Best oil pump?

[jeffp]

Hey Cody, how much did the pump cost you??? I would be willing to get one for my car also. That being said here is what I learned on the Datsun oil pumps, and believe me I have researched it out to the full extent.

 

There are three pumps made for the Lseries engines. the first pump is for the LD28 engines, that is a ended issue, it suffices to say it is the lowest flowing pump.

The second pump is the tandard Nissan L series pump. It has aluminum construction, and a 40mm drive gear. The pump is advertised 9GPM @ 3000 rpm.

The last pump is the turbo pump that came in two configurations. The standard shift pump and the automatic pump are one in the same, but the springs have been changed to increase the flow pressure for the automatic because they came with the oil cooler. Both pumps have a 45mm drive gear for the pump. They will flow the same rate, just shim up the spring in the cap with a .100 washer and you are in there. with the standatr shift turbo pump.

The last option for the Nissan pump is a add on bottom from Nismo. This takes the inlet of the pump and bypasses the internal inlet with an A/N fitting in the bottom of the pump and is fed by a fitting on the oil pan. Very expensive install, and I could not see the gains you would get making it worth whilr to spend the 300.00 or so for all of the hardware and the pump bottom.

 

Here is where I am interested. I found out hwo made this pump. MILLINGS makes that steel pump you are asking about, they are the ONLY ones that do make an after market pump for our cars as best I could find out. They made the 40mm pump and the (turbo) 45mm pump.

Here is what I wanted to try, since it is a steel pump body, the expansion rate of the metal will be different then aluminum. This being the case, I wanted to do this steel pump in much the same way I did my aluminum pump. Blue print the pump and make the tolerances close to see what kind of improvements there is when the oil is hot and the car is idling. I was able to improve my pump by doing this and using of all things a peice of white sheet paper for a gasket, thickness .003 so the pump was tight. I did see an improvement in the oil pressure at idle, and overall in the pump. With the cast part, I could tightenup the tolerance to say .0015 to .002 and see what the improvements are. I just did not want to shell out the money for a pump I really did not need. I did all of this for one reason and that was to get the oil pressure to increase at idle and that was the only reason, also with the tighter pump the rise time of the oil pressure more then likely would improve also.

So there you have it.

[Bob_H]

Jeff,

I'm interested in what you did to blueprint and decrease the tolerances in your pump. As I see it, if the rotors have excessive clearance, how would you decrease that? I like the idea of the smaller gasket to reduce the extra area above the rotors. I too have considered the iron pump because of the smaller expansion rate. However, I always forget when it comes time to replace my oil pump.

[Lockjaw]

Man that extra weight is going to slow your cars down.

[Cody 82 ZXT]

Jeff the pump was 72.99 plus tax at O'Reily Auto Parts. Just to add alittle here the I measured both of the old pumps I have here at my Apt. and the are both 40mm. One of them I know came off an automatic car and the other I'm not sure about. I didn't take the new one apart to measure it. I think that Nissan went from 35mm to 40mm. I've never heard of a 45mm. Plus I really don't see where they would get the extra 5mm in the current pump body. I guess if you wanted to have some parts made the cast body would be perfect for it. I'm sure you could get a couple more mm out of it.

[jeffp]

Hi Cody, you could be right, it has been about a year or so since I have looked at this thing. I could have swarn tho it was 45mm on the turbo pump. I do have one of the standard cast pumps in my garage. I can check that out and make sure.

Who knows, I guess I'm brain dead. anyway the turbo pump has a gear that is 5mm longer then the stock standard pump. Let me get back to you on this one. Now you are getting me interested again in this crazy thing.

[jeffp]

Hi Bob, I did a few things to my pump. The first thing I did was with the gear drive in the pump. When you take the pump apart you find that the drive gear has a hole through the center of it. Oil goes up through this to provide oil to the drive gear on the crank shaft, and the drive for the distributor. The oil holes for the pump(on each end of the grive gear that fits inside the housing also have about a .080 holle to lube the surface of the shaft to the housing. I tapped and installed a screw in the top of the gear drive, ground the screw down so the drive gear/rod wouold fit correctly in the top of the pump. I then drilled the center of the shaft to a .080 dia hole. What this did was to decrease the oil flow to the drive gear, and it decreased the oil that ends up at the top of the shaft at the base of the distributor. What I found was that when the pump turned, when the pressure got up to a point, the oil would come out the top of the pump, wash the drive gear and shaft with oil. Well, it was a bit excessive to say the least, we are talking about a 1/8" hole diameter or greater(I was able to tap a 6mm bolt into the center of the shaft) way to much oil to the gear and it was letting the pressure in the pump bleed off in stead of going through the oil gally where it was really needed for the rest of the engine.

I did this in an attempt to increase the oil pressure at idle, and it was somewhat suscessful. I got the pressure up to 15psi at idle with the engine hot.

The next thing I did was to flatten the bottom of the pump with fine sand paper on a granite surface to make it flat. I then went to the body of the pump and the drive gear and did the same. Now there was zero tolerance between the bottom of the pump and the housing and the drive gears. I then used a peice of sheet paper as a gasket, it is .003 thick. I assembled the part back together that way.

The last thing I did was to open up the inlet to the pump from the front cover with a dremel for better flow.

I have noted that the front cover gally hole needs some work on it as it is not smooth and would tend to cause some cavitation.

The pump works very well, the distributor base gets sufficient oil to keep it good and the pump has a 5 psi oil pressure at idle. That with a set of dual springs in the pressure valve the pump performs better in my opinion. I still get what I consider low oil pressure at idle (15psi depending on the oil I use, when it is hot) but the pump pressure comes very quick,and the pressure increases very quickly when you crack the rpm off idle. The max pressure I setup for the pump is 65psi when the oil is hot. You do have to watch the pressure when it is cold as I did at one time have the pressure to 85psi when I first cranked up the engine and ran it at about 2500 rpm's. That was a little to high for me so I decreased the shim on the springs. I did not want to blow past my oil filter at the time, but now I have a system1 filter.

I was thinking of getting two steel pumps, cutting one pump for an added 5mm of the housing, as well the drive gear, welding that together and machining the housing and see what the extra 5mm of drive gear would do for the pump, but I just haven't had the time to mess with it that much.