L98: Alternator pulley diameter?
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 397
From: Lakeville MI
L98: Alternator pulley diameter?
Anybody know the stock alternator pulley diameter or even the smaller March power and amp series alternator pulley diameter?
I have a larger March pulley installed now, but I've lost my original pulley. I must've returned it with an alternator core at some time in the past.
The larger alt. pulley is slightly complicating my supercharger installation, so I may go back to a stock size or even smaller pulley similar to the March power and amp series size. A smaller pulley may improve the belt routing and eliminate the need for an extra idler pulley.
I've found a source that sells pulleys for $14.95. I just need to know which one will be close to stock (or even smaller). I also have an underdrive crank pulley so I should be able to safely go somewhat smaller than stock.
http://www.alternatorparts.com/pulley_size.htm
I have a larger March pulley installed now, but I've lost my original pulley. I must've returned it with an alternator core at some time in the past.
The larger alt. pulley is slightly complicating my supercharger installation, so I may go back to a stock size or even smaller pulley similar to the March power and amp series size. A smaller pulley may improve the belt routing and eliminate the need for an extra idler pulley.
I've found a source that sells pulleys for $14.95. I just need to know which one will be close to stock (or even smaller). I also have an underdrive crank pulley so I should be able to safely go somewhat smaller than stock.
http://www.alternatorparts.com/pulley_size.htm
Last edited by tequilaboy; Oct 17, 2007 at 02:54 PM.
Le Mans Master
Joined: Jun 2006
Posts: 5,642
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From: One day you're a Comet...the next day you're dust... Arkansas
I have the March Power and Amp alternator pulley on mine. The outside diameter of the pulley is about 1.92". Of course I am not able to measure the arbor diameter with the belt on. I am using the 3 piece March aluminum set. Of course the alt. pulley is steel. I have the stock pulley somewhere but don't know where right now.
Race Director
Joined: Jun 2004
Posts: 13,963
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From: WI
tequilaboy I am happy to help out with this, but do you need the inside measured? Where would be best, the top of the rib? I have a micrometer and just took the above picture quick. That is the stock pulley from my '88. I have the three part March set on and I can measure any of those if you would like.
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 397
From: Lakeville MI
Thanks guys,
I think that's enough information.
It looks to me like the stocker is about 2 7/16" dia. and the power and amp is about 1 7/8" dia.
I should be safe with either the 2 1/4", 2" or 1 7/8" pulleys available from the link I posted.
1 7/8" would offer the most clearance.
I should have my idler pulley tonight to mock up and see how the belt fits, and if I don't like it, I'll go with the 1 7/8".
I think that's enough information.
It looks to me like the stocker is about 2 7/16" dia. and the power and amp is about 1 7/8" dia.
I should be safe with either the 2 1/4", 2" or 1 7/8" pulleys available from the link I posted.
1 7/8" would offer the most clearance.
I should have my idler pulley tonight to mock up and see how the belt fits, and if I don't like it, I'll go with the 1 7/8".
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 397
From: Lakeville MI
I measured my March alt. pulley tonight. Its about 2 3/4" in diameter at the top of the ribs.
The 1 7/8" will lower the belt almost 1/2" so I may be able to get away without the idler.
I have the idler pulley now and it appears that it will work after I enlarged the inner bore from 8 mm to 3/8".
Its a 2.5" (64 mm) diameter 6 rib pulley intended for an early 90s MB 190E or 300E. I got it for $18.99 at Auto Zone. TorqFlo p/n 835112. The Dayco equivalent: 89086 was around $40.
The 1 7/8" will lower the belt almost 1/2" so I may be able to get away without the idler.
I have the idler pulley now and it appears that it will work after I enlarged the inner bore from 8 mm to 3/8".
Its a 2.5" (64 mm) diameter 6 rib pulley intended for an early 90s MB 190E or 300E. I got it for $18.99 at Auto Zone. TorqFlo p/n 835112. The Dayco equivalent: 89086 was around $40.
Last edited by tequilaboy; Oct 17, 2007 at 08:19 PM.
