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acjohn

Still just pukes out snow

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acjohn
Ok, tried 4th gear with 3" of snow and the thrower wouldn't do anything like the pics I've seen here. Tractor is a 410S. Even in 4th gear I wasn't coming against the governor very hard. Thrower is 42" off a 700 series. I don't think I have enough auger speed. Did 300/400 series use a smaller pulley on the PTO than the 700 series? I am going to try a shorter belt and smaller pulley on the snowthrower. If anyone can put a tach on the pulley shaft on their thrower, I can tell if I'm in the ballpark, and if not I can calculate the right size pulley for the thrower. I'm guessing I need about 15% more auger speed. Thanks in advance.

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SmilinSam
The pulley the 700 series blower is designed to be used with that sits on the engine is somewhere around 6" dia. I would have to go out and measure to be sure exactly what it is, but don't have time at the moment.

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acjohn
If you could tell me for sure, I'd appreciate it. I think my PTO is 5" diameter. If a 700 is 6", that's a 16% increase in speed. EXACTLY what I think I need. I look forward to hearing back. John

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PatRarick
John, on my 914, the blower runs at 2600 rpm. On my HB-212, it runs at 2400. I know the pulley is right on my 914 is right, but not so sure on the HB-212. Both work equally well though. Pat

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acjohn
Just came in from measuring. PTO is 5.75, snowthrower is 6.75. At 3600 RPM on the engine, that would make the snowthrower pulley 3067 RPM. Multiply that by the reduction to the auger, and I'm still probably faster than you, Pat. I guess I'll just have to play with it and see what happens. Thanks all for the input and suggestions. John

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PatRarick
Just dawned on me that I gave the wrong information. I gave the driveshaft speed, not the auger speed which is slower. To calculate rpm's, take the speed of the drive system, whether it is engine, PTO, or BGB. In these cases it would be the governed engine speed of 3600 rpm. Multiply that times the drive pulley diameter. For this example, I'll use a 4 1/2" pulley. 3600 X 4.5 = 16,200. To figure a pulley size to drive a shaft at 2100 rpm, divide 16,200 by 2100. That gives you 7.71. You want a pulley as close as possible to 7 3/4". If you want to know how fast a driven shaft will turn, you divide the 16,200 by the driven pulley diameter. Using a 6" pulley as an example, you divide 16,200 by 6. You get 2700 rpm. On my HB-212, I have a 4" pulley on the engine. I have a 6" pulley on the snowthrower. That gives me a snowblower driveshaft speed of 2400 rpm. (3600 X 4 = 14,400 divided by 6 = 2400) What I neglected to calculate is that the driveshaft has a 12 tooth sprocket running a chain to a 29 tooth sprocket on the auger. That means the driveshaft turns almost 2 1/2 times for each revolution of the auger. 2400 divided by 2.5 = 960 auger rpm. If you can alter your pulleys (engine and snowblower) to achieve about 2400 to 2600 rpm on the auger driveshaft, you should have it made. You don't want to run the auger much faster. Tried that on an MTD snowblower that I altered to fit my 3112. As soon as any appreciable amount of snow fed into it, it shot the snow out quite a distance, but lost power so quickly that you couldn't use it. Slowed the auger down to about 1100 rpm, and it worked very well. Sorry about the earlier mis-information. Pat

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MPH
Pat, was talking to my bro in colo when I read your earlier post and we deducted you must have been talking about the driveshaft speed, couldn't quit figure how the auger would hold together cranking like that.

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dlcentral
AC, check spot behind center of auger on housing. It has to be close to spinning auger no farther away than 1/8" They get all bent back from stones,etc.and you lose "pumping/throwing action,,I had one like that,that wouldn't throw far,,pushed housing back closer and made a world of difference,

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acjohn
OK guys, it works!! I only had a 5" "A" section pulley so the belt rides a little high. I moved the hitch brackets to get enough belt tension and man, does it ever throw snow! I'll have to get an different pulley, shorter belt and I'll be in business. I did my neighbor's driveway (they have moved) which had about 2" of snow. It worked great. I pulled the cover on the chain case and the sprockets are 29T and 16T. With the engine and snowthrower pulleys the same size, that would make the auger speed just under 2000 RPM at 3600 RPM on the engine. Thanks everyone for all your help. Now I just need about 6"-8" to really put it to the test. John

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thedaddycat
I got the kit from Clarence on e-Bay that adds rubber "squeegee" paddles to the blower to take up the gap. I have to install them, though. You can just use the ratio of pulley sizes without all the other math to figure out RPM. 3600(engine speed) X dia. A/dia. B=driven RPM. Diameter A is the driving pulley and Diameter B is the driven pulley. With the example of a 4" PTO pulley and 6" driven pulley, driven RPM=engine RPM X 4/6(or 2/3) so driven speed = 3600 X 2/3=2400 RPM driven speed. Going from a driving pulley size of 5" to a 6" will yield a 20% gain in speed while going from a 6" to a 5" will yield a 15% loss in speed.

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Magoo
Me? I'm just back here in lansing NY sucken up all this info. Now I have to go check the auger and housing. Had to get a different pulley for the crankshaft 4 1/2". works good now but would like to have all of it right. So time to check the clearence. Thanks all. Guy A.K.A. Magoo

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