Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Just toying with the idea but would anyone know if a Honda GX620 v-twin engine will fit as a replacement engine for the B&S 305cc engine on a Simplicity 928? 

From a cursory eyeball inspection and comparing engine dimensions, it seems plausible.  The dimensional specs for the engine depth is a bit of a concern.  The Honda is approx. 1" deeper at 15.3" but the spec sheet didn't say if that included the output shaft length.  The B&S engine depth is 14.3 less shaft.   The other dimension indicate that the Honda will be shorter and narrower than the Briggs.  Which is hard to understand considering the Honda is a V-twin????   But the numbers say it is narrower.  Not that width really matters.   I've looked at the engine location on the Simplicity and think the exhaust from the Honda cylinders will require the fabrication of header pipes  into a Y and routed to one side to allow for a muffler to be placed on the side of the machine.  Not sure about the engine mounting bolt hole pattern or the height of the power take off shaft either.   Another thing is the power take off shaft on the B&S is 3/4" dia. 2-5/16 long.  The Honda is 1"  and very close to the same length.  I'll have to bore out the pulley to fit the Honda shaft or find a suitable replacement with a 1" bore. 

Anyone out there ever do something like this? 

If you're wondering why, well, just to see  how far 20 h.p. will throw snow mostly.   

Someone actually did put a 22 hp V-twin on a walkbehind two stage snowblower.

http://www.youtube.com/watch?v=BahOwtQrvuo

Well, after seeing that video, I'm left in a quandary. 

I'm thoroughly impressed with the performance but the guy did a bit more than just an engine change.  I'm sure the impeller mod added to the machine's throwing distance.

On the down side, I'd have to run the machine at half throttle otherwise I'd be putting snow in the neighbour's yards. 

Maybe a 15 h.p. will do...

There was quite a bit of work on that snowblower with the 22 HP engine.  At some point, more horsepower isn't going to make any more difference due to limitations of other parts.

I wonder how difficult it is to handle something with that much power.  If it buckles and skips around like a bronco, I rather put up with a shovel. 

I might be better off haunting the scrap yards for an older Ariens/Simplicity/Toro chassis.  I was at a scrap dealer last fall buying some flat iron.  I saw some old snow throwers that looked to be in good shape with blown or non-working engines.   That might be the best way to  build a Franken-blower.   All of this temptation is due to the Canadian dollar getting close to par with the U,S. dollar.  I've been eyeballing some very tempting prices at a couple small engine sites.  I think I saw a new Honda GX620 for under a grand.  They'd be well over twice that price in Canada.

That may be the best approach.  Save your good working snowblower from potential mishaps.  Something is bound to break, better to experiment on something cheap and not your main snowblower

All the horsepower in the world won't help if it still occurs at the same RPM. If your 305cc motor isn't bogging down from a lack of torque, the GX620 will still throw the same distance since the impeller is still running at the same RPM. You'll be able to push more snow into it without it bogging, but throwing distance will be the same. You need to use the extra torque the GX engine provides at its operating RPM (3600). You can use that torque to drive the impeller faster. You'll need a drive pulley that has a 1" bore and a larger diameter. Of course a longer belt will be necessary.

I'm just thinking with the extra speed of the impeller, those auger gear set might be the next weakest link.  That 20 hp engine is going to start breaking gears and shear pins on a regular basis.  The snowblower life will be short, however, throwing distance will be impressive though.

Very true. You can't burn the bulb brighter and expect it to last as long. However, there could be a "happy medium" in there. Maybe run the impeller 20% faster. It will never be able to use all 20HP, unless you speed up your drive even farther. Bun then you'll be able to be at a dead run behind your blower in 10" of snow.

If the snowblower is going that fast into 10" of snow, I''m going to attach a sulky to it.

>>I might be better off haunting the scrap yards for an older >>Ariens/Simplicity/Toro chassis

 

  Late 80’s to early 90’s Ariens 924 series is a good machine to refit.  I put an 11hp Honda GX340 clone on one which worked out well.  The weight (63lb) with that bucket (24) was just about the max though.  The Twin-V at 93lbs would probably be difficult to handle.  One good part about this setup was the motor was $230 with sales on coupon discounts at Harbor Freight.

 

   A Simplicity 870 is a substantial body but just barely fits it’s own motor because of the handlebars and linkage rods.  You have to move the motor to get the cowling off.  Most of them I’ve seen came with tires that were not so wide for the body but worked well.

 

   Newer Toro’s can come with a Japanese motor which I think is a Mitsubishi.  They run them on the same bodies as fitted with Briggs motors but at 4000 rpm.  With a 28 inch bucket to offset a big motor it would be good candidate if you could find one with a broken rod.

 

    Another is an older Snapper.  The base platform is pretty big and would take a big motor. The gearbox on the older heavy duty machines was one of the best ever made and the drive section robust.  The auger flange support came with zerks.  The buckets on the older models can probably be comfortably pushed to higher rev’s.  A great candidate for a big motor is a Snapper 10301 which is one of several models over a few years.  It’s a 10hp 30 inch with dual headlights and a big base and big very wide tires.  Many of the older heavy duty Snappers had the same parts.  Some of the series are 8260, 8265 and 1030X.  Around here at least they can be gotten in good shape for under $50.  Fitting a 10301 with a decent chute makes a great improvement over the original chute.

 

  An excellent candidate would be a big early 2000 Ariens with a large 4 blade impeller.  I think those were 28 and 32 inch.  You can find those bodies for about $200.

 

   Some of the drawbacks of an older bodies are they did not come with auger clutch locking with drive.  They mostly had dash mounted chute controls some with hood controls but some with low side cranks.  Most of the HD models came with big diameter tires but not all with very wide tires which are nice in a big machine. 

  From the 70’s through the 2000’s auger speeds went from 100 RPM to 140 RPM.  You’d probably want a model with at least 120 RPM as a starting point.  I have not found much of a relationship with 12 inch impeller diameter being at a disadvantage over a 14 for distance.  The best tossers I know of are 12 inch which throw a thinner stream.  A 14 inch Ariens 4 blade 11hp comes close to matching a Honda 9hp which I think is 12. 

 

   One of the desirable bodies for refit would be 90 and later Ariens but they are a problem.  Many of their models have a special arrangement for supporting the chute control rod so straying very far from the foot print of the original motor makes a problem.  I’ve got an excellent condition Ariens newer 11.5hp OHV 28 inch body that’s been sitting around waiting for a motor.  It’s been difficult to locate anything that will fit in without a lot of mods. 

 

 One consideration of making a “franken” machine is what to do with it once it’s done.  It has to be fairly practical if you’ll use it or especially for when you want to sell it.  Even a GX610 is 93 lbs.  A GX 390 is 63lb and would make a substantial machine but still be in the range of a practical machine when done.