Vt not starting after rocker install (backfires)

[Milesvtcalais]

Ecotec v6
Hi all, sorry for posting again but I couldn't find a direct answer so here I am... again :-(
So anyway I purchased some 1.98:1 ratio rockers off gumtree that were second hand and they came with some push rods which I believe were a little longer than stock, I think they were comp cam ones I believe. Anyway I installed these and stupid me didn't have any instructions so I just went with what felt good. I pulled the old stuff out and put the new stuff in, including the rocker plate. When putting the battery back in I arked out the positive terminal on the tie down point (thought I killed the bcm but I didn't as I replaced it with a new bcm, ecu and key from another Calais. When I tried to start the car it ran for 2 seconds then shut off, all it would do is turn over with no fire at all. I let it sit for 20 mins and tried again and it backfired and its repeated that ever since.
Anyone got any suggestions on what i may have done wrong on the install? Over tighented the rockers or something like installed the rocker plate on upside down.
Please help

 

[ant797]

i dont know much about that side of things but wouldnt you have to adjust the valve clearences to spec after doing that

 

[Trevor loves holden.]

So that explains it then, my advise take it or get a mobile mechanic out, longer rods will upset the timing I imagine, u going to need to reset the valve clearances, then I called be wrong.

 

[the_boozer]

are the valves closing if the push rods were longer? I didn't think there was any adjustment on ecotec valve clearances, have you got all the wiring back on where it came from haven't mixed up the supply and return fuel lines? If you have a compression tester do a test on a couple of cylinders to prove the valves are closing.

 

[mechanic]

Check the spark plug leads are on the right way.

 

[strgas]

Shim the rockers to obtain correct setting . No valve clearence due to hyd lifters . Sounds more like valves are hanging open due to incorrect push rod lengths. Placing shims under rocker pedstals will help but recheck tip contact to valve and rocker ...

 

[Milesvtcalais]

Shim the rockers to obtain correct setting . No valve clearence due to hyd lifters . Sounds more like valves are hanging open due to incorrect push rod lengths. Placing shims under rocker pedstals will help but recheck tip contact to valve and rocker ...

Hey mate, you were spot on. Even when the camshaft was supposed to be in the fully closed position the longer push rods were keeping it open, I pulled them out and put the stock ones and and made sure not to over tighten the rocker arms. Filled them full of lock tight so they wouldn't move though.
Haven't started the car just waiting for the lock tight to cure.

 

[losh1971]

I think you have two threads on much the same thing. Like i already said you need to measure the preload and torque the bolts to 25lb any more or any less you can have problems. A member stuffed it up a few years back and fucked the threads in the head resulting in the need for helicoils. Once we told him what he needed to do to fix the problem we never heard anymore, so not sure if he fixed or gave up.

 

[Trevor loves holden.]

Yip that's what I was getting at by clearance as there is no adjustment, if the rods don't allow the valves to seat correctly ( hanging open ) on each stroke it cant fire due to low combustion in the top of the cylinder and the fuel will end up out the exhaust, great you went back to the original rods so should be sweet now. Good way of bending valve steams,
*Valve lifter guide plate 26-34Nm
*Rocker assembly bolts 11-19Nm then turn a further 87-93 degree turn.
*Rocket cover bolts 7-11Nm.

 

[Milesvtcalais]

Yip that's what I was getting at by clearance as there is no adjustment, if the rods don't allow the valves to seat correctly ( hanging open ) on each stroke it cant fire due to low combustion in the top of the cylinder and the fuel will end up out the exhaust, great you went back to the original rods so should be sweet now. Good way of bending valve steams,
*Valve lifter guide plate 26-34Nm
*Rocker assembly bolts 11-19Nm then turn a further 87-93 degree turn.
*Rocket cover bolts 7-11Nm.

Hi trevor, got the car running just now and was wondering how to adjust the lifters, if I adjust them to where the car runs smooth the bolts are super loose, if I tighten them too far it runs like crap... what should I do. I also adjust them while the motor is running