Monday, July 25, 2016


 Let's ALTERNATE!  The photo above shows before and after my reconditioning work.
Though you can't tell unless you look very carefully, it also shows that one alternator
is for a two stroke Saab and one is for a V4, though both have the early cast aluminum fan.
 Now look at the FINS on each fan from the back. Note that the fins angle in opposite directions. While both engines turn the same direction [clockwise as viewed from the front], remember that the V4 fan pulley is on the BALANCE SHAFT, so the alternator turns the opposite direction.  It is also good to remember that an alternator doesn't give a shit which way it turns---it just produces alternating current [AC]. The "juice"
is then fed through a full wave rectifier whose output is direct current [DC], the stuff the car needs.  Cool, huh?
 This photo shows all the gubbins.  Note that I turned the commutator slip rings on the armature [brass color] down smooth on my lathe. The brush pack is on the extreme left. This alternator is a later unit [tho all are 35 amp, 12 volt] that used the stamped steel fan with the fins angled the correct direction for the Ford/Saab V4.  
 Here are three alternators that I just reconditioned. Left--late V4. Center--V4, sort of early, with aluminum fan. Note the arrow on the fan, indicating direction of rotation. The alternator on the right is a VERY early V4, also with a cast aluminum fan. So what is the difference between the one in the center and the one on the right?
The difference is in the electrical connections on the back. The one on the left and the one in the center use the 3-connector plug, plus a heavier B+ wire, plus a ground wire. The alternator on the right uses four separate connections, plus ground. All were used on Saabs, in various years, and all are 35 amp, 12 volt alternators.

I actually reconditioned six of the buggers, this session, but these three show the main differences that you might encounter. The most IMPORTANT thing to remember is that an alternator must have the correct fan. The arrow--either cast into the aluminum fan face, or stamped into several of the fins on a stamped steel fan--must indicate a counter-clockwise rotation for a V4.  A cast aluminum fan for a two cycle Saab will have the cast-in arrow showing a clockwise rotation.    Don't mix 'em up or you'll get to replace a burned-up alternator, and that's no fun...huh?    

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