new cam probs

[steveosupremeo]

ok here goes, a friend and I installed a comp cams 268 duration cam in my car yesterday, was told by comp cams it was a 420 lift, with stock lash pads i have about 2 mm left on the lifter side of the rocker arm pad on all of the rockers, so i know i will need to get some slightly thicker ones to center it, but it does run. its a lot more lopey than i thought it would be for such a mild cam. 110 degree separation. anyway, around 600-700 rpm, idling, i'm having what sounds like knock around the #3 and #4 cylinder area. when i first let off the throttle after break in, it idled at around 500 rpm, before the cam it was closer to 900 rpms. the cam sprocket is at the #3 setting, where it was with the stock cam. my timing was 14 initial. i have the 240sx tb and adjusted idle up to about 900-1000. it ran smoother with the timing set at 18 initial so i left it there, don't have but a basic timing light so i cant check total advance . i also have headers and full 2.5 mandrel exhaust, and cold air intake. car is bone stock internally other than the new cam. one other prob is i am running the zx dizzy with E12-80 module, new everything, fully rebuilt, including a fairly new vac advance from MSA. with the vac advance plugged in it will rev up on its on and stay around 2000 plus RPMs, or more, sometimes it won't do it till the first time you rev it, then it'll stay high. any ideas about the vac advance? what about the knock? thanks guys. PS, probably gonna put the cam on the #1 setting today.

edit: wouldn't hurt to say this is a 77 280z 4 speed, stock 3.54 gearing.

[steveosupremeo]

ok, set the sprocket to #1, even though i have some chain stretch, and adjusted the valves to 10 and 12 instead of 8 and 10, this moved my wipe patern slightly towards the middle (good) but i still have them close to the edge, after playing with some clipped off pieces of feeler guage, it looks like the .150 pads should be ideal. maybe i can still get them from nissan. still working on the vac advance. i noticed that with the lower vacuum in the manifold that i'm running a few more PSI fuel pressure at idle, nice. also this moved my idle up some and seems smoother but, but it could just be me.

[e_racer1999]

you can get lash pads from MSA.

 

did you swap out rocker arms or resurface when you installed the cam?

[steveosupremeo]

i resurfaced them, just enough to get the little edges off of them at the wear pattern. i'm not having any wear issues on the lobes or rocker pads. its looking like 150, maybe motorsport can get that size, someone said recently that they were out of some sizes and would have to get bigger ones and machine them down. i'm not down with that. lol.