BBC Alternator Tension
Thread Starter
Burning Brakes
Joined: Oct 2000
Posts: 779
Likes: 1
From: Minneapolis MN
DDN, hard to tell from the pic if you have the offset alt pulley.
Also I noticed that your lower alt bracket/strap (last pic-above) is bolted to the upper alt bracket. In the original bbc vette config, this strap is bolted to the water pump via top bolt right side if your standing in front of engine looking at it.
Not sure, but that might give you more tension, or try a shorter belt.
Also I noticed that your lower alt bracket/strap (last pic-above) is bolted to the upper alt bracket. In the original bbc vette config, this strap is bolted to the water pump via top bolt right side if your standing in front of engine looking at it.
Not sure, but that might give you more tension, or try a shorter belt.
You are correct about the strap. I have seen this configuration both ways, and my understanding is that they changed the setup mid-year. I'd have to get a longer strap, because that one won't reach to the water pump.
I don't see how a shorter belt would get me more tension though, I still have to be able to put tension on the alt and then tighten it down which is the problem I'm having. I hate how much these ****ty brackets flex too. Personally I think it's just poor design & engineering.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Roger, your right about the Vette, no PS.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
I have the same 71 BB w/AC/PS and I did use a soft piece of wood to pry the PS pump/pulley tight.....or tight enough anyway....On the alternator I just pulled the alternator by hand and the bolt is at the end of the adjustment but it is plenty tight, never squeals or comes off....I had up to 6400rpms....
I do have the idler as well.... My setup matches Bob Heinz pics of the LS5 w/AC, PS exactly...
I do have the idler as well.... My setup matches Bob Heinz pics of the LS5 w/AC, PS exactly...
Thread Starter
Burning Brakes
Joined: Oct 2000
Posts: 779
Likes: 1
From: Minneapolis MN
I have the same 71 BB w/AC/PS and I did use a soft piece of wood to pry the PS pump/pulley tight.....or tight enough anyway....On the alternator I just pulled the alternator by hand and the bolt is at the end of the adjustment but it is plenty tight, never squeals or comes off....I had up to 6400rpms....
Pro
Joined: Nov 2008
Posts: 542
Likes: 3
From: Bloomfield Hills MI
Thread Starter
Burning Brakes
Joined: Oct 2000
Posts: 779
Likes: 1
From: Minneapolis MN
I was able to get everything quite a bit tighter tonight and took it for a drive. No major squealing, but generally still seems to noisy.
The pulleys seem excessively hot after a drive too, so I'm guessing there is still too much slip.
Thread Starter
Burning Brakes
Joined: Oct 2000
Posts: 779
Likes: 1
From: Minneapolis MN
This isn't directly related to the alternator, but could part of the noise problem be that the pulley diameter on the WP for the Crank-WP is different from the Crank-WP-PS diameter?
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Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
I have reproductions of stock pullies and they are also different sized WP/Crank/PS pullies and my belt run is dead quiet.... My alternator is actually spaced forward slightly to clear the valve cover, putting the belt at a slight angle and even though its only hand tight, it never squeals, makes any type of noise or comes off...
Maybe you got a bearing going bad on one of the components and that is the culprit of the noise...
Thread Starter
Burning Brakes
Joined: Oct 2000
Posts: 779
Likes: 1
From: Minneapolis MN
Are they stock pullies?
I have reproductions of stock pullies and they are also different sized WP/Crank/PS pullies and my belt run is dead quiet.... My alternator is actually spaced forward slightly to clear the valve cover, putting the belt at a slight angle and even though its only hand tight, it never squeals, makes any type of noise or comes off...
Maybe you got a bearing going bad on one of the components and that is the culprit of the noise...
I have reproductions of stock pullies and they are also different sized WP/Crank/PS pullies and my belt run is dead quiet.... My alternator is actually spaced forward slightly to clear the valve cover, putting the belt at a slight angle and even though its only hand tight, it never squeals, makes any type of noise or comes off...
Maybe you got a bearing going bad on one of the components and that is the culprit of the noise...
I somewhat doubt it's a bearing since both the PS and alt are brand new.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Looking back at your pics. What kind of alt is that ?
Wiring doesn't look right.
What kind of pulley is on the alt,belt appears to be high in the pulley.
Is the pulley on the alt a serpentine pulley ?
Wiring doesn't look right.
What kind of pulley is on the alt,belt appears to be high in the pulley.
Is the pulley on the alt a serpentine pulley ?
Thread Starter
Burning Brakes
Joined: Oct 2000
Posts: 779
Likes: 1
From: Minneapolis MN
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Big blocks use deep groove pulleys such that the belt should be flush or slightly below the the outer edge of the pulley. When I bought an aftermarket alternator from O'Reilly's I had to transfer my original pulley over to it. The store actually did that for me.
cc
cc
Melting Slicks
Joined: May 2009
Posts: 3,079
Likes: 314
2024 C3 of the Year Finalist - Unmodified
If the pulley and the belt don't match, it can squeal and cause heat. Stock belts are .440 wide.
adjustment, alt, alternator, bbc, belt, bracket, configuration, corvette, crank, ps, pulley, rod, spacer, style, trigger, turnbuckle
