GM one wire alternator for addition of electric fan on radiator for cooling

[Joe R.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

John,

I have used the factory fit radiators with electric fans on both SB and BB setups. Worked great and painting them black will lead most people to not notice they are larger in capacity or physical size.
Would recommend that set-up. For sure don't consider a factory set-up even though Duke has witnessed them in Death Valley!!!!!!

[John L.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

Got it! I'm thinking I am going to do that! The company says its 40% better cooling capabilities. It's worth a shot to have a very drivable Corvette! Not worried about judging points now. Got though that part. Now driving! Thank you!

[William F.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

What do you mean "they all FAILED"? What kind of failure. I've got a '67 L79 C60 with R12 and no overheating problems down here in hot MS summers.

[Joe R.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

Next time you are in the July Martin Luther King Parade watch your temp gauge!!! Or better yet, just listen to the radiator cap popping open.

JR

PS. That's with a 50 year old stock 316 radiator or a DeWitt's reproduction radiator? Big idfference!!!

[Gene M.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

I'm a little confused. Is it the rotor or the stationary winds that are different for the 37, 42, and 55 amp 10DN alternators? The information David Perry shared has kit winds that are good for 105 amp according to the advertisement. I'll take that with a grain of salt, but still should be more than 55 amps. I'm assuming the rotor stays as stock. Thank you by the way for sharing that.

But back to the original topic. I have a 42 amp alternator with solid state voltage regulator all wired as original. The air conditioning is Vintage Air. My new radiator is Dewitt 1.25 inch core unit for worked over engines and air conditioning. Clutch fan is parts store replacement with stock fan blade. Thermostat is 160 degree and water pump is rebuilt with a cast impeller. Fan shroud is sealed up as well as possible. A 50/50 mix antifreeze. NO ELECTRIC FAN. My 65 runs cool at 180 degrees with the air on and alternator keeps up just fine. In stopped traffic the temp goes to about 200 degrees (difficult to estimate on stock gauge) and I have to keep revs up to keep a positive charge with the air running. I generally just turn the air off for those traffic hold ups. A 105 amp unit should rectify my issue when in stopped traffic and allow the air to stay on. There is a noticeable difference in idle speed between air on and off.

[Duke W.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

I mispoke in post #11. It's the STATOR windings that determine maximum current output. For vintage alternators that were typically rated from 30-something to 60 something amps, the only difference was usually the stator.

In a generator the field coils are in the frame and all the energy is developed in the rotor windings, and that full current has to transmit through the brushes.

Alternators reverse the design. The field is in the rotor, so the only brush current is what's required to energize the field, which is only about 2 amps, and the voltage regulator cuts this current at high frequency as required to prevent overvoltage if current demand is low and alternator speed is high.

Depending on an altenator families output range, a higher current rotor may be required to create a stronger field as output current rating increases.

Duke

[Joe L.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

I'm a little confused. Is it the rotor or the stationary winds that are different for the 37, 42, and 55 amp 10DN alternators? The information David Perry shared has kit winds that are good for 105 amp according to the advertisement. I'll take that with a grain of salt, but still should be more than 55 amps. I'm assuming the rotor stays as stock. Thank you by the way for sharing that.

But back to the original topic. I have a 42 amp alternator with solid state voltage regulator all wired as original. The air conditioning is Vintage Air. My new radiator is Dewitt 1.25 inch core unit for worked over engines and air conditioning. Clutch fan is parts store replacement with stock fan blade. Thermostat is 160 degree and water pump is rebuilt with a cast impeller. Fan shroud is sealed up as well as possible. A 50/50 mix antifreeze. NO ELECTRIC FAN. My 65 runs cool at 180 degrees with the air on and alternator keeps up just fine. In stopped traffic the temp goes to about 200 degrees (difficult to estimate on stock gauge) and I have to keep revs up to keep a positive charge with the air running. I generally just turn the air off for those traffic hold ups. A 105 amp unit should rectify my issue when in stopped traffic and allow the air to stay on. There is a noticeable difference in idle speed between air on and off.

Gene------


Something to keep in mind regarding conversions: as far as I know, the greatest output for a 10DN series alternator was 61 amps. The greatest output for an 10SI series alternator was 63 amps. In the mid-70's with increasing electrical load requirement, larger output alternators were needed. So, GM went to the 12SI and, later, the 15SI series alternators. These alternators had a larger case to accommodate larger internals. If a 100 amp alternator could be created within a 10DN or 10SI case as the aftermarket conversions do, why didn't GM do that instead of designing the 12SI and 15 SI units? I don't think it has anything to do with technology available now but not then because the aftermarket conversion kits don't look to use any technology that hasn't been around for a long time. Plus, GM had the benefit of a huge engineering staff at Delco-Remy. I'm pretty confident that if there had been a way to come up with a reliable, PRODUCTION-validatable alternator based on a 10-series case, they could have done it.

[Gene M.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

Joe,
I think you nailed that. That is why I said "........105 amp according to the advertisement. I'll take that with a grain of salt, but still should be more than 55 amps." But keep in mind the old reliable 10 case was good unit except for demand at low rpm as idle. I've gone to the modern case style in my big block Nomad with a big electric fan and even then I had to step up the (water pump optional) and crank pulley size to speed up the alternator RPM. But once everything is "balanced" out everything plays well together. So I guess my suggestion rather than using a small pulley on a high output alternator is to use a bigger pulley on crank. This has been an interesting post.

[Robert I.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

I had a 65, 350 hp, 4 speed with factory air: When new, it would run too hot in stop and go traffic. Had to shut the air off, in traffic.

My wife's father must have had some air conditioned car in those days and had to shut it off in traffic, because she still does that in our modern cars!

[Joe L.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

I had a 65, 350 hp, 4 speed with factory air: When new, it would run too hot in stop and go traffic. Had to shut the air off, in traffic.

My wife's father must have had some air conditioned car in those days and had to shut it off in traffic, because she still does that in our modern cars!

Robert-------


In days of old the only functionality that cars had to compensate for increased heat rejection requirements when AC was turned on was increased air flow provided by the fan clutch, if the car even had a fan clutch. Today, things are different. Cars often have multiple electric fans, one of which is activated when coolant temps get to a certain level.

In fact, as C4 master Gordon Killebrew often says, with a C4, if your car starts to overheat, don't turn the AC off, TURN IT ON!

[Kent S.]

Re: GM one wire alternator for addition of electric fan on radiator for cooling

I won't jump into the overheating question (but I have experience there unfortunately) but a word of caution on the alternator. Many times the output is measured at simulated highway speeds when, in fact, the low speed idling is when you really tax your charging system. My experience (with streetrods) is with products from PowerMaster. They specifically design their high output alternators to deliver at low speeds and will give you a printout showing output at various RPM's. I've also used their small diameter pulleys to help the situation. Don't forget a large diameter wire (6 gauge minimum) from the alternator to the battery (or starter) is a must.