Mataji
Active member
On my Nanni engine I have to re tension the alternator belt after about 6 hours of running. Am I not tightening the adjusting nut/bolt enough? I am always fearful of stripping the bolt thread if I over tighten.
Alternator belt coming loose.
- Thread starter Mataji
- Start date
Boater Sam
Well-known member
After every 6 hours running or just once after fitting a new belt?
LadyInBed
Well-known member
Are you getting black dust and / or squealing just after starting the engine, which indicates that the belt is slipping?
If not, I would say that the lock nuts are not tight enough, especially if you get a lot of low rev vibration.
If not, I would say that the lock nuts are not tight enough, especially if you get a lot of low rev vibration.
PetiteFleur
Well-known member
Try fitting a CRE (Cogged Raw Edge) belt - of the same size. They can transmit more HP than a standard vee belt, but do need tensioning correctly.
Mataji
Active member
I do have a cogged belt. I am not getting any black dust, probably because I tighten it up before it comes too loose. No squealing and it is not just once after fitting.
I think I am just not tightening the bolt on the adjuster enough. I do put a lot of effort into it but I am fairly puny so it might not be tight enough. Before I put an extension on the socket I wanted to ask how far I should go before I might strip the nut.
I think I am just not tightening the bolt on the adjuster enough. I do put a lot of effort into it but I am fairly puny so it might not be tight enough. Before I put an extension on the socket I wanted to ask how far I should go before I might strip the nut.
peter gibbs
Active member
Why are you retensioning? If there's no sqealing from slippage or, dust from a degraded belt you should be OK. When running there should be little vibration in the belt. Even if new there should be no cause to retension. A simple tension test is that the open part of a belt should not turn in the fingers more than 90 degs when at rest. All assuming the belt is of good quality of course.
VicS
Well-known member
Adjust the belt so that moderately firm pressure between the pulleys deflects the belt by 8-10mm
Tighten the bolts according to this table ( borrow a torque wrench just once to get the feel of how tight the bolts should be if you are uncertain)
If you are constantly having to re-tighten an oldish belt it may be nearing the end of its life and will break soon.
A new belt might need to be re-tightened after a few hours .
LadyInBed
Well-known member
The belt is the correct size (width and depth)?
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