Motor let loose this AM!

[Billy Bobbed]

When it sheared the crank key it caused the harmonic balancer to move it knocked it out of balance.If im not mistaken
these motors are like a 454 Chevy externally balanced.When the balancer moved it moved the heavy part of the balancer
in a bad spot,it broke the crank.Vibration killed the crank.See at the bottom of the balancer it is heavier than the rest of the balancer.

 

[txmytx_catahoula]

Billy, copy that! That's what I kind of figured, but I thought I'd get some "informed" opinions. I hope to have pics of the damaged crank, etc., in a couple of days. As soon as I can get the old engine on the stand and get it flipped over, I'll post them.

Thanks again for the info/feedback. It's great to have a place to go to!!!!!

 

[motormayhem]

I just changed mine out. The rubber ring was cracking and squishing out between the two masses. What causes the key to sheer? I would hate to have that happen to me.

 

[Dave Kay]

Because the cost of a failure is 4 times the cost of new balancer I think the lesson here is; if in doubt--- replace it!

 

[chuck0070]

Is the change out very difficult?

 

[txmytx_catahoula]

With a harmonic balancer puller, the thing comes off easy. The removing of the stuff in the way and getting it back on correctly...........more of a pain. It was a WHOLE lot easier with mine, as the motor was out. I will ditto Dave, "when in doubt, replace it".

Motor, I've not a clue what caused it. I purchased the vehicle from a group who got it from the military, so not much history. Someone in the past may have "ether" it or they might not have torqued to the recommended.

 

[Billy Bobbed]

I just changed mine out. The rubber ring was cracking and squishing out between the two masses. What causes the key to sheer? I would hate to have that happen to me.

More than likely the balancer bolt is not tight or not tight enough.The balancer wobles back and forth from on and off the throttle till it wears or sheers the key.

 

[ChiefMinion]

Balancer change...

I just did mine and posted some notes:

http://www.steelsoldiers.com/cucv/66270-harmonic-balancer-2.html#post852543

The whole thread is pretty good. Actually, there are a number of other good threads on the topic.

The torque for the bolt is 200 ft-lb as per the TM.

On a scale of 1 to 10, I would say 3 or so if you have the tools and have done your research.

You can get a pretty good view of the rubber ring in your damper from under the vehicle looking at the back of the damper. As you can see from the photo, mine was in pretty bad shape due to the ravages of time. Also pictured is the Craftsman puller, bolt used to press on the new balancer on, and setup for holding the balancer while torquing.

 

[txmytx_catahoula]

Evening before last tried to bleed the air out of the fuel system, but couldn't get any fuel out of the fuel filter bleed valve. Last evening I broke out the "redneck credit card" (I know you're not supposed to do it, I'm hard headed I've been told) and syphoned from the tank to the lift pump. After that it was smooth sailing from the filter to the injector pump to the injectors. Then.....the blazer cranked up!!!! Little bit of black smoke that I'm attributing to engine's fuel system sitting around for a time, but all other system operated normally. If the smoke continues, at least I know where there is a spare injector pump and set of injectors!

 

[jets1959]

Thank you very much for this thread!!!!!!!!!!!! Without it I would not have known about this issue. I just finished changing mine and believe it was just a matter of time before a major failure. Thanks again!!!!!!!!!!!!

 

[rickf]

That balancer is not bad, they all look like that after a few years. When the rubber swells and push out of the recess that is when it is time. Doing it ahead of time as you did is insurance though so no harm done.

Rick

 

[islandguydon]

Not sure what happened this morning, haven't started to tear into it yet, but the 6.2 let loose on the drive to work this AM. Don't remember it giving any hint before it happened and really, I'm just guessing, but total loss of power. Sounded like I blew two tires, pulled over as the motor died. No signs of fluid leaks, no smoke, nothing dragging or where it wasn't supposed to be. Motor cranked but wouldn't start. My guess is rod cap or timming chain. We'll see.

I have a question, did you just leave the gas station when this happened to your truck..? if so the same scenario just happened to me. I had flex fuel added to my 6.2 and my friend who did the mishap explained to me the same thing. He said there was a bang, then total loss of power. I was lucky there was no damage. Just a thought.

 

[rickf]

So what you are saying is you put 85% alcohol in your fuel? Make SURE you flush all of that out, up to and INCLUDING the injectors. Pull the glow plugs and after bleeding good fuel all the way to the pump crank it in 10 second spurts until you have clean fuel coming out of the return line. Then put the glow plugs back in. The idea of removing the plugs it to let the alcohol that is in the injector inject into the cylinder without firing which would cause damage. No compression, no fire.

Rick

I have a question, did you just leave the gas station when this happened to your truck..? if so the same scenario just happened to me. I had flex fuel added to my 6.2 and my friend who did the mishap explained to me the same thing. He said there was a bang, then total loss of power. I was lucky there was no damage. Just a thought.

 

[txmytx_catahoula]

Naw, I was halfway through a tanks cycle. I've been real careful as I've seen several people pick up the wrong "green handle" and pump in Gas. Thanks though for sending out your two cents worth!!

I have a question, did you just leave the gas station when this happened to your truck..? if so the same scenario just happened to me. I had flex fuel added to my 6.2 and my friend who did the mishap explained to me the same thing. He said there was a bang, then total loss of power. I was lucky there was no damage. Just a thought.

 

[txmytx_catahoula]

I was finally able to get the old motor on the stand and open it up for some pics. The first two are shots of the crank, where it broke behind the #1 & 2. The third pic is what's left of the balancer key way.

Blaze ( I know it's not original, my daughter named it) stretched it's legs and new ticker on the 4th of July. It didn't have the acceleration of the last motor and there was a noticable haze from the left pipe. After searching threads on this forum, I found the IP about 1/4" retarded. Placed it back on the scribed mark and "presto", there was the spunk back. I was actually able to pick up speed going over the intracoastal bridge south of town.

Well I guess this is all I have for this thread. Thanks to all of y'all who helped out!!!!!