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71_Bronco

Piston Wiggle & Bearing Plate

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71_Bronco

Got time to work on my Commando 8 today (doesn't happen often). I'm tearing apart and cleaning the replacement engine (K181 off a leaf blower with recoil start).

 

Got pretty much all the old stuff off (tins, flywheel, carb, head). When looking at the piston, I saw the top was pretty black, as well as the valves.

 

Cleaned it all up nicely, but noticed the piston wiggled a little when I was cleaning it. There is a noticeable ammount of wiggle perpendicular to the crank center-line.

 

It sounds like its still sealing okay though, as on the down-stroke, you can hear the hiss of the crank air escaping the breather as it should. I can't hear anything coming up through the piston.

 

The block was covered in an oily mess, so I would think it is burning oil, or something isn't right. The block did have oil, jet black, but no water thankfully.

 

If I leave it as-is, will this still run okay? Will it burn oil? Not have full power?

 

The engine is only going to be used to power it for mowing (if i decide to use it instead of the Kubota) and plowing my 100 foot flat paved driveway.

 

Also, I need help removing the bearing plate (last thing to remove). I'm converting this to a starter-generator, which I'm pulling the old parts off the blown motor in the Commando 8. Once I have the bearing plate off, I can start pulling parts off the old blown motor and building up this one for the swap.

 

I know the correct thing to do is send it to a shop and have it bored with a new piston, as well as possibly having the crank ground and new rod. Howver, I dont have the money to invest in this right now.

 

I do have another K181 on the shelf I could use, that one is set up with a standard starter (not a starter-generator). I havent pulled the head off that one yet to check it out.

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Pullstart

“Frank” has a sloppy piston and should be rebuilt.  He cruises around just fine.  That’s a K241.  It smokes pretty bad, but runs good.  I had a smoking K181 that stalled trying to just spin a 36” deck.  Same thing.  Ran fine, smoked a ton, but not enough power to work.

 

I might try to find a set of chrome piston rings for Frank as @wallfish mentioned a week or two ago, how someone put chrome rings in a rusted cylinder bore and had it running with no smoke by the end of the Big Show weekend.

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Pullstart

Here is a video showing the slop in Frank.

 

 

This shows how much it smoked, and still does.  I run Lucas oil additive in there and it still runs, still smokes.

 

 

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wallfish

Never tried the chrome rings myself but I was certainly impressed seeing how it worked in real life conditions, not on a video.

They're not expensive so if it doesn't necessarily work out for you or that engine, you can still rebuild it. But if it does, Woo Hoo!

 

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squonk

If that motor is as messy as you say it is, it's time for a rebore and complete overhaul

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pfrederi

You need a puller to get the end plate off.  See page 10.5

 

I use an old timing gear puller or something like the set which you can get on loan from some auto parts stores.  You may need some long bolts as the crankshaft stick put along way on some engines...

 

 

IMG_0138.JPG

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oliver2-44

Pull a piston ring from the original engine and follow this procedure posted by 953 nut. Post the results for the experts to review. 

let us know if you want this to be a weekly worker, or just a neighborhood & show cruiser.

 

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71_Bronco
4 hours ago, oliver2-44 said:

Pull a piston ring from the original engine and follow this procedure posted by 953 nut. Post the results for the experts to review. 

let us know if you want this to be a weekly worker, or just a neighborhood & show cruiser.

 

 

Pull a ring from the original motor (the blown one) or the replacement with the piston wiggle?

 

Mowing isn't nessecary, as I have my bigger Kubota for that. However, I dont have a plow for my Kubota, so I'd like to at least be able to plow with the Commando 8.

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oliver2-44

@71_Bronco if you don't have the piston out of the replacement motor, it should be fine to pull one out of the blown motor.  

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71_Bronco

Okay, got the piston out of the replacement K181 (the one with the piston wiggle). I will measure the ring gap as the link said, but ran out of time. I did take a few pics of the cylinder and rod.

 

One thing that makes me a little nervous is the little bit of what looks like galling inside the rod (where it wraps around the crank). Hope this isn't an issue.

 

 

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richmondred01

I think you answered your our question.

Bored, crank ground, and valve job. 
no sense in putting it back together knowing it won’t last. 

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