TWL: alternator belts
This month last year Larry Z and I posted a few messages regarding alternator
belts. At that time he referenced a Gates booklet which said manufacturer
matched belt pairs should be used on dual drive pulleys to avoid wear and tear.
Here is what else I think I know: (not much)
Belts seem to be good products....they seem to last well, but I don't run 24
x 7 either. I use now dual belts to reduce strain on bearings and hopefully
provide more trouble free operation. I read the belts should seat not more
than 1/16 inch above the pulley shoulder top. And of course they should not sit
deep down in the sheave (vee)....especially anywhere near the bottom of the
pulley sheave. Shiny belt sides especially with grooves indicates wear. In such
cases a fine grit sandpaper, maybe 200 or so should be used to scuff pulley
sheaves for better grip...and perhaps the belts replaced, especially if any
cracks are visible. Drive pulley sheave and alternator pulley sheave need to be
the same size (for proper belt fit and speed). A two foot piece of 1" x 2"
wood is a convenient lever to get some reasonable tension when installing new
belts.
I have some questions for the list:(because there is a lot I know I don't
know>)
(1) How do you line up your drive and alternator pulleys?
I use a straight edge at the front of the pulleys and insert a washer or two
if required to get alignment. Of course the engine pulleys are much bigger
diameter and the edge (shoulder) of the pully is thicker than the edge of the
alternator pulley, so I judge the difference to get the grooves aligned.
(2) I checked the Gates website and under "automotive" they list (of all
crazy things) "marine"...but show no information except some pictures of their
"marine" belts....I'll bite: Just what is a "marine" alternator belt? (I've
bought belts for forty years at auto stores.....I never even suspected!!...My
mechanics work shop has belts hanging up that look just like mine.)
(3) Do you prefer or have any technical information on smooth edge belts
versus grooved (cog) edge belts??....in other words, what are the pros and cons
of each? I tend to use grooved edge...they just look cool!!! (for a belt, that
is)
(4) Do you notice belt dust on your installations after,say, a 100 or 150
hours running time? (I'm tired of wiping this off my engine every winter.)
(5) How do you adjust belt tension? Anybody know of a tool for this?? And
don't give me that "....1/2" depression with forefinger (thumb)
baloney..."....unless of course the tension really needn't be very precise if which case almost
anything will do....(I use this silly test and suppose it IS better than
nothing.) Wouldn't dual belts tensioned this way put more strain on
bearings.....so should dual belts be left a bit looser...that's what I do...
(6) Anybody use belt dressing? That is, spray to increase friction between
belt and pulley. What do belt manufacturers say...is this a good idea or a cover
up??Does this adversely affect belt life...or enhance it???
(7) Anybody have a source/booklet/website for general pulley information??
(Larry??)
Here's a website for anyone interested in some alternator belt questions and
answers:
http://www.c34.org/faq-pages/faq-belt-alt.html
Another site offered the following emergency repair suggestion I tried the
old
panty hose trick....AND IT WORKS! I bought size Queen + in satin black (looks
better in engine bay than nude) (courtesy of Mike Savage).
Cheers,
Rob Brueckner
1972 Hatteras Yachtfish
The best belt-tensioner I've seen was on a sailboat. The man replaced the
normal flat-stamped adjuster with a threaded SS rod with double nylon
lock-nuts. He simply used a wrench to adjust tension and then moved up the
second nut to lock in-place.
I have no recollection how he furnished "eyes" on both ends to take the
standard bolts - but he did.
Ron Rogers
Rob:
Full of questions tonight. I will provide a couple of answers based on
my reading and experience.
As the belt wraps around the V pulley it bulges on the sides. This
bulge is critical. The belt wedges into the V pulley then expands
laterally to tighten itself further. If any part of the belt is above
the pulley it is not doing its share of the work. It does not matter
how deep in the V of the pulley the belt sits as long as it does not
touch the bottom of the pulley and as long as the sides of the pulley
are not grooved. On the other hand, pulleys and belts should be matched
and the proper belt will sit high in the V. Save the sandpaper. If the
pulley has developed a groove, replace it. Your sandpaper burnishing
may help for a short time but it will soon be polished by the belt and
the groove still prevents proper wedging of the belt in the pulley.
Alignment faults can be parallel or angular, subtle or serious. Trust
your eyes first. Don't obsess. Unless a pulley is loosening or your
systems have been modified, they should not migrate out of alignment.
Straight edges are difficult to set and read in cramped spaces against
pulleys that are not physically matched. The best you can do with the
straightedge is to read from one pulley to determine that your belt
remains parallel to the straightedge. Repeat check from the next
pulley. The dust you are reporting from your belts is not typical and
does suggest a possible problem.
Belts that are cogged are preferred where they are subject to reverse
flexing - that is they flex in one direction around one pulley and the
opposite direction around another. The cogs or grooves across the belt
are there to make the belt more flexible and make it generate less heat.
For a configuration that flexes only one way the cogs add nothing to
performance as far as I know.
Good pulleys and good belts don't need any dressing and I have never
used any. If it seems to be needed, something else needs attention.
My opinion only
Wesley
weldred@adelphia.net
GYMKIDD319@aol.com wrote:
This month last year Larry Z and I posted a few messages regarding alternator
belts. At that time he referenced a Gates booklet which said manufacturer
matched belt pairs should be used on dual drive pulleys to avoid wear and tear.
Is it possible to get the identical tension on both belts in a two pulley
system? Doesn't one of the belts usually carry a larger percentage of the
load? And wouldn't you want that one to be the closest one to the
alternator so there would be less torque on the shaft causing less wear on
the bearing?
Mike Gladwin
44' Trawler "Waterbed"
----- Original Message -----
From: GYMKIDD319@aol.com
To: trawler-world-list@lists.samurai.com
Sent: Wednesday, January 28, 2004 7:35 PM
Subject: TWL: alternator belts