Tightening Engine Belt on Universal 5411

shank

shank

.
Apr 20, 2016
125
Catalina 27 5231 Lake Champlain
I have trouble tightening the engine belt on this engine. The belt is adjusted by the highlighted bolt and it seems no matter how hard I push on that alternator on the bracket to slide it over I can't get enough pressure on it to tension the belt properly. Just wondering if anyone had any tips, homemade jigs, prayers or voodoo magic to tighten it up? It must be a common issue.

Thanks
 

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jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
22,254
CAL 35 Cruiser #21 moored EVERETT WA
There are home made jigs or you can just buy a tool.
An alternator belt jack

IMG_3774.jpeg


They fit like this. (This one is a UK tool with pretty blue ends)
IMG_3775.jpeg
Just turn the center threads to extend the ends tightening the belt. Then secure the alternator and remove the jack.
Sip a :beer:as reward for job well done.
 
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shank

shank

.
Apr 20, 2016
125
Catalina 27 5231 Lake Champlain
Thanks for the great ideas. I think I'll try and make one with a turnbuckle because I'm cheap. Ralph, what do you mean by 'flattened ends' ? Do you have a photo of one? Thanks
 
Ralph Johnstone

Ralph Johnstone

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Jan 4, 2006
7,032
Hunter 310 West Vancouver, B.C.
On @Ken13559 's turnbuckle :

1682723503427.png


............... he shows the ring just cut. When I did mine, I cut it as shown but then heated and flattened out the two rings so there was a larger contact area and more secure.

1682723415517.png


Minor improvement on my part and it was Ken who came up with the original idea. Without him, I'd still be wailing and beating on it with an aluminum bar.
 
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shank

shank

.
Apr 20, 2016
125
Catalina 27 5231 Lake Champlain
How cool is that? I'm going to measure the distance between the two pulleys tomorrow and buy a turnbuckle.

Thank you both again for taking the time to respond.
 
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D

dlochner

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Jan 11, 2014
12,315
Sabre 362 113 Fair Haven, NY
Have a few pieces of oak or other hardwood lying around? A piece o all thread and a few nuts and washers? Make your own custom belt tensioner.

1682731125509.png
 
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jviss

jviss

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Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
I had a problem on my new serpentine belt and pulley upgrade where I not only couldn't get proper tension, but I ran out of adjustment. And, because of the configuration, it was tough to get anything in there to lever the alternator. So, I permanently replaced the slotted alternator bracket with a tensioning strut, like this:

strut.jpeg


Works great!

I also use a Gates Krikit belt tension gauge so it's not over-tensioned and its repeatable.

A better but more complex approach would be to find a suitable belt tensioner pulley assembly and fit it.
 
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shank

shank

.
Apr 20, 2016
125
Catalina 27 5231 Lake Champlain
> tensioning strut

Another great idea.

I think ultimately something like this is what I'll need to do because I've found that even when I do finally get the right tension on the belt and tighten down the bolt on the alt bracket and even put some lock-tite blue on it, the vibration from the engine loosens again after a few weeks.
 
D

dlochner

.
Jan 11, 2014
12,315
Sabre 362 113 Fair Haven, NY
shank said:
> tensioning strut

Another great idea.

I think ultimately something like this is what I'll need to do because I've found that even when I do finally get the right tension on the belt and tighten down the bolt on the alt bracket and even put some lock-tite blue on it, the vibration from the engine loosens again after a few weeks.
Click to expand
A cheap solution is to use a double thick fender washer. This will increase the clamping power of the adjustment bolt.

Another alternative is a Belt Buddy from Balmar. They come with and without adjustment arms.


balmar.net

BBU - Balmar

Universal Belt Buddy Mechanism; for use with exising adjustment arms Does not come with the Balmar Universal Adjustment Arm (UAA). Caution: This approach sacrifices some “travel” in the existing adjustment arm so the BBU mechanism can be anchored to the arm. Make certain your alternator...
balmar.net balmar.net
 
jviss

jviss

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Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
I looked into the Balmar belt buddy and the new arm I'd have to buy, and it wasn't long enough, and besides, it was many times the cost of the strut. The arm plus belt buddy kit was $80, as I recall, and the strut about $15 on eBay. The belt buddy looks nice, though, if it will fit for you.
 
jviss

jviss

.
Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
shank said:
> tensioning strut

Another great idea.

I think ultimately something like this is what I'll need to do because I've found that even when I do finally get the right tension on the belt and tighten down the bolt on the alt bracket and even put some lock-tite blue on it, the vibration from the engine loosens again after a few weeks.
Click to expand
One thing I should caution on this, I couldn't find a strut with the exact hole size in the Heim rod ends that I wanted, so I went up a bit, and made my own stainless steel sleeves on the lathe. So, it make take some fiddling to get this to work right.
 
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Hayden Watson

Hayden Watson

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Apr 5, 2009
2,984
Catalina '88 C30 tr/bs Oak Harbor, WA
I am not familiar with the 5411 and see that you only have two pullies and was wondering where your water pump is. All of the M25's I have seen have 3 pullies
 
shank

shank

.
Apr 20, 2016
125
Catalina 27 5231 Lake Champlain
The water pump is just to the left of the pulley highlighted. I swapped it out last year. A whole different discussion but I replaced the original Sherwood pump with an Oberdorfer it was a good move

PXL_20230428_194311073~3.jpg
 
jviss

jviss

.
Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
shank said:
The water pump is just to the left of the pulley highlighted. I swapped it out last year. A whole different discussion but I replaced the original Sherwood pump with an Oberdorfer it was a good move

View attachment 215119
Click to expand
I think Hayden was referring to the coolant pump, i.e., fresh water pump, not the seawater pump.
 
Hayden Watson

Hayden Watson

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Apr 5, 2009
2,984
Catalina '88 C30 tr/bs Oak Harbor, WA
So is it a seawater cooled engine so only the Oberdorfer? You should get much less belt dust with 180 degrees of contact.
 
jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
22,254
CAL 35 Cruiser #21 moored EVERETT WA
Alternator belt tension maintenance can be a challenge. I've learned that just tightening what I found on the boat might not be enough. I defer to MaineSail and his magnificent website of everything electrical. I would encourage all who can to help keep this treasure filled resource available.

marinehowto.com

Marine Alternator Installation - Tips & Tricks - Marine How To

A Fresh New Alternator For many boat owners the task of upgrading their engines alternator can be intimidating. It does not have to be, and this article will help you understand how to do this job correctly. It includes numerous professional
marinehowto.com

At this length you will find information on alternator bolt size, adjuster arm lengths, bushings to correct alternator build flaws etc. I suspect somewhere in this article is the nuggets of a solution you seek.
 
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shank

shank

.
Apr 20, 2016
125
Catalina 27 5231 Lake Champlain
Hayden Watson said:
So is it a seawater cooled engine so only the Oberdorfer? You should get much less belt dust with 180 degrees of contact.
Click to expand
Yes, just the one pump on this engine. Freshwater cooled in my case.
 
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