positive ground. I think that there was someone who was recommended on this site but can't remember (CRS) to do this. I would appreciate any info on this especially from one of you that has done this. Thank's in advance. Also thinking of doing my 31 Chevy 6 volt neg. ground, sorry for mentioning Chevy. I would like to keep them original looking.
Gary.
 
I would like to hear the factors that you are considering for making the change. Is your truck 4 or 8 cylinder? The person you are probably thinking of is Ed Whitney, (714) 773-1611 in Buena Park, California.

Charlie Stephens
 
I just put an alternator on my `51 pickup. The alternator has just one wire that goes directly to the battery as per the directions that came with it. This does away with the cut out or voltage regulator altogether as the alternator is self regulated. My `51 was already converted to 12 volts and had an aftermarket volt meter. So I routed the the single wire through the volt meter using the existing wirimg and it all works perfectly. I would think you could do the same with your ammeter as you are staying with 6 volts.
 
I made seven 6 volt alternators in old Ford cases for my own cars that work great. They are the one wire type. I did these several years ago so I have a fair amount of miles on some of them. They charge to about 6.75 at a very low idle with a standard Ford fan pulley, I don't like small pulley's that don't have much belt surface grab that need to be super tight to get the RPM's up. As soon as it comes up to a fast idle they charge to 7.5 which I can change by a screw adjustment. One thing I descovered the other day when an old hose blew off the bottom of a 39 in the shop and I turned off the master battery switch it kept running. After replaceing both lower hoses which were soft I turned the master off while running and it ran off the power of the alternator with no battery connection. You can't start the engine because of no power to the solenoid or coil voltage. With the ignition on when the battery is removed the alternator is putting out at least 6 volts to run it. I have a digital volt meter and will have to see how much it puts out without a battery. I did have a Optima give out on a 1,200 mile trip 2 years ago. It went out about 200 miles into the trip, it burnt off the interior connection under the battery terminal all but about a 1/16" spot. It would almost pull in the solenoid but that was it. I had a 12 volt jumper pack with me and jumped it several times on the rest of the trip and even had bright lights for several hours of night driveing. I took the battery apart along with another that failed completely serveral years prior that I never got around to looking at. Both failed the exact same way but the first one had no connection at all. I suspect with the one wire alternator there will be a very slight battery drain through the diodes of the alternator. Another good reason for a battery disconnect switch. G.M.
 
Gary-

I will probably get a lot of flack on this but if you are considering running an alternator with a fan attached pulley such as you have in your '34 - DON'T. I have tried using them in various applications in early Fords and found them not worth the trouble.

Regardless, of its rating, six volt alternators only put out about 38 amps, maximum. This is not much more that a two-brush generator puts out. The really bad part is the "activation" speed required to get an alternator (six or twelve volt) to start charging. They really need to spin fast which explains why modern cars have such a small alternator pulley when compared to the larger crank pulley.

I tried putting an alternator on my '35 with a fan adapter so I could run the stock fan for radiator cooling. The fan was spinning so fast at an idle, I was fearful the fan would break-off and cause all sorts of under-hood grief at higher speeds! I am currently using a 35 amp two-brush generator with the regulator hidden under the dash to keep the engine compartment looking "stock." It has been trouble free.

One way to avoid this problem is separating the fan from the alternator with an accessory fan located in front of the radiator (behind the grill)- I have not done this but I have talked to others who felt that the fan in front of the radiator is good at idle speeds but tends to limit air flow at highway speeds which creates engine over-heating. Again, I have heard of this, I have had no personal experience.

However, getting away from the fan attachment problem an alternator can work very well in other applications. I do have a GM alternator on my '50 pickup and it works great and has been trouble free but, as you know, the fan is not not attached to the alternator.

Before you jump ahead, it might be worth asking others about their experiences with fan location on Pre-War models when using an alternator.

Tom
 
G.M. said:
I made seven 6 volt alternators in old Ford cases for my own cars that work great. They are the one wire type. I did these several years ago so I have a fair amount of miles on some of them. They charge to about 6.75 at a very low idle with a standard Ford fan pulley, I don't like small pulley's that don't have much belt surface grab that need to be super tight to get the RPM's up. As soon as it comes up to a fast idle they charge to 7.5 which I can change by a screw adjustment. One thing I descovered the other day when an old hose blew off the bottom of a 39 in the shop and I turned off the master battery switch it kept running. After replaceing both lower hoses which were soft I turned the master off while running and it ran off the power of the alternator with no battery connection. You can't start the engine because of no power to the solenoid or coil voltage. With the ignition on when the battery is removed the alternator is putting out at least 6 volts to run it. I have a digital volt meter and will have to see how much it puts out without a battery. I did have a Optima give out on a 1,200 mile trip 2 years ago. It went out about 200 miles into the trip, it burnt off the interior connection under the battery terminal all but about a 1/16" spot. It would almost pull in the solenoid but that was it. I had a 12 volt jumper pack with me and jumped it several times on the rest of the trip and even had bright lights for several hours of night driveing. I took the battery apart along with another that failed completely serveral years prior that I never got around to looking at. Both failed the exact same way but the first one had no connection at all. I suspect with the one wire alternator there will be a very slight battery drain through the diodes of the alternator. Another good reason for a battery disconnect switch. G.M.
Click to expand...
Hi GM. could you send me some information on how you did this? Materials & where to get them etc. it would be appreciated (I would like to do it myself if possible) Thank you in advance. Gary.
 
Thank all of you, but my goal is to have alternator wiring in original generator case so I can use original bearing & fan setup not to put an alternator in its place. Thank's again.
Gary.
 
flatheadfan said:
Gary-

I will probably get a lot of flack on this but if you are considering running an alternator with a fan attached pulley such as you have in your '34 - DON'T. I have tried using them in various applications in early Fords and found them not worth the trouble.

Regardless, of its rating, six volt alternators only put out about 38 amps, maximum. This is not much more that a two-brush generator puts out. The really bad part is the "activation" speed required to get an alternator (six or twelve volt) to start charging. They really need to spin fast which explains why modern cars have such a small alternator pulley when compared to the larger crank pulley.

I tried putting an alternator on my '35 with a fan adapter so I could run the stock fan for radiator cooling. The fan was spinning so fast at an idle, I was fearful the fan would break-off and cause all sorts of under-hood grief at higher speeds! I am currently using a 35 amp two-brush generator with the regulator hidden under the dash to keep the engine compartment looking "stock." It has been trouble free.

One way to avoid this problem is separating the fan from the alternator with an accessory fan located in front of the radiator (behind the grill)- I have not done this but I have talked to others who felt that the fan in front of the radiator is good at idle speeds but tends to limit air flow at highway speeds which creates engine over-heating. Again, I have heard of this, I have had no personal experience.

However, getting away from the fan attachment problem an alternator can work very well in other applications. I do have a GM alternator on my '50 pickup and it works great and has been trouble free but, as you know, the fan is not not attached to the alternator.

Before you jump ahead, it might be worth asking others about their experiences with fan location on Pre-War models when using an alternator.

Tom
Click to expand...
I agree with you, I was not considering replacing the Generator with an alternator. Just rewiring the generator.
Gary.
 
Tom I have a 35 roadster with my alternator and stock Ford fan and it charges and works perfect with a voltage range as described in my last post. I also have one on my 39 P/U which has the same type of fan mounted to the pulley. This one has an industrial 6 bladed fan. I have put a lot of miles on this P/U with no problems. I do often check to make sure nothing is loose which is good to do with any fan. Go back and read my operational volts at low speeds with a STOCK Ford pulley on the alternator. I built a machine to test the alternators I made and they are 25 amps. I tried 2 GM alternators a friend of mine and his son bought for their 35 and 36's and took them off after a week because they felt they were not as good as the generators. I took them to a REAL electric motor shop and the older owner said if we put a 24 volt stator in it would charge at lower rpm's. I did this with both of them and they worked great but I didn't like the look of that chevy thing in my old Fords. The stators cost about $35.00 installed. G.M.
 
Certified Auto Electric in Bedford, Ohio, makes a 1 wire alternator for 6 volt positive ground - works great!!! I have had one in my '52 F1 for 7 years now.
 
That's where the two I had came from that needed a SMALL pulley to increase the RPM's. The 24 volt stator corrected the problem and worked good with a stock Ford pulley. Ford made differant diameter pulley's. On the fan mounted generator you need the pulley where the 4 tapped holes for the mounting of the fan are out near the OD of the pulley. These are a little hard to find but they are out there. If we are going to talk of how good things work lets give some accurite voltages at a slow idle with a digital volt meter. Not just 7 volts but 7.2 volts or what ever it reads. i have an adjustable voltage regulator and can adjust the output by 1/10 of a volt. This adjustment is fairly critical up in the max output range of 7.5 If you get much over that you can damage the battery. The higher the output voltage the brighter the head lights. Not over 7.5 or battery and bulb problems and the lower the voltage the dimmer the lights. G.M.
 
About 12 to 15 years ago, I had a generator converted to alternator by a local electric shop. They were stuffing a Mitsubishi alternator into the Ford generator case. It has worked for years, but it also does not have a fan to deal with. It used the stock Ford pulley. From the outside, you can't tell what is inside unless you look through the slots in the back of the generator housing and you cannot see any brushes. It did require a wire to the coil to excite the alternator for it to work. I guess it was a one wire with an extra wire?
 
I used the 2 brush cases the 3 brush is to small in diameter. I had to mill 4 round slots from front to rear on the ID of the shell at 360-90-180 and 270 for the 4 "ears" on the alternator housing to slide into this also keeps the alternator from revolving in the Ford case. The "ears" also required some metal removal to fit. The rear bearing in the alternator case supports the rear of the rotor. The original rear cap with the generator bushing and brushes is now just a cap with the bridge rectifier and adjustable voltage regulator. The rotor, stator and brush have a plug. The rear cap has a mateing plug. I made 7 alternnators and 2 extra rear caps for spares. This was a few years ago and there may be smaller alternators available today. I put the front bearing in the alternator case with a shaft adaptor made to go through another bearing in an original Ford front mount. They line up perfect so I doubt I will ever have any front bearing problems. I also had to modify some brush holders because I removed the 12 volt regulator which had the brush holder molded on it. G.M.
 
Thanks G.M. for the explanation. I never had a Model A with the 2 brush generator so I never even thought about it. I have looked into putting a Toyota (Mitsubishi) 27060 inside a 3 brush case though. The outside diameter of the stator is about 4" and the front couple of inches of the inside of the Ford case would have to be turned out to that diameter. It would only leave about 1/16" thickness in the case in that area but that would still be strong enough because the major force is on the front and rear caps. The stator would be installed without the original housing and would use the front cap for rotor support. A new rear bearing support would have to be made that would fit inside the Ford case .
 
Heres a couple that I have done .
 

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There are 2 fans, one the front and one in the rear in the original alternator housings I used that keep them nice and cool. This is one thing you have to watch you don't want them running hot. G.M.
 
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