broken connecting rod

[caveman55]

I rebuilt my sons engine 3.0l 2001 ford ranger. Now after 6 months it snapped a connecting rod. Nothing was siezed up. the piston moved freely in the cylinder and the other end on the crank also seemed ok. The rod has a nice clean break about an inch below the piston. Any possible reason for this other than a defective rod. Any ideas appreciated before I put it back together again.

Thanks

 

[chance942]

How many miles did the engine have on it when you rebuilt it? What type of driving habits might the younster have? Did you break it in after rebuild,or him if he knew how?

How "clean" of a break is it? It is possible that it just snapped. I read on here where a guy's harmonic balancer just snapped off,along with the part of the crankshaft where the bolt was in.

How bad did it mess the bore up? Man that really sucks!!

 

[caveman55]

It had about 200,000 on it. The engine was punched out 50 over, crank turned and everything else new. I told him how to break it in and to take it easy. It's been about 6000 plus miles since the rebuild. The part left on the piston has a clean break, no twisting or stretching apparent however it is pretty tough to rock back and forth on the wrist pin. The end left connected to the crank looks a bit mangled but that slapped around and put a couple of real nice hole in the pan. The cylinder bore looks good no damage, the piston did move freely when I took it out.

 

[Runnin'OnEmpty]

I rebuilt my sons engine 3.0l 2001 ford ranger. Now after 6 months it snapped a connecting rod. Nothing was siezed up. the piston moved freely in the cylinder and the other end on the crank also seemed ok. The rod has a nice clean break about an inch below the piston. Any possible reason for this other than a defective rod. Any ideas appreciated before I put it back together again.

Thanks

That's an unusual break for a street-driven engine. Rods
sometimes come loose from their caps and are thrown, but
this type of break is probably from over-reving. Or running
at extreme RPMs for a long time.

The 3.0 is an engine that likes to rev easily, so maybe that's
what happened......???