Cylinder head/Cam advice

I'm working on replacing the timing belt on a new to me ALH TDI, and I'm seeing things that have me worried. The first uh-oh feeling came when I saw the marks from a previous mark and pray belt job. With the crank properly aligned by flywheel marks, the IP lock pin fits. The cam is just ever so slightly off. The cam lock plate will fit halfway in.

Fair warning: My pictures are HUGE.


Is this cam far enough off to create piston/valve interference, or is this small degree not enough to cause mechanical issues?

I'm also concerned about wear on the camshaft lobes. I'm fairly certain this car has not seen proper oil change intervals, and possibly not even the correct oil for all I know. I'm guessing this cam is toast?





Thanks for any advice you can give.

How many miles?

I'd look to line up the crank and the cam. IP might be off very slightly: or if it's off more then that's less disastrous than the timing between the crank and cam being off.

I don't like the look of the wear on the cam lobes, some pitting. In the second picture it almost looks like metal particles (which wouldn't be good).

UhOh said:

How many miles?

I'd look to line up the crank and the cam. IP might be off very slightly: or if it's off more then that's less disastrous than the timing between the crank and cam being off.

I don't like the look of the wear on the cam lobes, some pitting. In the second picture it almost looks like metal particles (which wouldn't be good).

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Not metal shavings, I wiped the lobes off with rag to get a good look and it left a bit of fuzz. 230k miles.

Correct me if I'm wrong, but since the IP and crank are in their proper positions, and cam is slightly out of sync, I should go ahead and lock the crank and IP then align the cam and lock it.

That's basically what you'd do when replacing the cam (which I think is in my near future). Have the crank and IP in the right positions, and align the cam.

Thought that material looked a bit consistent

If crank is at TDC (#1), then, yes, the cam is off. I just find that it's a bit tough to be exact on positioning the crank (tough on an automatic trans).

I've only done two TBs, and I index the IP last and it's been very snug: if I'd have lined up the IP and the crank then the cam lock might not have quite fit.

Seems as you say, that you're likely going to have to pull the cam.

I recently got a USB borescope that one can use on a smart phone. I'd for sure look to see if I could see anything going on inside the cylinders: run the scope down the injector holes.

Laserface said:

I'm working on replacing the timing belt on a new to me ALH TDI, and I'm seeing things that have me worried. The first uh-oh feeling came when I saw the marks from a previous mark and pray belt job.

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I think the mark-and-pray procedure is pretty common. I bought two ALH TDI's that were like that. I can't remember how far they were off, but they were off far enough that I couldn't get all three points locked down together.

Just set everything correctly with the new TB install, and motor on. You'll need VCDS to get the timing dialed in properly afterwards.

The cam isn't off enough to cause any damage. When you redo it, it will be all good again.

Cam's do wear out on ALH's, just not as common as the PD motor. My first 00 Sedan had a hole in the lifter and she ran great, apart from a slight tick.

The cam looks ok but look at the lifters for a better picture of wear.

Perfect time to get a Colt Stage 2,

UhOh said:

Thought that material looked a bit consistent

If crank is at TDC (#1), then, yes, the cam is off. I just find that it's a bit tough to be exact on positioning the crank (tough on an automatic trans).

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It's using a single mass flywheel with a manual transmission. No mistaking the alignment on that setup.

Rembrant said:

I think the mark-and-pray procedure is pretty common.

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This is my third TDI. The first had been with its previous owner since 17,000 miles. I'm the second owner of the second car. Both had maintenance records from reputable shops. I'm spoiled, and this is luckily the first I've encountered a mark and pray job. I have the proper tools and VCDS. I'll replace the cam and lifters for piece of mind.

Twas me I would lock the crank (or hold, screwdriver works) insert the cam lock, then align the pin with the pulleys loose. Lock it down, rotate a few cycles and check. Then fine tune with a VCDS or equal with just the IP pulley.
From what I can tell in the photos, the cam looks decent, no bad wear, chamfers look clean. When you rotate to check timing, inspect as much of the cam, lifters and stuff to find any damage.

"The cam looks ok but look at the lifters for a better picture of wear."

Can the lifters be replaced by themselves if they are worn, or are you automatically into new cam as well?
Also, can the lifters be taken apart and cleaned or serviced if they are good as far as wear is concerned?
Thanks
Pete

atownbrg said:

"The cam looks ok but look at the lifters for a better picture of wear."

Can the lifters be replaced by themselves if they are worn, or are you automatically into new cam as well?
Also, can the lifters be taken apart and cleaned or serviced if they are good as far as wear is concerned?
Thanks
Pete

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Lifters can't really be rebuilt. The cam and lifters wear as a unit and if you replace one, you must replace the other otherwise you'll cause accelerated wear. If you reuse your old stuff, keep the lifters with the lobe in the same position so you don't cause any issues.

Turbovan, thanks I was wondering because my car has some clatter at startup now, but clears up when the lifters get their oil. Kind of annoying. Haven't had the valve cover off of the car yet!

atownbrg said:

Turbovan, thanks I was wondering because my car has some clatter at startup now, but clears up when the lifters get their oil. Kind of annoying. Haven't had the valve cover off of the car yet!

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Diesels are inherently noisy when they're cold. And if you really want to hear how noisy they are head up North! (where they're a lot colder prior to starting up)

Running 5w-40, if you're not already doing so, is a good ide.

atownbrg said:

Turbovan, thanks I was wondering because my car has some clatter at startup now, but clears up when the lifters get their oil. Kind of annoying. Haven't had the valve cover off of the car yet!

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I'd change the oil with some Rotella or other quality 5w40 synthetic oil and see if the noise goes away.

Thanks for the advise, I have been changing the oil with T6 5-40 since taking ownership of the car.

UhOh said:

Diesels are inherently noisy when they're cold. And if you really want to hear how noisy they are head up North! (where they're a lot colder prior to starting up)

Running 5w-40, if you're not already doing so, is a good ide.

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Or a cold IDI diesel, heheehe.

turbovan+tdi said:

Or a cold IDI diesel, heheehe.

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Try a 7.3L IDI. Talk about clatter (and smoke)!

ALH cam and lifters are cheap and easy to replace. If you are getting a lot of lifter tick on startup then it would probably be a good idea to replace them.

I'm replacing the cam and lifters for my own peace of mind over the next 100k miles. The lifters look great, but the pitting on the tips of the lobes is what really sold me on replacement. Upon closer inspection, there is also light pitting on parts of the lobes besides the tips.