Upright T-4 Alt/Gen Pulley Modification


    In order to have the fan shroud mount equally between both cylinder banks, like on a T-1 engine, I found that the alt/gen pulley ended up being too far forward of the crank pulley to install a belt.  One solution is to just add a spacer between the pulley and the alt/gen, but too large of a spacer and you don't have many threads for the pulley bold to grab hold of.  Upon looking at the construction of the original pulley, I realized that the pulley was designed so that the fan belt is directly over the rear shaft bearing.  This means that the forward half of the pulley has substantially more dish than the rear half.  

    If I switched these halves around, I found I could effectively move the pulley assembly 13.5mm back (0.53")!!  Here's what I did.

    I started with a new pulley.  It's an aftermarket pulley, but I found the quality to be much better than the OEM Mexican made one sold at dealers for 4 times more.  The main thing about this pulley was that the center hub is ONLY spot-welded in place (cheesy I know, but it enables it to come apart from the pulley half easily).  The Mexican pulleys have a weld bead all the way around the hub making it impossible to separate it from the pulley half.

T-4-pulley1.jpg (46743 bytes)            T-4-pulley2.jpg (45123 bytes)

    Then I used a sharp blow with a hammer to break the spot-welds and separate the hub from the forward pulley half.

T-4-pulley3.jpg (50277 bytes)

    Next, I inserted the hub into the other pulley half .  Now you could weld it in place so that it doesn't come apart again, however, that is not necessary since the pulley nut on the alternator shaft, holds everything secure just fine.  Another advantage of having a pulley like this that is in three separate pieces is that you can fine tune the shimming on all pulley halves not just between the two halves for belt tension.  You can have the ability to add shims between the pulley hub and the fwd pulley half allowing for additional fine tuning of the pulley alignment with the crank pulley.

T-4-pulley4.jpg (43691 bytes)

    The result is a pulley which is 13.5mm ( 0.53") to the rear of it's original location without having to shim between the pulley and the end of the shaft.  

T-4-pulley5.jpg (43756 bytes)


UPDATE:  11/9/07

    I have decided to start offering pulleys that are pre-modified and ready for immediate installation.  Over the years I have received tons of e-mail requesting these as well as inquiries as to where to obtain the correct pulley for modification.  I have since secured a source for high quality pulleys that are perfect for modification for use with your type-4 conversion.   These pulleys start off as a high-quality type-1 alternator pulley that has the center removed, the front pulley half is then modified to work as a rear half.  Then both halves are powder coated high gloss black and reassembled.  Below is a photo of a modified pulley that is ready for shimming and installation on your conversion motor.

t-4-conversion-pulley.JPG (59012 bytes)

    The price is $45 each plus $5 shipping for a pulley.  If you order more than one, shipping is reduced for additional pulleys.  I sell these from my repair & restoration shop, ProVolks in Anacortes, WA.  I accept postal M.O. (No personal checks please) and Visa/Master Card (for phone orders).  My mailing address for sending orders and payment is:

Nate Morse c/o ProVolks / 12796 Quantum Lane Suite #14 / Anacortes, WA 98221

   Credit card orders can be taken over the phone M-F 9:00am-5:00pm (Pacific Standard Time) at: (360) 299-8860.  Hopefully offering these will make it just that much easier to get your dream of a type-4 conversion to a reality.


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