# B&S V-Twin Engine Swap



## grupe (Jan 23, 2011)

I have had snow blowers for many years, but last summer I finally got around to moving up to a two stage. I purchased this fine 26” two stage on a 100 degree day which made the unit cheep. When I got it I had a broken rear axle which was an easy fix since it is just a piece of 3/4 shaft. 

This is what she looked like when I got the shaft fixed. 




She made it through the winter okay, but is appears the engine had seen her better days. When I serviced her before the winter started the engine oil was really black and was black again almost as soon as I put new in. The air filter was also completely missing. Both good signs of course. Due to the lack of power, I decided the right thing to do was find a bigger engine and here is where the fun starts. 

A note before you beat me up to bad: I spent no time trying to make the build look good. My plan is to figure out if everything works the way I want it to, tear it down next summer, make everything look nice and then paint it. I am thinking flat black and red on the spout and auger. 

*Finding the Engine and the output shaft:*
I researched all the normal options on harbor freight, but that didn’t seem very creative and was a little more money than I wanted to spend. So one day on Craigslist I found a guy selling a B&S 14hp V-Twin that had come off a generator which had about 100 hours on it. I picked the B&S up for $210 which seemed okay to me. I had talked to a few people and they all assured me that I could find a pulley to fit on the tapper shaft that the engine had. It only took me about 4 hours to confirm in my mind that this type of pulley actually doesn’t exist. The 4 hours of course came after I had purchased the engine so I was kind of in a tough place. I did some checking with a few buddies that had access to machining tools and they all said it would be around $100 to turn the shaft if I took the crank out of the engine and brought it to them. 

*Fixing the shaft:*
Spending $100 and having to take the engine apart wasn’t sitting right with me so I came up with plan #2. I bolted the B&S down to my work bench. When I first tried to get it started it of course won’t start. I then mounted a fuel tank above the carb and by passed the fuel pump. Then it started right up. I semi remember the guy that I purchased the engine from telling me that the full pumps die from time to time. Hmmm. Anyway, I now had it bolted down and running. The next thing to do was to grind down the shaft to fit the pulley I had purchased. It took me about three hours, but I got the shaft ground down to a 1” diameter. Basically I would start up the engine and let it idle. Then I would grind for a few seconds to a minute with my hand grinder and then shut it off to see if I had it milled down to what size I needed. It was a very time consuming processes and I went really slow as I didn’t want to mess up the shaft. I then cut a keyway into the shaft with an air cut off tool. I can hear everyone reading this laughing at me right now, but I took a video of it running and played it back frame by frame and the pulley runs smooth. The guys with the machining tools also couldn’t believe it worked. The best part was that they all said that they would have done the work for $25 and we could have left the crank in the engine. I just love people that change their story.


































*New pulley:*
I used a 3.15” diameter pulley. The original pulley was 2.5”. I figured that I should be able to turn everything a little faster since I have extra horsepower.

*Disassembly:*
The next step was taking the old engine off. That of course only took about 5 minutes. I also took off the top of the shoot and the crank that turned the shoot. I should have ran the base down to the car wash, but I was a little too excited at this point to do anything but work on mounting the engine. 












*Positioning the Engine:*
This was likely the part that was the least amount of fun. The old belt was too short and it took four trips to NAPA to get the right one. They were very helpful as usual and also directed me to get a wider “A” belt. Once I finally got the belt that was the closest fit, I determine I would need to space the engine up a little. I used a ½ piece of square tube to space it up. The other concern with the mounting was getting the crank that turned the shoot past the exhaust and oil filter. I ended up mounting the engine quite a ways towards the right of the base. The next thing to do was add six inches of pipe to the spout so I could get the shoot high enough up so I could mount the turn table. My dad grabbed me some old water pipe. Not the best pipe in the world, but it should handle this job without an issue. I also had to do some minor fabrication on the mounting hardware for the turn table crank. At this point I bolted down the engine solid to the base. It took a few tries to get it perfect, but that was semi-expected.












*Fuel Tank:*
I did some research and it appears that a 14hp B&S will drink about a gallon of gas an hour. So I figured I had better find at least a one gallon tank. The first tank I found had been outside for years and was a rusty mess (the round one in the pictures). I ended up pitching it in the trash, but used part of its mounting bracket to build the mount for the second fuel tank. I used some cargo straps since most of my random metal is in storage at the moment. I also installed a fuel filter and a fuel shut off between the tank and the engine.

*Throttle:
*The next project was to build the throttle linkage. Since the engine came off a generator there weren’t mounts for the cable. I used a piece of angle iron to build the mount. B&S was nice enough to put an 3/8” tapped hole on the back of the engine that I was able to bolt the angle iron to. I robbed a throttle cable from a dead riding mower. The throttle came out a lot better than expected.












*Tires and Tire Chains:*
I don’t like my tires at all, but I haven’t figured out what to do yet. I took the chains off as they were lifting the front of the blower off the ground when one of the chain links hit the ground. The tires are about 10” tall and 3” wide. I am thinking of about finding some different rims and tires which will take some time. Any thoughts here would be helpful.

*Shields*:
Last, but one of the most important things was getting all the safety shields reinstalled. I had to modify the one that goes over the pulley and belts a little due to the pulley being bigger and the shaft being positioned higher off the base. I didn’t install the shield on the other side as the oil filter makes it next to impossible to come in contact with the belt. 

*The weak leak:*
As I mentions before, the axle was broken when I purchased the unit. It had been replaced before as the one that I removed looked like it had been installed by a 3 year old. It had broke where the bolt goes through the shaft to connect the sprocket. My guess is that is only a matter of time till it breaks again. Any ideas of what I can do here. The axle is just a boring old piece of ¾” stock.

And that is my snow blower engine swap. Thoughts? 











Here is a video of her running:


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## Shryp (Jan 1, 2011)

Looks and sounds great.

One problem -- No snow!

I see tires and rims on ebay a lot. Check the snowblower section.
tire | eBay


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## bwdbrn1 (Nov 24, 2010)

Shoould be quite the snow throwing monster!


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## grupe (Jan 23, 2011)

I *think* i found some rims locally. Hopefully the guy will email me back. I would like to at least have the rims in case my crappy hold rubber tires are as bad as i think they will be.


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## CAPTAINCONSUMER (Feb 18, 2011)

Great! It's guys like you that make me look sane! I just picked up a 10 hp tecumseh in buffalo....it had my 5th snowblower attached to it. Can't wait to see yours in action.


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## Wayne195 (Nov 16, 2010)

Exellent engine upgrade, grupe! Lookin' good!


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## HCBPH (Mar 8, 2011)

*Axel*

Just saw this today, very interesting project. Reminds me of one on YouTube where the guy did something similar to a John Deere IIRC.

On the axel, I don't know what yours looks like so here's something you might want to research. Older Craftsman blowers by Murray have 3/4" axels with welded on sprockets. There's 2 different diameter sprockets for sure, I know because I have 5 of them right now. These are the ones that model numbers start with 536 IIRC. I don't know if they'll work or not, but might be worth a look.

Paul


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## CAPTAINCONSUMER (Feb 18, 2011)

Where did you get the drive pulley?


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## grupe (Jan 23, 2011)

Paul - Thanks for the input. I will keep my eyes open.

Captainconsumer - Pulley came from Surplus Center - Hydraulics, Engines, Electrical and More They had the best prices that I could find in the size I needed. I am sure you could do better, but I got tired of looking after a while. The only think i didn't like about them is that they are in NE so i had to pay taxes. Grrrr.

I am headed back home this weekend. My buddy has a graveyard of ridding lawn mowers and i am hoping to find a pair of rims.


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## Quickrick (May 2, 2011)

Grupe, 

Isn't doing this stuff loads of fun? I repowered an older Snapper Lawnmower that meant all kinds of modifications were required. I did this over the course of the winter and it looks and runs as new. (actually better with 2 more HP!)

The best part of your mod is that a V-twin is so much smoother and quieter, beside being way more powerful. 

Do a good job on your paint work and look for a deal on a set of large Snow Hog wheels and tires.....it will look mean!

Great job,

QuickRick


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## grupe (Jan 23, 2011)

QuickRick,

Thanks for the input. It was a ton of fun and I can honestly say i am looking forward to the first big snow assuming it is november before we get it. 

I was able to rob a set of rims off the same dead lawn mower that donated the throttle cable. The tires and tubes are shot. Here is what i am thinking for tires and tubes:

Sno-Hog™ Snowblower Tire — 4.10/3.50 x 6in.
Sno-Hog&#153; Snowblower Tire &#151; 4.10/3.50 x 6in. | Snow Blower Tires | Northern Tool + Equipment

Martin Wheel Inner Tube — 410/350–6in. Tube, Bent Valve Stem, Model# T356-1B
Martin Wheel Inner Tube &#151; 410/350&#150;6in. Tube, Bent Valve Stem, Model# T356-1B | Replacement Inner Tubes | Northern Tool + Equipment

55.96 + 12 shipping. Seems a little high. Any thoughts on other places to pickup tires and tubes?


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## Shryp (Jan 1, 2011)

I got mine from jackssmallengines. This shipping wasn't so bad since I ordered some other stuff at the same time. Summit racing had them on sale dirt cheap a while back, but their web site is a pain to find anything on. Ebay often has near new tires and rims for cheap too. X-Trak is suppose to be a better tire design, but I used Sno-Hogs and thought they did fine.


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## grupe (Jan 23, 2011)

Shryp - Now that is the ticket. $48.45 shipped. Thanks for the help. To bad they don't take PayPal. ;(

3562STTI - tires
T356 - tubes


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## CAPTAINCONSUMER (Feb 18, 2011)

Do you have pics of your belt/pulley shield alterations (bigger pulley). I was thinking of using spacers to put shield higher and fabricating a sheet metal skirt around base.

Captainconsumer


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## Shryp (Jan 1, 2011)

Here are some pictures of one I made. It just uses roofing flashing so it is pretty flimsy.
https://picasaweb.google.com/117604838925049407526/20110314


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## CAPTAINCONSUMER (Feb 18, 2011)

*Thanks for the reply*

The pics are helpfull. I have access to a metal break..white soffitt. Material may be the ticket.

Captainconsumer


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## grupe (Jan 23, 2011)

I finally got around to getting the new tires and rims. The rims came off an old rear engine riding mower. I cleaned up the inside of them as they were fairly rusty. Here is a pic of the rims and the old tires:










and here is a picture of them going back together:


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## Kiss4aFrog (Nov 3, 2013)

I was looking forward to getting to the end of this thread and seeing that sucker throwing snow and being painted 

Seems like someone who went through that much work would be a regular here.


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## grupe (Jan 23, 2011)

I don't have a very good excuse, but I have been working through some issues. It hasn't snowed yet this year so I can't really comment on my 2014 improvements. In 2013, I was traveling every time is snowed. Good timing on my part i guess.


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## JerryD (Jan 19, 2014)

I can't wait to see a video of it moving some snow!


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## Kiss4aFrog (Nov 3, 2013)

No excuse needed, so surprised you're still around but it's why I "poked" the thread. Once in a while someone can be revived !!!

Would love to see what you've done with it and how well it throws.

Having a twin cylinder is just so Tim Taylor, Tool Time. I was eyeing an Onan twin a while back. Myself, I'm looking for any excuse to put a diesel on one of my Craftsman. The seven bills would be worth the sound of it powering down the drive and shooting snow over the neighbors house


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## woodtick007 (Apr 9, 2011)

*Gas guzzlers*

You will regret a twin..... there is a 16hp DuroMax 16 Hp., 1'' Shaft, Recoil Start Engine - XP16HP XP16HP I went the twin route on a piece of equipment..... and it double my fuel consumption along with exhaust emissions.... I am keeping my eyes open for a large OHV single cylinder and will not look back. 

The other problem your going to face is that the gear case assemblies are not designed to handle large amounts of RPM and torque. Some of the old cast iron cases are stronger but will definitely suffer from a much shorter lifespan. You would be much better off finding a machine with a very large impeller housing. Then increase the efficiency of the chute and umpeller/impeller housing with an impeller kit.


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## Kiss4aFrog (Nov 3, 2013)

Most snow blower engines turn at 3600 to 3800 RPM. The twin cylinder isn't running twice as fast it just has a second cylinder. RPM isn't a consideration as a two cyl engine is going to turn at the same speed. If it isn't set that way it can be adjusted to that RPM. Since his came form a riding mower it might be set at a different RPM. I have no clue off the top of my head what a riding mower engine spins at. I'm guessing it's the same since that's where it develops the best power.

Yes, the machine isn't designed for that much power. But that's the function of the governor. Most of the time I'm snow blowing I'm running on just the throttle setting and the full power of the machine isn't being used. Setting the throttle to the "rabbit" or all the way over doesn't open the throttle all the way and it isn't full throttle. It just brings the engine RPM up to the set high speed limit 3800. It's rare that it starts to load and the governor starts to give it more throttle (power) to maintain the RPM. But that's how you use all your horsepower. It's not spinning any faster, the governor just opens the throttle to apply more power to maintain that RPM and when it exceeds that RPM closes the throttle until back to 3800.

I have a '70s bilt 32" with a 10hp and I don't see a problem with it handling the power of a 16hp engine since it will be rare to run it into +25 inches of snow for any period of time other than an occasional drift.

The other thing you forget is the shear pins. If it still has the stock shear pins they are designed to break before anything else and they still should no matter what engine you put on, no matter how many cylinders, no matter the horsepower.

That said, anyone actually doing this is going to be mechanically smart, understand the risks and they likely are doing it just to have the biggest on the block. Good point about gas but for what little it uses I'd just add a second tank or get a bigger one.

1983 Madza RX-7 with a modified Chevrolet 454. Sure it could have a 350 and even then you wouldn't be able to use it all with the tires and suspension but I can't tell you how cool it is to be on the freeway and put your foot in it and all of a sudden you're passing everything like it's standing still. But, you can pretty much watch the gas gauge dropping in relation to how fast you're going.
And the scary thing is I'm not the biggest or fastest as there is a guy out there with a twin turboed big block !!


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## db9938 (Nov 17, 2013)

woodtick007 said:


> You will regret a twin..... there is a 16hp DuroMax 16 Hp., 1'' Shaft, Recoil Start Engine - XP16HP XP16HP I went the twin route on a piece of equipment..... and it double my fuel consumption along with exhaust emissions.... I am keeping my eyes open for a large OHV single cylinder and will not look back.
> 
> The other problem your going to face is that the gear case assemblies are not designed to handle large amounts of RPM and torque. Some of the old cast iron cases are stronger but will definitely suffer from a much shorter lifespan. You would be much better off finding a machine with a very large impeller housing. Then increase the efficiency of the chute and umpeller/impeller housing with an impeller kit.


Not to mention that the shear pins are rated to certain amount of torque before they fail.


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## nt40lanman (Dec 31, 2012)

That DuroMax looks good. And as a Honda clone type, it could probably be hopped up with some of the mods that work on the Predators. However, there's a certain amount of "Captain Morgan" panache with a V-twin that I like. *NICE* job Grupe.


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## Geno (Nov 29, 2011)

*big twin..*

My big twin (over-kill 20 hp) that I posted on here few days ago is on it's second winter and so far 0 issues. It was built for the 'hot-rod' kid in me even though I'm 60. Not built really to be cemetrical in proportion or to be economical- just to be 'fun' and mean looking. It accually is not bad on fuel and rpm's are controllable. I run my rpm's in gearbox at max but I also have the heavy cast iron gearbox in a 32" older Ariens. I can't afford a older muscle car so I built a muscle blower.. it takes less storage room/time/money and still fun to build and use. That said: You can expect possible pre-mature wear since more weight on axle bearings and the fact the gear box will maintain a more even rpm curve in deep wet snowbanks where a smaller motor would bog down thus slow the gear box down some-But not sure.. my thinking is a more even rpm in gearbox at regardless of conditions would be better on gears in there than the up-down of bogging? This is all so minimal I doubt much of any difference. Over-revving the gearbox or running wrong lube or running to low a level would be the killer- OHV twins will require valve adjustment, or atleast my Honda will.. but considering the hours of use not expected but every few years and that is a easy job. I Do think you need more warm up time though before putting load on it. I let mine run several minutes to five before using to assure oil is pumped up everywhere and more metal to get warmed. just my 2-cents on it- I think you'll love the twin though. I tossed between a 18hp vanguard or the Honda.. both great motors. -Geno


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