Well since my cars down I figured I might as well change the spring to the gm white spring, and while I have it all apart it would be kind of stupid to leave the stock 100k mile pump in there. I saw some threads about the melling changing their pumps to a thinner casting. Is the melling select pump ok to get or is there a better choice out there? And should I even change the oil pump, or is the stocker more than likley fine with 100k miles on it? This is the parts list I came up with from a quick search.

Oil Pump - MEL-10554
Pickup - 12550042
Spring - 3848911

This is for a 97 Z28 stock bottom end car with 100k on it. I'm just trying to get as much life out of the bottom end as I can.

 

all the research i did lead me to go with the melling select with white spring, i am pretty happy with it, around forty psi at idle and just over seventy off-idle

i am pretty sure it was the regular melling that had the thin casting but i could be wrong

 

GM 93442037 74.79
Jegs 134-7901 18.99
GM 12550042 10.86
GM 3848911 2.32
GM 1103868 42.73

I bought the following parts from GM Parts Direct, and the pump shaft from Jegs, the pump is the Melling Select

 

Get the melling select pump.
It comes with the hardend pump shaft.
The white spring is spring is cheap.
Dont forget the new sump screen.
If you have no problems with it why change it?

 

Because the stocker has 100k on it and I figured it would be a good idea to change it while I'm in there changing the spring. Its a big PITA to do and a new pump is only $70 so I figured I might as well change it.

 

i would agree that it is a good idea to spend the extra few bucks now, especialy at that milage

 

100k is nothing on these motors.
If the motor is out, then do the oil pump. Don't forget bearings and seals too.

 

Damn, forgot all about the oil pump when getting all my parts. I guess I better replace that 267,000 mile pump.

 

That's exactly the parts I just put in mine, works like a charm...Had 20 psi at idle and 40psi at highway cruise... Now I have about 35 at hot idle and 65 at highway cruise.

The pickup was a royal pita to get in...finally read to use an open end wrench that was just big enough to fit over the tube but catch the lip...carefully put the pump in a vice, then use the wrench head and tap on the wrench head with a hammer lightly until it starts going in.... The wrench head puts even pressure on each side of the tube as you tap it.

 

Wow just changing the pump upped the pressure that much? Did you weld on the pickup or just tap it in? I think your thread is where I got all the part #'s from.

 

its not changing the pump that causes that, its the white spring. mine is about the same, maybe just a tad higher

 

Yes, I spot welded the tube on once tapped into place.
As mentioned, its the white spring that upped the pressure, thats what it is supposed to do. Oh, and my oil pump had 98k on the clock.
Yeah, there's so many different Melling pumps it will make your head spin trying to figure out exactly what you need...it took me a while to settle on the 10554 one

 

Yeah but the spring shouldn't change the oil pressure at idle and low RPM's. My oil pump has 100K on it and your thread is what made me decide to change mine since its cheap insurance.

 

The spring changes some valve pressure in the pump, not sure what that does, but I don't think its only for the "max" oil pressure it can produce..otherwise those with pumps only making 40psi like mine was would see no beneift of swapping springs, but I know a few who have only changed the springs and kept the same pump and ended up with more pressure all around..
I haven't taken my old pump apart yet to see how worn it was compared to the new one...guess I should have done that tonight when I cut the oil filter up to inspect it but kinda forgot about it laying in the corner of the garage

Imight add, I've owned this car since it had 8k on the clock and I religously change the oil every 3k miles on it, and most of its life was behind my wife's foot at the throttle so it was babied, I'd be surprised if there was some unusual wear on the pump.

 

Any time I have ever changed a spring in a pump, it has affected pressure at all RPMs.