Chevrolet Repair: C-3500 7.4L down on power, valve train, hi tim

Question
QUESTION: Hi Wayne,
I own a 1995 C-3500 w/196,000 mi. My vehicle started running rough and I picked up a knock in the valve train. I pulled the intake manifold and changed out the lifters, the knock went away and the idle smoothed right out. The problem is the truck feels like it is really down on power. Any suggestions?
         I appreiciate your time,
         Tim N.

ANSWER: Hi Tim,

  Have you checked ignition timing when you pulled the distributor and put it back in?  You may have marked it but when you pull up on the distributor sometimes the allen drive for the oil pump makes it difficult to put it back in in exactly the same spot.  It is imperative that not only the distributor is in the same place but the rotor as well.  Regardless of where you put it ignition timing should always be set after a major repair.  There is a process to disconnect the EST to set base timing and if this was not done the timing may be incorrect.  If everything is together properly this could be the only thing that might have been assembled incorrectly.


Wayne


---------- FOLLOW-UP ----------

QUESTION: I was using a Chiltons man. and it did not cover disconnecting the EST to set a base timing. There are two plugs on my dist. a 2 and 4 pin, I believe. Could you give me a run down on setting the base timing please?

Answer
Hey,

  There is two possible locations for it but yours should be up under the dash by the glove box.  Its a black one wire connector with a brown with black tracer.  Unplug it and set the timing warm at idle to 0.  If the connector isn't there (sometimes its taped up and hard to see) then it could be outside right next to the accumulator for the ac on the firewall under the fuse cover.  I am pretty sure the 1995 is under the glovebox wedged between the HVAC box and the steel kickplate a little to the right of the passengers left knee.  If you can't find it at either place I will look up the specs in the morning to make sure.  The sticker under the hood sometimes shows the location but sometimes not.