jseklund

Well, I guess he could leave the cams in and try to turn them somehow so that all valves are closed? Given that he is a little confused, maybe that is the better way to go, but I think it may be difficult with the head off the engine....

While pulling the cams is a bit more work and a PITA, I don't think it is all that confusing, but I can see your sides too...

4Driver4

I'm not understanding how removing the cams mitigates any risk. I think it adds risk.

There is a timing mark on the crank and timing marks on the cams. Use them to get everything aligned. As a sanity check, it's easy to visually verify that there will be no immediate contact when the heads are installed.

Once you turn the cams anywhere but TDC, you create the problem of how you are going to turn them back to TDC without contact. And if you remove the cams, you create three issues: how to get the chain timing reset correctly, how to get the cams into the heads without them turning, and how to verify that there will not be contact.

tester123

[playing devil's advocate here]
While it is true that there is no way (other than removing head) to verify that "contact", it is my opinion that it is not so critical. Provided that crank is locked @TDC, pulling cams out and re-installing them is not such a compromising procedure. Many have done this including myself recently.
The trick is to make sure that chain link counts are correct.
Re-installing cams is simple. By ensuring that link count is not disturbed, install each bearing cap slowly and tighten them alternatively there by slowly lowering the cam (which will be under tension of valve springs) into its position. The trick is to make sure that no one bearing is taking more tension than the other(s). It has to be done evenly.
Link count is the main if not, the most important thing. Because, the chain alone determines the alignment of intake and exhaust cams. The timing belt determines the alignment of crankshaft to cams. You knew that . Anyway, pulling cams out does serve the purpose of receding ALL valves back to the head. So, in theory, it is a better way IF obstructions are noticed. Here is the kicker; those obstructions SHOULD NOT be there in the first place if all points are aligned. If they exist, then there is something seriously wrong. So, even if one does get over those "obstructions", by re-installing cams, there is significant possibility of bent valves at the first crank.

I am not trying to send mixed messages to the OP here. That was just an exploratory of 4Driver4's concerns.

I still stand by my original reply; do not pull cams out; You are just asking for it. Furthermore, the tension adjuster's gaskets would have to be replaced every time you pull cams out (you can get away, like I did, with thin silicone sealer layer all over the existing gasket -not too much as you could block its oil inlet).
Regardless of how the risks can be mitigated, it is simply not worth pulling cams out in my honest opinion. Period. UNLESS, the shop you gave the heads to f'cked up the chain link count/alignment.

tester123

I really want to help this guy. Perhaps our rhetoric has not helped his situation.

Thomas,
By any chance in all this time, did you rotate the Crankshaft AFTER the timing belt has been removed??? If you did, this explains why you are having obstructions when putting the heads back on. The crankshaft could be out of alignment. Below are steps from my own experience on a 4.2 engine. Haven't read manual for your engine so, there maybe some discrepancies. Refer to Manual when these steps are not making sense.

Here is what you do:

1) Secure the head on its side, towards an edge of a desk etc. (or ask someone to hold it very good.
2) Put that "diamond" shaped plate back on exhaust camshaft and use the cam lock bar to turn the camshaft. Keep rotating in its normal direction of rotation (i.e. engine rotation).
3) keep checking the alignment marks on cams (both exhaust and intake). When they BOTH align, stop turning.
4) Do the same to the other head.
5) On the engine, first find out WHICH cylinder should be at TDC.
6) Turn the crankshaft (in engine's normal direction, most likely clockwise when facing the car standing in front) until you see THAT cylinder's piston is at its peak. Continue turning slowly until it is going down. When confirmed, turn the crankshaft the opposite direction or Counter clockwise until that piston is back to top again. Now, it is at TDC.
7) Now try to put the heads back on. Don't bolt it etc. Just put them on. Are they sitting flush? No obstructions? Great.
8) Reach under and Lock the crankshaft with locking pin. Mark a notch of the crankshaft notch somewhere visible (even with t-belt on) with Whiteout etc. and another mark on engine body at the same place notch is. Now, with crank lock pin removed, you can tell when it is at TDC again (or at least it will help...you'll see).
9) Proceed with head bolts tighten them snug but don't finish the final torque sequence.
10) Put the cam lock bar on and don't remove it until the end. Follow instructions on how to install timing belt. If you have belt tensioner, release it.
11) Check to make sure the belt is under proper tension in all areas. Since it is "toothed" it could be tensed somewhere and loose else where. Just make sure it is installed properly as per manual. Now, remove the crankshaft lock pin. Remove the Cam lock bar as well.
12) Turn the crankshaft few times in engine's normal rotational direction. Turn it with just enough force to turn but not too much. Don't worry about alignment. You want to listen/feel for any hard stops/lock ups. The Camshaft tension adjuster may "pop" but don't worry about that. Keep turning and bring it back to the place where you marked on crankshaft notch before.
13) Now turn it 45° counter clockwise or opposite direction and turn it back clockwise to the marking place again.
14) Check camshafts on both heads. The notches on camshafts should be aligned to arrows on bearing caps. There maybe a slight deviation -due to tensioner's slack- still, they should be aligned.
15) Repeat from step 12 to 14 at least 6 to 10 times. Finally, you should see that the marks on camshafts align Perfectly when the crankshaft is at the notch where you marked it before.
16) Put tension back on the T-Belt tensioner and lock it with that slide pin or a nail. The t-belt should be loose now. Pull the t-belt out.
17) Proceed with final torque sequence of head bolts. Double check your tightening sequence.
18) Put the crankshaft lock pin back in. Since you are already at the notch you marked, the pin should go in without an issue.
19) Since you didn't touch the camshafts, you should be able to get the cam lock bar back on with slight wiggle etc. If not, turn required side and get the bar back on no matter what.
20) Go to step 10. Install t-belt, release tensioner.
21) Go to step 15.
22) If all goes as described above, you are done. Continue with rest and put the parts back together.
23) Check oil, coolant etc. and after installing serpentine belt, try starting engine. You could start it after t-belt, but, I suggest against it. If everything went well, there is no reason to start it. The timing is perfect. Plus, it is a safety hazard! So, don't do it.

24) When the engine starts, pay attention to its sounds. The tensioner "pops" may be there due to lack of oil initially but they'll subside. Don't "rev" it. Just let it idle. Check for any codes. If all is well, shut it off and finish putting everything back together.
25) Drink whatever knocks you out .

tj2k11

Thanks man well explained.... Finally the answer I was looking for... The motor is on a engine stand....So it should be easy for me to make sure everything is correct before installing back in the car... Besides I'm changing a lot of other stuff while engine is out starter alternator motor mounts oil pan gaskets etc .....

Thanks
Thomas

jwetering

Sorry for the resurrection but I had to congratulate you on this post.

I plan to replace my rear cam and tensioner seals and gaskets soon (plus timing belt etc) and I'm very concerned because a cam removal is indicated.

I do have two question though:

1) I have a Bentley manual on the way - is this the manual you refer to or will I require something more....german?

2) What's the point of the cam locking tool if there are notches and arrows on the cams and caps that I can line up ? If the valve covers are off (as mine will be) is the cam locking tool redundant?

Thanks and please look out for panicked posts over the next few weeks as I tackle this job.

CRuby

2) Cam lock bar hold both bank 1 & bank 2 exhaust cams at proper position & keeps them from turning when when the timing belt sprockets are re-tighetened, after installing timing belt. This, in combination with having the crank lock pin installed, assures proper timing between the crank & the exhaust cams. IMO, the use of the cam lock bar & crank lock pin is more precise positioning of the parts than relying on eyeball of the timing marks.

tj2k11

No problem man I did eventually figured out the whole process and I forgot to thanks everyone on here for there information it was really needed I did sell the car Im in a BMW 745li now so yea read this post alot of useful information for sure.


Thanks Audi Forum