Belt tensioners-decrease tension?

June 20, 2013, 05:10:00 pm

I've got a pair of brand spankin new Gates belt tensioners and have a question. I'm aware of the alignment procedure which has been posted on the forum and intend to follow it carefully. I seem to recall reference to reducing the belt tension a bit by redrilling the hole that the cast in dowel keys into. It does seem like the stock setting results in a very tight belt and I'd like to reduce it a bit. Does anyone have any recommendations regarding how far from stock position to drill this new hole? Can't really see any method to determine it short of trial and error, it'd be good to have a starting point at least. Edit: 8.3 Cummins 300hp mechanical

Thanks, Chuck

Re: Belt tensioners-decrease tension?

Reply #1 – June 20, 2013, 05:23:43 pm

Chuck,

I believe I was the first to detension the belt tensioner by drilling a detent hole clockwise from the original after the hydraulic pump manufacturer said belt tension was too much and had pulled the bushing out of the pump for the second time in 25,000 miles. After detensioning it, the pump was still going strong after an additional 100,000 miles.

Here is how I determined where to drill it:

Install tape in the area where you will be drilling the new detent hole.

Install the tensioner with enough washers to equal the height of the detent. Tighten the bolt so that that you can just rotate the tensioner body with a pair of water pump pliers, etc. Start winding the tensioner body with belt installed until you have the proper tension. Mark that location with a radial mark to denote the center of the new detent hole.

Remove the belt and loosen the bolt/nut enough that you can just rotate the tensioner body. let the detent "scribe" the part of the circle that will tell you how far from the bolt to drill the hole. Use the radial mark to determine how "far around the clock" so that you have an "X" to drill.

The bracket is mild steel and easy to drill.

Sounds more complicated than it is-- assuming you can get your drill to the area where you want the new detent. And, no issue drilling more than one new hole if you find you want to further fine-tune it.

Brett

Re: Belt tensioners-decrease tension?

Reply #2 – June 20, 2013, 05:32:20 pm

Thank you Brett, great description and as I now recall you were indeed the first to describe this mod. With the cost and scarce availability of the hydraulic components I'm wanting to do what I can to ease the strain on them. Great to see you're still hanging out on the forum, appreciate it.

Chuck

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