okay - this may be a dumb question but it could save me some time- basically car ran perfect after cam and valvetrain install, didnt have much power but assumed was due to no tune at time-next day basically car sputtered/wouldnt hold idle and died- now she wont turnover -

ive replaced - new opti - new coil - new alternator - new battery - new fuel filter - new vacum lines - new plugs - new wires - and checked everything - getting good strong blue spark - fuel injectors are spraying well- shes getting good fuel - checked to make sure opti was aligned properly- timing chain was on correct- checked all connections and has good vacum but she still just cranks and wont turn over -

so that leaves me with valvetrain- Is it possible to be able to loosen the locks on the rockers and set the valve lash 1/4 turn less on all rockers without putting each cylinder TDC ? or do i risk dropping a valve? i basically just want to loosen the valvetrain so i can be sure nothing is too tight and then if car starts ill know that was the problem and be able to reset all correctly.

thanks

 

Would be better to relash the rockers while the car is running. Loosen them one at a time until they start rattling and then re-tighten them until it just stops making noise.

Otherwise use the TDC method. Don't blindly loosen all your rockers.

 

thats the problem - car cant start - ohh well guess ill just bite the bullet and reset the valvelash completely the correct way -

ive just about given up on the engine and am ready to have it towed somewhere - my mechanic friends are stumped as well.

 

Put the front up on jackstands.
Pull the valve covers.
Turn the motor over by hand using a 5/8" socket on a breaker bar.
Watch #1 until they are on the back side of the cam.
Losen the rockers on #1.
Spin the pushrod in your fingers while tightening down the bolt. Right when it stops spinning in your finger, adjust 1/2. 3/4..whatever you think is the right adjustment. I do 1/2.
Turn the engine 90 deg...go to the next in line...8...4...3...6...5...7...2.

WHen you start...you mean turnover or start?

 

Did you try resetting the computer?

From the first day to the second, what happened? Did you sputter and not hold idle on startup or was it running then this started happening? How long was it running the first day? What cam are you running without a tune?

I don't see how the valvtrain could be so far off that it won't even fire, unless you never tightened the locks and they all backed out...

Sorry for all the questions, but they will possibly help in trouble shooting this...

 

Well - its easier to adjust using this method -

okay and since u asked ill give u the summation of the install - car is 97 z28 112k on clock - month ago tore her down and installed :

Parts installed -
CC XE 230 / 236, .510 / .520 112 LSA Cam
Comp Cams 26918-16 springs
Comp Cams 787-16 retainers
Comp Cams 601-16 valve locks
Comp Cams Pro Magnum 1.6 RR
ARP 7/16" rocker studs
Comp Cams 720H-16 pushrods
New Valve seals
AFR guide plates
LT4 timing chain

okay- we installed everything and started her up [ first try she turned over immediately] and she ran perfect except a high idle (1100) figured was just because of no tune at that point - held car at 2k for about 10 minutes just to get oil going then let her idle for about 30 min. [ video of her idle that night took her for a spin down the street just to check everything and parked her - I drove the car home couple days later and ran great the entire way would idle at a stop and good throttle responce. Well 2 days later i started the car up and she was running rough and having trouble idling, drove her around my parking lot and she wouldnt idle and would only run if i kept giving her gas.

popped the hood and found i had a cracked coolant hose which started spitting on my opti , also found crack breather line on vavlecover- So i cut out and replaced the coolant line and capped my TB and put a breather on the valvecover. Still wouldnt idle on her own- Got my MadZ tune in and she still wouldnt idle.

Did some testing and found my alternator was bad (powdercoater never taped off where bearings went and they were pushed out far enough to destroy the shaft) so he bought me a new alternator. bolt it on and car would crank but wouldnt start. she coughed like she was trying but wouldnt. Assumed battery might be on way out from running so much without alternator, so i got a brand new diehard thanks to their warranties. put it in but again car cranks and wont turn over. tries every now then but just cant get it to start.

So i assumed opti crapped due to the coolant- Friend had a brand new one in package and since he had upgraded to LS1 he gave it to me for free while replacing - i checked the sleeve was on WP and timing chain was still good - made sure to align opti correctly- installed my new plugs and new wires and a new coil. Put it all back together and she just cranks and wont turn over. Same as before. Since ive replaced fuel filter, tested the signal to injectors, pulled injectors and checked- tested fuel pressure, pulled some wires and im getting nice consitant blue spark from them. went back through and checked all harness connections- replaced any questionable vacumn lines- tested vacum and shes holding fine. In desperation even went through all the fuses and all are good (except finally fixed my ABS problem- guess fuse had blown last year and somehow i never thought to check fuses )

popped valvecovers and everything looks perfect on drivers side at least- havent pulled passenger because i ran out of time. But had friend crank engine and all rockers are moving.


Basically at this point ive just about run out of options- im on a college budget - at college where i maybe have 1 day a week to mess around on this - winter is here but luckily snow has held off - and ive got 2 more weeks to get the motor running so i can get the car back to connecticut. so..... any other ideas ? ive posted a number of times and no-one has come up with anything which could be culprit.

the reason for me thinking may be valvetrain is a buddy had similar problem.. car ran fine at first- then sputtered and died - couldnt turn over... turned out exhuast rocker on #8 loosened up enough where it wouldnt open his exhuast valve.

 

Not holding idle or not running unless the throttle is being pressed in tells me the IAC is messed up, do you have any way of scanning the car?

 

But you are also correct that if the rockers loosened up it could do this too...

 

no way of reading the IAC readings - but also forgot to mention that im throwing no codes on my OBII scanner-

 

How long did you let your intake maifold gasket cure for. I am in the middle of doing a cam swap and bought a bad batch of permatek silicone that didnt seal after 5 days. Car started right up and I boke in the cam but had a major manifold leak that kept it from starting again. I woul check that right away if I was you.

 

By far the easiest method....

 

was three days before i started her - ill check to see if perhaps the manifold isnt sealing- didnt realize that could cause her not to start-

thnx guys

 

Those were my exact thoughts but when I went to pull it off, the silicone was still wet and all slimy. Its like having a huge vacumm leak.