OK, quick rundown:
D16Z6 block, stock sleeves
D16Z6 head, stock valvetrain
Wiseco 75.5mm 8.5:1 pistons and Wiseco rings
Eagle H-beam rods
Clevite bearings, rods, mains, thrust
new OEM timing belt
head and block were just decked to make sure they were flat, no major milling
brand new aftermarket distributor
OBD0-OBD1 conversion including dizzy conversion plugs
megan adj. cam gear
brand new OEM wires and plugs
virgin P28 ECU
no CEL's

now lets get to the problem:
I recently got the freshly built engine in the car and at first had distributor problems (which is why i got the new one) and I'm sure they were dizzy problems because the same dizzy was tested on another car which had the same symptoms.
so, new dizzy in, check timing, seems to be OK, timing belt is just a little loose for my liking. oh well, lets give it a try and see what happens. still getting some bogging and hesitation.
so, i figure i may as well get rid of the gas that is in the tank and start with a fresh tank since i bought the car as a shell and wasn't sure how long the car sat with that tank in (it has sat in my posession since August). start it up and it seems a little better, but still not quite right.
open the hood and recheck the timing. it's off again. now i'm thinking that it might be my adj. cam gear as the culprit, but i compared the OEM cam gear markings to the ones on the Megan and they are right on. I go ahead and go as far as to take the timing belt cover off and triple check the TDC marking on the crankshaft sprocket and compare it to the cam gear. dead on. i even tighten the timing belt with the cover off so that I can assist the tensioner spring to get the belt a little tighter. reinstall everything, and recheck the timing.
i still can't get the timing to get within range. i rotate the dizzy all the way towards the firewall and it still is reading about 12*-13* BTDC. so, i figure that the aftermarket dizzy has the mounting surface a little off, so i round out the adjustment holes a little and try it again. now i can get it within range, but it still doesn't seem right at low RPM's. this is when i give up.

any ideas??




Modified by DelSolDon at 9:01 PM 2/2/2006

 

almost forgot to add (but doesn't seem like it would have anything to do with timing) that the car is turbo with everything bolted up, using OEM injectors, wastegate spring removed.

 

well, i think i figured it out with some help. it is probably the cam gear, because Megan probably only makes one cam gear for both Z6 and Y8 engines where they have a 0.5 degree difference in OEM timing. hopefully adjusting the cam gear will fix it. [crosses fingers]

 

Right before i read your last post i was about to post "Check out that cam gear and make sure everything is right with it." haha.

 

Have U Try replacing Back to OEM cam? My similar problem was (My setup : d16z6 stock all internal 450cc dsm, vafc2,255 pump, w/ greddy td04h kit @9-10psi) Ran my car for a while then notice the problem like yours (bad idling or hesitate to idle correctly so what came down was my 2 cyl comp was way low as other. Did U get comp test? About timing... try taking off the belt and put crank to mark, then move you dizzy to middle so u ca get some +/- degree later now put the cam to mark then slip the belt on. You will not get a perfect marking that why now u can move you cam to get the deg u perfer. Btw u got a timing gun? And after all that, if ur timing still move then replace that cam gear. If timing have not moved after u test it, and still have bad idling then most and likely its one of ur cly get comp test. Ur car what color is ur exhaust fume? I dont know all problem but I hope this help.

 

no, i haven't done a compression test yet, and yes, i have a timing light. gonna try to adjust the cam gear and hope that is all it is. i heard that compression could be the problem, but i don't understand why compression would not allow me to get my timing within range.

 

got the timing dead on after messing with the cam gear and advancing it 1 degree, then tweaking the dizzy.

then, i just drove it home and it is just fine at all RPM's except that it still stumbles when starting from a dead stop (i.e. 1st gear up to ~1500 RPM). is this because of the low compression pistons? or possibly because i am running with the wastgate spring removed and don't have any backpressure in the exhaust?




Modified by DelSolDon at 10:46 PM 2/3/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DelSolDon &raquo;</TD></TR><TR><TD CLASS="quote">then, i just drove it home and it is just fine at all RPM's except that it still stumbles when starting from a dead stop (i.e. 1st gear up to ~1500 RPM). is this because of the low compression pistons? or possibly because i am running with the wastgate spring removed and don't have any backpressure in the exhaust?
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