no not yet. I was waiting to hear back from you. I have asked everyone I know locally that is in the automotive industry and none of them even know someone who works on Audis. I called one auto machine shop to ask about a valve job and he said it could easily run into $1000 per head. " Hell the last one of those I did took me three days to get them tiny little valves to seat right". That leads me to the conclusion that I dont want to pull the heads IF i can set the timing right on the #1 side without pulling it. I also thought that IF that chain jumped a link on one cam when I did my "move" then trying to do a compression before fixing the timing could mess up more. The manual I have does mention taking the cams etc. off the head while still on the motor but I was really hoping for confirmation from someone who knows. I would hate to mess up the valves by doing something wrong while removing the timing chain and tensioner.

 

Just to check on my theory. Based on what I have learned about this motor so far, last motor I worked on to this degree was a 1976 400CID GM V8 with cast iron heads and block, IF i were to replace the timing chain and tensioner on one head but not the other it would not be long before I had this thing all apart again to do the side I didnt do now due to this being an "interference" motor ( whatever that means) the slop in the old side working against the new nice and tight side would cause faster wear on the already worn side and thus a failure would be quickly headed my way.

 

An interference engine is where the valve and pistons occupy the same space but at different times. When the timing is off, they try and occupy the same space at the same time with predictable results, bent valves and holes in pistons.
Fixing the chain and tensioner will not cause accelerated wear. I would get the timing correct and run a compression test again. If you have one cylinder low again, with the timing correct it may well run without any issues. I would still want to know if it was valves or rings.

 

OK got it. So if I just partially dissasemble the timing assembly such that I can back the one cam up to where all the timing marks on the cam sprockets are in line then do the compression test again I am not at risk to further damage? Thanks for all your help Paul!

 

I found a small piece of plastic that used to be cream color that is now dark brown under the intake manifold. I set it aside hoping to find out later where it may have come from. Found out today. I removed the timing chain tensioner and found the bottom side tensioner pad had one side broken off....my piece of plastic. The only way I can see that the broken pad would leave the piece under the intake is that it was broken by who ever had this car apart last and they either didn't see that they had broken the pad while re-installing the tensioner or they didn't want to mess with it and just let it ride. Waiting for a new set to arrive before I can continue.

 

My two main concerns now are. 1. I do have bent valves and all this that I am doing now to set the timing right to redo my compression test, which would still need to be done, will have to be redone to fix the heads should my test reveal problems. 2. Doing this big a job in my driveway means I cant really clean the heads prior to reassembly.

I dont want to replace the chain adjuster gaskets with my new ones in order to test the compression since if its bad I will have to redo it all, but If i dont and the test is good I will have to remove the adjuster anyway to put the new gaskets on. Man I wish I had not left that cam lock bar in place!!!

 

BUt i would not have found the broken adjuster pad had I not.....

 

Just an update for anyone who has followed this. Spoke with the machine shop today and I need 2 intake valves replaced and all the exhaust valve seals are at the edge of specs, thats how he said it, so replace those and re-seat all 12 exhaust valves. Not jumping for joy but I am pleased that it appears my mess up in the beginning actually pointed out the broken cam adjuster and then the bad exhaust valves, I think I did damage the two intake valves but had I put this all back together the adjuster would have caused a catastrophic failure had i not messed up so...I guess I am happy right now.

 

Not that anyone other than Paul cares but...I got the heads back from the machine shop today and will begin reassembly in the next couple of days. I must confess that based on conversations I have had with the machine shop and others this motor has me scared! the machinist told me the weight on the head alone is sufficient to bend a valve. That is a bit of info I would have liked to have had in the beginning of this project. I must also add that I am disappointed with this community as a whole. I started this thread asking about the "general" reliability of this motor and no one has ever responded to that question and Paul is the only one who has ever responded at all. I would have thought that a community of Audi enthusiasts would be more helpful to a new Audi owner undertaking what is basically the most extreme repair one would ever undertake short of trying to fix a head on collision. I have learned, from people outside of these forums, that this motor has had lots of problems not the least of which is that a slight amount of carbon buildup on the valves could result in bending a valve due to the fact that the tollerances are sooo tight. I also learned that this motor has timing problems due to the fact that the timing chain adjuster is powered by oil pressure that is , at start up, too low therefore it will break adjusters and other components. These are all things I had hoped to learn by joining these forums and asking about my particular motor. Paul has been very kind and helpful and I thank him.

 

now you have the heads done, make sure you use new head bolts and angle torque them as per the manual. Follow the manual putting the heads on, there is a correct position for the cam shafts that makes sure you don't bend valves putting the heads on.
The 2.8 engines are pretty robust if looked after but they do need more maintenance than an iron V8