Alternator Belt Replacement Layout

[nigelmercier]

I've just changed my Alternator Belt Layout, see picture:

Reasons for doing this:

The 12V alternator (on RHS of picture) is 120A, and gets through (9mm) belts quite quickly. The other belt (24V alternator) has not been changed in 10 years.
The load on the 12V belt was increased by being shared with the water pump.
The new layout reduces the load on this belt, and increases the wrap on the pulleys.
The drive spindle is now slightly smaller, so again this should reduce slippage.

Now I need to measure for new belts:
I was thinking of using some 3mm string with the alternators where I want them to end up, will this work?
How much movement of the pulley should I allow to fit the belts?

The more observant of you will have noticed a problem with the oil pressure sender, please discuss in this thread: http://www.ybw.com/forums/showthread.php?429464

 

[superheat6k]

If the belt is 9mm I would use a piece of 8mm rope to measure with. As long as you are within 10mm with your bracket adjusters say 1/3 along from min position you should be fine.

This will allow enough slack to get them on, and sufficient for tensioning.

For the oil switch can you space the LH forward and the RH back to use the other grooves (swap) ?

 

[nigelmercier]

For the oil switch can you space the LH forward and the RH back to use the other grooves (swap) ?

Thanks for measuring info.

I've just swapped them round on the grooves, hence the problem! This wasn't an easy task, it required several hours using an angle grinder on the brackets.

 

[scottie]

Change to polyvee belts and pulleys load is too heavy for V belts as you have found

 

[scottie]

http://www.marinepartseurope.com/PentaPictures200/24924.jpg

They may have had some thoughts on your ptoblem

 

[nigelmercier]

I've looked into replacing the belt type, way too expensive. I believe my solution will work a lot better than it did.

 

[rogerthebodger]

I had a similar Issue some time back and I just upgraded the belt that was wearing the most from Z section to A section. or even alpha section. Your main pullied look like they can take wider belts but I don't know about the alternator pulleys.

 

[nigelmercier]

Now I need to measure for new belts:

As you can see from the picture, the existing belts look OK, but I do want to move the alternator on the right outwards to fit a turn-bottle tensioner. Conversely, I want the alternator on the left as close as possible inboard to avoid fouling pipework.

I found an old belt (I think, see below) and cut 25mm off it, then taped it together. I couldn't get it on, so the existing long belt is OK. I'll use it to measure the short belt as well.

So the question remains: given a handful of belts, how do you tell which have been used?

 

[rogerthebodger]

So the question remains: given a handful of belts, how do you tell which have been used?

Used Vee belts generally have some polishing on the sides of the Vee.

Compair used ones with a brand new and you will see.

Some times if the used ones have been overloaded the sides of the Vee could be ripped and threads of the top brading hanging out.