Denso Alternator Swap
The Nippondenso or "Denso" alternators are compact, lightweight internally regulated units that were widely used on many Japanese and American cars and trucks. They can be adapted to fit M-bodies and other Mopars. They offer a weight savings (about 10lbs), superior charging at idle, simplified wiring and a more compact appearance. If your M-body is pretty much stock, you probably don't need a Denso alternator. The best reason to switch to a Denso alternator is if you are using Edelbrock heads. Edelbrock heads are physically longer than stock LA heads, and thus overhang the deck of the block enough to cause alignment issues with the stock alternator. Magnum HP
sells brackets to adapt the Denso alternators to Mopars. The text below is from some older notes taken from the Magnum HP site a while ago, so call Magnum HP to verify the alternator to use. Also compare the price of this setup and a separate alternator vs the Mancini Racing
Denso alternator and bracket kit. From Magnum HP Inc.
"Denso Alternator Brackets Magnum HP Inc. offers a line of alternator brackets designed to adapt several popular "mini" alternators to both big and small block Mopar engines. Weight savings of up to 10 pounds can be gained by switching to a modern Denso alternator. Not only do you save weight, but since the Denso alternators are internally regulated, you can simplify the wiring harness on your Mopar by eliminating the firewall mounted voltage regulator.
ARE-25 - Adapts the Toyota 4Runner alternator to any SB engine using the 1970 or newer water pump housing. The alternator that works with this kit is from 1985 to 1992 Toyota 4Runner and pickup trucks. Toyota part numbers that work are 27060-35060 or 27060-35061. The equivalent Bosch part number for this alternator is AL218X. These alternators are 60 amp units and come with a single groove V belt pulley. If you are getting the Toyota alternator at a wrecking yard, you should go ahead and get the plug in harness at the same time. Having the correct wiring plug will make your wiring task a little easier and will make for a cleaner installation.
Wiring Tips: The Denso and Powermaster alternators are all internally regulated, this means that the external regulator is no longer required, and it must be removed from the charging circuit. One fairly easy way to accomplish this task is to locate the 12 volt ignition switched wire that used to go the Mopar voltage regulator, and then extend it to the Denso alternator. Most Mopar vehicles used a dark blue wire for the 12 volt supply to the voltage regulator. A copy of the proper wiring diagram for your vehicle should confirm the wire that you are looking for. Double check with a volt meter before proceeding. The Toyota alternator also needs to have a sense wire connected from the wiring harness to the alternator. This sense wire should go to a central 12 volt source that is located some distance from the alternator. The stud on the starter relay would be a good place for this or maybe even the back of the ammeter or voltmeter in the dash. What you are trying to accomplish with this remote sense wire is to tell the alternator what the voltage level in the wiring harness is so it can regulate itself. There is an excellent discussion of remote sensing at www.madelectrical.com
if you are interested. Mad Enterprises also sells a variety of wiring supplies that come in very hand if you are re-wiring your charging system.
Drive Belts: We have found that a 25/64 wide V belt about 45 inches long works for most applications with stock pulleys. With aftermarket race pulleys you will probably need a belt that is slightly shorter. On the small block with the Toyota alternator, Gates belt #7460 is a better fit. These belt recommendations only work with factory original pulleys.
Drive Pulleys: For the small block, the single groove lower pulley 3614375 or the double groove lower pulley 3614378 will work. The water pump pulley on a small block should be the deep one marked 2951836. Other combinations of pulley may work but these are the ones which have been
verified on our test engines.
Here is a handy item for wiring in your new alternator: A company by the name of Northwest Regulator Supply makes a Toyota repair harness. It comes with the correct plug that locks into the back of the Toyota alternator. The bare leads can then be spliced into your wiring harness using butt fit connectors. Northwest Regulator can be contacted on the web at www.nwreg.com
or by phone at 1-800-242-6367. The part number for the Toyota repair kit is 50-12159. The list cost was
about $6 last time we checked." Excerpt from a post by Mark Mullins:
"I'm using the 60 amp Mancini kit. Came with brackets and the plug. It's a mini-Denso from an 89-90 Toyota 4 Runner. It's internally regulated and charges at idle a thousand times better than the 73 amp round-back I had on there before. No problem keeping up with all the power accessories, lights, etc. The primary reason I used the mini is because it fit the Eddie heads like it was made for them. For wiring I run 4 gauge audio amplifier cable to a 100 amp breaker that's mounted on the driver's fender, and then to the battery."Photos:
- Mark Mullins' Mancini Denso alternator and bracket kit in his 360 powered Fifth Avenue.
- Another shot of Mark Mullins' Mancini Denso alternator and bracket kit.
- Factory squareback alternator hitting an Edelbrock head
- Installed Edelbrock head (painted engine color) showing the overhang.