Chevrolet Repair: oil presure on a lt1 motor, shaft gears, crank pulley

Question
QUESTION: i replaced oil pump and still have no oil pressure what could it be
ANSWER: Hi Levi,

Is it knocking?  Are you getting oil at the valve covers?  No knocking, and oil being supplied at the valve covers (under cover at valve rocker train) indicates that you do have flow.  You probably in that case have a bad oil sending unit.  This is what tells the guage what to read.  If no flow present, suspect the oil pump drive gear.  This is driven by the cam shaft and is located where the old fashioned distributor used to be.  

Good luck.

C J S

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

QUESTION: no oil at top of motor and no knocking but i can here the lifters gears are good...thinking i may have to rebuild the motor

Answer
Hi Levi,

I'm am sure you know this but:
The oil pump is driven by the cam shaft, by way of a gear in the rear of the motor.  This gear is attached to the distributor shaft in the old days, when the distrubutor was located in the rear of the motor.  Now, the distributor is located in the front of the motor, behind the crank pulley.  But the old hole is still in the rear of the motor.  Where this old distributor used to be, a cut-in-half distributor shacf is there.  This allows the cam to still turn the oil pump.  You need to remove the 'crow's foot' hold down bracket, and pull this oil pump drive shaft out, to see if it is in good shape.  

Once this shaft is out, look down the hole for anything out of place.  Between the oil pump and this shaft, is a hex shaped rod.  Make sure this rod is in place.  If not, it may not be turning the pump.  Many times on pump replacement, this rod misses the hole, can disconnect from the distributor shaft, may have even fallen to the side.  Make sure the cam shaft gears are OK.  Touch the cam shaft gears with a long screw driver.  Does the cam shaft seem to be snapped?  Does the gears look OK, and the shaft seem solid?

If the hex rod is in place (leave engine off), remove a valve cover.  Tape a 6-point socket that fits the hex rod, onto a long 3/8" extension.  Using an adaptor that allows your household drill to connect to 3/8" sockets, attach the drill to the long extension.  Use this extension to turn the hex shaft and thus the oil pump.  You should get a tiny stream of oil spraying out of the rockers where you removed the valve covers.  The faster you run the drill, the harder the tiny streams should be.  If no oil to the side you pulled the valve cover on, pull the other one and check the other side.

This is an hour spent, to determine if the pump has the ability to deliver the oil.  If the valve cover area of the head stays dry, then your pump is no good.  It could be by-passing.  The pick up tube may be plugged, or have fallen off.  It could also be twisted too high to reach the oil in the oil pan.  At least you know the motor won't need a rebuild.  

In my experience, a total loss of oil is a profuse leak (broken valve tree, broken rod, bad pump by-pass, crack somewhere important), bad pump, or bad pick-up tube, cam shaft is broken and the gears on it cannot turn.  

You see, the oil journals are independant of eachother.  You could spin a bearing and not loose oil to the whole motor.  You could plug the oil filter up, and not loose oil.  Only 15% of the flow goes to the filter.  The rest of the flow goes around.  

I hope this helps.  

C J S