Engine swap - Snowblower

[sparky961]

Is that a common drive mechanism for snow blowers?  It's amazingly simple, but intuitively I'd think it would slip in use.

[Brass_Machine]

Is that a common drive mechanism for snow blowers?  It's amazingly simple, but intuitively I'd think it would slip in use.

Not sure how common it is now. This machine is from the 70s so things may have improved. As far as slipping? Haven't really had that problem. This blower got heavy use two years in a row. We had a lot of snow. So it seams to work well.

[RotarySMP]

That was thoughtful of Honda to put that nice four bolt flange pattern onto the nose housing. What speeds do you actually use in practice?, I would guess that you would only use one or two speeds once you have gotten used to the machine.

That friction drive on the disc is going to be a lovely damper for the system, so you won't need to worry about torsional vibration, which can eat a gearbox pretty quick.

Look forward to seeing your Mad mod.
Mark

[Brass_Machine]

The gears, shaft and bearings came in over the weekend. I had ordered a 24 tooth and 48 tooth gear. And damn, if the are not heavy.

Both had a .5" inner diameter hole. Both gears can be bored, so I took the smaller of the 2 gears to.75" to match the drive shaft.



Now the hurdle to overcome is fitting 2 gears and 2 pulleys where there is supposed to be only 1 pulley. The larger gear is too thick and doesn't allow any room for a mount/bearing on the inboard side (close to the motor)





Serious head scratching as to how I could make this work. Started to think about cutting and welding. Trimming the gear itself down... Then it hits me. Bore a pocket in the big gear!

So onto a boring job! Ignore the step, I started a little too deep. At least it is lighter now!



FYI... I just finished replacing the bearings on my lathe and adding a 4" realbull spindle...

And I think it is going to work!



Now I have to figure out how I am going design the mount. I still may not be able to fit a bearing on the inboard side. Might have to use a bronze bushing.

It will take me a few more days to work out the mount.

Eric

[awemawson]

Looking good Eric 

I'm a bit puzzled by the axial position of the pulley though. Surely you want it OUTSIDE the front plate of the new gearbox 

[Brass_Machine]

Looking good Eric 

I'm a bit puzzled by the axial position of the pulley though. Surely you want it OUTSIDE the front plate of the new gearbox 

I thought so too. I just don't have enough room to do it that way. The pulley that is used to drive the wheels is located very close to the motor. That would locate the gears directly in the way of the pulley on the crankshaft driving the auger/impeller. Lack of space is forcing me to come up with a strange solution.

It will be clearer in a few days (I hope!) 

Eric

[Brass_Machine]

I ordered a few more things today. Namely the aluminum needed to make the bracket. Ordered tap/drill and some grub screws to secure the gears. I also ordered some heavy duty C clips so the shaft doesn't work itself out of the bearings.

Hopefully this weekend I will start the bracket. I have been mocking it up in CAD.

Eric

[awemawson]

Eric, we need to see that mock up

 

[Brass_Machine]

Eric, we need to see that mock up

 

And you will as soon as I get further on it. Right now, I have only been laying out the mounting holes etc...

I have a lot more to do 

[Brass_Machine]

Here ya go Andrew. Very rough draft...



The back side will be bolt to the engine case engaging the gear on the shaft.



Still have some spacing issues to work out.

[awemawson]

I wish I could do rough drafts as rough as yours - those are good ! Is that Fusion 360 ?

[DMIOM]

Looking good Eric 

I'm a bit puzzled by the axial position of the pulley though. Surely you want it OUTSIDE the front plate of the new gearbox 

I thought so too. I just don't have enough room to do it that way. The pulley that is used to drive the wheels is located very close to the motor. That would locate the gears directly in the way of the pulley on the crankshaft driving the auger/impeller. Lack of space is forcing me to come up with a strange solution.

It will be clearer in a few days (I hope!) 

Eric

Are you going to run the gears dry Eric? 

Dave

[Brass_Machine]

I wish I could do rough drafts as rough as yours - those are good ! Is that Fusion 360 ?

It's Alibre 2011. Kind of old, but does the trick.

Eric

[Brass_Machine]

Are you going to run the gears dry Eric? 

Dave

Hi Dave,

I hadn't really thought about it. There's nothing in the data sheet for the gears that say they have to be oiled/greased... So I was going to run them dry. Maybe some a drop or two here and there.

Eric

[awemawson]

If they are open (ie not enclosed) I'd use a sticky oil like chain bar oil or lathe way oil to stop it flying off. But they need some form of lubrication if they are to last.

[DMIOM]

If they are open (ie not enclosed) I'd use a sticky oil like chain bar oil or lathe way oil to stop it flying off. But they need some form of lubrication if they are to last.

The pulley already looks to have its shoulder inside the gear - I wonder if it'll need to be a bit further out so you can rig some sort of baffle to stop the oil lubricating the belt as well?

Dave

[Brass_Machine]

The pulley already looks to have its shoulder inside the gear - I wonder if it'll need to be a bit further out so you can rig some sort of baffle to stop the oil lubricating the belt as well?

Dave

You are right Dave. The pulley slid in too much when I took the picture. Good eye!

[Brass_Machine]

If they are open (ie not enclosed) I'd use a sticky oil like chain bar oil or lathe way oil to stop it flying off. But they need some form of lubrication if they are to last.

I was thinking of using motorcycle chain lube.

[Brass_Machine]

I played with it some more last night. I reshaped the space between the two plates and made it a bit thicker as well. I am going to turn up some spacers to help hold things in the right position.



Waiting on the stock to get here. Hope to get some parts cut this weekend... if the mill is willing!

Eric

[Brass_Machine]

I might cut a trial back plate today/tomorrow to test the location of the gear. I want to make sure it is meshing properly with the gear on the crankshaft.

Eric

[awemawson]

Too late now as you've bored it, but I'm surprised that you used a gear with a hub. If it was a plain gear fixed to the shaft with a keyway then the whole thing could have been considerably thinner 

[Brass_Machine]

Too late now as you've bored it, but I'm surprised that you used a gear with a hub. If it was a plain gear fixed to the shaft with a keyway then the whole thing could have been considerably thinner 

Not worried about the bore. The pulley will still use it's grub screws to secure against the D-shaft. The gear is bored so I can take up some space as needed for placement. The spacers would just prevent the gear from backing up. When I was talking about placement of the gear, I meant in relation to the gear on the crankshaft... the distance between the two.

I was having difficulty finding what I needed for gears. Plus, time is limited for this as I have other things that need to get done in short order before winter is here. Not to mention the lack of any real planning  !  McMaster Carr had these and they would work... so yeah, not the best possible solution, but I think it will work. Eh.. Live and learn I guess.

[Brass_Machine]

Looked at it some more a few minutes ago. I have to redesign the bracket just a bit. The gear/pulley needs to move up in relation to the camshaft about 10mm to get decent tension on the belt. No biggie... will do it this afternoon.

Eric

[ddmckee54]

Eric:

I know this is late in the game, I just found this thread, but couldn't you have just put in a bell-crank to reverse the direction of throw from the shift lever? So that it was pushing the driven wheel across the output shaft to the left for the forward direction instead of pulling it to the right.  I could have the direction backwards, but that's what the shiny areas in the photos seem to indicate.

Don

[Brass_Machine]

Eric:

I know this is late in the game, I just found this thread, but couldn't you have just put in a bell-crank to reverse the direction of throw from the shift lever? So that it was pushing the driven wheel across the output shaft to the left for the forward direction instead of pulling it to the right.  I could have the direction backwards, but that's what the shiny areas in the photos seem to indicate.

Don

Hi Don,

That was an initial thought. 2 Problems with that, every speed would have been twice as fast (Cam pulley spins at half speed) and there is not enough room to get full forward speed. Wish it would have been that simple...