wlstanhope

So it was time to do the second replacement of my timing belt on my 2005 A8 4.2 V8. Routine maintenance, nothing apparently wrong. I got the belt, new pump, pulleys, etc - the whole kit and proceeded to strip the car, putting it into service position, taking photos of everything that i took off along with notes, bagging and tagging along the way. everything was going great.

The previous timing belt was put on by Audi at around 80k miles. one thing that i did notice when i took the old belt off is that the eccentric pulley was on in the tightest position possible, and the piston applying force on the pulley tensioner was fully retracted - the belt was tight. I have the correct tool to lock the cams together in timing. I proceeded to put on the new belt - but putting it on following specifications so that there is 5mm of piston on the pulley tensioner and the correct torque. all seemed well.

I then went to slowly hand crank through two revs of the crank - i got nearly half a crank through and came to a stop. I was able to reverse back to TDC and go back nearly half a revolution. so in total - i can get about 95% of the way through a revolution.

The first thought is - it must be out of timing. I know i need to revs of the crank to know for certain by that method and i cant get that far. so i remove cam case covers to watch cams and valves, i make and mark a dipstick for TDC and BDC. when it stops there is a piston on each bank a few MM off TDC, on the drivers side it is in compression stroke - valves are closed. on the passenger side - it is just completing exhaust stroke. The cylinder adjacent on the same cam just cleared exhaust stroke.

To further trouble shoot i advance, the retard the crank timing a tooth off TDC to see if it would stop the crank in a different position - but the crank stops in same position (i am not using brute strength - when it stops so do i - using a ratchet - so if interference it would not damage)

I have also been using a borescope through the spark plug hole - the valves on the cylinder in compression stroke appear seated. the other cylinder does not appear to have piston and exhaust valves interfering.

For ****s and giggles i took the lower and upper oil pan off to see if there was anything interfering with the connecting rods and crank - dont see anything.

I am lost for words now. Am i overlooking something here on the timing? Could a faulty starter or torque converter or anything else cause this symptom too? What else should i diagnose? I am probably missing part of my diagnosis - i have been troubleshooting different things on this!

Thanks!
Wes

aTOMic

Hello Wes, welcome to AW.

Is it possible that engine compression is stopping your test-turns? I forgot if removing all the plugs is specified in Bentley.

Post your query in the D3 forum; no one reads the individual engines IMO.

Tom

wlstanhope

Hi Tom,

Thanks for troubleshooting.
Forgot to mention that when I felt resistance I then pulled all spark plugs to rule out compression.

Thanks

Wes

aTOMic

Wes,
Ha, told you there'd be more response from the D3 forum. You have the two smartest guys on the board helping you out!
I think Misha has a French Canadian accent and uses speech-to-text, a lot of times he has what appear to be typos but if you read it to yourself you can hear the Francaise.

Sorry for my freshman attempt at diagnosis re the plugs, after reading the other thread it's obvious you know what you're doing... but Occam's Razor.
Link to thread for future searchers.

Good luck my friend!
-Tom

PS Fill in your profile (location at least) when you get a chance. Always nice to know where fellow Audienthusiasts live (New Word I just made up). There are guys on D3 board from Alaska to Brazil, even Romania is fairly well represented!

wlstanhope

Hi Tom,

Thanks for the advice! I did not see the D3 forum, so good to know. I have hit a mental road block so good to have others throw in some ideas to trouble shoot. I lived in Ireland for 17 years.. so if i use speech recognition it does not work all that well.... in between accent. I have also had a 2003 C5 Audi (saved my life when i was rear ended by a jeep commander at road works - i was stopped the jeep was travelling at 78mph.... now that is what i call good engineering ehh?) and a B5 before that. I have also had an E39 bmw and E30 bmw (both straight six, manual, and RWD) prior to my Audis'- i like the german cars.

I will update the profile too - talk to you later buddy!

Slainte!
Wes


Ha, told you there'd be more response from the D3 forum. You have the two smartest guys on the board helping you out!
I think Misha has a French Canadian accent and uses speech-to-text, a lot of times he has what appear to be typos but if you read it to yourself you can hear the Francaise.

Sorry for my freshman attempt at diagnosis re the plugs, after reading the other thread it's obvious you know what you're doing... but Occam's Razor.
Link to thread for future searchers.

Good luck my friend!
-Tom

PS Fill in your profile (location at least) when you get a chance. Always nice to know where fellow Audienthusiasts live (New Word I just made up). There are guys on D3 board from Alaska to Brazil, even Romania is fairly well represented![/QUOTE]