Need advice - repair or replace damaged B&S crankcase and crankshaft

[Martin Collins]

Howdy All!

I just picked up a Troy-Bilt 2011 Riding Mower with a blown B&S 17.5HP OHV Engine (31C707-1346-B2). From what I can ascertain from the internal carnage within the crankcase, it would appear that it was connecting rod failure. From the pictures attached to my post, you can see quite clearly the sheer force that was directed towards the side wall of the crankcase, there is a clear crack on the inside and outside of the case. Furthermore, if you look closely at the picture of where the camshaft slots into the bottom of the case, you can see a hairline crack which starts at the top and runs down inside the camshaft carriage. There also appears to be some damage/pitting to the surface of the crankshaft journal (see pics) and damage/pitting to the external face of the crankshaft approximately where the oil seal sits. Indeed before I tore down the engine, I filled the crankcase with oil to check for leaks and could see quite clearly that oil was leaking slowly down the crankshaft from the PTO side from the oil seal.

So the big question on my mind is whether I can repair the damage (I am thinking JB Weld) or whether I should just junk and replace the crankcase and crankshaft.

What does everyone think? What would you do?

Thanks in advance!

 

[Scrubcadet10]

crankshaft journals might can be saved, a soak with muratic acid will take off aluminum transfer from the connecting rod, then you can see the condition of the rod journal better.
That crack is bad enough in the block I wouldn't trust JBweld, maybe an actual WELDER or someone who can solder and fill the cracks and regain some structural integrity, yes. but if it were mine i would Muriatic acid the crankshaft journal, and replace the Crankcase.

 

[Scrubcadet10]

As you can see, this was done OUTSIDE in a WELL ventilated area, with gloves. this stuff is NO JOKE.

 

[sgkent]

personally unless you have a rare $500,000 riding mower where saving the engine is one of a kind, I'd be looking for a used or new engine. There are riding mower salvage yards where you might be able to get a functional long block or engine for your mower, where someone wore out the mower or transmission etc., had storm damage etc..