Harmonic Balancer Broke

[kenmaglio]

So I'm in the throws with a service shop who did a Timing belt service for me Nov. 2008 (about 24000 miles ago). However, now after having to replace my catalytic converter and exhaust, as they were clogged (something my dealer said the timing being off for an elongated period could have prematurely clogged these components), the timing of my 4Runner was off. Something I questioned as to how that could happen only 2.5 years after a timing belt. So I had the dealer do the only thing I could do, another timing belt service... and boy was I shocked.

Basically what the dealer told me was that the prior service job was a bust. They were able to break the crankshaft bolt without even a break bar, just a normal ratchet. So needless to say the 217ft/lb of torque was not applied properly. This as I'm being told by the dealer resulted in the following pictures. (more after the picture)

So my 4Runner is at the dealer, and the shop I had the original timing belt had to have an "inspector" come out and evaluate the claim against the shop I filed; that they screwed this up. This was their conclusion.....

==============================================
The inspector observed a triangular shaped section of the harmonic bamancer approximately 1/2" on each side had separated from the harmonic balancer at the keyway. The technician stated he found the broken piece of the harmonic balancer in the bottom of the timing cover when it was removed. The inspector observed the crankshaft key was broken and a small section of it was seized int eh balancer. The inner surface of the harmonic balancer was mostly rusted and the mating surface on the crankshaft showed rust in spots. The timing belt was intact. The technician stated he could not remove the crankshaft timing gear from the crankshaft using a puller which is why the shop wanted to replace the crankshaft and gear. A broken piece of the crankshaft key was protruding past the crankshaft gear. The crankshaft bolt threads were was intact and not pulled or distorted and the thread inside the crankshaft were also intact and not elongated, flattened or pulled. There were no gouges observed on the underside of the head of the bolt to indicate irregular contacts with the harmonic balancer occurred that would normally be associated with a loose crankshaft bolt.

Cause of failure/conclusion:
The harmonic balancer failed from metal fatigue and allowed the engine to jump time. The previous timing belt replacement performed over 2.5 years and 23,959 miles previously was a quality service that neither caused nor contributed to any of the current damages.
===========================

What I'm wondering is if based on the pictures (they took more - this is all I have for now as it's at the dealer), does the inspectors story hold up? I don't trust them as they are from Nationwide Inspection, Inc. and I'm sure they are not unbiased.

Sorry forgot to say what year, miles, etc. my 4Runner is:
2000 Limited 4x4 (automatic) at about 125k miles.
Timing Belt service 100k miles (new water pump)
New Tires 100k
New plugs / wires 100k
Transmission, Front and Rear Differentials Flushed (115k)
Only addition to the truck is an upgraded stereo I did myself (head unit, amp, cap, sub)

 

[A.Wilson013]

How many miles are on the truck?

 

[kenmaglio]

How many miles are on the truck?

About 125k right now. I had the timing belt done right at 100k miles, shortly after purchasing the 4Runner with 98k miles.

 

[ryankmasuda]

I feel your pain, I had the same thing happen to me a few weeks ago. My situation all started when the crankshaft bolt came loose and the harmonic balancer/crank shaft pulley came loose and it basically looked the same as your pictures. If you use PB blaster and soak the timing gear for a day, then use a puller with a combination of heat and brass head hammer you can get the timing gear off. Toyota will want to charge you $350 for the crank shaft pulley but some auto stores sell them for $199, Toyota is the only place to buy the timing gear and it runs $55 if I remember correctly.

 

[kenmaglio]

I guess my biggest question is:

Could the negligence of the shop who did the timing belt, to not tighten the crankbolt to 217ft/lb of torque contribute to excessive stress on that pulley/balancer, making it snap as extra pressure was being put on the area where they key was; where it snapped.

 

[A.Wilson013]

I guess my biggest question is:

Could the negligence of the shop who did the timing belt, to not tighten the crankbolt to 217ft/lb of torque contribute to excessive stress on that pulley/balancer, making it snap as extra pressure was being put on the area where they key was; where it snapped.

Your biggest and only question, that I have seen. =)

The way that I see it, 217ft/lbs of torque is REQUIRED, not recommended, for a reason. It's not some random number that Toyota thought they would throw on it for kicks. I would say that it could definitely have something to do with it failing. Granted, I am by no means a mechanic.

Another thought: When I think of metal fatigue, I do not think of triangular chunks coming out of a round object, whose only job is to spin on its axis...?

 

[ryankmasuda]

I would say yes, if the crank shaft bolt wasn't tightened to spec then it could have worked its way loose then allowing the harmonic balancer/crank shaft pulley to slide off the key way. With the pulley not having enough of the keyway in it's notch it broke under the pressure of the key way spinning on the crank shaft. I think the Haynes manual even says to put a very small amount of loctite on a couple threads for this reason.

 

[ryankmasuda]

This is what my crank shaft pulley looked like. I bet if I let it go longer it would have broken off in a triangular shape


<a href="http://s11.photobucket.com/albums/a155/ryankmasuda/Toyota%204Runner%20Build/?action=view&current=IMAG0164.jpg" target="_blank"><img src="http://i11.photobucket.com/albums/a155/ryankmasuda/Toyota%204Runner%20Build/IMAG0164.jpg" border="0" alt="Photobucket"></a></a>

 

[kenmaglio]

Well according to the dealer the bolt was still on, but not very tight. 40ft/lb torque.

 

[toyotaoutlaw]

Well according to the dealer the bolt was still on, but not very tight. 40ft/lb torque.

this is how i see it.

if they did not tighten that bolt properly you should have noticed it probably fairly quickly. now im not saying they didn't tightened that bolt down within specs. but that pulley is spinning constantly and really fast at some points. so if that bolt was lose you would have known that pretty quickly. not 24,000 miles later. as far as it only being tightened to 40 foot pounds. the bolt was tight weather its 40 foot pounds or 217 its holding the balancer on and should not make it do what it did. i would have to say that the balancer failed.
being that it was around 40 foot pounds it should still hold it in place being in the right spot with the key way. its not a lot for that bolt but it shouldn't allow it to slide out away from the key way. for it to slide out of the key way it needs to slide out an eight of an inch maybe less maybe more. i dont know exactly but it would have to be a little bit. so if the bolt is tight it should not allow it to slide out that much. hopefully you get what i mean by that. i could be wrong im not sure but thats my oppinion.

now i could see it doing what it did if the bolt was finger tight. tightening a bolt at 217 ft lbs versus 40 ft lbs wont be an 8th of an inch difference. i think the balancer failed. you cant tell how many ft lbs a bolt is on by loosening it it could be more than 40 could be less you will never know just buy someone taking it off. most of the time when i take a crank pulley bolt off i use an impact gun and most likely they did also taking it off so there is no way to tell how many ft lbs that bolt actually was.

hey ryan did that bolt come completely lose on your truck like finger tight??

 

[kball]

So I'm in the throws with a service shop who did a Timing belt service for me Nov. 2008 (about 24000 miles ago). However, now after having to replace my catalytic converter and exhaust, as they were clogged (something my dealer said the timing being off for an elongated period could have prematurely clogged these components), the timing of my 4Runner was off. Something I questioned as to how that could happen only 2.5 years after a timing belt. So I had the dealer do the only thing I could do, another timing belt service... and boy was I shocked.

I could see if the bolt was not torqued near enough the constant vibrations and wiggling of the pulley over 25K miles could make a crack and eventually break off. But, the torque on that bolt has nothing to do with your timing being off.

If your timing was off, then it was off the whole time. Ever since you got the job done. I think you would have noticed the engine not running right if that was the case. The crank pulley does not have anything to do with the tension on the timing belt. For the pulley to affect it, it would have to fall off and let the belt come off that timing gear complelety and then your engine would quit running.

So who is telling you your cat is clogged and why?

 

[moneypit]

Improper keyway insertation

This is from a Miata web site. Numberous problems with the 1.6 engine destroying the crank keyway and balancer after removal and reinstalling after a timing belt change. Might be applicable to your situation.

 

[TheDurk]

To me it looks like a fail due to insufficient crank bolt torque. The balancer is not driven by the key; the key barely extends into the balancer (less than 1/4"). The balancer is secured by the massive 217 ft-lb. bolt torque pressing it against the timing gear. When the torque is not applied, all the resistive force of the driven belts is applied to that itty-bitty nub of the key as the crank forces it against the balancer keyway. The key deforms and effectively becomes a wedge expanding the inside of the balancer until it fails right at the end of the keyway.

Thus there is no deformation of the threads on bolt or crank because the bolt remains engaged--it just is not applying pressure to the balancer and timing gear. IMHO, the inspection report is BS.

The question not answered is "Was the timing in fact out?" I suspect not, as the balancer does not affect the valve timing, only the intact timing gear does (as kball points out). The engine probably could have kept operating until the balancer failed more spectacularly as the bolt worked itself out further. Then you WOULD have had thread and bolt damage. It only didn't happen because the balancer was pulled before it COULD happen. I also agree with kball that the cause of cat clog was elsewhere.

 

[kenmaglio]

So I talked to the technician myself this morning (at the dealership). He said the following:

"It 100% was a failure do to metal fatigue, however there is absolutely no way it was do to rust, as the rust is only surface level. The reason the metal was fatigued, is because the crankshaft bolt was loose (only about 30-50ft/lb's) and because of that the harmonic balancer had "play". This put undo stress on the keyway as the harmonic balancer was trying to rotate at a different speed than the crank. The fact that the keyway was completely worn off, as in it looked polished down, was a result of the crankbolt not being tighted to spec. Maybe it started near 80-100ft/lb of torque, however after time, it became looser, giving the harmonic balancer wiggle room to move on the crank. The surface rust seen, is actually a cause of the crankbolt not being tightened to spec, it allowed moisture to get inside, and is actually a cause of the bad service. 100% this issue is the result of the crankbolt not being tightened, I've worked on Toyota's since 1994 and I've seen this happen to other 4Runners with bad Timing Belt service, in exactly the same situation as yours. Toyota even for a while, was very explicit to dealerships and service departments to ensure that the crankbolt was tightened to the 217ft/lb of torque as they were seeing an increase of the issue. I don't agree at all with the conclusion that rust caused this as the metal from the HB was not rust fatigued, it was only surface rust (where the part broke was clean metal for one). "

 

[yc4runner]

this same thing just happened to me, and my bolt actually spun itself out of the crank and it and the HB were laying in my skidplate, but not before destroying the HB inside.

All it takes for these HB's to become loose is just a thousand of an inch play and that will eventually work itsself into 1/8" play and so on all it takes is a little movement and over 25k miles it can turn into a bad situation.

So I agree the previous shop did not follow the 217 ft/lb torque specs, and when I talked to my local toyota mechaninc he told me that they actually recommended 217ft/lb's and red loctite to ensure proper fitment.