Project #1-3 Form Hooda-Snowblower modification

[hooda]

So, In case you haven't checked out my post on my latest Craigslist adventure, I recommend reading it. But anyway I ended up with a 7 hp Ariens Snowblower. I knew it needed engine work (7hp tecumseh sno-king), because when I pulled the rope, there was no compression, and I mean NO compression. I got it home, pulled the spark plug, stuck a screwdriver down the hole, and pulled the rope. Nothing. The pic below should explain that.



Needless to say, the hunt for a replacement engine was on. The sweet part is that when the rod exploded, it put a couple of holes in the engine case, PERFECT practice material for my new EXT when it arrives. In fact, If the rod proves to be the $30.00 rod, and not the $130.00 rod, I may repair the case, put in a new rod and rings, and get the engine running.

I made a trip to the small engine shop that I buy most of my parts from looking for a 7HP Tecumseh to bolt onto my chassis. John(the owner) tells me "yup, I got a couple back here, goin' rate's $125.00 for a tested, good engine." He pulls 2 off the shelf for me to look over. Darn, just a little more than I was hoping to spend.
While I'm browsing through the dozen or so other used engines he has on the shelf, customers are coming in and out, so, John's attention isn't exactly focused on me. I spy a 8HP tecumseh back in the corner. It's painted white, and I can even see part of the "Ariens" logo on the side.
I walk over and tap John on the shoulder. "What about this one?" He says "That hasn't been tested yet", and resumes his conversation with the other customer. I give the rope a tug. Yup, got compression. I pull the $50.00 bill out that I have in my front pocket and tap him on the shoulder again. He stops his conversation mid-sentence and looks at me (I get the vibe that I'm starting to annoy him). I hold out the fifty and say "Take fifty for this one, as-is?" He snatches the bill from my hand and says "Yeah, why not" So, I load it up, and bring it home. Here it is.



I immediately go to work making sure that it's gonna fit. I mean, How much diff can there be between a 7hp and a 8hp tecumseh, both out of Ariens snowblowers? Turns out there's a good amount, but not so much as to make the swap impractical.

Here's the original mounting holes on the 7 horse



And here's the 8 Horse



So, you can see immediately that there's a thickness difference. The other concern is actual location. Luckily, the height of the output end of the crankshaft is the same, BUT, the distance from the mounts to the pulley is different, so, we got issues. More on that later

[hooda]

The first issue with the swap is the thickness of the motormount bolt-holes. Pictured below is the chassis in it's original state. Notice the 4 studs sticking out of the base where the motor sits? These are not only too short, but welded in from the bottom.



I forgot to snap pics before welding, so it suffices to describe the mounting studs as looking from below like carriage bolts, minus the square part at the base. I did a few trial fits of the new engine vs the old, and came up with 2 issues:length, and location. Length is obvious. The thicker base of the 8 horse is going to require 3/8-1/2" more stud protruding thru the base in order to get a nut and washer on it. Also, as it turns out, the output sheave (drive pulley) hangs out a little more than an inch further than that of the original powerplant. Now, take a closer look at the photo above. There are 4 holes neatly drilled at the factory in the area of the mounting studs. As it tuns out, when I align the 8horse motor with these holes, the drive sheave aligns perfectly, not just one groove, but both the auger drive, and the wheel drive. My educated guess is that this part of the chasis was used for models carrying both engine options, and the correct studs were installed in the correct holes during manufacture, back in 1977. So, the solution to the problem is to remove the short ones, and weld studs of the proper length into the correct holes...Like this



and this



giving us something which, on the other side, looks like this



I used grade 8 bolts, each backed with an SAE washer, and brazed them into position. Why brazing? Because that is all that I had readily available, and in this particular situation, clearance wise, it was easy to get way in there and get enough brass fused in to assure that the studs will be there for the duration. More later

[geezer]

Hooda,,,I had a close look at that connecting rod in the first picture,,,in my humble opinion I think it's beyond repair....LOL...

[zoama]

Hooda,,,I had a close look at that connecting rod in the first picture,,,in my humble opinion I think it's beyond repair....LOL...

He was gonna replace the connecting rod and repair the case.

[hooda]

Hooda,,,I had a close look at that connecting rod in the first picture,,,in my humble opinion I think it's beyond repair....LOL...

Are you SURE that my new EXT doesn't have a "conrod repair" setting that I can push to weld'er up?

[hooda]

So, after the trip down memory lane, (brazing is a skill taught to me by my grandpa starting around age 10), I figured that one good whack with a 3lb ball peen (yes, the flat end) should knock out the old studs, one by one. Right? WRONG!! First firm, carefully placed blow just mushroomed the end good'n proper, and the "feel" was such that any more horsepower behind the striking instrument was going to do nothing but dent the perfectly flat surface that my new(er), high(er) performance engine was destined for. Whatever welding technique the factory used to weld those studs in, the remains will be there forever, so, out came the cutoff wheel, followed by a flap wheel. And wouldn't you know it? I looked up in the "paint" section of my shelving area and found a can of "mopar engine orange". A few coats later, and I'm ready for install.



The paint match was such that, once reassembled, it won't be noticed, whereas had I skipped this step, it would have been pretty glaring where the welds burnt off the paint, then subsequently rusted. I have the snowblower reassembled, and operational. Even though we haven't had SNOW, I can report that overall, I get the feeling that the extra 1HP will make a difference. The new motor had it's own drive sheave installed, and I originally thought that both pulley grooves were the same diameter, at assembly this proved to not be the case. The auger drive groove is the same, but the wheel drive groove is bigger, bigger enough where the belt is "pre-tensioned" that is-with the engine bolted down, the tension on the drive belt is PERFECT, leaving the tensioner idler riding along as just an ornament. This had the benefit of speeding up the travel speed a good amount, where in high gear forward, you're at a FAST walk, yet LOW gear is still slow enough for those 2-3 foot drifts that we're BOUND to get sometime before spring. The biggest benefit is that reverse is considerably faster, but then just about every snowblower I've ever encountered has been way too slow, usually to the point of annoyance, in reverse, this is much better. I will post pics of the finished machine as soon as I take some. It looks like a factory install.