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I turned it over to TDC and the tension's back - it feels very "even" now (piano string is a good way to describe it)
Thanks all & sorry for the confusion
Now one more, here's the crank and bank 2 cams at TDC. The intake cam is (as the computer told me) retarded. Is this proof that the adjuster's bad, or proof that the cam sprocket is off, or proof of nothing because the position of the intake cam is not guaranteed?
I turned it over to TDC and the tension's back - it feels very "even" now (piano string is a good way to describe it)
Thanks all & sorry for the confusion
Now one more, here's the crank and bank 2 cams at TDC. The intake cam is (as the computer told me) retarded. Is this proof that the adjuster's bad, or proof that the cam sprocket is off, or proof of nothing because the position of the intake cam is not guaranteed?
That does not look like an adjuster problem...not typical...looks like outer belt timing off (retarded) on that side.
Not only do you need to be at the correct TDC (cylinder #5...2 TDC's per cam revs) which you apparently are, BUT the holes on the cam belt pulleys (see drawing) must be dead level all the way across, with large holes facing inwards...at this position, the cam lock bar can be placed on there...I don't even own one, but you can check this with a long straight edge (yard stick) which is close enough for checking.
If the holes are not at dead level when the crank is at TDC #5, then the belt (not the chain) is off a tooth or two on bank 2. You can't get an accurate check of the cam chain gears until you have TDC and holes dead level on the cam belt pulleys first. Once those are correct, the intake cams should be lined up with the marks on the head under the valve covers. IF not, the chain may be off a tooth.
The amount of retard and advance done by the adjusters is so mechanically subtle, it would barely show on the timing marks...especially at engine rest, since the adjusters return to the most retarded position anyway (for easy starting) when you shut the engine off.
So, check all the outer belt timing first, before looking at the adjusters or chains. If the belt is off a tooth or two there, it would also likely generate your over-retard code.
That does not look like an adjuster problem...not typical...looks like outer belt timing off (retarded) on that side.
Not only do you need to be at the correct TDC (cylinder #5...2 TDC's per cam revs) which you apparently are, BUT the holes on the cam belt pulleys (see drawing) must be dead level all the way across, with large holes facing inwards...at this position, the cam lock bar can be placed on there...I don't even own one, but you can check this with a long straight edge (yard stick) which is close enough for checking.
If the holes are not at dead level when the crank is at TDC #5, then the belt (not the chain) is off a tooth or two on bank 2. You can't get an accurate check of the cam chain gears until you have TDC and holes dead level on the cam belt pulleys first. Once those are correct, the intake cams should be lined up with the marks on the head under the valve covers. IF not, the chain may be off a tooth.
The amount of retard and advance done by the adjusters is so mechanically subtle, it would barely show on the timing marks...especially at engine rest, since the adjusters return to the most retarded position anyway (for easy starting) when you shut the engine off.
So, check all the outer belt timing first, before looking at the adjusters or chains. If the belt is off a tooth or two there, it would also likely generate your over-retard code.
Thanks for the reply, I did do my best to make sure the TDC markers were level, and they do seem to line up (but I don't own the tool so...)
I think the teeth are wide enough apart that being one tooth off would be obvious, but maybe you seasoned audi veterans can spot something I can't
Looking under the valve cover I think someone's had the head off this engine recently, there's some scratches around the bolts, not to mention the markings on the cam sprockets.
Although, the belt sprockets on the cam aren't keyed right? so technically it could be 1/2 tooth off =)
it really looks like the chain is just off to me. I didn't have time to pull the bank 1 vc before the rain started so I don't have anything to compare it to yet
Although, the belt sprockets on the cam aren't keyed right? so technically it could be 1/2 tooth off =)
it really looks like the chain is just off to me. I didn't have time to pull the bank 1 vc before the rain started so I don't have anything to compare it to yet
Actually, on the 40v engine, the exhaust cams are indeed keyed to the "tabs" with the holes on the cam pulleys...so if cam-lock tool is in place (holes dead level) the exhaust timing has to be correct.
So, if the chains are in place correctly, the intake cam timing would also be correct.
Unless you already have, might wanna do a chain link count. You really need to look at the angles shown in the drawings to get it right...one link-counting angle of view is (as you may see) offset a lot compared to the others (bank 1 exhaust cam).
It's a different chain count from bank to bank...I've heard a few stories about mechanics without a manual matching the count side to side, causing retard/advance in just one cam.
from what I can see the bottom pad of the adjuster is fine but I'll have to get a better look at it when I can get it out (I had to order the de-tensioning tool & the gasket for the adjuster)
That begs the question, is it possible the intake cam jumped a tooth on the chain if the tensioner's fine? I'm thinking it's more likely that this engine was just re-assembled by idiots
Chain jumping seems extremely unlikely to me. There would be a really terrible noise if the chain was that loose and you'd see signs of wear from the chain hitting the valve cover.
Chain jumping seems extremely unlikely to me. There would be a really terrible noise if the chain was that loose and you'd see signs of wear from the chain hitting the valve cover.
I'd vote for incorrect installation.
"this engine was just re-assembled by idiots"
Absolutely agree...can't see chain jumping in this design at all, unless the adjuster lost a pad(s) and was driven until it destroyed the rest of the adjuster.
09-13-2014, 07:02 AM
