How do I Adjust the Alternator Belt Tension?
Do I use one pulley or two?
Do I need different belts for different size alternators?
Do belts put too much side load on the engine pulleys?
Subj: Re: [C34] M25 & M25-XP Belt Tension & Alternator
Sizes
Keeping belt tension is a constant problem for some of us using
a 100amp alternator with single pully systems. I found that after
tightening it didn't take long before the belt started squealing and
smoking, then the tightening procedure starts all over again. This
is not a nice or easy job while shorthanded in the middle of the
ocean while the boat is rocking and the engine is hot. So the best
thing is to add a second pulley and a second belt.
I really feel that one belt is not enough for a Balmar 100. I never
had any problems with the original setup.
Leo Missler, Dutch Lion, #1183, DutchLion1@aol.com
Subj: Re: [C34] M25 & M25-XP Belt Tension & Alternator
Sizes
Ron, As always confusion reigns supreme. There are different
size pulleys for the Balmar alternators - I had 3 different ones
while trying to solve last summers "belt eating" problem.
The trick turned out to be to get one that was sized for the same
size belt as the pulley on the engine. While too large a pulley on
the alternator allowing the belt to bottom out in the belt groove
was not conclusively the problem, finally getting the
"right" pulley installed ended the chewing up of belts.
Fore and aft pulley alignment was not the problem for us. It was
checked by each of the mechanics we stopped to consult and none
found it to be off. My biggest concern after this conversation is
that tension on the belt is putting too much side load on the engine
pulley. Don't know what I can do about it except make sure that the
belt is not over tensioned.
Mike Ingham, Air goddess, #584, mikeingham@mediaone.net
Subj: Re: [C34] M25 & M25-XP Belt Tension & Alternator
Sizes
The engine is seated on rubber mounts to take up the lateral
vibration. A ridged attachment like a turnbuckle (alternator to the
bed) will negate the mounts and like Leo said may even tamper with
shaft alignment.
If you are eating up belts there is one primary cause - the pulleys
are out of alignment! Take a 18" to 24" straight edge and
place it on the bottom drive pulley (touching both sides of that
pulley) and angle it up to the alternator pulley. The straight edge
should also just touch both sides of the alternator pulley. If not -
the belt is running at a side angle and wearing. If that's so you'll
need to adjust the top alternator spacers until it's straight. If
you look at both the engine and alternator ends of the adjustment
arm you'll see that the female holes (in the engine &
alternator) are the drilled and taped all the way through. I
replaced both 1/2" length bolts with 1" length. Each
should also have a "live" lock washer against a solid
washer. Then you can really tighten without worry of stripping the
threads. Also make sure that the belts have "cooling"
ridges and aren't solid. Don't buy bargain belts, get the Gates
brand.
Go to a NAPA auto parts store and buy a $8 belt adjusting tool -
it's money well spent. No more screwing around with long
screwdrivers and pries while the other person tightens the bolts .
It's a one person task with that tool. Word of caution - if you over
tension the belt you'll be replacing the internal water pump because
of too much side tension on pump bearings!!
I kept the same 7/16" Gates belt on for 5 or 6 years in which
we went to Key West and back to the Chesapeake Bay with the fridge
running 24hrs a day. A few thoughts.
Ron APACHE #788, ronphylhill@erols.com
Subj: Re: [C34] M25 & M25-XP Belt Tension & Alternator
Sizes
Just a thought on the issue of chewing up alternator belts.
Just prior to a trip to Maine last year we added the Balmar 100
alternator. After a long and frustrating series of torn up belts and
conferences with various mechanics along our route, we discovered 2
things. First, and the biggest problem was that the belt sheave on
the alternator was the wrong size for the belts required by the
sheave on the engine. Because the sheave was too big the belt
bottomed out on the sheave. It would tear up a top quality Gates
Green Stripe belt in a couple of hours.
The second problem was that the mounting bracket configuration ( I
am not sure whether it was the original Catalina or not) would
loosen and ease the belt tension.
The fix was to get the right size sheave and to have a mechanic
build an alternator mounting bracket that did not slip.
In the process of going thru this I talked to the Balmar factory.
Their feeling was that a single belt was marginal for a 100 amp
alternator. Based on that input, I would have gone the 2 belt route
but that would have meant replacing the water pump (not the
original) so I am going to try the single belt. It got us back from
Maine OK last year so we are hoping.
Mike Ingham, Air Goddess, #584, mikeingham@mediaone.net
Subj: Re: [C34] M25 & M25-XP Belt Tension & Alternator
Sizes
How do you determine how much tension should be applied to the
alternator belt when tightening. I have the Balmar 100 on a M35B
engine with one belt, I used it this way from August thru October
last year with good results, however I am keeping a close eye on it.
I talked to the Balmar distributor at last years Catalina get
together in the Solomon's and he stated I should have no problem
with this arrangement and a 7/16 belt.
Ron mentioned a belt adjusting tool from NAPA, does anyone have a
part number and what does it consist of.
Richard Beecham, rbeecham@home.com,
"Refuge", C34 MK II Hull # 1430, Rock Hall, MD
Subj: Re: [C34] M25 & M25-XP Belt Tension & Alternator
Sizes
Mike, Dick and Stu : Ron Hill did in fact state in many
recommendations that the maximum size of the alternator should be a
90 amp. What should have been viewed with this recommendation is
that I take into consideration a boat's year and hull number so I
know which engine is involved. I always recommend a maximum of 90
amp, especially for the M25 (21 hp). I have a 75 amp dual output
Balmar (on an M25XP--23hp) which has a smaller case and
"almost" has the same output of 100 amp at the lower rpm a
Universal engine turns at. For those who have the 30 or 35 hp M35
engine, the problem isn't side load drag down of hp, it's simply the
geometry of fitting a larger alternator in the space available. My
"75" generally starts out with an output of 65 amps at
1500 rpm. As the batteries recharge, the amperage of course, goes
down as the voltage builds.
As with all companies, you need to know who to talk to so you get
the
Right story. I like to work with Gary or Bill at Balmar. Over the
years I have gathered that Balmar has the same "deep V"
pulley on all their single pulley alternators. The "deep
V" will accommodate numerous thickness of belts. That's why
they do it. Mike, it isn't the depth of a pulley that will eat up a
belt, it's the misalignment fore and aft of the belt going into the
pulley that eats up a belt. The "deep V" will give you
better traction the deeper the belt goes into the V on the
alternator pulley, but if it isn't aligned laterally it will chew up
the belt faster because it is in a "deep V." That's why
the alignment procedures that I mentioned yesterday are so
important.
Dick, I can't give you the NAPA part number for a belt adjustment
tool because I don't know the number and I didn't buy it at NAPA.
You ought to be able to get this at any automotive supply parts
store. Here's what it looks like.
There is a concave curved bracket that fits in one pulley on one
end, and a curved concave bracket that fits in an opposite pulley.
There is an adjustment screw in the center and one end has a left
handed thread and the other end has a right handed thread. So as you
screw the adjustment in one direction, it tightens both ways. When
you screw in the opposite direction, it loosens.
Ron , APACHE, #788, ronphylhill@erols.com
Subj: Re: [C34] 25 & 25-XP Belt Tension & Alternator
Sizes
Ralph, Sorry about the delay, but I had to get the M-25XP parts
list out to get the number for you. It is 302159 (Universal #) for
the main pulley. It's in the Westerbeke/Universal edition 1 parts
manual. Marysville Marine can be contacted by 800 367-0987 for their
outlet in Michigan. This is a big company, so you want somebody that
is familiar with the M-25. For instance the water pump pulleys for
the M25 and the XP-25 are different. One has to be careful.
The dual pulley conversion is very easy to mount. Simply lay the
pulley over the front pulley on the engine and screw in the three
allen-head machine screws that come with the kit and that's it. You
will also need the two groove water pump pulley. There is no part
number for it, but Marysville Marine knows about it. It comes off
with three small retaining bolts. BTW, the water pump is also a weak
link in the system regarding side-load on belt tension.
A couple of years ago Balmar changed the output ratings of it's
models so there is some confusion about what is what regarding
alternator output. It seems the 75, 90 &100 amp models are the
most recommended models as they are the best compromise between
output and stress on the existing mount and pulley setup. These
models vary a lot with how much they put out at what rpms. Some are
designed for high output at low rpms at the cost of maximum output.
These are probably best suited to what we are doing. Who wants to
run the engine at 2800 rpm to charge the batteries?
I remember Herb Schneider mentioning in a Mainsheet about running a
Balmar 90 and saying that he thought that that was about the max
amount that could be pulled over a long period of time from a single
belt. Manufactures don't want a lot of liability in regards to over
stressing their products either. A lot depends on how big your
battery bank is and the settings on your regulator. Everything else
being equal, a larger battery bank will pull more current from the
alternator over a longer time period.
Balmar (blamarvst.com) is very knowledgeable about this engine also
as they use a variant of a similar Kubota block in some of their
water-maker / generator equipment. They will be glad to tell you
about problems they had while trying to use the front pulley for
power takeoff. Balmar stresses that all PTO belts are not the same
and they make strong recommendations about using only top quality
belts. If there is black residue around the alternator, then there
is probably an alignment problem. My installation only required that
the alternator adjustment arm had to be modified by adding exactly
one inch to the alternator end. $10.00 and an extra trip to the
boat/shop.
It seems that from the best information I could assemble from these
sources the two belt route was the most logical and trouble free way
to go.
After the install I did notice that the two belts have slightly
different tension. (ok, so I'm a bit anal) It seems that the added
belt is somewhat tighter than the inner belt. I'm not sure that this
is a problem yet. I need to get some more hours on the setup to see
if this is going to be a concern. If it is, I'll get the shop to
take a little off of the new pulley.
I'm running a small case Balmar 150 dual output into four golf cart
batteries and a small starting battery, so the acceptance charge is
not going to seriously tax the alternator for long. If you are
running larger batteries then you will have the alternator working
harder longer because the increased capacity of the batteries and
their greater acceptance will put more demands on the system.
When you start adding up all of the pieces, this turns into a pretty
significant upgrade. It would be well to make it as reliable as
possible.
Please confirm this information from primary sources for yourself.
The list is fine for ideas, but for peace of mind and responsible
care of guests and crew, you need the best quality information
possible. "When the thing blows up in your face, it really is
going to be your fault". (That's what Ken's dad used to say).
He also had some ideas about women, but that's off topic!
Ken Dickson, Family Affair C-34 876, kdickson@mo.net
Subj: Re: [C34] M25 & M25-XP Belt Tension & Alternator
Sizes
In twin belt installations ALWAYS buy belts in a matching pair!
They are sold that way. Change both at the same time and you'll save
heartache. You will also maximize your benefits and reason for going
to twin belts in the first place.
Gary Wiseman, Up Spirits #894 gwiseman@ftn.net
Subj: Re: [C34] M25 & M25-XP Belt Tension & Alternator
Sizes
Gary is correct. If you can't purchase the size you need as a
matched pair, just make sure that all those other numbers on the
belts ( beside the size) are identical. That means they were cut out
of the same extrusion.
Ron, APACHE #788, ronphylhill@erols.com
Subj: Re: [C34] M25 & M25-XP Belt Tension & Alternator
Sizes
Mike : Gary at Balmar led me to believe that Listic had one
standard "deep V" pulley. Sorry to add to the confusion.
As I said I've had my 75 amp duel output sense 1991 and it's been
problem free. I did upgrade from a BRS to an ARS III regulator. I
changed the belt after 5or6 yrs. on general principles. Don't over
tension. I like to be able to press on the belt and have it move
about 1/2 inch between the water pump pulley and the alternator
pulley
Ron, APACHE #788, ronphylhill@erols.com
Subj: Re: [C34] 100 Amp alternator w/ m25xp
I installed a Balmar 91-75 alternator on Sjora last spring and
have had no problems whatsoever with the belt. The only problem was
finding an appropriate adjusting bracket. While the 75 does not have
the same maximum output as a 100 amp model at typical charging rpm's
it's output is the same or greater so I would expect belt loading to
be about the same also. I think it's important to use a regulator
that allows a time delay at engine startup and a gradual ramp up to
max output which takes high starting stresses off the belt. When I
removed the belt this fall for lay-up it was as good as new except
for one chipped cog.
Bob L. Sjora #1420, SvSjora@aol.com
Subj: Re: [C34] 100 Amp alternator w/ m25xp
<<I'm determined to go with 100 amp, could I hear from
those of you that went the 100a route. I would really like to know
what make, model and what the cost was.>>
At the risk of adding more confusion to the alternate alternator
discussion, here's what I did: We have a local (northern Wisconsin)
alternator-starter rebuilder who does a lot of business nationally
and has supplied rebuilt units for many boats in our marina over the
years. While at his shop a couple of years ago, he told me he could
supply a 100 amp alternator for an external regulator at a
reasonable price. I purchased one for around $120 if my memory
serves me correctly and he put a fan on it which would clear the
stock Universal bracket. The pulley was matched up to the old
alternator so that the belt would ride properly as well, so it fit
the engine without any modifications.
I've used this now for two years with a Heart Interface smart
regulator and several others at the marina have purchased them as
well. Never had a bit of trouble with either belts or alternators.
Though the units are rebuilt, not new, the stators, bearings and all
wearing parts are new and they provide a warranty - and the price is
definitely right. The company which supplied the alternators is
called Blue Circle Electric. If anyone is interested, I will get the
details and post them to the list.
Both Balmar and Heart Interface smart regulators are $190 in the
West catalog and a bit less in the Defender catalog. Either will
plug directly into the alternator Blue Circle alternator.
Jim Moe, Windseeker #976, jmoe@worldnet.att.net
Subj: Re: Duel Alt. Pully
Ralph : Approach the duel alternator pulleys with caution. As I
mentioned the duel pulley will even put more of a moment on the
water pump bearing - being that much further out.
Ken corresponded with me a couple of years ago. He was planing to
put on a 200 amp alternator so he could have AC while motoring! I
think that Westerbeke (on my insistence) discouraged him from that
venture. He later said he had decided for AC on dock power. Never
figured out if that original AC was for the cabin only or whether he
had some kind of enclosure for the cockpit - or the helms person
just had to take whatever ambient was?
When you measure let me know if you'll have to remove any of the
insulation on the inside of the steps - to accommodate the double
pulley on the water pump or if your engine is mounted too far
forward.
Ron, ronphylhill@erols.com
Important: The opinions expressed here are
those of the individual contributors to this page, and not those of
the Catalina 34 National Association or Catalina Yachts, Inc.
Additionally, this material has not been reviewed by Catalina
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suggested modifications or upgrades. Please obtain assistance from a
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