Mixed up my rod caps. 5HP Briggs Flathead

[freakincage]

The motor I was using had burnt rings. My buddy gave me a motor that runs great, but the pto was broken off. I decided to take the crankshaft from the smoking engine and put it in the good one. While doing this I mixed up the connecting rod end caps. Does anyone see this as being an issue? Is there a way to tell what end cap went with which rod? Right now I have a 50% chance of getting the end cap on the rod it was originally one.

Thanks.

 

[CarPlayLB]

There are some identifying marks on the cap that should help you. I don't think that both sides are identical. One side should have some extra material that would match up with the same extra material on the rod. I can also check tonight when I get home

 

[freakincage]

I know about the orientation of the rod cap with the oil hole and casting mark, but thank you all the same. My problem is that I have a running engine and a parts engine. I took the crank out of the parts engine to put in my running one and now the caps that go on the connecting rod are mixed up. I don't know which cap was from the parts engine and which one was from the running engine. Does it matter if I don't use the cap that was originally on the connecting rod?

 

[Havasu Dave]

Other than checking to see if you can match up wear marks between rod and cap, there is no way to tell that I can find. I cant find specifications for wear either.

Perhaps assembling both rods and measuring with an inside micrometer for roundness, looking for side wear, taper, and the like would provide an answer.

I'd definitely get the best looking one of the two and torque it on the crankshaft and see what it feels like. At correct torque, (I "think" it's 100 inch pounds, but check first) it should feel smooth with no binding. (apply 30wt oil before torque)

If this area did not suffer catastrophic damage, it will probably be okay either way. It is a bushing after all, not a bearing like a car engine, where you smash plastigage and have to measure it. Best I can do, but there are far better engine builders here who may provide a better answer.

 

[freakincage]

Thanks for the advice. Neither engine has had any major "blow up". The parts engine is just worn out (massive blow by) and the running engine had a broken output shaft, hence the crankshaft swap.

 

[MB165]

yeah try and match wear marks, maybe try and see if the surface finish or color is different. try and assemble them and see if there is any binding.

 

[freakincage]

Thanks for the replies guys. I looked over all the pieces and the one engine had the number 13 cast on all the parts. Something I found interesting is that the parts motor was off a rototiller and had all the I/C stuff on it, but it is a cool bore block.