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Help - a few of us making less power after Cam install

Posted: Mon Dec 31, 2007 11:26 am
by 6spd_ek
this has been an on going saga for some of us - with a wide variety of cams being used (different brands IPS k2, k2 mkII, skunk, etc)

-dowel pins on cams checked & not pushed in
-cam plates checked & arrows properly line up with parting line of cam caps
-cam gear timing marks line up properly with 9 links space between vertical markings (both pointing in the middle of a link)
-crank gear properly timed - the marked sprocket (a 7 o'clock) points in the middle of a link
-checked cam plates with a 3/16 dowel inserted through holes
-made sure exh cam plate is on exh cam & vise versa with intake plate & cam
-after tensioner reinstalled cranked a few full revolutions to make sure timing is still on @ TDC

I tested muliple intake manifolds & 2 headers made by the same company made to work with these cams. obviosly vtc was datalogged & k-pro shows vtc working as it should

some similarities between some of us are:
-cams make most power with unusual high VTC than those with same cams (that don't have problems making power) ie ~15 more vtc across the hole rpm range
-a few of us switched to RDX injectors (which I had flow tested by RC engineering & flowed much better than stock with a better spray pattern than stock & RC440's) - does polarity matter with these? how about the positioning of the injectors in the manifold - maybe pattern is too wide & catches the end of the passage way?

can a sensor be going bad & NOT throw a code - particularly crank or cam sensors. any other ideas? obviosly valve lash will be rechecked

why does helms manual say to keep magnets away from timing chain?

-Greg

Posted: Mon Dec 31, 2007 3:43 pm
by 6spd_ek
one thing to add is - the above has been done after reinstalling the chain. Prior to reinstalling the chain the 3 timing marks (exh gear, intake gear, & marked sprocket of the crank) lined up inbetween 2 links b/c chain slipped off of crank during cam install. On a k20 all 3 marks MUST point in the middle of a chain link according to some experienced in cam installs

even tho all three were off were of the same amount it seems this could somehow mess up timing. I am not sure if I understand it - but the proof will be when dyno again.

I will be sure to post an update when I do