I am rebuilding my magnum 5.9l. It will be stock expect for a camshaft. I have bought a high volume oil pump for it. I have seen mixed reviews about it. I am not running high rpms or anything to make my pan go dry. Do I have anything to worry about? Will it be fine to run? I bought it a while ago. I've seen where some say it won't hurt just isn't necessary. I don't care if it's not necessary, I just don't want it to hurt anything.

 

It doesn't really matter what size pump you have. Volume doesn't help if the engine isn't designed for more flow. Some swear by it though.

 

But it will work just fine though without negatively hurting the engine?

 

As long as it is high volume, not high pressure, it will be fine. If you're doing a total rebuild, you don't really need it but it won't hurt. Now high pressure will blow seals and bearings out. If you're freshening a used engine up, it's the way to go to compensate for worn bearings.

 

During a rear crankshaft replacement seal, I had the oil pan off n decided to replace the oil pump at the same time. I got a higher volume one as well. Same price as regular one. Anyhow, I did discover my oil pressure went up a little n I definitely appreciated it when I got an official mopar PCV valve. I'm guessin' it caused higher pressure than the old one, or the old one was goin' out, but either way, a mopar PCV reduced oil consumption. Go figgur?!? Hope this info helps.

 

Personally, I use a high volume oil pump in my 5.9 engine. Since you are rebuilding your 5.9 engine, here are some recommended upgrades you can do to improve oil flow in your Dodge small block:

A ENGINE OIL MODIFICATION
Regardless of whether you use a hydraulic, solid, or roller cam, we recommend the following modifications.
Purchase an 8” to 10” long 9/32 drill bit. Remove the main caps. On the mains number 1-2-3-4 there is an oil passage which goes from the top on the main saddles to the lifter galley on the passenger side on the block. Slowly drill these 4 passages to 9/32”. Cast iron is very hard to drill without the bit trying to hang up, so do not try to rush this job. If you happen to break the bit, you will have real problems.
Take your oil pump and drill the neck of the pump (the section between the rotor and the main cap) ½” Take a sand paper roll (the kind used in porting heads) and go in the pump above the rotors and debur and slick the area above the rotors. You will need to slick the hole in the pump neck that you have drilled also. Drill to ½” the rear main cap where the oil goes through and polish with sandpaper roll.
You will need a 10” long ½” drill bit for the next step. With the rear main cap removed, look in the hole where the oil goes into the block. There is a 9/16” freeze plug which diverts the oil through the oil filter. Remove this plug by inserting a ¼” rod through the hole where the oil pressure gauge goes in the top side of the block. Drill the hole ½” up to the lifter galley where the plug was removed. Remove the oil filter and any adapter plates from the block. Remove the pipe plug from the block that is under the filter. Drill to ½” both holes that go from the filter to the passage that leads the lifter galley. Now remove the pipe plug in the rear of the block behind the oil filter and drill this passage to the center of the oil filter bolt ½”.
DO NOT DRILL PASSAGES FROM THE MAINS TO THE CAMSHAFT. DO NOT RESTRICT THE OIL TO THE ROCKER ARMS.
Once all passages are drilled, completely clean the block very well. We use Milodon #34010 brush kit to clean all the oil passages. Once the block is clean, replace the 9/16” plug that diverts the oil to the filter and the plug under the oil filter. If you make the above modification, you have greatly increased the volume of oil that feeds the crankshaft and the bearings of your A engine.

 

What you did was compensate for the worn bearings inside the engine. You have just as much pressure, it's just getting through the whole engine, not bleeding out before it gets to the sending unit and rockers. It's a simple modification that will extend the life of your engine by a substantial amount.

 

Ya know, it's funny you should mention 'worn bearings'. I checked 3 of the 5 main crank caps n 1 of the conn rod caps with plastigage. Amazingly enough, was almost no wear. This was about 220K miles n, no, I didn't check every bearing. My rings ARE worn tho. I have a couple'o cylinders that read around 120psi on the dry crank test n in the very low end of the green scale on the bleed down test. Accuracy, who knows, they're harbor freight meters, but 'picasso' is still truckin' down the road with little or no oil burning n she still pulls like a rented mule!