# Engine Swap: Different size shaft - Ariens Platnium 30 (921018)



## LuvSnoTilMar (Jan 15, 2016)

Hi all-

First, thanks to everyone who repeatedly offer advice, suggestions and direction for folks like myself. Forums like this offer invaluable service to people like me who may not have that person in their network to ask such specific questions. 

I was given a five year old Ariens Platnium 30, model 921018 for free by an in law after he blew the engine and purchased the same, new model. Awesome. 

We attempted to purchase a replacement engine, relying on the model of the engine and approximate production year. Well, I made what I know to be a grave mistake and didn't take it down to the Briggs & Stratton TYPE, only looking at the model and not the type. Unfortunately, I now have an engine with a 3/4" shaft instead of a 1" shaft. Everything else about the engine lines up perfectly including the hole pattern and the shaft height from base. 

I looked into one of those shaft sleeve adapters (ex from Amazon: http://www.amazon.com/Shaft-Adapter-Sleeve-Predator-Pulley/dp/B00T6V3TS4/ref=sr_1_1?ie=UTF8&qid=1452819732&sr=8-1&keywords=3%2F4+to+1+shaft+adapter)

but the issue with these is that the existing pulleys have the keyway built in, so no place for the steped key that comes with the adapter to slide in. 

After a few days of research, I believe I am left with three options:

1) Try to purchase and match the pulley setup in the attached pictures for 3/4" bore pulleys.

2) Proceed with purchasing the adapter sleeve and try to find a machine shop to drill out the existing key on the existing pulleys.

3) Suck up the costs related to shipping a 70 lb motor back to North Carolina and find a different replacement engine. Not sure what I else I can find for $400 for a similar motor.

Both motors are Briggs and Stratton 1650 Series Professional Snow, where the original is Model & Type 21m314-0114E1 and the new one is 21M314-2470F2.

I (hopefully) attached a couple of pictures of the pulleys to show you what I am up against. I've learned a bunch in this process so far, (thanks to this forum) but engine work is out of my wheelhouse, obviously, so I'm wondering what you all may recommend. Thanks again for any help.


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## Shryp (Jan 1, 2011)

The Harbor Freight 13 HP engines come with a 1" shaft and are only around $350 if you catch the right sale.

3/4" pulleys can be had online for $10-15 each, but the double pulley for the augers might be hard to find.

That luck sucks. Definitely pay attention to crankshaft diameter in the future. 

For a lot of engines from the same family it is possible to change parts like crankshafts, camshafts and front covers. It might be possible to put the old crank in the new engine. That is dependent on how damaged the old one is though.


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## skutflut (Oct 16, 2015)

I think I would be inclined to try option 1 first. Pulleys are not all that expensive, and you might get lucky locally and find what you need. That might be quickest and cheapest. 

What is the depth of that built in key? Is it possible its deep enough that it would make it through the 1/8 thickness of the adapter, and into the crank keyway so you wouldn't need the step key? Check the width of the keyway in the new crank to see if it matches the width of the key in the pulley

Can the place you got the engine supply the correct version with the crank you need? How much is shipping?

Machining out the built in key might work, but they also have to cut a new one to fit the sleeve stepped key. Maybe its the photos, but the holes don't look like the would come out perfectly round after machining, the shape near the keys looks a bit off round. Maybe get a quote, so you can find out if its possible, and then you know what the three options are cost wise. Maybe get the same shop to quote on making you a set of matching pulleys with the correct shaft size, if you cannot find them online. Be a great project for the shop apprentice


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## 43128 (Feb 14, 2014)

i would go with a 420cc predator engine. should be a direct swap


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## LuvSnoTilMar (Jan 15, 2016)

Shryp said:


> That luck sucks. Definitely pay attention to crankshaft diameter in the future.
> 
> For a lot of engines from the same family it is possible to change parts like crankshafts, camshafts and front covers. It might be possible to put the old crank in the new engine. That is dependent on how damaged the old one is though.


Ha, thanks. Pretty sure I'll never buy another engine without checking the crankshaft first. Definitely a dumb mistake!:wavetowel2:

I did start going down the road of taking the old crankshaft out to put in the new engine. A bit more background is required here...the previous owner (my father in law) never changed/added oil to the blower, hence the blown engine. He was told the engine was blown, specifically blew a rod. So, with that in mind we decided that trying to switch the crankshafts would result in finding out it was damaged from the blown engine, it would not be a direct replacement, or it was a just a bad idea to begin with . Anyhow, my main question would be on that front, is getting into that area a bad idea in terms of making that engine any more un-usable than it already is? What about voiding any warranty the new B&S motor has?



skutflut said:


> Can the place you got the engine supply the correct version with the crank you need? How much is shipping?
> 
> Machining out the built in key might work, but they also have to cut a new one to fit the sleeve stepped key. Maybe its the photos, but the holes don't look like the would come out perfectly round after machining, the shape near the keys looks a bit off round. Maybe get a quote, so you can find out if its possible, and then you know what the three options are cost wise. Maybe get the same shop to quote on making you a set of matching pulleys with the correct shaft size, if you cannot find them online. Be a great project for the shop apprentice


I assumed returning the engine would be cost-prohibitive after the $50 I paid for shipping, but after double checking the place I purchased, Jack's Small Engines (jackssmallengines.com), returning is apparently not an option at all: "Engines
Engines are sold as final sale (not returnable). Please allow a customer service representative to assist you in this kind of purchase in order to guarantee that you are receiving the correct product.":wavetowel2:

Thanks for the advice on asking a machine shop to actually build(?) a matching pulley set, that may be an interesting thing to throw at them. I've actually never interacted with a machine shop in this fashion before so I'll add this to the learning moments I'm experiencing k:.


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## dodgetrucker (Jan 15, 2016)

I wish I knew why everyone is so in love with these Predators. I would not have anything to do with one. All (conventional, domestic) engine manfacturers have made several variations of every engine they have ever made. Crank differences, 2:1 extended cam (or not), reduction gear, different throttle/governor setups, tapered shaft, splined shaft, threaded shaft (for pumps) and more possibilities. so you gotta watch that stuff. often you can swap parts from the old engine to the replacement so that it works properly. 

I have made other engines work in place of originals in about every way imaginable, often what engine I transplant depends on what I have laying around. I have swapped pulleys, had pulleys rebored and rekeyed, swapped crankshafts from old engine to new engine, removed crankshafts and had them remachined to the configuration I need to work with the original pulleys, and a couple of other methods. It depends on the machine and what is available to repower at any given time. One thing that I never do, is to make an engine swap look like a cobble job. When I am done, I do all I can to make it look like it came that way from new. 
I usually try though to find another engine of the same brand, at least as what came off.


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## LuvSnoTilMar (Jan 15, 2016)

@dodgetrucker Thanks for replying to the thread! For better or worse, I'm not able to switch to Predator unless I eat 100% the cost of the B&S engine I bought. So, fortunately we don't have to debate the pros/cons of the Predator engine. 

With that said, with your experiences, what is your opinion on the better of three options: new pulleys; old pulleys, machined; or crankshaft swap? 

Thanks!


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## GustoGuy (Nov 19, 2012)

LuvSnoTilMar said:


> @dodgetrucker Thanks for replying to the thread! For better or worse, I'm not able to switch to Predator unless I eat 100% the cost of the B&S engine I bought. So, fortunately we don't have to debate the pros/cons of the Predator engine.
> 
> With that said, with your experiences, what is your opinion on the better of three options: new pulleys; old pulleys, machined; or crankshaft swap?
> 
> Thanks!


New steel pulleys with a locking set screw can be bought for a reasonable price. I did not use the original pulleys from the original engines on either snow blower and "*No I did not Cobble the job either since I used high quality steel pulleys most likely of a higher quality than what was originally on the engines."* Belts and pulleys are not too hard to align just use a strait edge. I seen a guy in a Youtube video who welded the stock pulley to his lock screw pulley to extend out the reach of his PTO on the replacement engine to the same reach as the original.


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## Shryp (Jan 1, 2011)

When the rod broke did it punch a hole in the block? The old engine might be fixable if all it needs is a rod.


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## CarlB (Jan 2, 2011)

in the past i have made adapters from a piece of 3/4" black iron pipe the i cut a slot in for the key way. While not beautiful it did work fine and cost nothing to build. I also had to modify a piece of key stock as the grove in the pulley was larger then the pulley in the crankshaft but grinding the key was easy.


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## skutflut (Oct 16, 2015)

LuvSnoTilMar said:


> So, with that in mind we decided that trying to switch the crankshafts would result in finding out it was damaged from the blown engine, it would not be a direct replacement, or it was a just a bad idea to begin with . Anyhow, my main question would be on that front, is getting into that area a bad idea in terms of making that engine any more un-usable than it already is? What about voiding any warranty the new B&S motor has?
> 
> 
> I assumed returning the engine would be cost-prohibitive after the $50 I paid for shipping, but after double checking the place I purchased, Jack's Small Engines (jackssmallengines.com), returning is apparently not an option at all:
> ...


Did you ever open the damaged engine? The crank is probably the same size, except for the output shaft. They vary quite a bit depending on what the equipment manufacturer needs. The important specs are shaft length, diameter, keys, taper or not etc. 

If the connecting rod broke, due to lack of lubrication, then the crank bearing surface may be scored up and bits of aluminum embedded in it. Hard to say without looking at it, but a swap is possible if it's in good condition. Warranty on the new engine with the old crank, good luck with that.

Did you talk to a rep at Jack's to order the engine or did you just order it online. 

I wonder if there is any market for your new engine on CL, that might be a route to try, but if you are pressed for time to get the thing working, probably not a good option.

Let us know how you progress.


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## Kiss4aFrog (Nov 3, 2013)

:welcome: to the forum LuvSnoTilMar


I think before anyone can give you advice on your three options we need to know the condition of the old engines crankshaft. Do you have it and can you take the time to open it up to determine the extent of damage ??

Can you post the full model/ser number of the new engine you have ??


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## dodgetrucker (Jan 15, 2016)

LuvSnoTilMar said:


> @dodgetrucker Thanks for replying to the thread! For better or worse, I'm not able to switch to Predator unless I eat 100% the cost of the B&S engine I bought. So, fortunately we don't have to debate the pros/cons of the Predator engine.
> 
> With that said, with your experiences, what is your opinion on the better of three options: new pulleys; old pulleys, machined; or crankshaft swap?
> 
> Thanks!


Can't say without seeing what you have. I am in the midst of a crank swap on one at the moment on one. 
Though the new motor I have isn't a brànd new motor with warranty. It really depends on what you have to work with, and whàt resources are available to you. 
In my case if the original crank were shot in my case I would be having my son take the original crank to work with him and have him remachine the end of that one so it will work for me. In my case the replacement crank is too long, too fat and no keyway. But the original crank from the old engine ißnt hurt a bit.


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## Hybridchopshop (Jan 27, 2021)

GustoGuy said:


> New steel pulleys with a locking set screw can be bought for a reasonable price. I did not use the original pulleys from the original engines on either snow blower and "*No I did not Cobble the job either since I used high quality steel pulleys most likely of a higher quality than what was originally on the engines."* Belts and pulleys are not too hard to align just use a strait edge. I seen a guy in a Youtube video who welded the stock pulley to his lock screw pulley to extend out the reach of his PTO on the replacement engine to the same reach as the original.


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## Hybridchopshop (Jan 27, 2021)

Do you have pictures of the pulleys with set screws? Where do you get em with the large offsets needed? I'm in the middle of putting a 36 inch auger and 12 hp from a st1236 on a deluxe 30 drive. The pulley from the st1236 centers are not spread apart enough.


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## Hybridchopshop (Jan 27, 2021)

Hybridchopshop said:


> Do you have pictures of the pulleys with set screws? Where do you get em with the large offsets needed? I'm in the middle of putting a 36 inch auger and 12 hp from a st1236 on a deluxe 30 drive. The pulley from the st1236 centers are not spread apart enough.


Only need a single belt auger pulley with the drive pulley. This model 36 inch had only one belt.


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## Kiss4aFrog (Nov 3, 2013)

Welcome to SBF Hybridchopsho









It's really not a good idea to tack your question onto a 4 yr old thread. Starting your own new thread is a much better way to get the answers you're looking for.


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