GM alternator swap questions

jvandyke

jvandyke

True Classic
Considering GM alt swap as my flickering light issue has returned. Pondering this as a mounting option. Turnbuckle. Probably get at hardware store cheap enough.
ccrp_1011_06_o+ccrp_1011_small_block_chevy_dress_up+turnbuckle.jpg
 
I'd say should be good to go as long as you can come up with a mounting where the long plane of the turnbuckle is parallel with the plane of the drive belt....that way you know tightening it is not going to "cock" the body of the alt and put the belt out of alignment with the other pulleys.
 
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K.I.S.S. - Jeff...

Go here... http://www.network54.com/Forum/12159/message/1142890167/GM+alternator+conversion

Also read my October 2008 update suggestions as well.

Bernice Loui also used a Nissan alternator and made some custom bracketry... but I believe she had the alternator and was bored.

I don't think you can do this any less expensive or any "better" really than the illustrated method with the GM alternator. The Nissan is smaller and lighter, but probably more costly. The GM is WIDELY available and very inexpensive. Some are $35 - $45 bucks rebuilt with "Lifetime" warranties! I'll never buy another...
 
I'll poke around the hardware store and eyeball it but might be more hassle than it's worth. If it works it would eliminate the need to cut and drill the generic bracket. Seems like there would be a replacement alt with mountings clocked closer to ours. I know when I did this to my Opel I found one.
 
Thanks for pics. Looks like the turnbuckle will have a hard time reaching over the alt. Would be nice to find one with the mounting ears clocked better. OEM is roughly 3 o'clock for pivot and 11 for adjuster.
Just musing.
gmalt.jpg
 
I agree a 9 and 3 oclock configuration is not ideal. Your 11-12 and 3 would be perfect. Less vibration, etc. That said, this does fit and work in my 75 with a header and no AC. I have enough room to adjust it from the engine bay with out an access panel in the trunk.


Can't wait to see your approach if you decide to do an alternator mod.
 
There's an unused bracket with hole hanging off the water pump. No idea what it's there for but it might be a good mounting point for something (although the hole is kinda big), generic bracket or adjustable rod. Eyeballing it and it almost looks like the rod might reach even the 180º ears.
alternator2.jpg

turnbuckle.jpg


These all seem to have the adjustable ear at 2 o'clock. (officially: pivot/foot at 6, adjustable ear at 10 as viewed from the rear)

91 cutlass supreme 3.4

88 camaro 2.8

90 buick regal 3.1

91 Buick Skylark 2.3
 
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Here's my two cents.

The GM alternators you guys are talking about are aftermarket ones, not genuine GM. In my experience the aftermarket ones, from O'Reily's, Auto Zone, etc. are not good quality. Sure, they have lifetime warranty, but who wants to replace them every 2-3 years. Vic's has Fiat remanufactured alternators for about $150-160. Not unreasonable. 60-65 amps. No re-designing mounting, brackets, etc.
 
If you ever pull the engine

jvandyke said:
There's an unused bracket with hole hanging off the water pump. No idea what it's there for but it might be a good mounting point for something (although the hole is kinds big), generic bracket or adjustable rod.
Click to expand...

If you ever pull the engine, you will figure out what that bracket is used for. :)
 
The adjuster rod you first referenced had Heim joints at each end... so it can move/pivot without undoing the mount points... the one you suggest using will be rigid mounted at either end, which means you have to loosen both ends BEFORE adjusting - not worth it.
 
lookforjoe said:
The adjuster rod you first referenced had Heim joints at each end... so it can move/pivot without undoing the mount points... the one you suggest using will be rigid mounted at either end, which means you have to loosen both ends BEFORE adjusting - not worth it.
Click to expand...
Just turn the coupling center one way, both ends go out/tighten belt, turn it the other both retract, loosen belt, I put a jam on it to keep it still. It was $3, give me a break, I hate the box, kick the box! If I can score a cheap alt with the right mounts I'll try it if not I'll get back in the box.
 
The lower pivot must move rearward to be effective.

Even then, it is a tight fit, especially on AC-equiped X's. I have worked on mine for a couple of decades and I am not satisfied with the mounting.
 
Oh, I get it. I thought you meant you'd have to remove a whole end to adjust. Loosen up an end to adjust I can handle. I'm going to an old school junk/reman car electrics shop tomorrow and see what I can dig up with the 6/2 clocking since it seems like it'd work better no matter what bracket you go with.
 
Well Ron...

You have a point... but its not entirely correct. You actually give these alternators too much credit.

Most of these alternators are indeed GENUINE GM... but are REBUILT with the cheapest parts available. Some aren't even really rebuilt with new bearings and the like... just cleaned up, have what diodes replaced as needed... new brushes, slapped together and tested... then boxed and shipped out.

BUT... its been my experience that most are heartier and more robust than a stock Marelli or Bosch... come with a minimum of 63 amp capability and as much as 105... and can be found anywhere in a pinch. (I believe the stock Marellis were 45 amp and the later ones for A/C equipped cars were 55 amp.) The bracketry mods are really quite simple... Some folks just can't leave simple alone though... HA!

In the past 28 years I have replaced 4 alternators in my car due to rectifier failures and my 45 dollar rebuilt GM has been in there since 2008 I guess... with no problems so far. I just offer this up as a very good alternative... and in my humble experience, a better alternative for the reasons I've mentioned.
 
Minor correction...

The late models had two options:
  1. Marelli A 125-14 V-55 A, 55Amp.
  2. Bosch K1-14 V-65 A 21, 65 Amp.

:grin:
 
Thanks Greg...

And as you cite... it appears the factory kept upping the ante on the load capability as well. There must've been a "need". HA!

I must say though I have never seen the 65-amper and at ONE point in time... my wrecker had literally a hundred or so lying around. I bet they were mostly found on A/C cars which I've never really seen in the around here.
 
Called shop. Found out they clock from the backside so pivot mount at 6, adjustable at 10 would seem ideal, usual 6 and 12 are obviously fine as many have done it. I wonder if a 6/10 one would let you use the factory upper bracket? I will score one and find out but I'm first going to pull and examine my Bosch. This one pictured is from a '91 Cutlass Supreme 3.4 but many from that era used it. Available for about $50, 100amp, all new parts from autowarehouse. Would have to put a V belt pulley on it, wonder if the Bosch pully would swap over?
alt2.jpg
 
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