Snow Equipment Owning/Operating Snowblowing Engine Speed

[BoylermanCT]

Just bought a used Pronovost Puma 64" snowblower. Get to use it for the first time tomorrow, we are expecting 8". I know you are supposed to blow at 540 rpm. On my Montana tractor, 540 rpm is at 2400 rpm. If I want more blowing power, can I run it higher than 2400rpm? I've never had it above 2400 but I am sure it can go higher. The tach goes up to 3000 rpm. Can the engine over-rev, or will the throttle lever stop at full speed, whatever RPM that is?

Engine is a Mitsubishi 4 cyl 1.5L diesel.

 

[Oldoak]

I never run any tractor over the PTO rated RPM and engine equivalent.

Also keep in mind most PTO driven equipment is designed to be operated at up to 540 RPMs. Augers and fans in snow blowers aren't precision balanced, if they are balanced at all. Driven at higher than designed speeds produce more wear and tear on equipment.

I think you will find that with the two stage snow blower you have, running the PTO at 540 RPMs will be more than enough to do the job you want. Just adjust your travel speed depending upon how dry or wet the snow is.

Let us know how you make out. I think you will be surprised.

 

[Trails End]

I have a Pronovost Puma 74, also designed to run at 540 rpm, but I seldom
need to run it at full bore. I find that 2000 rpm engine speed is more than
adequate for most snow blowing. To obtain 540 rpm, my engine speed
would be around 2400 rpm. The puma has handled all snow conditions
with no problems or clogging so far. I doubt if you ever have to go over
540 rpm. Enjoy!!!

 

[RNeumann]

The higher RPM doesn’t equal more power. Diesel engines are designed for peak torque at lower RPMs. The engineers designed the tractor to work at 2000-2400 RPM and that is why the PTO etc is designed for that RPM. Raising the RPM above that won’t help with power and isn’t needed. The diesel in the tractor isn’t a high RPM car or motorcycle motor.

As stated above you will find you probably won’t even need to go to 2400 RPM unless you start to bog down (slow down first) or you want to throw the snow into your neighbor’s yard.
Enjoy the machine- let us know how many rocks you chuck- everyone does it!!! You may break a sheer pin or three as well!

 

[tractchores]

I run at the rated PTO speed and it works great. More speed is unlikely to be helpful. You can move more slowly if it seems to bog down (it won’t in 8”)

 

[pmsmechanic]

Well I'm going to go against the flow here. When blowing snow I run my tractor at full throttle. It ends up being about 300 rpm over pto speed. If I hit a patch of heavy slugging I'll let the engine lug down about 500 rpm. Any slower than that and I loose too much distance.

 

[KennyG]

I would run it at the rated speed and that should work fine. However, you don't have to worry about over revving it. You can't really overspeed a tractor engine and you won't be pushing the blower much. My guess is it will not go much past 2400 rpm. As noted, most tractor engines are optimized to run about the PTO speed and will only run a few hundred rpm higher.

 

[CobyRupert]

Well, technically more rpm's is more power, but probably not more torque, and perhaps LESS torque for a diesel.
But I wouldn't over-rev it past the rated 540 rpm (PTO).
[Unless for some reason you must throw the snow FARTHER (as opposed to traveling FASTER).]
Control power demand of blower by controlling tractor ground speed / snow feed rate.

For these N'easter wet heavy spring snows, lubing up the blower auger and chute really makes a big difference on how easily snow slides through it and reduces plugging and build up on the auger. Sometimes snow builds up so much on an auger it no longer "augers" to feed the fan.
Some people recommend lubricants that stick and are water resistant. Many use Pam (TM) cooking spray cause it sticks, I use a silicone spray cause it sticks, coats and is water resistant, but also use any lubricating spray I have handy.

Open station tractor eh? Got snow goggles?

To paraphrase Jim Croce:
"You don't tug on Superman's cape
You don't snowblow into the wind
You don't pull the mask of that old Lone Ranger
and you don't mess around with....." ....sticking your hands anywhere near a snowblower. (Even if its turned off when plugged.)
-Ok, Jim Croce never said that....

 

[Reb954]

I'v always just set the throttle at full rpm which on the current tractor is slightly over what would give 540 rpm at the pto. On my old tractor the tach didn't work so I don't know what rpm it was running.

 

[Reb954]

If I'm doing the math correctly the following applies,

2400 rpm = 540 pto rpm. That equals 1 pto revolution for every 4.444 engine revolutions. If your engine tops out at 2600 rpm, 2600/4.444=585 pto rpm.

Just to confirm, another way to figure it is,

2400 engine rpm divided by 540 pto rpm = 22.5%. That is, the pto is turning at 22.5% of the engine rpm's. 22.5% of 2600 is 585 pto rpm.

To me, 45 rpm isn't a significant difference. About 8.3% faster rpm.