Installing Alternator

[Ross Leckie]

Does anyone know how to install an Chevy alternator into a Factory Five Roadster?

[scottiec]

Just did this actually. I got my chrome chevy alternator from Mike Forte from Forte's Parts. You have two options (that I know of) when it comes to mounting it on a small block. You can call Mike and order the alternator and his mounting kit along with the pulleys so it is nice and simple. Or, if you are like me and had a March Performance alternator bracket laying around, you can use that. The only thing you need to do is drill out the two bolt holes on the chevy alternator to accommodate for the larger diameter bolts the March bracket uses. Hope this helps.

[edwardb]

Hard to give definitive advice without more details, e.g. what engine, how it's set up, etc. Lots of different engine choices and layouts for the Roadster, so one answer isn't going to fit all. I'm guessing by "Chevy alternator" you mean more specifically a GM one-wire alternator? Those are easy enough to wire in, although you will get some advice that they're not the best choice. I've found they work OK, but there are better choices.

Welcome to the forum BTW.

[rich grsc]

Ya, tractor alternators.

[karlos]

Ya, tractor alternators.

And that's the key. Just gotta install it the same as it's setup on a tractor. Meaning a short, fat, low resistance charge wire.



Source: http://www.madelectrical.com/electri...reewire2.shtml



Pretty easy to set up like a tractor since we're doing the electrical from scratch anyway.







About 3 feet from the MegaFuse to the disconnect switch. Add another foot to get from the other side of the fuse to the alternator and you're looking at about 0.003 Ohms of resistance, which, at an 'average' draw of 35 amps, equates to a voltage drop of about 1/10th of a volt. Probably about the same as what's present in the tractor pictured above - basically negligible.







The disconnect switch then feeds the distribution block using a 4-ga battery cable. Zero resistance over its 2-ft length. So we end up with essentially the same voltage at the distribution block as what's present at the alternator. And that makes remote voltage sensing unnecessary.


Then there's the matter of what to do about the dashboard charge light. An outfit called 'SparkBright' (http://www.sparkbright.co.uk/sparkri...ge-monitor.php) makes a battery voltage monitor that works well as a replacement for the standard charge light. Here's what it looks like mounted in the dashboard (amber light below the tach).





This actually has advantages over the standard charge light in that it's illuminated continually, even when the car is off. This gives a quick visual means of verifying the battery state at all times, engine running or not. It uses a multi-color LED that glows green when the engine is running and the alternator is charging the battery, amber when the engine is off but voltage is greater than 12.45V, and red if less than 12.45V. Versatile little bugger.


The one-wire alternators are fine if set up correctly. Just gotta keep the resistance low all the way to the distribution block. Like a tractor. Probably not a good choice if you're converting from what used to be a three-wire setup (because the charge wire is likely long and high resistance). But these cars can easily be setup during the build process to work around the one-wire shortcomings. And that brings us to the real reason for doing it...it's hard to find a blingy 3-wire alternator