Leece-Neville 90 Amp Alternator
This post is about an alternator installation I installed a long time ago, 1998, on a Catalina 36.
This boat was originally outfitted with the stock 55 Amp internally regulated Motorola alternator. The future system was to include an update to the house battery bank for more total amp hours. If I increased the capacity I knew the stock alternator would certainly be maxed out.
This picture shows the alternator I used and it's sales and model number. I chose this alternator, over some others, because it was the only one using the identical case size that the original stock Motorola did. Leece-Neville also used to build many of the alternators for Balmar and they build decent little alternators.
Frustratingly I soon discovered there was only one unit available from Balmar that was a exact case fit on the Universal M-25. It is called the Model 81 but cost nearly $600.00 and was virtually identical to the Leece-Neville 8MR series. At the time however it was not available which meant using another "close enough" Balmar unit.
Not using an "exact fit" on this engine could mean a trip to the machine shop for a custom bracket to accommodate other units with slightly different cases. I did not want to do this. Having installed a fair number of marine alts I recognized just how difficult it is to align a non-direct fit alternator with custom mounts. When these alternators pull that kind of amperage it becomes very important that the pulleys line up.
I decided that taking the Balmar route would be more trouble & expense than it was worth to make if fit correctly. I certainly did not want get involved in modification of the alternator brackets or get into custom welding so I chose the Leece-Neville as a direct, bolt on, fit.
Adjustable Voltage Regulator
This is the 8MR2069TA as it comes from the factory. On this boat I chose to remove the factory installed regulator and use a Balmar ARS-4 multi-stage regulator. In hind site I could have saved myself a lot of money by using the existing stock regulator.
On a later boat, our Catalina 310, I used the alternator, as show here, without an external regulator.
If you want to use an external regulator read on..
Leece-Neville External Regulator Adaptor Plate
When I got ready to buy I called Leece-Neville and found the name of a local dealer here in Maine. The next day I visited Ronís Auto Electric and was impressed with Ronís knowledge.
When I arrived at Ronís shop I had my old Motorola alternator in hand. After a brief discussion he said ďYuhí I got just whut ya neehdĒ and took me upstairs where the shelves were thick with electrical parts and pieces like only a true Maine woods shop could be.
At this point I was convinced this guy could fix anything electric and never need to order parts. Hell, he already had enough parts on hand to re-wire the Pentagon. Deep in my heart however I knew he would not have the external regulation plate I wanted for my set up.
In a very abrupt and direct Maine way he walked over to a wooden shelf, reached out his calloused burly hand and grabbed a 90 Amp 12 volt marine alternator the Leece-Neville 8MR2069TA. This is the identical case as the original Motorola as Leece-Neville/Prestolite bought the rights to the Motorola alternators. It had the regulator already mounted to the back, from the factory, and Ron told me this is the way they ship them no if's, and's or but's. "Ya cahn't buy em any otha way"..
I then asked if he had the plate for external regulation conversion and before I even got the sentence out of my mouth he was holding the external regulation plate in his hand. Yee haa!
He told me that he could install the plate, and my old pulley, and I could pick it up in about an hour. Doing the conversion is actually very easy to do but I took him up on it as it saved me some time.
I then double checked to make sure this alt had the same number of poles for feeding my tachometer. On an a diesel the tachometer is sensed off AC current side of the alternator before the diodes hence the term "AC Tap". He just looked me square in the eye and said "this units got the same darn numbah ah poles as the one in ya hahnd." That was his way of saying this is plug and play....
Crude Wiring Diagram
Romper room is my style here unfortunately it's the only way I knew how to label stuff in the early days of digital cameras.
In the picture you can see the 6 gauge jumper wire from the hot output of the alternator to the starter post. I actually prefer to direct wire the alt to the house bank but for this installation going to the "C" post of the battery switch, via the starter wire was perfectly fine. By sizing this wire appropriately you can better achieve a non restricted output. From the factory this wire was 12 gauge. Be sure to put a good strain loop so you don't weaken the terminations and allow for enough flex.
Bypass The Orange/Red Circuit
Here's the quick and dirty fix. Try to focus on the red wire between the back of the alternator and the starter post. Simply jump the alternator output to the starter post and disconnect the orange wire. With this jumper the alternator output bypasses the 20+/- feet of teeny tiny 10GA wire and uses the large gauge starter wire to make its way back to the battery switch and then to the battery banks. Minimal voltage drop compared to the 10GA circuit and much less resistance and heat without going through all that small wire and two trailer connectors.
Please note that I generally advise running the alternator output directly to the house bank, not to the starter as shown here. You can then install an automatic combining relay (ACR) or an Echo Charger between the banks to charge both simultaneously. Doing this will remove the potential for fried diodes via the flipping of the battery switch through the OFF position. While not 100% necessary it is a good upgrade,and , as I always say, "while you're in there" might as well.
Even if you choose not to run the alternator direct to the house bank you are far safer with the new jumper than you were before.
I've never liked stamped pulley's. I find that they tend to allow slightly more belt slippage. While I was at Ron's I asked him to install a cast pulley for me and even with a single belt and a 90 amp alternator I had virtually no belt dust or slipping issues, but the alignment was perfect.
The Total Package
This is a picture of the final installation showing the ARS-4 regulator, which replaced an ARS-2 and the Leece-Neville alternator.
*WARNING: We now know that installing a regulator in the engine compartment is NOT advised by Balmar. This particular regulator failed in less than three months. Balmar suggested the heat killed it. The second one also fried, and the third was moved outside the engine compartment and is likely still going.
Keep in mind that this install was done over 12 years ago back before we really knew about the heat issues with the potting epoxy on Balmar regulators.
I highly suggest calling Ron at Ronís Auto Electric (207)-549-5918 if you canít find a competent Leece-Neville dealer. He may ask you to send your old alternator in so he can match it up with a new one but with this article you should have the part number you need to order it from him, if your original alternator is a Motorola and you're installing it on a Universal M-25. I believe he will ship just about anywhere but I would call him to make sure.
The Leece-Neville model number for the external regulation plate cover is 114-307 & Ron stocks them.