Woes of a 300k mile TB job (BEW)

So I'm in the middle of my 300k mile timing belt job. I've done an audi 1.8T and a jetta 2.0 TB with no issues, this is my first TB on a tdi. It looked like the cam seal was leaking, so I removed the sprocket (almost seemed welded on, had to rock it back and forth with some taps from a hammer to loosen it), and the tapered section now appears (to me) to be in sub-optimal condition. Also in the process of removing the center hub, when it finally cracked loose, I didn't counterhold it well enough, and it felt like it may have wacked a valve/piston together. The cam may have turned 30 deg or so, and the crank is locked at TDC. Do I need a new sprocket/hub? Should I be worried about a bent valve just from the force of the wrench? Also where should I suspect the oil is coming from? After removing the hub, it almost looks to me like it's coming from the valve cover. This is becoming very stressful, any advice would be greatly appreciated. I don't know how to post pictures here, but here's a link to them in my google drive: https://drive.google.com/open?id=0B2TU4RzezqLUUnpNOFNIZko0eXc

No Expert...but..

The camshaft sprocket from your photos doesn’t look to good with the gouges and all. Since it’s a tapered fit on the camshaft, I would be worried it might slip and cause major damage. At 300k, a new camshaft/lifters, seal and sprocket would be good insurance if everything else is ok.

The seal on the camshaft does looks off but it’s also possible your oil leak was from the valve cover. You need to make sure the gasket is good and bolts are tigened in the right sequence.

Someone else chime in, but I don’t think it’s likely you could have damaged the valves.

Cleenlivin said:

The camshaft sprocket from your photos doesn’t look to good with the gouges and all. Since it’s a tapered fit on the camshaft, I would be worried it might slip and cause major damage. At 300k, a new camshaft/lifters, seal and sprocket would be good insurance if everything else is ok.

The seal on the camshaft does looks off but it’s also possible your oil leak was from the valve cover. You need to make sure the gasket is good and bolts are tigened in the right sequence.

Someone else chime in, but I don’t think it’s likely you could have damaged the valves.

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Thanks for the advice! Do you think I should replace the hub too? Or just the sprocket? Both surfaces are a bit funky looking. I'd rather not replace it, but I like having a working engine too

I think you should be OK all around here as long as the cam and hub isn't damaged where they meet. The gear is held on by the bolts, just file that smooth and I think that should good. It does look like your cam seal was probably OK. The seals are pretty good and rarely give any trouble. For $275 I do the belts while you wait and relax here in Sunbury.

dedededanny said:

Thanks for the advice! Do you think I should replace the hub too? Or just the sprocket? Both surfaces are a bit funky looking. I'd rather not replace it, but I like having a working engine too

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From those pictures, the hub is what I'd be worried about, and should be replaced. That looks nasty.

The sprocket is maybe not so bad from what I can see.. I'd only be worried that it wouldn't sit right on the damaged hub. On a new hub it may be fine.

When you're putting it back together and tensioning the belt, you want the cam sprocket to be able to rotate a little as you set the tension. With the gouged up hub, I'm not sure it would.

Maybe you can clean up the hub. Basically you need the sprocket to be centered on the hub, and be able to turn freely when the three bolts that hold it on through the slotted holes are a little loose.

I guess I'll get a new sprocket and hub just to be safe. Thanks for all the input! As to the valve cover, I have all 13 bolts completely loosened and the valve cover seems cemented on from all sides. It won't budge. I was planning to replace the VC gasket as suggested, and inspect the cam and followers, but the cover won't come off. Forgive my cluelessness, I just turned 20 today, and taught myself purely from the internet, so my experience with such things is rather shoddy. But from videos and how-to's I've found, the cover should just come right off, no? I tried pulling and gently prying from all angles, and it's not moving. I don't know how to remove/replace it without destroying anything. I'm tempted to just re-tighten the bolts and leave it alone.

Hub and sprocket wouldn't give you trouble, but since you took it off, replace for a nicer one.

About the valve, piston surface is perfectly perpendicular to the valve trajectory. I don't think it would bend, would probably break a lifter first.

jasantos40 said:

Hub and sprocket wouldn't give you trouble, but since you took it off, replace for a nicer one.

About the valve, piston surface is perfectly perpendicular to the valve trajectory. I don't think it would bend, would probably break a lifter first.

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Oh, I don't know why I assumed it would be at an angle, that makes me feel a little better actually I would imagine at a decent angle, it wouldn't take very much force to damage it.

Did you ever get your valve cover off? It shouldn't be very difficult after you've removed all the bolts. One bolt is hidden under the EGR valve, so you have to remove that to get at it. Two bolts are through the top of the cover into a couple of the cam caps.

If you're finding it very difficult to remove, I'm guessing you might have forgotten a couple bolts.

Mike_04GolfTDI said:

Did you ever get your valve cover off? It shouldn't be very difficult after you've removed all the bolts. One bolt is hidden under the EGR valve, so you have to remove that to get at it. Two bolts are through the top of the cover into a couple of the cam caps.

If you're finding it very difficult to remove, I'm guessing you might have forgotten a couple bolts.

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I looked up a picture of the cap and counted 13 holes. I took 13 bolts out, so I can only assume it's all of them. I'm waiting for the new gasket in the mail, so I haven't gotten to it. Now the cam sprocket is on back order until December, so I have to figure that out :/