Timing chain replacement- Crank Sprocket moved?

[blubaru]

I'm in the middle of a timing chain replacement and was getting ready to put the covers on when I noticed the crank pulley bolt was suddenly not as easy to remove by hand. I had been using the nylon washer and had switched to the pulley to verify timing marks. I'm worried that when I released the pin on the tensioner, the crank bolt may not have been on tight enough as it took maybe half a turn with socket before the sprocket would move (when I went to rotate the engine over a few times and check timing).

The symptom - crank bolt is too tight to remove by hand, need to use a socket until it is about halfway out, then can use hand. The bolt goes from being loose/easy feeling for about half a turn to being harder to turn. This makes me think that the sprocket hub may not be totally flat. Previously when taking the bolt out I could thread it all the way by hand and tension was uniform.

Should I pull everything back off and reseat the sprocket or will torquing down the pulley be sufficient? I can't tell if I'm being paranoid / overly cautious or overreacting.

[A4 Centaur]

Hey, just did mine and had a similar experience. There are marks on the crank gear assembly and the pistons will tell you where TDC is located.

Rotate the engine and put a long screwdriver in the #1 hole and that way you can see that you are at TDC.

The crank gear assembly can only go on one way. There is a notch and that will get you comfortable with the correct timing marks.

Check out Naptown Tuner and he has a few vids that will allow you to get her sealed up and feeling good!

[A4 Centaur]

Zoom in you might be able to see the marks:

[blubaru]

Thanks for the replies! I’m confident that the timing is good, I’ve rotated the engine 6x or so and triple checked it. The part that concerns me is that something changed between switching from the pulley to the nylon washer and back, did this a couple times for various reasons. And I think the sprocket itself may have come unseated or shifted slightly because the crank pulley bolt isn’t coming out and going back in smoothly anymore. I could thread it in by hand without too much resistance all the way to the pulley or the nylon washer, and now it’s got tight spots in the threads.

I’m thinking about just undoing everything and pulling the sprocket off and making sure the key way isn’t damaged, and also taking a closer look at the threads, testing the bolt with no chain tension, etc. I’m worried that if I just put the pulley on and send it, that if I don’t get lucky and it re-seats properly it may damage something and could lead to jumping time down the road.

Unless anyone can confirm that with everything under full tension the bolt would have some resistance?

[StockDC2]

I also recently did my timing chain and didn't experience any resistance tightening the crank pulley bolt. I'd take it apart and double check because if you tighten the bolt and the sprocket is misaligned, you may damage the teeth on the crank.

[CTBob]

I would:
a: be worried as you are for something to be a tooth off!
1. Plugs out, top timing cover off.
2. Bring #1 cyl up as posted above.
3. Look to see cam marks are both up.( if not, spin crank 1 turn) recheck marks.
4. Damper timing mark should be VERY close to the tdc mark on the lower cover.
5. Using a NEW 7 dollar crank bolt, tighten it to 100 nm. Then CRANK it 180 degrees ( 1/2 turn). Or as your manual says of course.
Wondering if you replaced the sprocket as Audi requires. This seems to help keep that delicate critical assembly locked and lined up where it needs to be, while exchanging that screw and plastic for the damper. Good Luck.

[blubaru]

I would:
a: be worried as you are for something to be a tooth off!
1. Plugs out, top timing cover off.
2. Bring #1 cyl up as posted above.
3. Look to see cam marks are both up.( if not, spin crank 1 turn) recheck marks.
4. Damper timing mark should be VERY close to the tdc mark on the lower cover.
5. Using a NEW 7 dollar crank bolt, tighten it to 100 nm. Then CRANK it 180 degrees ( 1/2 turn). Or as your manual says of course.
Wondering if you replaced the sprocket as Audi requires. This seems to help keep that delicate critical assembly locked and lined up where it needs to be, while exchanging that screw and plastic for the damper. Good Luck.

I’m going to pull it apart tonight to be sure. The timing is good, not worried about that right now and I haven’t torqued the pulley bolt down yet. I think the hub may have pulled slightly from the block and may not be totally flat. Going to inspect the key way for damage and test the bolt and make sure the threads are even tension and I can do it by hand again. Then just be really careful on re assembly.

[blubaru]

I’m going to pull it apart tonight to be sure. The timing is good, not worried about that right now and I haven’t torqued the pulley bolt down yet. I think the hub may have pulled slightly from the block and may not be totally flat. Going to inspect the key way for damage and test the bolt and make sure the threads are even tension and I can do it by hand again. Then just be really careful on re assembly.

Also I did not replace the sprocket, I bought the kit from FCP Euro and it didn’t come with one. I do see in the manual they recommend to replace if needed, and YouTube tutorials are 50/50 if they do it or not. I might look into that as well.

[A4 Centaur]

^ Yea, I didn't either on 2 timing chain rebuilds. I thought about that part as well as a new oil pump. Figured I will do that once I find another CPMB engine and do a fully built engine.

I've spent enough on this repair cycle to drive for another 100k miles and the only thing I'm doing next engine wise is a carbon cleaning with walnuts.

Good luck on wrapping this work up!

[blubaru]

Anyone use Bremmen parts (ECS) or OE Supplier (FCP) for sprocket? Or is this something to definitely get genuine Audi for.

[Veedubber12]

I'd take the sprocket off and look at the back of it and make sure the notch that you use to mate it to the crank isn't rounded out or deformed. The other thing is the pulley may not have been correctly seated when you started tightening it down. It's suppose to go on 1 way onto the sprocket.

[blubaru]

Figured it out! It was the damn Cambridge. I didn’t have the crank pulley on tight enough and when I was installing Cambridge I had to wiggle it and tap on it with my palms and that was enough to mess up the sprocket slightly. Took Cambridge off and bolt was easy again. Did some tests and reproduced the tightness if bolt wasn’t super tight when installing Cambridge. Lesson learned, make sure it’s wrench tight before doing anything that could cause sprocket to move.

Pulled sprocket off and no visible damage, still going to replace it but it basically fell off as I was removing the chains. Another lesson learned, keep that thing tight!

[CTBob]

I frugally went with URO Parts 06H105209AT Crankshaft Gear. I put it on and it seemed to stay put. The car started easier-faster than I expected after the chains, a cam and head R&R for the 8 bent valves. But I do know, only time will tell.
Good you took some time to look it over. Def not a job I would want to do ALL over again on the same beast, back to back.

[seppok]

top.jpgBottom.jpg
I have a small problem with these marked chain links.
If I adjust crankshaft link to pointing arrow on crankshaft
I need to turn it off the TDC. Should I just leave it off and leave it as it is now
or what should I do?

[blubaru]

top.jpgBottom.jpg
I have a small problem with these marked chain links.
If I adjust crankshaft link to pointing arrow on crankshaft
I need to turn it off the TDC. Should I just leave it off and leave it as it is now
or what should I do?

You sure you are at TDC? I made a mark on the sprocket and on the block at the 12 o’clock position to reference once the cover was removed. You do have to move the sprocket slightly to take out the slack on the right side when you are putting in the guides - but not when putting on the chain. It should line right up.

[seppok]

I am sure because I had whole head out and I marked TDC that time. I also had long extension bar which has mark when in TDC position.

[blubaru]

I am sure because I had whole head out and I marked TDC that time. I also had long extension bar which has mark when in TDC position.

You can measure the cam marks to be sure, should be 61-64mm from center of guide to right one, and 121-125mm from cam to cam (may want to doublecheck these are accurate).

[seppok]

Hello,

It's Timing Crankshaft Sprocket what is slipped. Got a new one with the kit but how do I install it?
When putting chains and tensioners on and removing crankshaft bolt to get cover on
it jumps out.

[blubaru]

Hello,

It's Timing Crankshaft Sprocket what is slipped. Got a new one with the kit but how do I install it?
When putting chains and tensioners on and removing crankshaft bolt to get cover on
it jumps out.

Use the tool with the crank bolt to hold it tight. I’d recommend tightening the nylon washer style tool to the point where the crank is beginning to move. That will keep everything nice and snug while you put the chains and cam bridge on. Leave it tight until you get the cover installed and swap it for the pulley. You don’t want it to have any chance of moving, that’s what happened to me.

Edit - I actually removed the tool and bolt before doing the cover. I held the sprocket tight with one hand while loosening the bolt. If you don’t do this you’ll probably turn the crank and jump a tooth. Practice a couple times before you get everything on there.