New Product Offered by Moyer Marine - Alternator Tensioning Arm

[Administrator]

How do the majority of boat owners tension their alternator belts? By leaning on a pry bar? How do they know when the belt tension is right? The belt deflection technique? That’s a rough approximation at best and is greatly affected by the unsupported length of the belt. Other manual jackscrew tensioners don’t account for proper tension. They only eliminate the pry bar.

Neil Dutton, a senior contributor to the Community Forum, observed that the relatively small alternator belt used on the Atomic 4 frequently presented a challenge in getting enough tension on his belt to prevent slippage (and the resulting black belt dust on his “showcase” engine), while at the same time avoiding so much tension that alternator and accessory drive bearings were put at risk. Neil has designed and developed a spring-loaded adjusting arm designed to place the alternator belt under proper tension to prevent slippage while avoiding unnecessary side loads on bearings.

This tensioner was born out of the serpentine belt tensioners found in nearly all automotive applications these days. Some of its advantages are:

• Accurately calibrated tension on the belt.
• Prevents overtightening the belt and associated alternator bearing wear.
• Maintains proper tension as belt wears.
• Easy 10-minute installation.
• One full turn of the adjustment nut applies approximately 15 lbs. force.
• Prototype testing has shown roughly 45 lbs. of force to be the proper tension using the Lycoming SI 1129A (for aircraft) reference on belt tension. Combining their standards for new and old belts averages 12 ft-lbs. torque applied to the alternator pulley hex nut before belt slippage occurs.
• A light conical spring holds the lower bracket against the tensioning spring, facilitating installation.
• Installing the device as an unloaded and aligned assembly positions the lower bracket properly.

The arms are shipped preassembled as pictured so as to make installation as simple as possible. Instructions are included to facilitate the actual adjusting process.



Click here to order.

You can log on to the Community Forum to see Neil’s other considerable contributions, including a world class electrical schematic for the Atomic 4, a re-circulating fuel filtration system, and many other innovations. We hope this product will inspire others from the Forum fraternity to develop Atomic 4 friendly products.

[ILikeRust]

Hehe!!

Finally.

Neil showed me the prototypes when I was out in L.A. back in June, and swore me to secrecy. I was waiting for the official public announcement.

As soon as they became available on the MMI website, which happened last week, I called Ken and placed my order. I am the proud owner of what I believe to be #1.





Unless someone else managed to beat me to it?

I will, of course, report back when I install the wee beastie, and will of course provide photographic evidence...

[sastanley]

Wow....pretty impressive!!!

This should go nicely with my updated alternator bracket that spreads the load over water jacket side plate a little better too - (of course, modeled after Neil's work on that too..)

[roadnsky]

Neil Dutton, a senior contributor to the Community Forum, observed that the relatively small alternator belt used on the Atomic 4 frequently presented a challenge in getting enough tension on his belt to prevent slippage (and the resulting black belt dust on his “showcase” engine), while at the same time avoiding so much tension that alternator and accessory drive bearings were put at risk. Neil has designed and developed a spring-loaded adjusting arm designed to place the alternator belt under proper tension to prevent slippage while avoiding unnecessary side loads on bearings.

Does SENIOR member refer to Neil's age?

Congrats! Great tool.
It'll be a nice addition with the new Alternator.

[ndutton]

Does SENIOR member refer to Neil's age?

Eh? What's that you say sonny? I see the same distinction under your name too.

I'll add this to the tensioner arm discussion:
During prototype testing I was surprised at how much less tension was required than what I had been applying manually (prybar method). With the new tensioner installed I ran the engine hard under load (witnessed by ILikeRust Bill and Thatch during our sail) with no squeal of any sort. I suspect there are many of us, perhaps even a majority, who are running with considerably more belt tension than necessary.

I expect I'll enjoy greater auxiliary drive, alternator bearing and belt life with the tension dialed in just right.

edit:
I wanted to admit that although my name is all over this thread, this venture was a collaborative effort. I received great input from a variety of co-conspirators.

[lat 64]

Awesome product. Really neat that you were so helpful to the cause. This reminds me of back in high school. We used to make chain tensioners for the drive chains on our beat up dirt bikes by putting a skateboard wheel on a spring-loaded arm. The geometry has got a little better on motorcycles now I think.

I was apprenticing in a small foreign car shop when I learned to put a belt to just enough tension. The old Mercedes Diesel water pumps would last a lot longer if we gave them a break and backed off a bit.

[thatch]

"Tensioner Review"

All,
I was fortunate enough to have worked with Neil during the developement of his new tensioner. I am currently running one of the earlier prototypes on my A4 and have had zero problems with it's performance. Being able to adjust the belt tension accurately and knowing that it's going to stay that way is a definate bonus. In my particular case, I have an older low output alternator, and was able to lessen the belt tension slightly without experiencing any belt slip. Having worked with v-belt systems for many years, It became obvious that there was a direct relationship between belt tension and bearing life. Replacing alternator bearings is no big issue but having to rebuild an accessory drive is a completely different situation. I am so completely impressed with this units operation that I am in the process of adding similar tensioners to any of the other v-belt systems that I have.
Tom

[hanleyclifford]

I just ordered my copy of the new Dutton Device. In particular I want to see how it will handle my dual belt set-up. It seems that no matter how "matched" a set of belts are, they never look quite the same running. I'm thinking this new item will help equalize the two belts.

[joe_db]

Do you have a diagram/plans for the second alternator bracket?

[Carl-T705]

belts

Hanley , Are you aware they make a siamized belt for this type of use. I've run dual belts on equipment for decades and never have I been able to eliminate slippage. You are correct in that equal tension cannot be achieved. In no time after running will the the belt marks be equal, one is always slipping.

[ndutton]

I just ordered my copy of the new Dutton Device. In particular I want to see how it will handle my dual belt set-up. It seems that no matter how "matched" a set of belts are, they never look quite the same running. I'm thinking this new item will help equalize the two belts.

If you could fashion a bracket to hold two rotary type automotive serpentine belt tensioners aligned so there's one bearing on each belt, and use longer belts with the tensioners deflecting them inward, you would realize a number of benefits:

1. Uniform tension on each belt regardless of small length differences.
2. Like this device, not too much or too little tension on the system.
3. More belt contact (radially) with both pulleys.

I understand you just bought the Moyer tensioner but I don't think it will help the mismatch issue you described. Then again, it might. Looking forward to your results.

[hanleyclifford]

I looked into the project of fashioning dual idler/tensioners for the system and the cost for parts is around $300. Obviously, this would be the ideal solution but I want to try the spring tensioner from Moyer Marine first. When running dual belts last trip with 2:1 I had zero slippage. I realize 3:1 is going to be different - trials with the new device will be reported back to the forum.

[ndutton]

Even a non-tensioning idler could give you more belt contact with the pulleys.

Just thinkin'

[jpian0923]

I'm wondering (hoping) you get a cut of the profits!

(Why do I always have to be a wiseguy?!)

[ndutton]

I'm wondering (hoping) you get a cut of the profits!

As this device was born out of the Atomic 4 family here on the forum, there is no design fee or royalty arrangement. I hope it's considered a worthwhile device and perhaps seen in the same light as the Kaminsky modification.