Snow 47 Blower Not Throwing Snow Very Far

[RWEST]

My brother picked up a "47" blower over the weekend, and installed it on his 755. When he tried it out, it only throws snow about 1 foot!!

Comparing it with the 47 on the another 755 we have, he noticed there is about 1/2" clearance between the impeller blades and the cylinder the impeller rotates in, while the other 47 (which throws snow admirably) only has about 1/4" clearance in the same area. Thoughts/ideas?

 

[George2615]

Is the 47" blower the same brand as the other one. If not, maybe it operates with a different gear box ratio and requires a higher RPM for the PTO. Also the clearance of 1/2" seems a bit much. Perhaps this blower needs a new impeller with a closer tolerance. Its possible that this blower may require a 1000 RPM PTO instead of a 540. Try rotating the good blower PTO shaft by hand and count the number of turns it takes to make one revolution of the blower impeller then do the same on the one he just picked up. If they are the same then the impeller is worn out and needs replacing

 

[Spudland_Dave]

What did the 47" Blower in question come off of?
I started had started shopping for a 47" Blower for my F935 (which ultimately led me to buy a 3520 Cab...go figure)....but I think there are a few variations/configurations of gearboxes for the 47" Blowers...from the sounds of it, your not turning fast enough.

A quick stroll thru the JD Parts catalog might be your best next step...

 

[RWEST]

It's a front mount blower, which is where it's mounted now, came off a 755, and, according to the previous owner, "it worked fine".

 

[Shawk]

My brother picked up a "47" blower over the weekend, and installed it on his 755. When he tried it out, it only throws snow about 1 foot!!

Comparing it with the 47 on the another 755 we have, he noticed there is about 1/2" clearance between the impeller blades and the cylinder the impeller rotates in, while the other 47 (which throws snow admirably) only has about 1/4" clearance in the same area. Thoughts/ideas?

If everything is hooked up ok... it sounds to me like you simply may have a sheer pin broke somewhere??? Take a peak....

 

[mfreund]

I don't think a 1/4 " difference in impeller is the problem. I'm with Shawk, sounds like shear pin broken. If that is not it I would compare the # if turns the PTO shaft makes to turn the auger 1 turn and compare to other 755. That way you know if it is the right blower. There are some (for 650/750 I think) that turn the opposite way. I would think that would be VERY apparent if that was the problem. All the rest are for the 2000 rpm mid PTO.

Let us know what you find, I am curious

 

[RWEST]

Okay, last night we had a fabricator friend make up/weld some flat to each of the impeller blades, to bring the clearance down to ~1/4". Big difference - now it really throws the snow!!

 

[Redneck in training]

I don't think a 1/4 " difference in impeller is the problem. I'm with Shawk, sounds like shear pin broken. If that is not it I would compare the # if turns the PTO shaft makes to turn the auger 1 turn and compare to other 755. That way you know if it is the right blower. There are some (for 650/750 I think) that turn the opposite way. I would think that would be VERY apparent if that was the problem. All the rest are for the 2000 rpm mid PTO.

Let us know what you find, I am curious

FYI The force it throws snow is proportional to speed squared. The volume of snow it is able to throw is proportional to speed. Thus power required to throw snow is proportional to speed cubed. In other words to double the speed the required power demand increases eight times and it should throw twice as much snow four times as far. Needles to say that this is valid for ideal case and maximum flow of snow.

 

[mfreund]

Glad you got it fixed, I am suprised that little of impeller would make that big of a difference!! Lesson learned

Next question,

What caused the wear. That would be a lot of use for snow to wear down impeller 1/4". Or am I wrong again

 

[RWEST]

What caused the wear. That would be a lot of use for snow to wear down impeller 1/4".

We're still trying to figure that one out. One of the problems with buying something used is you have to take the other guy's word for its prior history. The guy said he'd never gotten into rocks or anything, but I dunno..

Actually, all this is a moot point - my brother slipped on the ice yesterday and broke his arm, so he won't be doing much snowblowing, or anything else that requires a right arm, for a while. Brother #2 or I will be doing it with our blowers (mine is a 60" Lucknow 3-pt; Brother #2's is a 72" front mount monster on a Kubota 4740).

 

[dirtworksequip]

FYI The force it throws snow is proportional to speed squared. The volume of snow it is able to throw is proportional to speed. Thus power required to throw snow is proportional to speed cubed. In other words to double the speed the required power demand increases eight times and it should throw twice as much snow four times as far. Needles to say that this is valid for ideal case and maximum flow of snow.

Was this formula one of Newton's "lost laws" ?

Sincerely, Dirt

 

[Redneck in training]

Was this formula one of Newton's "lost laws" ?

Sincerely, Dirt

I just test big compressors for living. Believe it or not the impeler is a simple compressor so I thought that somebody might be interested in the relationship between rpm, required power, snow volume and throving distance.

 

[mfreund]

What bad luck!! We are supposed to get to near 50 on Saturday so at least what we have will melt. I hope we won't get much more this year!!

 

[Karl2]

I don't think a 1/4 " difference in impeller is the problem.

You would be surprised, I certainly was. Two-stage blowers use the air pressure created by the impeller inside the chute (discharge) to propel snow and depending on volume a small difference in blade clearance can translate into a large difference in air pressure.

Interestingly some walk-behind blowers such as those made by Honda use advanced impeller/chute designs that produce rather spectacular throwing performance despite relatively modest hp, they routinely achieve throwing distance of 60 to 100 feet using 7 to 9 hp engines. If such designs were available for tractor blowers I could throw snow clear across town I imagine.

Seriously though, more advanced designs could allow smaller tractors to achieve better results.

 

[Redneck in training]

You would be surprised, I certainly was. Two-stage blowers use the air pressure created by the impeller inside the chute (discharge) to propel snow and depending on volume a small difference in blade clearance can translate into a large difference in air pressure.

Interestingly some walk-behind blowers such as those made by Honda use advanced impeller/chute designs that produce rather spectacular throwing performance despite relatively modest hp, they routinely achieve throwing distance of 60 to 100 feet using 7 to 9 hp engines. If such designs were available for tractor blowers I could throw snow clear across town I imagine.

Seriously though, more advanced designs could allow smaller tractors to achieve better results.

Due to the fact that aerodynamic drag acting on snow increases with the square of velocity the throwing distance might not increase as much but the volume of snow thrown will be proportional to power consumed by the impeller.

The design of the impeler is absolutely crucial to efficiency of the thrower. Simple designs just wouldn't achieve it.

 

[irvingj]

I'll go along with the impeller-to-housing clearance issue-- my ol' Toro walk-behind would have some serious throwing problems due to bent impeller blades ..rocks... While it never dropped to one foot, it would easily halve the normal 6-8 feet to 3-4 feet.

Heated & bent blades back into position twice, then went ahead & replaced impeller. The difference was due to an increase in the clearance from 1/4" or less to 3/8" to 1/2"-- enough to seriously affect throwing distance!

Took me a while to figure out just what the problem was, but when I put 2 & 2 together it all made sense. With the clearance dropped back to normal, machine acted like it was new again!

Too bad it didn't have bolt-on (replaceable) tips on the impeller; at one point I considered trying to make some, but that may be a bit beyond my talents. Still sounds like a good idea, though.