# Want help on pulley swapping



## darcy32171 (Nov 28, 2013)

On my old 2003 Murray 10/28. Model #: 627108x31E
I would like to try and make this thing a "Snow throwing monster" lol.
I remember someone mentioning about swapping pulleys.
My auger housing is a 12 inch diameter.
Bottom Auger pulley is a 8.40 inch O.D
Top pulley is a 2.25 inch pulley.

Which one does a guy mess with? I`ve heard and seen videos where guys say they lowered the pulley by 2 inches on their machine. How hard is it to find a proper sized belt that would be easily found???


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## jonboat (Dec 19, 2013)

I would think that moving the pulley wouldn't make a difference, but tinkering with pulley size would. Going with a smaller pulley on the shaft that drives your auger, or a larger pulley on the end of the crankshaft, would increase auger and impeller speed. You would sacrifice torque for speed by doing this. Think about it in terms of the sprockets on an old 10-speed bicycle. Bigger at the pedals and smaller at the wheel, means more speed, but will wear you out quickly under a heavy load such as going up hill.
Depending on how your blower is set up with idler pulleys to tension the belts, you could possibly go with the same size belt if you don't change the pulley diameter by too much (and I wouldn't change it too much, as you risk putting too much load on the engine and having it do something nasty like throwing a rod).

All you really need to find is a pulley with the same ID and same size keyway - different OD. A lawn-equipment junkyard would be where I'd look Chances are you can find a pulley to fit on another make/model of Snowblower, or eben on a mower deck or engine crank on a lawn tractor.

Good luck!


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## darcy32171 (Nov 28, 2013)

Thanks! I pulled the belt guard off and without going right into disassembly, that top pulley seems like it is all one with the drive pulley. I might end up having to change the lower pulley on the auger instead.


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## nt40lanman (Dec 31, 2012)

Darcy, how many belts do you have? I did it on mine but I have 2 belts. If you only have 1 belt, it's harder because increasing the crank pulley size will increase the auger speed but it will ALSO increase wheel speed, which you don't want. Post a pic of your belts.


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## Kiss4aFrog (Nov 3, 2013)

IF . . . you increase the drive pulley on the engine or decrease the driven pulley on the impeller/auger you will be spinning faster but you are giving up power (torque). In light to medium snow it might be helpful and blow more, faster and further due to the speed but if you get into heavy snow it might not be able to have the power to drive the machine and try to throw snow even at the lowest gear.

The pulley change is cheap but the way to really make it a monster is bigger engine and slightly faster impeller/auger speed.

Has anyone done this and gone too far where it was noticeable that you lost power in heavier snow and how big a drive or small a driven pulley did you try and on what machine ???


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## darcy32171 (Nov 28, 2013)

2 belts, but the two pulleys seems like they are one unit:


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## Shryp (Jan 1, 2011)

I have an old 24" Ariens with a 212cc Predator.

I swapped my engine pulley from 2.5" to 3.25"

This took me from 1000 RPM at the impeller to 1300 RPM at the impeller. I can hear the engine load up, but I don't think I have noticed any bogging down. I haven't gotten to use it too much, but I have driven it through piles I have shoveled together, so it was somewhat packed down.

Actually I think the 8 HP originally came with a 2 5/8" pulley for 1050 RPM and the 7 HP came with the 2.5" pulley for 1000 RPM.

Easy math. 3600 RPM at engine * 3.25" at engine crank / 9" at impeller shaft = 1300 RPM on impeller.

The 7 HP ones used separate pulleys, but the 8 HP ones used one pulley for both belts. Should be as simple as swapping both assuming you can find a wheel drive pulley as small as your current one.

I got my 3.25" pulley here from the steel V-belt pulley section:
Pulleys & Idlers | Lawn Mower Parts | MFG Supply

Unfortunately 3" is as small as they go for 3/4" bore. Some of the specialty ones are smaller, but much more expensive.

I believe Gustoguy got his from here:
https://www.phoenix-mfg.com/

When I did mine I also rebuilt the auger gearbox with new bearings and seals and the bearing behind the impeller.


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## Kiss4aFrog (Nov 3, 2013)

Great detail Shryp !! Now I hate you as I'm thinking I might want to try something along those lines too


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## nt40lanman (Dec 31, 2012)

I bumped mine from 2 5/8" up to a 3.45". Mine originally had a one piece dual pulley but I got a wheel drive pulley off a junk engine and bought this auger drive pulley. I went from 7hp to 10hp. I may have gone a touch far on the pulley but it throws nice.


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## GustoGuy (Nov 19, 2012)

Shryp said:


> I have an old 24" Ariens with a 212cc Predator.
> 
> I swapped my engine pulley from 2.5" to 3.25"
> 
> ...


Shryp. Boy I wish I would have bought my pulleys there. Nice prices about 4 dollars less per pulley than what I paid for the same size pulley. I will keep them in mind if I need to buy some pulleys

Put in a home made Baler belt impeller kit. It works awesome all by it self increases throwing distance because it almost act like an air pump with the tight seal. I can feel a strong jet of air being shot out of my chute. Just the impeller kit alone will make a decent difference along with a slight pulley speed increase. Do not increase size too much or it will bog your engine out and kill all the torque of the engine. Go from like a 2.75 to 3.25 like Shryp said. Enough to bump up rpm another 150 to 300rpms. Magic number to shoot for is about 1300rpm on the impeller since that is what most new snow blowers impeller operate at.


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## Kiss4aFrog (Nov 3, 2013)

Another one to try is PrimeLine

Prime®Line Power Equipment | Parts that works as hard as you do
They sell all sorts of small engine stuff.

I look up the part number on PrimeLine and punch it into Oreilly auto parts to see if it's available and the price. Nice thing is Oriellys stocks a far amount and the price isn't bad and usually there is a warranty. I also try ebay and amazon to check the price too.


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## Blue Hill (Mar 31, 2013)

darcy32171 said:


> 2 belts, but the two pulleys seems like they are one unit:


Seems like you're pretty much hooped on the engine shaft Darcy, unless you change them both, which isn't that big a deal. Princess Auto may even have the pulleys you'll need. Otherwise Motion Industries or Bearing and Transmission over on Dewdney Ave.


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## darcy32171 (Nov 28, 2013)

Blue Hill said:


> Seems like you're pretty much hooped on the engine shaft Darcy, unless you change them both, which isn't that big a deal. Princess Auto may even have the pulleys you'll need. Otherwise Motion Industries or Bearing and Transmission over on Dewdney Ave.


 Thanks! Have you ever tried CMS over on Winnipeg and 7th? They have everything under the sun!


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## darcy32171 (Nov 28, 2013)

Has anyone seen a pulley like mine? Is it truely a dual one piece pulley system or "Do they split apart"?


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## nt40lanman (Dec 31, 2012)

I can't say I have ever seen one like that. It looks more "modern". First, I'd do the impeller kit they are talking about and see how that goes. Then I'd pull that crank pulley and look it over as well as the crankshaft. That pulley looks like it bolts from the end so make sure you have a non-tapered crank, and a keyway that goes long enough for 2 individual pulleys. You'll need a key, which any decent local hardware store will have. I'd only increase 1/2 inch or less so as not to tax the engine too much. A 10% bump in RPM will give you far more than 10% in performance. Then you may need a belt. If your current one isn't long enough, bring it to a Napa and have them measure and add an inch or an inch and a half.

Here's some pics of my pulleys

http://www.snowblowerforum.com/forum/13197-post45.html


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## darcy32171 (Nov 28, 2013)

Thanks. I`ll check the top pulley, but I`m starting to think I am going to tackle the lower pulley. I had it off once already when I did the Impeller mod not that long ago. My lower pulley is a 8.40" so say 8.5"....if I drop it down,could I safely go to a 6.5"? 
That would mean I would need roughly a 1" smaller belt.


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## darcy32171 (Nov 28, 2013)

My belt now is a 38.5"


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## nt40lanman (Dec 31, 2012)

Here's some math. Diameter X Pi = circumference, X the belt contacting 5/8 of the circumference

8.5" X 3.14 = 26.7 * .625 = 16.7" belt contact

6.5 X 3.14 = 20.4 * .625 = 12.75" belt contact

You'll need around 4" less belt.


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## Blue Hill (Mar 31, 2013)

darcy32171 said:


> Thanks! Have you ever tried CMS over on Winnipeg and 7th? They have everything under the sun!


CMS is great too. I don't know if you're old enough to remember what CMS was like 20 or 30 years ago, but I liked it even better. You never knew what you might find there. I even came away with some nice blacksmithing equipment back in the day. You just had to snoop through all of the bins. It's a lot more organized now, but you don't find the real treasures like you used to.


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## darcy32171 (Nov 28, 2013)

Blue Hill said:


> CMS is great too. I don't know if you're old enough to remember what CMS was like 20 or 30 years ago, but I liked it even better. You never knew what you might find there. I even came away with some nice blacksmithing equipment back in the day. You just had to snoop through all of the bins. It's a lot more organized now, but you don't find the real treasures like you used to.


 I bet!!!


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## darcy32171 (Nov 28, 2013)

So far coming up empty handed. Tried a couple places (Peavey Mart, Auto Electric and an agri-dealer). I guess I throw it back together untill the next time I head into Regina.


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## CarlB (Jan 2, 2011)

changing the engine pulley is the way to go. First thing to do is take the old pulley off and make sure what you have . If the pulley will split then you only need to get the front pulley for the auger and leave the other pulley for the drive alone.


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## nt40lanman (Dec 31, 2012)

I agree. The smaller size pulleys are easier to find and cheaper. Darcy, what size is the crank? 3/4?


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## darcy32171 (Nov 28, 2013)

nt40lanman said:


> I agree. The smaller size pulleys are easier to find and cheaper. Darcy, what size is the crank? 3/4?


 I never took the top pulleys off. I took a real good look at them and I`m almost 100% positive they are one unit. In between the two is a real big hex type shaft that connects the two. 
I need to do some blowing today, maybe after that I will try to pull the top assembly off.


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## Blue Hill (Mar 31, 2013)

darcy32171 said:


> I never took the top pulleys off. I took a real good look at them and I`m almost 100% positive they are one unit. In between the two is a real big hex type shaft that connects the two.
> I need to do some blowing today, maybe after that I will try to pull the top assembly off.


I've no doubt that you are right Darcy. It sure looks like one unit to me. That would save time on the assembly line. Once you have the first pulley lined up, the second one has to be. But once you take it off, you will need two pulleys to replace the assembly. No worries, the small pulleys won't be expensive or hard to come by. You will just have to make sure that both of your new pulleys line up perfectly with whatever it is that they are driving.
Easy peasey, lemon squeezey (he says while sitting on the couch in his nice warm house)


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## dbert (Aug 25, 2013)

darcy32171 said:


> I never took the top pulleys off. I took a real good look at them and I`m almost 100% positive they are one unit. In between the two is a real big hex type shaft that connects the two.
> I need to do some blowing today, maybe after that I will try to pull the top assembly off.


I hope that hex spacer isn't extending the pulley too far beyond the shaft.
It does look like you maybe could cut the fwd pulley off and leave the drive pulley and key more or less as is. Like Larry said...easy for me to say.
pic above


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## Blue Hill (Mar 31, 2013)

dbert said:


> I hope that hex spacer isn't extending the pulley too far beyond the shaft.
> It does look like you maybe could cut the fwd pulley off and leave the drive pulley and key more or less as is. Like Larry said...easy for me to say.
> pic above


Woah!  Now that I look again at your picture Del, I see that the hex section is most likely extending the engine shaft. Without that extension, my idea doesn't hold water. Darcy has nothing to mount the outboard pulley to.
Right?


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## dbert (Aug 25, 2013)

Pulling the bolt off the end and looking down the bolt hole should tell him if this is more of an extender than a sleeve. If it is an extender, it's back to his earlier plan of locating a smaller lower pulley for the impeller/auger.


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## nt40lanman (Dec 31, 2012)

OK D, yank that thing apart and let's end the speculation!!! Inquiring minds want to know!!!


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## darcy32171 (Nov 28, 2013)

nt40lanman said:


> OK D, yank that thing apart and let's end the speculation!!! Inquiring minds want to know!!!


 Sure, just let me know how much torque to put the pulley back on?


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## dbert (Aug 25, 2013)

In lieu of something more official
Standard Dry Torque in Foot-Pounds
Steel Bolt Torque Specifications Table - Engineer's Handbook


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## nt40lanman (Dec 31, 2012)

darcy32171 said:


> Sure, just let me know how much torque to put the pulley back on?


40 wrist pounds, or alternatively, the Italian method, torque it until it breaks, then back it off a half turn.

I've never torqued a single bolt on a snowthrower.


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## darcy32171 (Nov 28, 2013)

I already have one bolt hole that needs new threads (one of the ones that holds the blower housing to the rest of the machine, oh well there are two more on that side so I am safe till summer). I didn`t really think I over tightened it. Those ones, you would think could be tightened right up because they are cruicial. When it stripped, it seemed like running a hot knife through butter.


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## Blue Hill (Mar 31, 2013)

Apparently the previous owner thought that the correct torque rating was 1/4 turn past stripped.


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## darcy32171 (Nov 28, 2013)

Blue Hill said:


> Apparently the previous owner thought that the correct torque rating was 1/4 turn past stripped.


 Oh well, I will finally be able to use my tap/die set for the first time in two years. One of those: Just have to have it, but never use it lol


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## Blue Hill (Mar 31, 2013)

Great to have it handy when you do need it though.


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## darcy32171 (Nov 28, 2013)

Blue Hill said:


> Great to have it handy when you do need it though.


 You got that right! Same goes with manuals. I always think: "I should get rid of them", then I shake my head lol.


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## Shryp (Jan 1, 2011)

Blue Hill said:


> Apparently the previous owner thought that the correct torque rating was 1/4 turn past stripped.


I usually go for about 10 turns past stripped. For some reason I think if I keep turning it that it will get tight.

Now for removal torque it is usually 1/4 turn past snapped right off.


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## darcy32171 (Nov 28, 2013)

Maybe later today I will tackle the top pulley. We have a sad xmas day today, going to spend xmas today around a grave stone. My Fiance`s Dad passed away 2 years ago from Cancer. He died on the same day as he was to retire from work. Today is the day we go out. If I am back in time, I`ll tackle the blower.


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## darcy32171 (Nov 28, 2013)

Shryp said:


> I usually go for about 10 turns past stripped. For some reason I think if I keep turning it that it will get tight.
> 
> Now for removal torque it is usually 1/4 turn past snapped right off.


 Isn`t that where "Gobs" of teflon tape come in handy?


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## nt40lanman (Dec 31, 2012)

darcy32171 said:


> I already have one bolt hole that needs new threads (one of the ones that holds the blower housing to the rest of the machine, oh well there are two more on that side so I am safe till summer). I didn`t really think I over tightened it. Those ones, you would think could be tightened right up because they are cruicial. When it stripped, it seemed like running a hot knife through butter.


The thing to do is put in a longer bolt, and fish a nut down behind and crank it tight.


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## Kiss4aFrog (Nov 3, 2013)

If it stripped that easily it's likely someone before you cross threaded it. Longer bolt and a nut if you have access. A tap likely will not help at this point as the hole is not larger than it should be for the tap to have metal to cut back into threads. You could go a size larger. Using loctite or some kind of tape won't get it either as that stuff is used to restrict it's ability to turn but isn't in itself physically strong enough to actually hold parts together against stress.

Longer bolt and a nut, drill and tap for bigger bolt or heli-coil it this spring/summer when it's comfortable to work on it and your fingers don't freeze.


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