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JohnnyBoyUpNorth


Location: New Brunswick Canada
Joined: Dec 30, 2007
Points: 72

Repower question
Original Message   Jan 13, 2008 6:59 am
Hi all,

I am the not so proud owner of an old Artic 75 made by Bolens. I am a new homeowner and I bought this machine a few months ago for $50 from a friend at work. This machine is built like a tank, but the engine, a Tecumseh H70 died yesterday when I was tinkering. It has been problematic (stalling for no apparent reason, hard to start, continuous tinkering to keep it going etc etc), but now it's dead. I was letting it warm up so that I could adjust the friction wheel clutch linkage, and it piled up. There is oil in the cylinder and covering the spark plug, and it makes a dreadful scraping sound when I turn it over. I am not a mechanic, but I've heard that sound before...

I am certain that there are great examples of this engine out there, but I don't have one. What I do have is an older trash pump with a Honda GX340 on it. The motor works great, and I am thinking the obvious...

I am disassembling the pump today to install the engine on the blower. I would look into replacing the H70 with a 8-9 hp model if I didn't already own the Honda. As I said before, I am a new homeowner and it's only short time since Christmas, so money is a concern.

I am not concerned with drilling holes, fabrication and all that. What I need is to tap into the experience of this forum to tell me if it is too much engine for the blower. It seems very well made, and all greased up and ready to go. I am not hard on equipment and don't mind keeping the throttle at 3/4.

What do you think?

Thanks!

John

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JohnnyBoyUpNorth


Location: New Brunswick Canada
Joined: Dec 30, 2007
Points: 72

Re: Repower question
Reply #2   Jan 13, 2008 3:36 pm
borat wrote:
If you feel you have the mechanical ability to make it fit, go for it.  I doubt there will be a problem with too much power provided the Honda runs at 3600 rpm.  Higher rpms will have an effect on auger/impeller and drive speed.  I think your main issues will be getting the pulley fit and engine placement fit just right.   Rather than sacrifice the pump (if it's in good shape) you could sell it and buy a Tecumseh or B&S that are designed for winter use and their shaft sizes are made to fit the pulleys.    



Thank you Borat. I'll need to keep the pump. I am told that I'll need it in the spring to clear some standing water in the corner of my lot. I can take it off and put it back on in 5 mins.

I am confident that the running gear of the snowblower can withstand a few more HP. When you mention "engine placement fit just right", do you mean so that the pulleys are lined up perfectly? Was there something else I should concern myself with?

Thanks again,

John

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borat


Joined: Nov 10, 2007
Points: 2692

Re: Repower question
Reply #3   Jan 13, 2008 4:17 pm
The pulleys all have to be on the same vertical plane so the belts run true.  The distance center to center from the drive pulley to the driven pulleys is also critical.  When a Tecumseh engine is replaced with a B&S engine,  the vertical distance between the drive and driven pulleys is reduced.  Therefore, B&S provide spacers to put under the engine to get the correct pulley placement, as well as drilling new holes for the B&S engine.   If the distance between the drive and driven pulleys changes form stock, you might have a problem getting belts that fit.  If the belts on the machine are good, you can use them to help line up the pulleys.  If they're stretched, you'd be wise to get a new set. 

The type of shaft on the Honda will also influence the engine switch.  If it's threaded or tapered and your old engine had a keyed straight shaft that will be a problem as well as the diameter of the shafts.  The Honda might have a 1" dia. shaft and the old Tecumseh a 3/4" dia.  shaft.  If there is a difference in shaft type and diameter, you might want to take both engines to a bearing supply outlet to see if they have pulleys the will work for you.  If they don't, they can probably point you in the right direction. 

This message was modified Jan 13, 2008 by borat
JohnnyBoyUpNorth


Location: New Brunswick Canada
Joined: Dec 30, 2007
Points: 72

Re: Repower question
Reply #4   Jan 13, 2008 5:46 pm
borat wrote:
The pulleys all have to be on the same vertical plane so the belts run true.  The distance center to center from the drive pulley to the driven pulleys is also critical.  When a Tecumseh engine is replaced with a B&amp;S engine,  the vertical distance between the drive and driven pulleys is reduced.  Therefore, B&amp;S provide spacers to put under the engine to get the correct pulley placement, as well as drilling new holes for the B&amp;S engine.   If the distance between the drive and driven pulleys changes form stock, you might have a problem getting belts that fit.  If the belts on the machine are good, you can use them to help line up the pulleys.  If they're stretched, you'd be wise to get a new set.  <p>The type of shaft on the Honda will also influence the engine switch.  If it's threaded or tapered and your old engine had a keyed straight shaft that will be a problem as well as the diameter of the shafts.  The Honda might have a 1&quot; dia. shaft and the old Tecumseh a 3/4&quot; dia.  shaft.  If there is a difference in shaft type and diameter, you might want to take both engines to a bearing supply outlet to see if they have pulleys the will work for you.  If they don't, they can probably point you in the right direction. 


Excellent information, thank you! Being new to this, you're a great source of information.

So there is not an "infinitely" variable belt source, meaning I can't order a 37.5" or other odd size belt if I needed it? Good to know. The old Tecumseh was 4" from the base, and the Honda is 5.25" meaning I'll have a slightly longer belt. The tensioner has quite a bit of travel in it, seeing as it's a manual swingarm (for lack of the proper term) type design, I can't get a "close" belt as before and run it?

Another question, the new height of the engine might (almost positive) make the belt cover too short to bolt on. Is it absolutely necessary that the belts be 100% protected from blowing snow and moisture? I can extend it up an little bit, and fabricate something to protect it altogether if it is. In asking this, is the only purpose of the belt cover to protect the belt, or to protect a fool like me with clumsy fingers?

Thanks again!

John

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nibbler


Joined: Mar 5, 2004
Points: 751

Re: Repower question
Reply #5   Jan 13, 2008 9:38 pm
The belt cover does both, protects the belts from outside stuff and from fingers or other body parts from getting caught. Its a VERY good idea to keep them covered.

If you are going with the same diameter pulleys then there shouldn't be any need for modifying the cover. If the engine is taller then new belts will probably be needed and that can be a trick. Regular v-Belts die a quick death so you need to use belts that are designed for snowblower use. The auger belt has a bit of leeway since it uses an idler wheel as a clutch mechanism. The traction system is pretty tight.
JohnnyBoyUpNorth


Location: New Brunswick Canada
Joined: Dec 30, 2007
Points: 72

Re: Repower question
Reply #6   Jan 14, 2008 3:34 pm
Excellent info, thanks very much!

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JohnnyBoyUpNorth


Location: New Brunswick Canada
Joined: Dec 30, 2007
Points: 72

Re: Repower question
Reply #7   Jan 20, 2008 7:57 pm
Hi all,

I've mounted the engine, all's going well. It was a simple enough operation. The only problem I have will be to re-route the chute auger, but I have a line on a spare blower to cannibalize and fabricate with. Should be fun tinkering.

I do have a question, and that's to do with the increased horsepower. I would like to take full advantage of this. I went from 7hp to 11hp, and I am wondering if it would be of any benefit to "step up" the pulley on it. Would I be pressing my luck if I increased impeller/auger speed to take advantage of the new horsepower? The old H70 and newer Honda run at roughly the same RPM.

I am certain that there are limits to this, and I don't want to approach critical values, just wondering if someone has done this with favourable results. Please share your opinions and experience.

Thanks

John

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borat


Joined: Nov 10, 2007
Points: 2692

Re: Repower question
Reply #8   Jan 20, 2008 11:38 pm
Johnny Boy:

Nice of you to give us an update and I'm glad it's going well for you. 

Yeah, I know the temptation to squeeze a little more performance out of something is hard to resist.  As a kid, I destroyed a few lawn mower engines trying to increase power.  Still get the urge to this day.  Fortunately, I have machines that lend themselves to being hopped up (1970s vintage Yamaha RD350s ad 400).  That satisfies my desire to tweak. 

In your case, you have plenty of power and torque.  I strongly recommend you stay with the stock gearing.   Remember that you're putting on a pretty potent engine on a machine designed for at best 7 h.p. that likely was delivering closer to 5 h.p.  The increased torque that the Honda delivers will be on such as scale that components in the auger drive system will be subject to extreme loading.  Under normal working conditions this should not be an issue.  However, if you attempt to move heavy wet snow at full throttle, I wouldn't doubt that you will be destroying auger drive belts.  Now if you change the gearing and the components are  required to spin faster than they were designed to go and handle twice the power they were intended to handle, I can see big things going south in a hurry.  If the auger drive belt manages to stay together and you're spinning auger and impeller beyond their specified limits it doesn't take too much imagination to predict what will happen to the auger drive gears.  Remember that machine is already fairly old and has seen plenty of service.  What you're doing is equivalent to dropping in a 426 c.i. hemi into Model A  Ford.   Go stock gearing for a while.  If you have to change it, wait until the end of the season.  That way when you tear it up, you won't be needing it as badly and will have the summer to find parts to repair it or replace it.    Good luck.  Let us know which way you go.  If you do change the gearing, have some one nearby with a video camera when you fire it up.  I'd like to see that. 

This message was modified Jan 20, 2008 by borat
Gelid


Location: Maine
Joined: Nov 19, 2007
Points: 84

Re: Repower question
Reply #9   Jan 23, 2008 7:09 pm
Borat is right, increased power in a snowblower is not meant to make it run faster but to prevent it from slowing down under heavier loads.

Honda HS928 TCD - If you lived where I live you'd have one too
JohnnyBoyUpNorth


Location: New Brunswick Canada
Joined: Dec 30, 2007
Points: 72

Re: Repower question
Reply #10   Jan 23, 2008 7:35 pm
Thanks for the advice, and I took it. The new Honda works like a top and I kept the stock pulley ratios. Being a 26" cut, the engine has no trouble at all. The throwing distance increase is of no consequence though. I was a little disappointed when it wasn't shot into orbit, but so goes my life. My driveway was already cleared, but like most of us dorks, I couldn't wait to use it, and decided to clean a path in the backyard. I am sure I'd burn a belt before it ever started to choke.

While this is a little off-topic for my original post, I'd like to know if there are any tricks out there to increase throwing distance. I've got high banks from a heavy few snowfalls (eastern Canada), and have a hard time clearing them so close in. The front end of the machine has a fair bit of rust from some previous neglect, and it appears that snow sticks to this. Is there a "non-stick" paint available? Does the Krazy-Karpet trick work?

While I am full of questions, I should be full of praise. Thank you to all who've taken the time to answer me. It's very much appreciated and extremely helpful.

John

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nibbler


Joined: Mar 5, 2004
Points: 751

Throwing Distance Tricks
Reply #11   Jan 23, 2008 8:03 pm
  1. Make sure you feed enough snow into the machine, if its not loaded the governor does not kick in and you are at a fast idle. I go as fast as I can without snowplowing, you cna usually hear the engine start to roar;
  2. Most 2 stage machine have the impeller turning clockwise ( from the operator position). This means that the snow will be thrown faster to the right ( in line with the way the impeller is moving);
  3. Many people have posted glowing comments on the Clarence impeller paddle kit, details can be found here;
  4. Change the pulley ratios, carefully and not too much, vibration goes up with the square of the speed ( 2x speed = 4x vibration)
Its not surprising that the throwing distance doesn't change. If the engine is running at about the same RPM then the impeller is turning at about the same speed. This means the snow is leaving the chute at about the same speed and the same maximum volume can be thrown. More power means the machine is less likely to bog down under load, not that it will travel faster.
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