350 tpi built 3 years ago...and 5k miles on it....what would cause the balancer to break into 3 pieces...bolt is MIA

 

#1 question is who belt the motor and how or what did they use to install the harmonic balancer.

 

I built it..and I have an installer tool...no hammers allowed...balancer was new when it was installed

 

Next question would be if it was a GM balancer or other. Do the places were it broke look like old cracks or new ones. Parts of the cracks might be old with other parts being new.

 

My guess would be that the retaining bolt wasn't tight enough , worked loose and fell out , allowing the balancer to "walk" far enough off of the crankshaft so as to begin wobbling and break the sleeve in the way it is broken .

Musta made one hell of a racket when it finally let go , yes ?

 

Ed..correct...the first crack started on the key way, old oil, dirt stain....than 180 degrees another crack till about 1/4 inch to the base...the base is completely clean.....

My guess is since the crack started on the key way...just with centrifugal force made the other side crack enough until it couldn't hold anymore.

not a GM part...>Doorman

 

init4fun....didn't sound good at all... luckily I was only 1/2 mile from the house...no bottom damage though...pulley is fine, belt is fine...and the threads on the crank are good...

So I am considering this a flesh wound to what it could have been

 

Yes sir you were lucky on this one, good luck on the next balancer. Maybe a G.M.?

 

That is REALLY great luck that the end of the crank wasn't damaged !!

I'm glad to hear that the fix will be easy . Gotta admit , in all the years I've worked on cars , this is the first I've ever seen of such a balancer failure . I've seen the rubber separate and let the outer portion of the balancer go free several times , , , and I've seen one or two destroyed by the "hammer instalation method" .... but this is a new one to me ... I'm still curious about the MIA bolt , , and wonder how it worked loose .

I know it aint easy to get the right amount of torque on the bolt since the engine wants to turn as the tightening torque is applied .

 

Not the 1st dorman I've seen come apart. check the width of the keyway slot. It shouldn't be bigger than the key. Also, as has been said the bolt could have not been torqued down correctly or been defective and come loose.

 

Looks like a defective balancer with the old cracking leading to new cracks.

 

I agree...thinking it was a defective part...but it's all back together again and running good...I did put loc-tight on the bolt this time...just because.

I did get very lucky on the install as well....was using the tool and heard a crack and ....aw--F***k....was real careful about removing the tool, found it cracked in the middle of the threads where it goes in the crank,,,,but it all came out in one piece...

.JUNK HARBOR FREIGHT CRAP

 

Wow you must have the big mechanic in the sky on your side this weekend.