LT1-LT4 Modifications 1993-97 Gen II Small Block V8

After rebuild startup problems??

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Old 05-21-2012, 10:26 PM
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Default After rebuild startup problems??

Well after getting everything bolted up I tried to start the Firebird. Got it to fire up with some gas but its not running on all cylinders and wants to die. So thinking my rockers may be to tight. Pulled the drivers side valve cover to find it a lot dry. So turned it back on to find no oil is coming up. I primed the oil system till I was getting oil to the rockers an all but cylinder 1 and 2 was not strong. That was 5 days ago. Anyways here is a video of it running.
http://www.youtube.com/watch?v=KCoor8VYEgw

Then after that it sounded like it was not firing when you turned the key without pressing the gas. Should it sound like this with a new engine that has not been broken in.
http://www.youtube.com/watch?v=MInH7cCB-Eg
Old 05-21-2012, 11:06 PM
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Your rocker arm geometry is way off & from the looks of it the poly locks are ran all the way down If you didnt bend any push rods Google proper sbc rocker arm geometry & go from there Rocker arm adjustment varies on different cams Stock is Zero lash plus 1/4 to 1/2 turn Some aftermarket cams are Zero lash only Alot depends on your combo More info will help Too tight can equal bent push rods , valves & pistons if your cam is huge & the heads & block have been shaved Hopefully you didnt have a real expensive oh ****
Old 05-21-2012, 11:31 PM
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Polys are close to the rockers. And how much clearance do you have at the retainer? Needs to be .050" minimum. And are you running without a tune? How did you set the lash? What cam ? Need more info...
Old 05-22-2012, 06:44 AM
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The unevenness when cranking suggests that some rockers might not be adjusted correctly. It often takes a long time to get oil to all rockers on a fresh build, but you should at least pour some oil on the complete valvetrain before running it.
Old 05-22-2012, 11:31 AM
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Well here is the run down. Setup is a stock 355 rebuild with a cc503 cam,1.6rr,stock length hardened pushrods. Worked with a lt4 hotcam so swapped to the cc503(They sit right in the middle of the valve). Computer was tuned by pcm for less. Its a mail order tune. Compression is around 10.8-11:1. Heads have been milled .010 and the block has not been decked.

Well after reading some information on the 4th gen tech articles. I have way to much preload. When I did preload I would spin the pushrod till it stopped spinning the added 1/3 turn of preload. Looks like I need to go back and redo it all over again. I will check all the push rods and make sure they are straight.

Then I will go back and find tdc on cylinder one or 6 and start this method.

When at #1 TDC you can adjust the following valves:

Intake: 1, 2, 5, 7
Exhaust: 1, 3, 4, 8

Rotate the crank one revolution until the pointer is again at 12 o'clock. This will let you adjust the remainder of the valves. If you did #1 the previous time, you should be now at #6 TDC.

When at #6 TDC you can adjust the following valves:

Intake: 3, 4, 6, 8
Exhaust: 2, 5, 6, 7
Old 05-22-2012, 12:46 PM
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Originally Posted by shbox
The unevenness when cranking suggests that some rockers might not be adjusted correctly.
Exactly. It's either that or there is another bad reason why pressure is not able to be maintained in your cylinders. Your battery sounding like it's almost dead does not help matters when trying to start it either.



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