Author Topic: Intermediate shaft pulley failures, anyone?  (Read 4513 times)

February 08, 2016, 11:31:21 am

Smoker

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Intermediate shaft pulley failures, anyone?
« on: February 08, 2016, 11:31:21 am »
Pardon the long post, but I'm trying to be thorough.

I picked up a mk2 recently with a 1.6td. Eco engine with pump and turbo from a regular 1.6td. I bought it sight unseen with what sounded like a timing belt failure... it was clean and cheap enough that I didn't really care too much what was wrong.







So I dug into it and found this...



My first thought was that someone over-torqued the bolt and/or over-tensioned the belt. No worries, I have a few parts motors here... I ordered new i/m shaft bearings and pulled a complete pulley and shaft off of one of my other motors (as an assembly... I didn't take the pulley off the shaft). To my surprise, the bearings looked perfect when I finally got to see them. So I put it all back together with a spare good head.

It was running great until I found out the hard way (and 350 miles from home) that you're supposed to re-torque head studs.  But before I realized that the head gasket was giving me issues, the water pump started peeing. So we found an auto zone and I swapped it out in the parking lot.



When I pulled the intermediate shaft pulley, you guessed it... The keyway was fubar'd, and you could tell the pulley was starting to spin further and further on the shaft. I didn't think to get a pic at the time.

So that was a really long story leading up to a really simple question: Is there something wrong with my engine that's making it eat those pulleys?

I kind of assumed that the current pulley had that wear when I installed it, and it was a coincidence. When I called my parts guy this morning, he said he's never heard of those pulleys failing like that. He's thinking that the oil pump and/or vac pump is tight, putting too much force on that pulley. I spun it by hand the first time I was putting it all together, and didn't notice any abnormal drag/resistance.

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« Last Edit: February 08, 2016, 11:34:46 am by Smoker »



Reply #1February 08, 2016, 11:39:13 am

Smoker

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Re: Intermediate shaft pulley failures, anyone?
« Reply #1 on: February 08, 2016, 11:39:13 am »
Unrelated: I got in touch with a few of the PO's... One of them claims it has a Giles pump. Is there any way to verify this? I've had quite a few n/a 1.6's and tdi's but this is my first 1.6td, so I don't really know how it should feel. The pump looks rough, and if it was rebuilt, it was a while ago. It does make 30 psi pretty easy if you put your foot down, though.

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Reply #2February 08, 2016, 03:06:05 pm

RabbitJockey

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Re: Intermediate shaft pulley failures, anyone?
« Reply #2 on: February 08, 2016, 03:06:05 pm »
its hard to tell if it is a giles pump with out maybe emailing him the serial number or taking the pump apart, you can probably tell from looking at the boost pin, but the governor springs would be a give away,

how are the thrust bearings in the bottom end?
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Reply #3February 08, 2016, 03:24:54 pm

vanbcguy

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Re: Intermediate shaft pulley failures, anyone?
« Reply #3 on: February 08, 2016, 03:24:54 pm »
That's a weird looking intermediate pulley, looks like it is made of aluminum? That's definitely not stock!

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Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
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Reply #4February 08, 2016, 03:58:13 pm

Smoker

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Re: Intermediate shaft pulley failures, anyone?
« Reply #4 on: February 08, 2016, 03:58:13 pm »
All the intermediate pulleys I have are aluminum... (?!)

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Reply #5February 08, 2016, 03:59:32 pm

Smoker

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Re: Intermediate shaft pulley failures, anyone?
« Reply #5 on: February 08, 2016, 03:59:32 pm »
I'll definitely be a little more thorough in my inspection of the bottom end the second time around... Why do you ask about thrust bearings specifically?

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Reply #6February 09, 2016, 02:44:35 am

Dakotakid

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Re: Intermediate shaft pulley failures, anyone?
« Reply #6 on: February 09, 2016, 02:44:35 am »
"Unrelated: I got in touch with a few of the PO's..."
Exactly, how MANY "guys" have been piddle-diking with this engine?
It is starting to sound like a girl brought home from Woodstock!

Here is what I would do....I tend to be kind of "square" and straight-laced: seeing how that oil pump has not been rotating in any sort of normal manner for (let's say) 200 or more miles, myself...I would yank the engine and totally open it up...provided you have the time and place to work on it.

I would be VERY suspect of all the bearings. Yes, you saw the intermediates. However, THAT was before the oil pump sort of went on vacation.

Do you have any idea if the crank bearings were ever replaced by the former "Einstein" mechanics? If so, I am willing to bet they inserted a unitized center/thrust bearing. Perhaps, that is why the other guy is asking the question about the thrust bearings. Those unitized thrust bearings have a very short service life if the other drivers sat at lights and such with their foot on the clutch.

I think Van is referring to the hole-less int. med. pulley. Usually, they have holes in them under the pulley surface. However, I have never owned an AAZ...so, perhaps I don't know squat.

The Jetta is a handsome little rig (at least in the photos). Myself, I would have bad vibes about the state of the engine as it currently sits. Roached bottom-end bearings tend to do adequately well enough....right up to the point they allow the crank to go "bang."

But, bear I mind I generally go the "safe" route and really hate waking home across the frozen tundra.
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Reply #7February 09, 2016, 08:07:18 am

RabbitJockey

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Re: Intermediate shaft pulley failures, anyone?
« Reply #7 on: February 09, 2016, 08:07:18 am »
i said thrust bearing because i thought maybe if the crank is  pushing front to back in the block it would fatigue the im shaft pulley and eventually cause this.   ive never seen an im shaft pulley that was solid like that, but i've never seen one that wasn't aluminum.
01 Jetta TDI 100% stock daily
81 Rabbit:TDI-M ported head, Frank06 cam, PD intake, hybrid T3 turbo, Renault intercooler, Syl20 11mm pump, light weight fw, and yellow California Clutch clutch kit

Reply #8February 09, 2016, 08:36:07 am

Smoker

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Re: Intermediate shaft pulley failures, anyone?
« Reply #8 on: February 09, 2016, 08:36:07 am »
Fair points. This car has definitely been 'around the block'. And now I see what you guys are getting at with the thrust bearings. I'm hoping to get the car home tomorrow... I'll pull it apart and report back.

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Reply #9February 09, 2016, 11:12:47 am

Smoker

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Re: Intermediate shaft pulley failures, anyone?
« Reply #9 on: February 09, 2016, 11:12:47 am »
Also, yes, all other pulleys I've seen have had holes in them. I'm really starting to think that the broken pulley was a cheap aftermarket replacement, and the second pulley was worn before I ever put it on.

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Reply #10February 09, 2016, 03:47:50 pm

RabbitJockey

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Re: Intermediate shaft pulley failures, anyone?
« Reply #10 on: February 09, 2016, 03:47:50 pm »
that is possible, but i haven't seen many of those go bad especially not like that.  more so from people prying on them when theyre just soft aluminum.
01 Jetta TDI 100% stock daily
81 Rabbit:TDI-M ported head, Frank06 cam, PD intake, hybrid T3 turbo, Renault intercooler, Syl20 11mm pump, light weight fw, and yellow California Clutch clutch kit

Reply #11February 10, 2016, 03:29:50 pm

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Re: Intermediate shaft pulley failures, anyone?
« Reply #11 on: February 10, 2016, 03:29:50 pm »
  Sometimes the thrust flange on the I-shaft breaks too.
  I believe (and many doubt) that a bad injection pump bushing causes the belt to ride off the end of the sprocket.
 As the belt crosses the I-shaft pully it is pulled back toward the block by the crank sprocket.
 This drags the I-shaft toward the block with it. Banging it into the block over and over again.

 How loose does the injection pump sprocket feel/ Lots of side-to-side movement?
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Reply #12February 11, 2016, 07:48:53 am

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Re: Intermediate shaft pulley failures, anyone?
« Reply #12 on: February 11, 2016, 07:48:53 am »


How loose does the injection pump sprocket feel/ Lots of side-to-side movement?

I finally got the car home late last night. I'm planning on digging into it today. I'll report back.



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Reply #13February 12, 2016, 01:54:45 pm

diesel dub

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Re: Intermediate shaft pulley failures, anyone?
« Reply #13 on: February 12, 2016, 01:54:45 pm »
I've definitely experienced a bad injection pump bushing causing timing belt to ride off the sprocket. Belt got chewed by the front cover. Had 1/2" of belt left. Saved just in time.

 

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