Aternator Belt Tension

[Ocean Girl]

Thanks for the feedback, after looking about the internet I am unable to purchase a pulley spanner(or fan belt tensioner), tomorrow will try the local auto parts store. If not, will try Gords idea of reversing a clamp or svHyLyte's turnbuckle. I would prefer the turnbuckle, don't know if I am strong enough to trigger the clamp to the desired tension. BTW I have very little clearance, plus I have a vdrive so will be working under the cockpit sole (fun!).We will see tomorrow.

Thanks to all!
Erika

[Ocean Girl]

Tension:
I am told and have read that if I pinch the belt and am only able to turn 90 deg is a good tention, any more too loose any less too tight...any other pointers for tension? is this a alternator preference? or is it the type of belt since ribbed require less tension..?
Thanks, Happy 4th!
Erika

[skipmac]

Originally Posted by John A

In a former life this worked on all sorts of farm equipment.

I'm sure the reference to hammer is the use of the handle as a lever to apply tension to the belt while tightening the bolt on the bracket.

Actually using a hammer is dual purpose. Yes, mainly use the handle as a lever on the alternator but when the alternator bracket won't cooperate you can use the other end to whack it a few times. Doesn't help tension the belt but good for relieving your personal tension.

[GordMay]

Originally Posted by Ocean Girl

Tension:
I am told and have read that if I pinch the belt and am only able to turn 90 deg is a good tention, any more too loose any less too tight...any other pointers for tension? is this a alternator preference? or is it the type of belt since ribbed require less tension..?
Thanks, Happy 4th!
Erika

See 1 ➥ Belt & Pulley - Cruisers & Sailing Photo Gallery

And 2 ➥ Belt & Pulley - Cruisers & Sailing Photo Gallery

[Laidback]

Originally Posted by Chief Engineer

You tighten the belt until untill you cannot turn the alternator with hand pressure.
I see way too many overtightened belts......and the corresponding water pump failures.

CE has it spot on, one alternator and one waterpump on one belt, one groove in the pulley = ok!
But 2 alternators should have their own belt in the groove nearest the engine --- and the waterpump on its own in a separate groove.

[Ocean Girl]

the more I am learning about alts the more I realized you guys needed more info, so here is a pic, the tensioning arm bolt (thingy) is at the bottom from what I can tell. I only need to back off of that bolt a turn or two, leverage the alt a bit and retighten bolt..correct? I then check tension to see if it feels good? It being a ribbed belt, I read I do not need it as tight as a reg belt(**maxing out- how tight?). I will try to get the pulley spanner, just seems I will be able to make smaller adjustments, (a finer tune).
Sorry I didn't post this sooner, my internet connection bites.
Erika

[GordMay]

The proper tension for a drive belt is the lowest tension at which the belt won’t slip or squeal under peak load.

See also ➥ http://www.maskapulleys.com/images/p...tensioning.pdf

[svHyLyte]

Try this (Turnbuckle from Lowes $2.98 USD):

[sigmasailor]

Originally Posted by Ocean Girl

Anyone know where I can buy a qadget that helps you to tighten an alternator belt. I don't even know what the name of the tool is.

From what has been described to me, this tool holds the alternator belt inplace while tightening the appropriate bolts. I have a volvo MD2020, but don't think it matters.
Thanks,
Erika

My favorite tool is a really big screw driver. Just insert it between some engine part and the alternator and pull with your left hand. Tighten the nut with the spanner in your right hand. The belt will stay on as soon as you have it around the pulleys; no need to worry about that.

[colemj]

Originally Posted by Ocean Girl

the tensioning arm bolt (thingy) is at the bottom from what I can tell. I only need to back off of that bolt a turn or two, leverage the alt a bit and retighten bolt..correct?

Almost. You will need to loosen the top bolt a bit also, or it will be very difficult to adjust. The top bolt is the hinge point, but if it is tight, it will be hard to move.

When they are loose, just use a long-handled screwdriver, or other bar-like thing and place it between the body of the alternator and the engine and pull back on the top. The alternator will swing over on the bracket and tension the belt. Tighten the bracket bolt while applying pressure, then tighten the top bolt.

Mark

[Ocean Girl]

Well I crawled to the other side of the engine and found out why my alt belt is slipping. I am missing a the nut on the lower bolt for the alt belt arm thingy. I looked around for the nut but couldn't find it, plus the bolt rubbed a big chafe spot in the water hose (dagnabbit!!). So OG is yet another project away from sailing..sigh.

[Laidback]

Originally Posted by Ocean Girl

the more I am learning about alts the more I realized you guys needed more info, so here is a pic, the tensioning arm bolt (thingy) is at the bottom from what I can tell. I only need to back off of that bolt a turn or two, leverage the alt a bit and retighten bolt..correct? I then check tension to see if it feels good? It being a ribbed belt, I read I do not need it as tight as a reg belt(**maxing out- how tight?). I will try to get the pulley spanner, just seems I will be able to make smaller adjustments, (a finer tune).
Sorry I didn't post this sooner, my internet connection bites.
Erika

As you have outlined above.
If you have the correct spanners (US : Wrenches) and a large screw driver (or a bar of some sort) you will not need any other gadget to adjust the tension.
Here is your engine picture again - this time with some arrows :-
Here is the simple procedure to tighten the crankshaft/alternator/water-pump belt to a tension that will not allow slipping of the belt on the alternator, or over tension which may result in stretch or damage to the water-pump.
#1 loosen the bolt on which the alternator swivels -- Red arrow (no more than a couple of turns)
#2 loosen the bolts on the adjusting bar -- Blue arrows
#3 Insert leverage bar (big screwdriver) between the alternator and the engine block-- Orange arrow, force them apart. Until #4
#4 Until you can depress the belt no more that 1/2" (12mm) at the Green arrow
--
#5 Tighten the bolts - Blue arrows
#6 Tighten the bolt - Red arrow
#7 Remove the leverage bar

[Therapy]

You may never find the nut but at least you know it is down there!

[Ocean Girl]

You guys are great! Thanks for all the ideas and input, and especially clear set of instructions with pictures and arrows!! I'm going back in when it cools off a little more.
Cheers,
Erika

PS the chafe spot from the bolt is all the way through the hose, but jeepers, that should be pretty straight forward replacement (did I just jinx myself?).

[Ocean Girl]

Can you guys clarify how the belt is to sit? (not about tension) Someone told me it is not to rub an exact "flat" on the pulley but ride a side or edge?? Maybe a better question is - What is the right wear mark on the pulley and belt?
Erika

ps
Gord that tension instruction link is fantastic, thanks.