a few words of praise for Fenner Drive linkbelt...

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Tazling

Veteran Member
Joined
May 17, 2021
Messages
73
Vessel Name
DARXIDE
Vessel Make
Grand Banks 32
My old F-L 120 has this issue... familiar I am sure to all owners of same... that the alt/pump v belt which runs in a triangle between the main engine shaft pulley and the two devices driven by it, runs behind the main coolant hose descending from the header tank. In other words, you have to drain the coolant and pop that main hose off in order to change a belt. This is sheer gibbering lunacy imho, but that's how it is.

Some previous owner installed two extra belts because of just this issue. But some (other?) previous owner didn't tie them up properly ... so by the time I got around to checking them out, they had been gnawed by a pulley and both had big bites taken out of them. So... not reassuring. Pretty useless as spares, at this point.

Anyway, much head scratching ensued until I finally googled my way to (vaguely recalled) Fenner link belts. I figured I would buy a few metres of link belt and take it with me this summer, just in case; the link belts can be broken and rejoined at will, easily, quickly -- and so can be installed even in a cockamamie setup like this where they thread their way behind and through the plumbing.

Well, fast forward to this summer's longish coastal trip. Taking a little sightsee on the central coast of BC, suddenly I notice that there's no alternator output -- and then holy cow, the engine temp is pegged! so of course I pull the kill switch asap and go investigate. The v belt has disintegrated in a spectacular way -- delaminated along its length and then shredded -- there are bits of belt scattered here and there in the engine compartment.

Luck was with us. We were adrift, but the wind was light and the tide was carrying us away from a nearby reef. At a guesstimate we had about an hour to fix the problem before drifting to the other side of the channel. So out came the brand new link belt -- and now a real quick OJT lesson in how to install one. On a very hot engine, which was no fun... but no one got actually burned, and we only used about 30 minutes of that hour. (now, with experience, we could do it a whole lot faster).

Anyway, the short version of the story is that it worked (yay) -- the overheat did not seem to have damaged anything -- we limped back at cautious RPM to the nearest port with admittedly inadequate belt tension from our first-time installation attempt -- alternator slipping, but water pump working, engine temp normal -- and then had all the time in the world to wrestle with it some more at the dock.

The really important thing to know is that the link belts have to be "set" (get rid of all the small slop in X number of links, in this case 63 links to start with) at which point they have loosened... and you have to take the belt off and remove a link (or several) and reinstall it. (If we had only known -- just a few minutes of run time, or even a couple of whacks of starter, is enough to take out the first dose of slack.) Then put a few more engine hours on it ... and you have to take it off again and remove a link, and maybe 10 or 12 hours later you might have to do it again... so this process happened a couple of times as the engine hours mounted up during the rest of our cruise.

But the end result is very good -- the belt has bedded down nicely into the pulley grooves, there's no more stretching, the tension is perhaps a bit less taut than I might have liked, but adequate (no slipping alternator, engine coolant good).

These belts are said to be heat proof and oil proof, and after the slack is all taken up they are said to be stretch proof as well. I hope they live up to their rep because they are also bloody expensive. :) But not as expensive as drifting onto something sharp and pointy while desperately trying to drain the coolant system, swap a belt, then refill the coolant system! Just swapping the belt takes quite enough time without all those extra steps. And handling boiling coolant in a seaway under time pressure does not sound like OSHA-approved fun to me.

So I would like to raise a ragged cheer for Fenner Drive link belt, and recommend it to folks who (a) have multiple V belts of various sizes (make any size you want on demand) or (b) silly setups like mine where you can't swap a belt without getting into a plumbing project.

if anyone knows anything bad about Fenner's product, please tell me now before I get to trusting it too much :)
 
Great result. I read an article about someone trying to replace a belt on that engine and getting seriously burned by the extremely hot coolant. Had to be medivaced.
 
Great result. I read an article about someone trying to replace a belt on that engine and getting seriously burned by the extremely hot coolant. Had to be medivaced.
[shudder]

yeah, that's exactly the kind of thing I could imagine happening. the engine block was so hot it was really quite unpleasant to be in contact with it for more than a half second or so. not hot enough to burn, but getting there.
 
The guy in the story pulled the hose off and got sprayed with boiling coolant, ugh.
 
The guy in the story pulled the hose off and got sprayed with boiling coolant, ugh.
I guess he forgot the bit where you drain it first? but even so, draining near-boiling coolant on a moving boat into a bucket or whatever ... just a big nope if you ask me.
 
Sitting here with my morning cup waiting for bottom paint to dry in LaConner, after last night's deluge... I sense a delay.

Anyhow, I keep reading how wonderful Ford Lehman engines are, how Brian is the goto guy, etc. etc. Then I read this and am reminded of the Volvo Penta MD17C belt issues we dealt with on our Albin 25. On that and similar MD engines, the starter required removal to replace the belt. The starter is easy to remove, its the bolts that are difficult. Depending on how the aftermarket FWC was set up, it could also require similar coolant draining issues. Major PITA design flaws. OTOH, we never had issues with said belt even after upgrading the alternator. Preventative maintenance is key. The link belt fix is very good to know about. Thanks!
 
Tazling,
I read your write up with interest. Maybe I am blind but you don't mention the
actual catalogue number. I have looked up Fenner belts but they have a large range of belt products so I am asking you to advise us which specific belt you used.
 
Tazling,
I read your write up with interest. Maybe I am blind but you don't mention the
actual catalogue number. I have looked up Fenner belts but they have a large range of belt products so I am asking you to advise us which specific belt you used.
Sorry! Fenner does make a bewildering variety of belts. I initially inquired about their NuTLink (has metal pins and requires tools for installation) but the rep told me about PowerTwist, the more recent product with no pins and no tools needed (though I found a pair of midsize needlenose pliers handy). So what I purchased was PowerTwist A/4L.

It comes in 5 ft lengths or in bulk, but the bulk is very large amounts so I bought 3 5ft packs. What I was shipped is bright red, but I don’t know whether that indicates this model of belt or the width or just Fenner’s trademark colour.

This stuff is not cheap. If I didn’t have the captive belt problem I probably would not have spent the money. But having used it in an emergency, I now have zero regrets about the expense.

A/4L should replace a 1/2inch v belt iirc. Here is what the package literature says: “Fit and forget, no re-tensioning required” (well that is a bit misleading as you do have to re-tension it a couple of times when first installed). “Lasts longer than rubber V belts in harsh environments”. “Fast easy installation even on captive drives.” “Make up any length by hand”.

Installation video is available at fennerdrives.com

Hope this helps. You can buy the belts direct from Fenner, or they have distributors all over N America.
 
Tazling,
THank you for the information and write up.
 
I seem to remember a picture some one submitted where they rerouted the hose such that the belt could be installed with out removing the hose....
 
You inferred it in the original post but let me reemphasize that the accepted standard of spare belt precaution with the FL 120 belt is to place at least one spare belt in place while the engine is cold by quickly taking the upper end of the hose loose while slipping the extra belt behind it. I didn't lose more than a cup of coolant. Properly zip tied in place, mine lasted many years always ready to quickly go on in place of a shredded one (never happened to me). Ten-minute job if you are slow. About every 5-10 years I would just replace both the active and spare belts on each engine.
 
Sorry! Fenner does make a bewildering variety of belts. I initially inquired about their NuTLink (has metal pins and requires tools for installation) but the rep told me about PowerTwist, the more recent product with no pins and no tools needed (though I found a pair of midsize needlenose pliers handy). So what I purchased was PowerTwist A/4L.

It comes in 5 ft lengths or in bulk, but the bulk is very large amounts so I bought 3 5ft packs. What I was shipped is bright red, but I don’t know whether that indicates this model of belt or the width or just Fenner’s trademark colour.

This stuff is not cheap. If I didn’t have the captive belt problem I probably would not have spent the money. But having used it in an emergency, I now have zero regrets about the expense.

A/4L should replace a 1/2inch v belt iirc. Here is what the package literature says: “Fit and forget, no re-tensioning required” (well that is a bit misleading as you do have to re-tension it a couple of times when first installed). “Lasts longer than rubber V belts in harsh environments”. “Fast easy installation even on captive drives.” “Make up any length by hand”.

Installation video is available at fennerdrives.com

Hope this helps. You can buy the belts direct from Fenner, or they have distributors all over N America.
I like this idea. However, this still does not seem to be a complete part number. The website lists a Power Twist 13L A/4L, and describes it as a "round" belt replacement. Does that sound right. And it didn't list 5 ft packs. It was red. Can you clarify? And is it for 1/2" v belts? Thanks.
 
I like this idea. However, this still does not seem to be a complete part number. The website lists a Power Twist 13L A/4L, and describes it as a "round" belt replacement. Does that sound right. And it didn't list 5 ft packs. It was red. Can you clarify? And is it for 1/2" v belts? Thanks.
Sorry I was out cruising for a couple of weeks and offline. I will take another look at the belt packaging and try to get an official fenner part number off it. boat's on the dock for a while (maint and paint) so it's easy to check on stuff like that. stay tuned.
 
Staying tuned. This looks like a good option to carry with the supplies in the engine room.
 
The type a/4l is the 1/2 replacement.
Another benefit of the link belt is that it doesn’t take a “set” when it sits inactive for extended periods. This lets it run smoother, with less vibration than standard v belts.
I use it on industrial woodworking equipment as it transmits less vibration to the cutting heads.
 
The type a/4l is the 1/2 replacement.
Another benefit of the link belt is that it doesn’t take a “set” when it sits inactive for extended periods. This lets it run smoother, with less vibration than standard v belts.
I use it on industrial woodworking equipment as it transmits less vibration to the cutting heads.
Thanks very much for this. The link is perfect. For what it's worth, the Fenner website does have a number13 inserted in the middle of the a/4l, but it doesn't matter because they no longer sell via the internet, and will refer you to a local distributer. The above link goes to Amazon, and they sell two (2) 5' sections for $63.78. Good stuff.
 
My old F-L 120 has this issue... familiar I am sure to all owners of same... that the alt/pump v belt which runs in a triangle between the main engine shaft pulley and the two devices driven by it, runs behind the main coolant hose descending from the header tank. In other words, you have to drain the coolant and pop that main hose off in order to change a belt. This is sheer gibbering lunacy imho, but that's how it is.

Some previous owner installed two extra belts because of just this issue. But some (other?) previous owner didn't tie them up properly ... so by the time I got around to checking them out, they had been gnawed by a pulley and both had big bites taken out of them. So... not reassuring. Pretty useless as spares, at this point.

Anyway, much head scratching ensued until I finally googled my way to (vaguely recalled) Fenner link belts. I figured I would buy a few metres of link belt and take it with me this summer, just in case; the link belts can be broken and rejoined at will, easily, quickly -- and so can be installed even in a cockamamie setup like this where they thread their way behind and through the plumbing.

Well, fast forward to this summer's longish coastal trip. Taking a little sightsee on the central coast of BC, suddenly I notice that there's no alternator output -- and then holy cow, the engine temp is pegged! so of course I pull the kill switch asap and go investigate. The v belt has disintegrated in a spectacular way -- delaminated along its length and then shredded -- there are bits of belt scattered here and there in the engine compartment.

Luck was with us. We were adrift, but the wind was light and the tide was carrying us away from a nearby reef. At a guesstimate we had about an hour to fix the problem before drifting to the other side of the channel. So out came the brand new link belt -- and now a real quick OJT lesson in how to install one. On a very hot engine, which was no fun... but no one got actually burned, and we only used about 30 minutes of that hour. (now, with experience, we could do it a whole lot faster).

Anyway, the short version of the story is that it worked (yay) -- the overheat did not seem to have damaged anything -- we limped back at cautious RPM to the nearest port with admittedly inadequate belt tension from our first-time installation attempt -- alternator slipping, but water pump working, engine temp normal -- and then had all the time in the world to wrestle with it some more at the dock.

The really important thing to know is that the link belts have to be "set" (get rid of all the small slop in X number of links, in this case 63 links to start with) at which point they have loosened... and you have to take the belt off and remove a link (or several) and reinstall it. (If we had only known -- just a few minutes of run time, or even a couple of whacks of starter, is enough to take out the first dose of slack.) Then put a few more engine hours on it ... and you have to take it off again and remove a link, and maybe 10 or 12 hours later you might have to do it again... so this process happened a couple of times as the engine hours mounted up during the rest of our cruise.

But the end result is very good -- the belt has bedded down nicely into the pulley grooves, there's no more stretching, the tension is perhaps a bit less taut than I might have liked, but adequate (no slipping alternator, engine coolant good).

These belts are said to be heat proof and oil proof, and after the slack is all taken up they are said to be stretch proof as well. I hope they live up to their rep because they are also bloody expensive. :) But not as expensive as drifting onto something sharp and pointy while desperately trying to drain the coolant system, swap a belt, then refill the coolant system! Just swapping the belt takes quite enough time without all those extra steps. And handling boiling coolant in a seaway under time pressure does not sound like OSHA-approved fun to me.

So I would like to raise a ragged cheer for Fenner Drive link belt, and recommend it to folks who (a) have multiple V belts of various sizes (make any size you want on demand) or (b) silly setups like mine where you can't swap a belt without getting into a plumbing project.

if anyone knows anything bad about Fenner's product, please tell me now before I get to trusting it too much :)

I've used a lot of link belts as both backups and in spots that are too tight to otherwise deal with. I used them on my milling machine but didn't like it and went back. I liked one on my drill press and horizontal saw and found them smoother. The main save the day was on my tractor-loader-backhoe. I'll just say it's as much a b*tch as the boat... the designer decided to route the drive shaft through the belt (comes out od the aft part of the engine). I *had* to get a substantial tree root out by noon the next day whan the belt ate itself, so I grabbed my Fenner off the nail in the shed and through it on. Here's the part where a useful lesson happened...... I knew about the "dial it in" phase and did that. But it never ended. It just kept sinking in more deeply into the sheaves and with all the adjusting, got about 20 min of actual work done in the next hour, and half ate the belt.


The problem was.. and I'm forgetting the correct nouns here.. the sheave angle was shallower and made for a different belt profile.. supposedly for situations with big starting torques. It was too late to track another one down so I made (hacked) three pulleys together on the lathe with my approximation of what was left of the Fenner I bought and got it done and then put the factory pulleys back because they were hacked together and unreliable in my opinion. I bought the right Massey belt (x3) and hung two on the hook. They (quality conventional) last forever in my experience if you babysit the tension.

I've known Fenner's top reputation for a long time, and I also know about the halo effect. Other people may have access to more experienced recommenders than me but I eventually ended up at the place where I need a good reason to splurge on a Fenner. Otherwise... here's where I become "that guy"... I've been happy and maybe happier with Harbor Freight link belts in non critical situations.. especially in a backup role. Works for me but I love when my yuppie friends look down on me for repairing my generator oil leak with JBWeld for $18 instead of $10k to hoist it, and 1 hr instead of 9 months, and at least the same tensile strength. After I leave... [whispering]... "He probably watches Hee Haw!!!"

It was a while back when the tractor thing happened. I can't remember the sheave factor... profile?.... VX? for the tractor's higher torque. But the lesson was... I got the Fenner and it was wrong and I think I got cross-referenced over from some site and it waited on that nail to screw me for a few years. I was lazy and deserved it. I recall usually a belt is a belt but you can lose a lot of time not getting must the right one or over-trusting the wrong cross reference.

G
 
Using the wrong profile belt will do the same thing as using a new belt on worn sheaves. If the profile doesn’t match the belt will prematurely wear and fail.
There are cheap belt profile gauges available so you can verify.
 
I was once briefly shipmates with a Ford-Lehman 120 which had a couple of feet of thin-walled metal tubing (cannot remember whether AL or steel) formed into a configuration which resulted in the vee-belt being outside of the cooling loop.
 
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