Repairing aluminum crankcase

Aug 21, 2015 3 Replies

My little tractor has had a mishap , it put a con rod out the side of the motor . Motor in question is a Kohler KT17 opposed twin . Since these are rather hard - and expensive - to replace , I would like to repair the hole by welding a patch over it . This unit is over 30 years old and oil soaked ,,, I've had reasonable success a couple of times , but nothing I'd write home about , and I'm pretty sure the reason is I haven't been getting all the oil out of the pores . How long and at what temp do I need to bake this thing to be reasonable sure I've got most of the oil out ? It will be degreased with solvent first followed by a thorough scrubbing with detergent before baking . The part looks to be die cast , which I believe means it has a fair percentage of silicon in the alloy , which rod is recommended ? I have on hand 4043 and



5356 , but can get other if needed . Or do I just need to bite the bullet and drop 130 bucks on a replacement ? There is one on fleabay right now ... it's not that I don't have the money , I just hate to replace something that I can repair .

Given the uncertainty of getting all the oil out of the casting, can you bore out a clean hole where the rod went through, and put a plug in it?

It's been rendered moot , I bought a crankcase half today . I still plan to attempt the repair , for practice if nothing else .

Late-breaking update , the case half I bought had been "cleaned up" with a power disc sander . Precision macined sealing surfaces were damaged ... so I cleaned up the one I had and welded a plug of 1/8" 6061 T6 in . Also got a refunfd in full ... The motor is back together now , and has been thru several heat/cool cycles with no apparent problems . -- Snag posting fom the shop

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