Copyright © 2008 Brian McCamish,  All Rights Reserved

Note about the photos on this site:
Most photos were taken by me.  I usually allow people to use my photos for personal use or websites.  Simply Email me.  
Upgrading the Alternator to a Factory
OEM Toyota 150 amp unit on the
With high demands such as extra lights and winching, the stock 1FZ alternator, which makes about 80 amps does
perform adequately, but its always nicer to have more power.    Usually after market alternators come with a price of
being too expensive and not as high of quality as the stock Toyota OEM alternators.    There is one alternative that
offers the best of all worlds.

Toyota produced a 130 amp high output alternator for the 4.7 V-8 offered in the Tundra, 100 series and Sequoia.  It
also produced an even higher output 150 amp alternator in certain late model Sequoias and possibly other models.    
This alternator is bigger than the 1FZ alternator, but with the addition of a custom bracket and some minor reworking
of the stock plug, it can easily be made to fit, making this a nearly bolt in affair to almost double stock output using a
factory reliable and umodified Toyota alternator.

This thread on explains most of everything and this is where I obtained the bracket you see here.  It
may no longer be available as you read this.   I sourced the alternator from and did a search using
2004 Toyota Sequoia.   This 150 amp alternator had only 14,000 miles on it and cost about $100.
Fan Belt idler pulleys
Photo shows the new AC idler pulley (top) and old pulley disassembled in order from left to right (bottom).

The 1FZ has two engine belt systems.   A double belt runs the alternator, water pump and engine fan.  These belts run against a fixed idler pulley
and are adjusted via the alternator lower mount.    The AC compression has its own single belt which is adjusted via a seperate adjustable idler
pulley.    Both of these pulleys have internal bearings which eventually fail.   Usually a pulley bearing that is failing will make noise long before it
siezes.  But once it siezes, the potential for belt failure is not far behind.    Both of these pulleys are easily replaceable from Toyota.

Usually idler pulleys can be rebuilt by simply replacing the bearings.  The metal parts should last the life of the engine.  However, the alternator idler
pulley is built with two halves assembled and rivited with the bearing in the middle.  It's not possible to replace just the bearing.   The AC idler
pulley's bearing can be removed and replaced if you can find the right size bearing.

I chose to go ahead and replace both idler pulleys from Toyota as a PM.   As it would turn out neither one showed any signs of bearing wear at all
and worked perfectly, but since I had already purchased new units, I put them on and kept the old ones as spares.

Tip:  The alternator idler pulley simply unbolts off.  Very easy.  The AC idler pulley needs to be taken apart to be removed from the vehicle.   There are
several pieces that need to go back in order when putting the new one on.   See above picture.
Alternator upgrade
Photos from left to right.....Sequoia V-8 150 amp alternator with 1FZ pulley (left) verses stock 1FZ alternator with Sequoia pulley (right)....Sequoia
alternator with custom adjusting bracket attached.

Stay tuned for more pictures and results when the project is finished.