Back-story: My daily driver '98 Audi A4 1.8t was originally purchased with a busted timing belt, the head was removed and sent to a head shop for refurbishing and replacing 12 bent exhaust valves! The head was installed, car put back together but never really made as much power as it was supposed to and the fuel economy was also disappointing. I drove it this way for 50,000 miles. This time around I chose to put in new lifters and cam seals.
While setting the timing to its marks before tear down, things where not lining up quite right. When the cam gear was pulled off we noticed that the cast wood drift key in the cam gear was busted off! It also probably not lined up exactly on the cam. Meaning my timing has been off for the past 50k! Meaning that the machine shop didn't bother to tell me that the cam gear was broken, and all this time all that prevented the cam gear from slipping on the cam was the cam gear bolt.
I sourced a replacement cam, actually a couple of them, as the slot in the cam for the wood drift key looked a little damaged. An observation is that 1.8t exhaust cams are not all the same. Some have a whole slot cut, others have a half moon cut out. However all cam gears seem to have the half moon shape. I have no idea about cam duration or lift. Some Google searching hasn't reviled any difference.
Much thanks to my friends Darrin L.and Andrew C., David S. for helping!
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