Crack in crankcase cover, ideas for sealing?

[Lawnman23]

I discovered this crack on the bottom of the aluminum crankcase cover of a Powermore 140cc vertical shaft engine on a cheapo MTD walk behind mower.

I originally replaced the crank seal as I thought that's where the leak was coming from, didn't discover the crack until I pulled the engine and power washed it. It leaks fairly slowly and I was using the mower since last year, runs great other than this issue. For context, I picked the mower up off the side of the road for free. Guessing the original owner didn't want to deal with the new leak after hitting something.

I wouldn't mind replacing the cover altogether, unfortunately it is OOS/back-ordered from most places and its ~$70 Supposed "good" used ones on Ebay are $25 or so.

So my question is, does anybody have thoughts on how to seal this externally? Permatex Red or Ultra Black? Other products? Not sure with the heat/vibration/aluminum what would stick enough and hold up.

I pulled this engine off the mower and replaced it with another, this one is going to be used on a different project. Just looking to reduce the leaking as much as possible for as cheap as possible before I mount it on its new home.

Thanks for any ideas!

 

[ctechbob]

Thing is, to keep it from getting worse, you're going to have to drill the end of it, putting an even bigger hole in the crankcase.

 

[SupremePossum]

I would drill a hole at the end and JB Weld it

 

[SC Maintenance]

I would drill a hole at the end and JB Weld it

^^ this is what I would do also.

 

[ripcord]

Degrease as well as possible, first. Or, instead of the JB Weld, this might be a good excuse to get that TIG welder you always wanted.

 

[Cujet]

For a more structural repair, make a steel patch plate that screws on, using 5 or 7 small machine screws that penetrate through. Stop drill the crack and use that as a machine screw hole also. Seal with structural epoxy of your choice such as JB classic.

 

[92saturnsl2]

I think anything other than a proper repair (TIG welding)

Degrease as well as possible, first. Or, instead of the JB Weld, this might be a good excuse to get that TIG welder you always wanted.

That'd be a tedious repair for a TIG welder, and you'd need a decent machine with AC capability. Cast is slightly porous, so something like a front cover, it's nearly impossible to remove all the oil. Even then, the heat affected zone that welding would create has a tendency to propagate more cracks in cast aluminum.

All the above (JB welding, drilling, welding, etc.) sounds like a lot more work than the $25 Ebay replacement.

 

[c502cid]

And once you've drilled and the JB weld dries, put a layer or two of this on it. It works miracles.

 

[Lawnman23]

Good ideas. Keeping in mind that the engine will not be used for serious mowing duties anymore so preventing the crack from increasing is really not a concern, what method/material would have the best shot at just sealing the crack?

For context, this will be going on one of my old Lawn-Boy decks that has been doing nothing for a few years since the original F engine seized the crank. I discovered that the three Powermore mounting holes line up perfect with the bolt holes on the deck after spinning the engine 180 degrees.

Yes, its stupidly ridiculous and wrong. Yes, there really isn't a practical reason for this. No, I'm not on any mind-altering substances. I have too much time on my hands and this idea popped into my head one day so I'm making it happen.

The one, the only, the Franken-Boy:

 

[spasm3]

Drill the end of the crack, small bit. How about an aluminum brazing rod, the ones you can use with a propane torch ?

If not that, spray the crack with it upright, with brake cleaner to get the oil out of the crack, and JB weld epoxy.

 

[Gyro Gearloose]

Any time a problem can be 100% solved for a $25 part and a gasket, then that's the fix. If on the other hand this is a research project, then let us know how it comes out.

 

[Jetronic]

I would weld it (not JB weld). but $25 for a new part doesn't sound bad. I'd still weld it though.

 

[zzyzzx]

I'd replace the part.

 

[wag123]

Like others have said, replace the part, but, only if the crankshaft is not bent.

 

[tig1]

I would drill a hole at the end and JB Weld it

As a welder I have fought JB Weld for 40+ years. I've repaired cracks in several OPE engines with excellent success.

 

[Lawnman23]

As a welder I have fought JB Weld for 40+ years. I've repaired cracks in several OPE engines with excellent success.

I finally ordered a tube, will hopefully be here this week

 

[SupremePossum]

Buying a new cover would be easy, but we wanna see results!

 

[Owen Lucas]

I'd replace the part.

I'd just let it leak.

 

[Lawnman23]

I'd just let it leak.

After replacing the lower crank seal initially and that not solving the issue, I eventually went the 20w-50 route and sent it.

Occasionally some drippage on the floor after sitting, not always, topped off as needed. When I finally pulled the engine, it looked like a love letter to the Exxon Valdez on the underside of the deck and bottom of the engine case.

When I first got the mower home, I cleaned out the carb, main jet was plugged solid. After that, fired up and ran great. I swapped in a NGK IX plug, new "extreme" mulch blade and a larger pleated air filter. Yes, I tend to go overkill on OPE.

I've actually enjoyed using it as the whole mower is so light its easy to get around trees and corners and whatnot. My commercial Lawn-Boy is a beast but a heavy girl, even with the self propel. Other than it being a puny 140cc engine, its been fine for side discharge and mulching when appropriate. As long as I went slow enough to not overwhelm it, it cut great and just chooches along.

Anywho, sorry to ramble. As I mentioned above, this engine is going on a Lawn-Boy just because I can and once all said and done, will be used to mow when I feel like making the neighbors question my sanity. I repowered the MTD mower with a Bilt Hard engine which has actually been pretty solid, considering the price. Same engine as a Predator. Amazon gets a blue cover, HF gets a black one and higher price apparently.

 

[Lawnman23]

Buying a new cover would be easy, but we wanna see results!

Will post pics and update once I get the J-B weld and get it all mounted