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im going to reset my c4's timing because after my mechanic replaced the intake manifold the valves rattle as engine warms up...i think i just need to advance timing...i have the light...do i need a special wrench to fit below distributer or just normal tools...its an l-98 LONG BLOCK 350. any help is much appretiated.thanks.:patriot:
 

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Suggest that you check the timing and if not at the setting as prescribed on the placard under your hood then reset it to that proper setting. Your mechanic might have not set it properly after working on the car causing your pinging. Also, advancing the timing would cause even more pinging.

You need a special distributor wrench to easily get to the set bolt for the distributor, and even with the proper wrench it is a bitch.........
 

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Before attaching the timing light find and disconect the EST wire. It is a single wire weather-pack connector running under the brake master cylinder. If you do not disconnect it the ecm will just change the timing to spite you. What you actually set is the "base" timing. The ecm resets actuall timing several times a second after that wire is reconnected. After setting the base timing disconnect the battery for about a minute to purge the trouble code set by the disconected EST wire and this also sets it to relearn fuel maps from new base timing value.
 

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My bet is that this will not fix your rattle. It could be that the rockers were not set at correct lash. Another possible is a small vaccum leak, but that "usually" causes a rich condition not lean.
 

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im going to reset my c4's timing because after my mechanic replaced the intake manifold the valves rattle as engine warms up...i think i just need to advance timing...i have the light...do i need a special wrench to fit below distributer or just normal tools...its an l-98 LONG BLOCK 350. any help is much appretiated.thanks.:patriot:

If your mechanic only removed and replaced the intake manifold your valve adjustment shouldn't have been changed and therefore wouldn't make your valves noisy. I suggest unplugging the EST wire then set your timing to the stock 6 degrees.
 

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My bet is that this will not fix your rattle. It could be that the rockers were not set at correct lash. Another possible is a small vaccum leak, but that "usually" causes a rich condition not lean.
Vacuum leaks cause a lean condition, also, as tobroke says the valves would not be messed with to R&R the intake manifold.........
 
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