Small Engine People, Can I still use this block?

Andrew03Mach

Andrew03Mach

Forum Member
I have an older 12hp flathead briggs and the connecting rod broke. I removed the remains of the old rod and piston from the block and left the crankshaft in. The cylinder walls don't appear to be damanged, maybe a really small scuff in one area. However, inside of the the crankcase just before entering the cylinder wall there appears to be an area with some bent and missing metal. I am trying to figure out if I can just buy a new piston assembly and go back to running the engine or if this damage is a larger issue than it looks...

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I am concerned on the area to the left of the clearance notch. The edge is bent back away from the cylinder a bit and if you keep following the cylinder around to the left there is some more damage to the otherside.
 
Does the piece missing deal with compression? Will a ring "pop" lower than the area above it? If that area deals with any sort of rings (oil or comp) I'd write it off as a junked block.
 
I would run it. I agree with Beigg. The skirt might go the low in the bore, but that's all. Besides, it's not a race engine, if you have to, clean it up with a bur or stone and it should be fine.
 
Thanks guys. I think I am going to pick up a used connecting rod of ebay and give it a shot. I don't want to sink a lot of money into this motor as is anyway.
 
It shouldn't matter... That lip was probably so the assembly people could just drop the sleeve in.
 
I was looking at the pics again this morning. The rod might have chipped that material away. It's at the bottom of the cylinder sleeve and looks to be consistent with the thickness I see on the opposite side of the bore. I still say new Rod, piston and clean it out. There isn't any coolant concerns, so it should be fine.
 
The bottom lip is likely there from overmolding the iron bore liner to the aluminum block. Make sure you don't have any obstruction in the path of the piston, and run it.
 
my89notchback said:
Sure. Just check the skirts for metal debris. Depending on how much time is on it, I'd use the same ring set too.
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26 years and a lot of hours. The engine is out of an 89 Murray tractor.

I am trying to keep cost down on repairs given the age and some other issues with the tractor.
 
Might as well straight stone hone it to make sure the cylinder wall is straight. Also, mic the crank pin to make sure it is in spec and not out of round. You can buy an undersize rod and grind the crank .010 if need be.
 
enginecraft said:
Might as well straight stone hone it to make sure the cylinder wall is straight. Also, mic the crank pin to make sure it is in spec and not out of round. You can buy an undersize rod and grind the crank .010 if need be.
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Engine craft is my engine guy. He's the best.
 
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