Replacing Alt. Belt etc...

[dprice]

Hi All,

I am upgrading the original alternator to a 90 AMP Leece-Neville (Prestolite) (Sales# 110-602) with the external regulator plate (Sales#: 114-307) as was described in this article. http://www.catalina36.org/Article_alternator-battery.htm

This is on an M35B.  The existing alternator is a Mando 50 Amp.

I have gotten as far as removing the exisiting alternator and ordering the replacement (http://www.palcoelectric.com/ had it in stock) and had a few questions.  

To remove the existing belt I had to remove a water hose.  This seems like a bad design and visually it appears that this hose should be able to be re-routed so this is not an issue.  Has anyone done this ?  The alternator was already off when I looked so it may be harder than it first appears.

I researched on this site and found several references to how a 3/8" belt is good to about 75 Amps after which 7/16 or 1/2 is preferred.  The new alternator has a 17MM shaft and Prestolite only offers a 3/8" belt pulley for this shaft size.  Which makes me wonder why they woudld do this if 3/8" is not adequate.  I expect I may be simplifying the issue too much.

As was recommended here I am trying to source a Gates 7/16" industrial belt but have had no luck finding anywhere that they even make an industrial belt of this size.  I am tempted to stay with a 3/8" belt and give it a try.  Maybe have a local Gates Supplier match the existing belt for size and see if I can upgrade the quality.

Dave

[tsoko]

Dave,
I installed the LeeceNeville 90A last spring, and kept the 3/8" belt.  I saw no appreciable wear after one season.  I did, however, put a very thin washer as a spacer between the pulley and the alternator, to make sure that the belt was perfectly in line with everything.  No more black dust!

[dprice]

Thank you both for your replies.

I received the Alternator today and it does not appear to be a direct replacement for the Mando that was on there before.  The pulley appears to be about 1/4" further forward than the original.  This is measuring on the bench.  I will bolt it up tonight to the engine and take a closer look.

If this is indeed the case I am not clear how to fix.  I can probably move the water pump pulley forward with some spacers but I am not sure how I can move the main pulley.

The original alternator actually mounts to a bracket which is mounted to the engine so I am assuming that this bracket was used to compensate for the different pulley locations.  

I was wondering if anyone else run into this problem ?  

The joys for retrofitting.

Thanks
Dave
UnPlugged

[tsoko]

Dave,
I'm not sure the LeeceNeville was intended to be a direct replacement for a Mando alternator on an M35.  Rodd Collins replaced a Motorola alternator on an M25, as did I.

[dprice]

I appear to have skipped over that minor detail when planning this.  

Torrensen gave me a part number for an alternator bracket that appears to be for both the M25XP and the M35B which seems to suggest that the alternators as well should be interchangeable.  I am still looking into this.

Thanks

[Mike and Theresa Vaccaro]

Dave,

As someone who consistantly engineers himself into a square corner (must be the history degree)--I've found that next to life jackets and a good fire extinguisher, the most important piece of emergency/survival gear on board is BEER.  Absolutely critical when mulling things like this over...

Best of luck!

Mike

[dprice]

Good thought.

I couldn't agree more.   :)

The upside is if I drink enough I will have enough Aluminum Cans to melt down and make my own bracket.

Now to figure out how to use my new Butane Pocket torch to accomplish this without torching the boat.

[dprice]

Ron,
I was debating this myself.  Being that the alternator is the more expensive of the 2 parts I was considering modifying the bracket.  However, modifying the alternator would actually be quite easy. It will just require a bit more courage to take a hacksaw to my brand new alternator that it would to a $30 bracket.

When I started this project I assumed (dangerous word) that the certain dimensions for different alternators would be standard.  Once you get past small case/large case etc...  

When you look at catalog cut sheets for Balmar or Ample Power they don't even provide the dimension of how far the pulley is from the face of the mounting foot.  Since this is what controls alignment I would think this would be critical information unless they are assumed to be all the same.  

When comparing the old Mando 50Amp to the new 90Amp Prestolite the only significant difference is the location of the mounting foot in relation to the pulley.  The prestolite being 2/10" further back causing the pulley to be too far forward by that amount.  If I cut 2/10" off the rear of the mounting foot I can move the alternator back and then pad the mounting bolt with washers in front of the foot.  I am going to rethink this and maybe go in this direction.

I've been looking around to see if I could find drawings of other alternators with dimensions so I can see if there is an accepted standard and which of my 2 alternators is the strange one.

Thanks

[Ran139]

David,

   I put the hackssaw to my Balmar to get the right pulley alignment. Be carefull to not allow fileings into the case.Make sure the cut is true. If you take too much off, you can shim back to correct alignment.
   
  - Ran