Just changed out valve stem seals on my 2009 cooper. Also did chain/guide/tensioner while I was at it. Everything seemed to go fine and cat starts and runs fine, but I have a loud ticking noise now. I thought it was in the exhaust side valve train so I pulled the exhaust cam back out and checked/reseated rockers and lifters but no change. Video attachment for reference. Thoughts?

 

Try to pinpoint noise source using an engine stethoscope.

 

I did that. Lead me to believe it was on the exhaust side but apparently not lol.

 

Did you raise the front end on stands and use the stethoscope around the oil pan, timing chain area, serpentine belt, tensioner, alternator, friction pulley, and water pump?

Were any of the replaced timing chain guides broken? If so, did you recover all of the pieces?

 

Guides were all in tact. I pulled the valve cover again this morning. Found the problem! One of intermediate levers on Cylinder #1. I'm guessing the spring wasn't seated correctly on that one. Checking now to make sure I got all the pieces. Lots of tiny roller bearings. I'll fit a new intermediate lever and we'll try again.

 

Glad you found it! Good luck with fix.