Alternator

[leversole]

What year did Mack start putting alternators in trucks?

I have a 72 or newer 675, presumably out of R model...

Would this engine have come with an alternator?

I have a generator now and would like to replace with an alternator

Thanks

[theakerstwo]

I think about 68 you could get either way.

[leversole]

Read thru the archives and determined the Delco 10SI was most recomended...

Will the stock pulley turn it fast enough to charge at idle?

Where/what diameter pully?

3 wire or single wire?

Thanks

[Rob]

Read thru the archives and determined the Delco 10SI was most recomended...

Will the stock pulley turn it fast enough to charge at idle?

Where/what diameter pully?

3 wire or single wire?

Thanks

I just run a standard three wire 10SI series Delco alternator. These use an internal regulator. As you look at the rear of the alternator housing with the spade terminals on top, attach the left spade terminal wire to the "BAT" post via a ring terminal end, and run switched voltage to the other terminal. Also attach the large 10 gauge wire that actually charges the batteries to the "BAT" terminal. The switched voltage comes from your ignition switch.

You will also need a conversion pulley to drive the alternator as the automotive belts are a little smaller in size than the industrial standard size used by Mack trucks. Although the original pulley supplied with the alternator will work, it is hard on belts. To run an automotive style belt that fits the alternator will bottom the belt in the pulleys on the water pump and crankshaft on the engine.

I've seen these slip quite easily. However if your truck operation is limited it will last for a while without problems.

The company I've used for conversion pulleys is no longer in business so I can't help you there much.

The alternator setup will charge batteries at idle with a load on them much better than a generator will so you'll have no problems. You will need to fabricate brackets and ensure you belts line up. Side loads kill bearings and bushings in that series alternator as they are small to start with.

Rob

[leversole]

I just run a standard three wire 10SI series Delco alternator. These use an internal regulator. As you look at the rear of the alternator housing with the spade terminals on top, attach the left spade terminal wire to the "BAT" post via a ring terminal end, and run switched voltage to the other terminal. Also attach the large 10 gauge wire that actually charges the batteries to the "BAT" terminal. The switched voltage comes from your ignition switch.

You will also need a conversion pulley to drive the alternator as the automotive belts are a little smaller in size than the industrial standard size used by Mack trucks. Although the original pulley supplied with the alternator will work, it is hard on belts. To run an automotive style belt that fits the alternator will bottom the belt in the pulleys on the water pump and crankshaft on the engine.

I've seen these slip quite easily. However if your truck operation is limited it will last for a while without problems.

The company I've used for conversion pulleys is no longer in business so I can't help you there much.

The alternator setup will charge batteries at idle with a load on them much better than a generator will so you'll have no problems. You will need to fabricate brackets and ensure you belts line up. Side loads kill bearings and bushings in that series alternator as they are small to start with.

Rob

Thanks...did you use an indicator light in the switched circuit? Many of the conversion digrams on the internet talk about the need for a indicator light in that circuit to make the alt work...Also, how did you keep the ammeter in the circuit, pull the bat wire off the the old regulator and attach to the bat terminal on alt?

Thanks again

[Rob]

Thanks...did you use an indicator light in the switched circuit? Many of the conversion digrams on the internet talk about the need for a indicator light in that circuit to make the alt work...Also, how did you keep the ammeter in the circuit, pull the bat wire off the the old regulator and attach to the bat terminal on alt?

Thanks again

Yes to the wire on the alternator and the indicator lamp is not needed for operation. It is sometimes incorporated to let you know the ignition switch is supplying voltage to the fields.

I wired mine direct with a 3 ampere fuse in series so to allow protection if a field winding shorts. It will blow the fuse and stop voltage application to the alternator preventing a possibly burnt up part, or truck.

Rob

[leversole]

Thanks...I got it working, will post some pics and pitfalls later...charges great at idle!

Thanks for your help