The Stovebolt Site Forums The Shop Area Engine Shop Putting new oil pump in the 46, Need wisdom.

Well the 216 feels strong but I'm puting on a new oil pump because the needle is just above 0 at idle and possible 10 psi at cruse. Just being in this hobby/lifestyle for 2 yrs I always appriciate advice from those much wiser. What pitfalls should I look out for? Is it just a straight up pull the pan, remove the old, prime the new and install. What short cuts are there? Is there an easy way to install the gaskets?
Thanks as always,
Rick..........

I wouldn't bet on the cause of your lower pressure being the pump. I would suspect other causes such as the main bearings or cam bearings. However, if you are changing it, it is pretty straight forard. The shaft is held in by a bolt with a jam nut, up inside the side of the block. It might be a good time to adjust the shims on all the bearings and if you have a rear main leak, replace it too.

I read in one Chev publication, I can't remember if it was a shop manual or the Service News, that a bad oil distributor can cause low oil pressure. That is the valve behind the three screw cover on the drivers side. OIL DISTRIBUTOR LINK

From the Chev literature that I have, one should be concerned about the pressure when it drops lower than 7 lbs at speed. I can't find anything definitive about idle. Mine barely moves the needle at idle but I know my cam bearings are really worn. I also installed a new pump when I had it apart.

I guess its also possible that the pressure line to the guage is full of crud as well, giving a false reading ?

I would say no to that one. Your gauge measures pressure, actually air pressure so if it was blocked it wouldn't work at all.

actually air pressure

???

Yes. Many times the air is not bled out of the lines to techncally the gage is reading the preassure of the air. Of course ThAT pressure is from teh oil pressure so in most cases no one worries about it. It can be a good thing in that it dampens pressure oscillations avoiding wear on needle movement.

The FIRST thing I would do is put a gage on that engine that I can trust to be correct and check that installled gage is telling the truth.

Dan Bentler

What weight oil are you running?

Before you go to the trouble of replacing the oil pump, try switching to a straight 30 weight oil, not a multi-viscosity like 10W-30, etc. If the pressure rises noticeably, the pump isn't the problem, bearing clearance is. It might be possible to remove shims from the main bearing caps and close up the oil clearance slightly, but be sure to check for proper clearance with Plastigauge or by using a small piece of shim stock between the main bearing and the crankshaft to see what the clearance is. For instance, if installing a small piece of .002" shim between the bearing and the crankshaft results in very stiff rotation, That's the oil clearance. I like to fit the bearings to about .0015" to .002" clearance if possible. The rod bearings can be checked the same way, but they won't affect oil pressure because of the dipper system- - -there's no direct oil pressure supplied to the rods. Check the oil distributor valve to be sure it's keeping most of the oil flow to the bottom end of the engine. The oil supplied to the cylinder head has reduced pressure to direct most of the flow to the main and cam bearings.
Jerry

Do you have an oil filter installed? If so, it should t (oil line and pressure line). I have had krud develop there. I left the filter but blocked the motor. Dont really need a filter but looks cool. The other thing I have had, is there is a soldered-in oil pipe out of the housing the oil pump connects to. I thought the pump was bad but the pipe had dislodged slightly lowering the pressure to almost nothing. New gasket and painted pan, good pressure also.

How would you go about checking the oil distributer valve? What are you suppose to look for? How do you know if it is working properly?
Rick.......

I think the only way is to buy a new one and put it on. It is really accessible and easy to install.