Belt alignment....

shaune

shaune

Well-Known Member
Supporting Member
Converting from a generator to an alternator and I am wondering about belt alignment. This has become more than I bargained for but I knew this would happen. Running a straight edge from alt pulley to water pump pulley with the belt on and everything tighten, over the distance of 9” I am out 1/32”.
The alternator is “cocked” a bit off but is that misalignment enough to give me grief ? Toss the belt, or squeal ?
I am not at the point to fire it up yet as there are several more connections to make.
 
I doubt if you'd have a problem with that. But if you took the time to measure, why not make the adjustment with shims or tweak the bracket 0.032".
After all the Corvair belt sort of worked if tensioned properly and you kept the revs down. :D
 
I have tweaked it twice now. I could have bought a bracket for $100 ($65 US) but oh no....I’m a smart guy I can make my own. I may take it off for the 11th time and file the one hole more oblong for better alignment. I will try to post a picture of my handiwork too.
 
Shaune: Using a right angle triangle calculator & solver I found online, using your 9" measurement for the base, and 1/32" (0.0325") for the vertical, the misalignment is 0.20690052668 of a degree.
I'll let you be your own judge of whether that is enough to be an issue:D

Here is the calculator I used, it has five different scenarios, I used Calculator 2 - You know the two sides of the right triangle

https://www.analyzemath.com/Geometry_calculators/right_triangle_calculator.html


EDIT: Just checked in here this AM, and noticed that I typed 0.0325 above, and knew immediately that I had missed a digit, as 1/32 in decimal form is 0.03125!

So, inputting the corrected value, your misalignment is now only 0.19894287936062627 of one degree.........yah, I know, splitting hairs:)

Anyways, bottom line is, unless your engine revs like an F1 car, I don't think you have any worries!

James
 
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Hehe, I will have to think about this and see how ambitious I feel when I return home :D
 
Neil: Not even:) A dime is ~1.22mm thick, or about 0.048", so it is even shy of 1/16", which would be twice as thick as needed.....
If the 1/32" measurement is accurate, I don't think it's bad enough to waste any calories trying to correct it......

James

Bash and scratch said:
That's like maybe a thin washer? :cool:
Click to expand...
 
James wouldn't it depend on how far along the radius it is? The farther away from center point the less degree it would be. :confused:
 
My straight edge was a 12” new hacksaw blade, so center to center of pulley is about 9 or 10” and the “off ness” of the belt is visible. When I measured it the difference is as I mentioned. I remember we had a Beech Baron that flipped belts with frustrating regularity. It turned out to be misalignment with the pulleys but I can’t remember how far off it was. When I get back into better wifi I will post a picture of my bracket, you can see how I need to oblong the one bolt hole for alignment. A washer addition would be much simpler but not how I built the bracket.
 
Looks to me like if the holes for the bolt connections between the 3 brackets were oversize you could move the alternator around enough to get it lined up and square. Then once you are happy with the alignment, remove the bracket from the engine and stitch weld between the 3 pieces so they don't move relative to each other over time.
 
You could also slot the holes between the two U brackets and then use ni-lox to bolt them and hold them tight?
 
Hole was slotted a bit more and now alignment is straight on. I use fine thread ny lock nuts on everything. I may give it a zap with the welder once I run it. Nothing is getting painted or plated yet in case of adjustment.
 
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