87 IROC engine problems
EdgeZero87IROC
09-06-2005, 12:14 AM
I have just redone my gaskets on my heads and my intake manifold, and put in new spark plugs, wires, distr. cap, rotor and I timed it. It runs but ruff then it did. And when i start it, the throttle goes way up it 2500 and goes down slow, it goes down to 500 and runs really ruff, and dies. Also when i start it up when it has been running awhile it is really hard to start. please help if anyone has any susgetions thanx.
Morley
09-06-2005, 12:58 AM
Triple check your valve lash.
EdgeZero87IROC
09-06-2005, 02:39 PM
what is the valve lash????
aweiserbud
11-03-2005, 05:47 PM
distributor could be 180 degrees off or u could have ur firing order messed up on ur wires. double check them. both are common mistakes.
demon9766
11-07-2005, 08:55 PM
I don't think it is 180 out if it was it would backfire out the carb and wouldn't run at all. But he might have two of his wires out of order,and the timing might be out a little,and it sounds like he might have a vacuum leak at the intake if the rpms go up like that.
silicon212
11-08-2005, 12:27 AM
demon9766 nails it. I'd look for a crossed wire, and vacuum leaks. Particularly the intake manifold gaskets. Look for the presence of oil or combustion gasses in the coolant, and/or the presence of coolant in the oil. This could indicate a leak either in the intake gaskets or the head gaskets.
BTW don't worry about valve lash. If there was a problem with the valve lash, it'd be hammering mad when it's running. However, if you tightened the lifters down too far, then the valves might not be fully closing which could cause the symptoms you have, as well as backfiring etc. Valve lash is the measurement of space between the rocker arm and the valve when that cylinder's cam lobes are on their base circle. On a hydraulic cam/lifter setup the valve lash should be zero - nonexistent. If there was excess lash, as stated above, the rocker would hammer the valve on the opening causing the "click", "tick", or "smack" that you often hear coming from the upper end of older engines.
BTW don't worry about valve lash. If there was a problem with the valve lash, it'd be hammering mad when it's running. However, if you tightened the lifters down too far, then the valves might not be fully closing which could cause the symptoms you have, as well as backfiring etc. Valve lash is the measurement of space between the rocker arm and the valve when that cylinder's cam lobes are on their base circle. On a hydraulic cam/lifter setup the valve lash should be zero - nonexistent. If there was excess lash, as stated above, the rocker would hammer the valve on the opening causing the "click", "tick", or "smack" that you often hear coming from the upper end of older engines.
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