Pre-oiling


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By Cactus - 15 Years Ago
I had another engine rebuilt, and it has been sitting for about 6 months until I finally got it in the car.  I have been trying to pre-oil it with an electric drill running counter clockwise with no luck.  Is there a way to prime the oil pump and how long do I have to run the drill before I get any oil pressure?
By paul2748 - 15 Years Ago
Did you feel then drill 'catch' when first starting? If so, this means that the pump is working.



One thing you can try is to remove the plug on the drivers side of the block or the oil pressure sender unit (both are on the oil galley) and then turn the drill on. If it spurts oil, the pump is working.



Try turning the engine over about a 1/4 turn and then try. Theoretically, if you have a grooved cam this should not be necessary but sometimes it works.



Make sure that the rod is inserted into the pump
By mctim64 - 15 Years Ago
You should get oil pressure fairly quick, if you don't you may need to prime the pump. There is a number of ways to do this but I think the easy way is to take the oil filter off and squirt a good amount of oil behind the filter plate, not down the center, this should get the pump wet. It would also help when doing this to turn the pump backwards (clockwise) to draw some oil to it. Then put your filter back on and run the pump Counter Clockwise till you see oil run out the rockers. If you have a cross drilled cam and not a grooved one you will need to turn the engine slowly by hand till you see any oil come from the rockers, as Paul stated.
By Ted - 15 Years Ago

My own preference for pre-oiling is to to use a speed handle instead of an electric drill.  I’ve picked out problems with oil pumps that would not have been noticed with an electric drill but can be felt when hand turning a speed handle.  No more than thirty-forty seconds by hand cranking and beginning with an empty filter is the norm in getting oil pressure built up and oil flow visible at the rocker arms if a grooved camshaft is being used.  Like Tim mentions, if the cam is crossdrilled, then the engine may have to be rotated to get oil to the topend.  Regardless of the method used to turn the oil pump, once oil pressure builds up, the drive to the oil pump will load enough that you can feel it.  Using an electric drill will obviously get oil pressure much quicker than my 30-40 seconds.

 

As a rule, the oil pump needs lube in it before pre-oiling the engine can take place.  If the pump is assembled dry and installed on the engine like this then the rotors do not seal adequately at first to get that initial pull of oil started.  Removing the pump and shooting a few squirts of oil into the inlet side of the pump will usually fix this.  Tim's suggestion of filling the chamber behind the oil filter plate with oil is also a good one.

 

Another issue to consider is if the rubber grommet on the inlet tube is not seated correctly which causes air to be pulled in at that point and in turn prevents any oil flow.  If the oil inlet tube is bent and not square with the entrance into the pump, then this can also present an opportunity for an air leak around the rubber grommet.

By Cactus - 15 Years Ago
Thanks for all the replies. I will get to work and check all of the things recommended.  Ted, I have one question, why start with an empty filter? Is that so that you have more oil in the pan?  I already filled my filter, but I could get another and some more oil if you think that is a good idea.   Thanks again, Jan
By Ted - 15 Years Ago
Cactus (4/28/2009)
Ted, I have one question, why start with an empty filter? Is that so that you have more oil in the pan?

Nothing high tech with using an empty oil filter.  An empty filter just doesn’t make a mess while installing it on the new engine.  The fifteen-twenty seconds or so it takes to fill the filter on the engine while pre-lubing is a non-event compared to any spillage that could take place otherwise.  The O ring on the filter is still coated with a light film of oil though before installing.