Re: Howard's 47 Custom project

Posted by HH56 On 2016/1/17 13:04:20

Keith, Another alternator would work and on some later engines easy enough. IMO, that approach is lacking and problematic for this car. It would need a battery load because suddenly connecting and completely disconnecting a stand alone energized alternator could lead to some interesting experiences. There are a few cars owned by forum posters which have that alternator/battery arrangement but you still need to provide a space for both.

The big problem with the 356 engines is there is no easy way to drive a compressor let alone another alternator with stock components. The fan belt is 1" wide so finding pulleys and usable length belts is almost impossible. Other than the stock length repro belts Ulrich has made available, a longer but still short enough belt would be hard to find. I want the car itself to stay 6v and look as stock as possible so using a single large belt and trying to wrap that over another pulley for an alternator could be an adventure. Pulleys would have to be custom made so that would be another issue with a small alternator. There is one company that will make a custom pulley if you buy their standard alternator to replace the generator. That conversion hasn't been ruled out -- particularly if the pulley would work on a Powergen but it would still be 6v. Like you, I don't know of any dual voltage alternators.

The AC portion is just as interesting. Packard chose to drive the prewar compressors with an extra groove off the fan pulley. That pulley was repro'd some years back and fortunately I bought one when they were available. Not sure they can be found today. Even that belt is almost 7/8 wide but I was lucky in that a standard D size V belt in the smallest length available worked. There is a single groove truck compressor clutch pulley which also works and is what I am using. Trying to mount an alternator off that setup would again be interesting.

In the end I chose to do it all with the extra batteries hidden in a small box in the trunk next to the unit. The box kind of looks like it could have been for something that belonged. Even with the engine off this arrangement will provide some equalizing charge from the main battery to the small ones if the disconnect switch is left on. Wouldn't want to leave it that way more than a day or so because the approx 80mA constant drain could eventually run the battery down. I haven't tested to see how far it would drop before the minimal hold current thru the relay falls to a point the relay would open and cut part of the drain. Even then without a disconnect it will still take an extra relay contact to totally stop the drain.