Are Gates v belt tension specs too high?

[thematt]

Hey folks,


I finally got a balmar belt buddy installed to properly tension my alternator belt. Gates recommends ~100ft/lbs tension measure with their kricket tool on a 15/32" width belt. I was able to achieve this, but the belt is tight enough to make a nice thunk sound that I'm sure can be measure as a note with a guitar tuner.


I'm worried since my westerbeke w50 has no specs or recommendations providing the tension requirements. The raw water belt, which is a half inch belt is even tighter at ~110ft/lbs as per recommendation



That sound about right to you folks? I often over worry about these things when it seems like older engines don't care and keep working as long as the oil and fuel is good.


extra info: 100 amp balmar 6 series tuned down to 80amp. And an old sherwood brass water pump">raw water pump, freshly rebuilt.


Thanks for your input!

[Bowdrie]

I've not measured tension and do use Gates belts.
From your descriptions I'm sure that the Gates engineers would consider mine as too loose.
It's ok, the belts do what's needed without complaint, including a higher output alternator.

[thematt]

I did see some dusting on the alternator belt since I think asking 80amps from a 15/32 belt is pretty much it's limit. You're saying as long as no dusting is happening it's fine to run under spec?

[Greatest Lakes]

If it's not dusting or squealing, it's fine. Without a tensioner, it's hard to set that tight anyhow. Carry a spare belt next to your spare raw water impellers.

[thematt]

For the alternator I have a tensioner. For the water pump, the haft of a mallet works as a lever. Both have been set to the recommended tension. My concern is for the the bearings on the alternator or water pump. Should I be attempting to easy off tension to avoid excess bearing wear?

[FPNC]

The recommended v-belt tension from Gates is all about the belt and how tight it needs to be to not slip on a properly sized drive and driven pulley.

They don't take into account what you are driving and if you have 2 or 3 pulleys in the system. If you are driving water pump and an alternator with a relatively small pulley, you may expect the recommended tension to not be applicable.

Typically, v-belts will slip some if you have a small diameter alternator pulley on a high amp alternator. Meanwhile, it can also be detrimental to the bearings of the water circulation pump if you try to tighten a v- belt to the the tension that gives you no slippage at the alternator. There are good reasons that v-belts are being replaced by flat multi-groove belts.

[thematt]

Thanks for the reply! Sounds like I'm in a tension in check situation.

[Scubaseas]

Originally Posted by thematt

I did see some dusting on the alternator belt since I think asking 80amps from a 15/32 belt is pretty much it's limit. You're saying as long as no dusting is happening it's fine to run under spec?

Dusting is usually an alignment issue, not a tension issue unless you hear squealing. The Gates spec is a bit high for some bearings but 80A load will require the belt to be tight. some cheapy belts will shed dust, Gates usually doesn't as long as your using their premium belts.

[donradcliffe]

100 ft/lbs is not tension. 100 lbs tension is definitely too much, and you will destroy the bearings in the alternator and/or water pump.

[thematt]

You're right. My apologies, 100lbs. Based on the tension guide here: https://www.gates.com/us/en/knowledg...alculator.html