Caught Cracked Cam gear in time (whew)

mrvermin

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Dec 3, 2007
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2001 Jetta TDI
I posted this in the Ontario section, but I am posting it here to get more opinions on it...

WOW, after picking my car up at the shop today I find out just how lucky I am that I decided to take it in today...

While driving these past few weeks I started to notice that the Valve noise was getting progressively louder. I did the Ghetto Stethoscope thing and it sounded like ticking from the lifters. So I made an appointment with my Mechanic to bring the car in today and borrow one so I could work while he worked on my car. When I got back to pick up my car I got the news...

Now, a bit of history...

I had my stock CAM replaced with a Colt Stage 2 Cam with new lifters a while ago, so getting the lifter noise now is a bit strange. Anywho...

Back to the present...

I found out that a few of my lifters were failing, so all were changed out, and in doing so a few things were found. One is that the Cam Journals (sp?) were scored :( (I'll have picts of that later). It was explained that it was not a critical issue and that it will not cause engine failure, but it pisses me off that it happened :mad:

Second I found out that my Cam Gear on the Timing Belt was cracked in multiple places and had almost failed.... :mad: picts below (sorry, cell phone camera...)

http://pics.tdiclub.com/showphoto.ph...-gear&cat=5528

http://pics.tdiclub.com/showphoto.ph...ear-2&cat=5528

http://pics.tdiclub.com/showphoto.ph...ear-3&cat=5528

http://pics.tdiclub.com/showphoto.ph...ear-4&cat=5528

http://pics.tdiclub.com/showphoto.ph...ear-5&cat=5528

So my mechanic replaced the Cam Gear and reset the timing again. The Cam was also checked out and there are (thankfully) no stress cracks or blemishes in the Cam :)...

From how it was explained to me, the only way to cause those "injuries" to the Cam Gear was to install it using an Air Gun to tighten it instead of a proper Torque Wrench. Apparently, when my mechanic tried to get the Cam Gear off, he found that it had been tightened to about 200lbs/ft :eek: causing it to crack :eek:...

Anyway, I was really lucky today, if I had not decided to have it checked out, the gear would have failed and my engine would have seized after dropping valves into pistons and my car would have been toast :(

I live to learn, and won't get fooled again...

MrVermin
 

blackty

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You've been minioned...
 

Herm TDI

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It never ceases to amaze me as to what some prople do to these great engines.
What is shown in those photos is nothing but neglect if not intentional sabotage.
 

mrvermin

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2001 Jetta TDI
So how long did those lifters last? Any speculation as to why they had so short a life?
I changed the Cam out from the stock one to the Colt Stage 2 about 7 months ago and that is when the lifters were also changed. So, if what I think happened, then I have been running with a damaged Cam Gear for that length of time :eek:

I am still surprised my Cam is still in one piece with no cracks in it :eek:

MrVermin
 

jimbote

Certified Volkswagen Nut
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spiral arm, milky way (aka central NC)
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can't really tell from the pic's but it looks like a very fresh crack as in never run in the broken state...I can't see any burnishing along the fractures...again the pictures are slightly out of focus...
 

mrvermin

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can't really tell from the pic's but it looks like a very fresh crack as in never run in the broken state...I can't see any burnishing along the fractures...again the pictures are slightly out of focus...

I took the picts with my poor quality cell phone, I'll take better picts with my proper camera tomorrow and put them up. :eek:

MrVermin
 

gaddman

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I wonder if the cam pulley has been removed previously with a hammer from the back side rather than a proper puller?
 

jimbote

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spiral arm, milky way (aka central NC)
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I wonder if the cam pulley has been removed previously with a hammer from the back side rather than a proper puller?
Using a punch and hammer is the correct way to remove ahu/1z/alh cam sprockets.... its a misconception that doing it this way damages the sprocket....this sprocket was damaged from gross negligence ....proper use of tool as per vw service manual will NOT cause this kind of damage.....check out the bentley new beetle alh cam sprocket removal procedure .....punch and hammer ....same cam and sprocket as jetta/golf
 
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mrvermin

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I wonder if the cam pulley has been removed previously with a hammer from the back side rather than a proper puller?
Hmmm maybe a hammer with the aid of a chisel, as there seem to be chisel marks on the inside inner ring....

Suffice to say that evidence suggests that the previous individual who installed my stage2 Cam removed the Cam Gear with the improper tools and then installed it again with the improper tools causing the Cam Gear to be in it's current state. :mad:

MrVermin
 

jimbote

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spiral arm, milky way (aka central NC)
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it's possible the previous installer torqued the cam sprocket well beyond what's required to hold it to the taper...necessitating excessive force to remove it....when torqued correctly it take surprisingly little force to knock the sprocket loose...just a tap :)
 

Franko6

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People who think the use of a punch and hammer damage the sprocket would never have been happy with the 1.6. That was the way it always was done. Also, if you strike the hub of the sprocket, you aren't going to do any damage. We use the sprocket puller tool just for convenience, but have no problem with the sprocket being removed 'the old fashion way'.

Driving the sprocket bolt with an impact is simply STUPID. He's out of his blinking mind...

Changing out worn cam followers is a problem. We recently had an issue that reinforced this concern for us.

A customer had a disastrous timing belt failure. The cam itself appeared undamaged, but there were some lifters that were showing 'bow tie' wear. The old lifters were replaced with new ones. He then drove 2000 miles to my place. Three of the brand new lifters were showing the same wear as before... in that few miles.

Conclusion: The cam wears the lifters as much as the lifters wear the cam. Any cam specialist will make the same recommendation: Replace cam and lifters as a unit, as they wear out as a unit.

In this event, I would keep an eye on the lifters. In another 5-10km, I'd be looking at the lifters again. If the wear repeats, consider cam and lifters being replaced.
 

mrvermin

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People who think the use of a punch and hammer damage the sprocket would never have been happy with the 1.6. That was the way it always was done. Also, if you strike the hub of the sprocket, you aren't going to do any damage. We use the sprocket puller tool just for convenience, but have no problem with the sprocket being removed 'the old fashion way'.

Driving the sprocket bolt with an impact is simply STUPID. He's out of his blinking mind...

Changing out worn cam followers is a problem. We recently had an issue that reinforced this concern for us.

A customer had a disastrous timing belt failure. The cam itself appeared undamaged, but there were some lifters that were showing 'bow tie' wear. The old lifters were replaced with new ones. He then drove 2000 miles to my place. Three of the brand new lifters were showing the same wear as before... in that few miles.

Conclusion: The cam wears the lifters as much as the lifters wear the cam. Any cam specialist will make the same recommendation: Replace cam and lifters as a unit, as they wear out as a unit.

In this event, I would keep an eye on the lifters. In another 5-10km, I'd be looking at the lifters again. If the wear repeats, consider cam and lifters being replaced.
I have not checked the lifters for abnormal wear, and will do so tonight, I was told by the mechanic that the Cam looked like there was no wear on it, however, I will be checking again.

Frank, if you are at the next TDIFest, maybe we can look at the Cam wear and go over a few things.

MrVermin
 

Franko6

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DPG,

Seriously, that kind of question has been asked of me. I found no good reason to answer. I don't think we do any service to the one who botched the job by mentioning his name, nor do we truly do the Club any great service. I'm glad that there were no ill effects, other than a cracked cam sprocket to deal with.

I think witch-hunting is crude. I would rather think that the advantage of this thread is a teaching aide that would help avoid a repeat of the same situation, rather than a forum to publicly flog a bad mistake.

Who among you will cast the first stone?

I will revise my comment of 'stupid' to 'ignorant'. Stupid means unable to learn. Ignorant is not aware. I think it is better to treat the problem as ignorance that can be corrected.
 

South Coast Guy

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DPG,

Seriously, that kind of question has been asked of me. I found no good reason to answer. I don't think we do any service to the one who botched the job by mentioning his name, nor do we truly do the Club any great service. I'm glad that there were no ill effects, other than a cracked cam sprocket to deal with.

I think witch-hunting is crude. I would rather think that the advantage of this thread is a teaching aide that would help avoid a repeat of the same situation, rather than a forum to publicly flog a bad mistake.

Who among you will cast the first stone?

I will revise my comment of 'stupid' to 'ignorant'. Stupid means unable to learn. Ignorant is not aware. I think it is better to treat the problem as ignorance that can be corrected.
If a dealer had done this, the posting would be headed (in all caps) "Dealer destroyed my engine" or something similar. And the name, address and phone number of the dealer would be included.

I agree with you that everyone makes mistakes and that all cars are complex pieces of equipment.
 

Fix_Until_Broke

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I agree - I can't see how overtorquing the bolt would do that kind of damage. Either the bolt would strip, twist off or fracture the tapered hub of the gear axially.

I'd suspect that the gear was pulled by an external puller on the outer perimeter of the gear and caused the cracks which fatigued over time.
 

FredS

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Nothing is complicated if you follow the proper procedure, and know your limitations. These engines are like any engine. You need to learn their specifics, in order to do proper work on them, like any other engine.

By the looks of the gear, its almost like they tried to pry it off before loosening the bolt. The one part on the gear is cracked pretty good, then the way the ears attach to the center hub almost look like either a puller or they pried really hard on it. Like mentioned they pop off rather easy, as there isn't that much torque on the taper when the bolt is properly tightened. But the fact the taper isn't cracked seems even over torquing wouldn't cause that damage.
 
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oldpoopie

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Nothing is complicated if you follow the proper procedure, and know your limitations. These engines are like any engine. You need to learn their specifics, in order to do proper work on them, like any other engine.

By the looks of the gear, its almost like they tried to pry it off before loosening the bolt. The one part on the gear is cracked pretty good, then the way the ears attach to the center hub almost look like either a puller or they pried really hard on it. Like mentioned they pop off rather easy, as there isn't that much torque on the taper when the bolt is properly tightened. But the fact the taper isn't cracked seems even over torquing wouldn't cause that damage.

Is is my impression as well. Also, as another poster said, the cracks look fresh. Is it possible that the current mechanic caused the damage and is blaming it on the prior one? Not trying to cause a stir, but it seems plausable. I just cant see that cam gear holding together enought to run in that state.
 

Ol'Rattler

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PNA
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I dont see how using a impact to tighten the bolt would cause that damage.
A 1/2 drive impact at the full setting is capable of torquing to 450 ft. lbs. If you turn it down, you will not have a good idea of how much torque you end up with. Extremely boneheaded of the first mechanic.

The OP might take the shattered sprocket to the first mechanic and have a little talk. If he just didn't know any better, he may want to know how he FUBARed and instead should have used a holding tool and a torque wrench.
 

scdevon

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Overtorque didn't damage that gear. It was abused in some other way.

Lucky catch.
 

gaddman

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06 Jetta (RC3, PD150 Injectors, GTB1749V, 2.5" Downpipe), 04 Touareg V10 (RC1)
I wonder if the cam pulley has been removed previously with a hammer from the back side rather than a proper puller?
I should have stated it clearer than that. There is the proper way to use a hammer and punch to remove it from the back side.
 
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