Alternator Question
Thread Starter
Racer
Joined: Jun 2009
Posts: 409
Likes: 3
From: St. James, NC
Alternator Question
I have a Summit Racing alternator I want to use in place of the OEM alternator on my 1971 Big Block. The Summit alternator puts out more Amps (100) and at lower RPMs. I have the loads split between electric cooling fans and the rest of the electrical system. The alternator is identical to the OEM unit except that the alternator case is bolted together 90 degrees out of phase with the OEM unit, which causes the ground connection to interfere with the engine valve cover. One of the product reviewers (on Summit’s site) indicated that he had to rotate the head on an alternator 90 degree for a perfect fit. What would it take to rotate the case 90 degrees? The case is held together with four (4) bolts. If I remove the pulley and the 4 bolts and separator the case enough to rotate it 90 degrees are any internal parts going to be come dislodged that I won’t be able to get back to together in working order? Can the case be rotated 90 degrees?
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
Hmmm.... Do you even have to remove the fan/pulley to re-clock it? I know that you will have to hold the [internal] contact brushes in place by inserting some straightened paper clips or pins into those little access holes in the back side of the housing; but I think if you do that, you can remove those four long assembly screws, separate the housing about 1/4-1/2" and turn it to align it 90* turned. Put the screws back in, pull the brush retainer pins, and that should do it.
{I think....
}
{I think....
}
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
You shouldn't need to remove power pulley. That's so rotor can stay in place and brushes don't pop out. Paper clip end will work. Make sure springs and brushes are in holder before you put it together. Pull out paperclip and give pulley a spin before installing alternator, make sure there is no noise. It sucks when omitting last step and rotor won't spin and then it does as pieces fly about.
Le Mans Master
Joined: May 2003
Posts: 8,874
Likes: 3,551
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
Hmmm.... Do you even have to remove the fan/pulley to re-clock it? I know that you will have to hold the [internal] contact brushes in place by inserting some straightened paper clips or pins into those little access holes in the back side of the housing; but I think if you do that, you can remove those four long assembly screws, separate the housing about 1/4-1/2" and turn it to align it 90* turned. Put the screws back in, pull the brush retainer pins, and that should do it.
{I think....}
{I think....
}
Le Mans Master
Joined: May 2003
Posts: 8,874
Likes: 3,551
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Thread Starter
Racer
Joined: Jun 2009
Posts: 409
Likes: 3
From: St. James, NC
Race Director
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,170
From: Hermosa
Not a bad video but you don't have to do half of what he did.
Don't need to remove pulley or fan and do not need to push the front of the alternator down.
Just remove the 4 bolts and rotate the back half. No need to separate the two even a millimeter. As a bonus you will have no worries about the brushes coming out either if done this way.
If allowed to separate too far, now you got to take the back half off put the brushes back in and insert a a straightened paper clip in from the outside to hold the brushes in place while you put it back together.
Mark the two halves relationship to each other so you know how far you rotated it or at least so if it does separate too much you can start from a know starting point when putting it back together.
I just had my 10SI apart yesterday to grease the rear bearing and noticed that clocking require no gap between the front and rear halves.
Don't need to remove pulley or fan and do not need to push the front of the alternator down.
Just remove the 4 bolts and rotate the back half. No need to separate the two even a millimeter. As a bonus you will have no worries about the brushes coming out either if done this way.
If allowed to separate too far, now you got to take the back half off put the brushes back in and insert a a straightened paper clip in from the outside to hold the brushes in place while you put it back together.
Mark the two halves relationship to each other so you know how far you rotated it or at least so if it does separate too much you can start from a know starting point when putting it back together.
I just had my 10SI apart yesterday to grease the rear bearing and noticed that clocking require no gap between the front and rear halves.
Last edited by REELAV8R; Jul 24, 2017 at 11:03 AM.
Le Mans Master
Joined: May 2003
Posts: 8,874
Likes: 3,551
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
I would agree on not removing the pulley. Just remove the bolts and put it on it's back with the pulley facing up holding it together as you do so. Then, lift up the front half of the case a little and rotate it to the right position.
Last edited by lionelhutz; Jul 25, 2017 at 01:27 PM.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,170
From: Hermosa
You MUST rotate the back half of the case and the stator together. The stator is the piece between the 2 halves of the case. You will damage the wires connecting the stator to the rectifier in the back half of the case if you only rotate the back half of the case.
I would agree on not removing the pulley. Just remove the bolts and put it on it's back with the pulley facing up holding it together as you do so. Then, lift up the front half of the case a little and rotate it to the right position.
I would agree on not removing the pulley. Just remove the bolts and put it on it's back with the pulley facing up holding it together as you do so. Then, lift up the front half of the case a little and rotate it to the right position.
A significant difference between the stock delco-remy and the aftermarket 10SI is that the aftermarket mounting brackets do not interfere with the rear portion of the alternator in order to rotate the back half.
I compared my 110 aftermarket to my stock 63 amp and the stock one has the mounting brackets overlapping the point where the alternator splits which does require you to split them an additional 1/4" to 1/2" or so in order to change the clocking. The aftermarket alternator does not interfere with the clocking of the front to the rear.
Also noticed the aftermarket alternator has small holes drilled into the brushes so that a wire could be inserted prior to taking back half off to prevent the brushes from popping out. That is if the brushes are not too worn down.
Stock may have. On mine I can't tell, as the brushes are worn pretty short, beyond where a hole may have been located if it had been there.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
Yes, but the back half and the stator are not attached to each other, just the wires are going between then. So you can attempt to turn just the back half of the case.
I can't see a hole in the brushes being very useful because that wouldn't push the brushes back further into the holders so they clear the slip rings.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,170
From: Hermosa
Last edited by REELAV8R; Jul 26, 2017 at 12:09 PM.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
You're wanting to learn something because your picture doesn't show anything new that I didn't know....
You have to push the brushes into the holders and then pin them so they are held pulled away from the slip rings.
Short reason for holes - the holes just allow you to pin back longer brushes.
Long reason for holes - those holes will be used in conjunction with another hole through the brush holder assembly. Together, a pin through all the holes will hold the brushes back far enough that the face of the brush DOES NOT contact the slip rings as the alternator is assembled. Then, once you pull the pin out the brushes will move out against the slip rings and you won't be able to get the pin back through the holes. The holes simply allow the pin to be used with longer brushes vs putting the pin across the slip ring face of the brushes.
So, your description of being able to use the holes before disassembly is simply wrong.
You have to push the brushes into the holders and then pin them so they are held pulled away from the slip rings.
Short reason for holes - the holes just allow you to pin back longer brushes.
Long reason for holes - those holes will be used in conjunction with another hole through the brush holder assembly. Together, a pin through all the holes will hold the brushes back far enough that the face of the brush DOES NOT contact the slip rings as the alternator is assembled. Then, once you pull the pin out the brushes will move out against the slip rings and you won't be able to get the pin back through the holes. The holes simply allow the pin to be used with longer brushes vs putting the pin across the slip ring face of the brushes.
So, your description of being able to use the holes before disassembly is simply wrong.
Last edited by lionelhutz; Jul 26, 2017 at 01:52 PM.