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View Full Version : stumbling/chain noise after vanos install



dust4life
07-22-2009, 09:57 AM
i'm too exhausted to search http://www.m3forum.net/m3forum/images/smilies/frown.gif if theres a thread please link me.

just finished up my lifters/upper chain tensioner/upper chain/DrV stg2 install and everything sounds great. once the oil circulated up through the new tappets all the annoying racket is quiet. everything idles fine, maybe a little more lope then before. my timing may now be ~1 degree retarded, the TDC mark may have been a tiny bit off during the timing of the new vanos.

took it for a test drive and putting around everything feels amazing. sounds great, everythings smooth and even feels a bit more tourqey then before. when i get on it 1/3-1/2 throttle it picks up nicely and climbs for about 1k before theres an awful chain on metal sound and it stumbles hard. if i hold 1/4 throttle the revs will build smoothly up past 5k without issue its only if i give it a little boot. once i let off everything returns to normal.

any ideas? i'm fried and currently stumped. install was smooth as silk minus searching for missing bits http://www.m3forum.net/m3forum/images/smilies/facepalm.gif and everything was properly tq specd...

Balthazarr
07-22-2009, 01:49 PM
Did you tighten the lower tensioner to spec?

dust4life
07-23-2009, 12:52 AM
Did you tighten the lower tensioner to spec?
biggest failure of the install: didn't fully torque it before the first turn over, noticed a sweet wave of oil pouring out after a minute or so. its now solidly torqued, and it seems impossible that during the minute of "mostly but not entirely torqued" operation the cam could've skipped a tooth. cams look to be perfectly in phase (just reopened the valve cover) but i'll check tomorrow with the blocks.

Craig S
08-17-2009, 11:34 AM
You ever figure this out?