oil pressure spring?

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rustytoolss

rustytoolss

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How much increase in oil pressure would I get by installing the mopar Hi pressure oil pump spring.
I'm new to small blocks (have put washers behind the spring on BB) before. So how do you replace the spring (sounds stupid..but have never done this on a small block)
right now I'm running about 10psi at 800rpm. hot 10w30
 
The book indicates around 10 psi increase for the big blocks. Doesn't say on the small block. I would guess about the same though. I'm thinking the small block spring and plug is held in by a pin.
 
I don't believe the pump bypasses hot 10/30wt oil at 800 rpm. Have you already installed a high volume pump?
 
The spring is behind a plug which is held in by a pin. see it in this pic on the bottom? 10 at 800 is fine.
$(KGrHqN,!rcFIWZ,RgM3BSJwcUmF!Q~~_32.JPG
 
Here's a picture of the spring kit:

View attachment MP HP spring kit A02 B.jpg

Here's another picture of the spring kit:

View attachment MP HP spring kit A03 B.jpg

Here's the picture of the cotter pin and cup plug that you have to remove to change the spring. I don't like drilling the cup plug to remove it, as the chips can get in the pressure relief valve and cause it to fail. I use a punch and a sharp blow with a hammer to punch a hole in it and then remove it with a screw and washer.

View attachment Oil Pump A01 B2.jpg

Here's a picture of the cup plug without the cotter pin installed. Notice it is backwards from how the ones in the blocks typically go. Just pull out the original spring, and install the high pressure spring from the kit. Then install the new cup plug and cotter pin, and you're ready to go.

View attachment Oil Pump B.jpg

Here's a picture of how the cup plug goes.

View attachment Oil Pump A03 B.jpg
 
Yopu probalby know this but just keep and ey on the pressure at high RPM's after you do this. Too much pressure can pump excess oil to the heads and leave the sump dry.
 
Too much oil pressure can explode a oil filter too.
The oil pump along with its spring is inside the pan. Far too much work involved in experimenting there.
Removing the thermostat is a much easier experiment If the oil pressure stays at a more comfortable level when the engine is running lower temperature, the pump and its spring is not the problem.
What happens is the main bearings and cam bearing loosen as they heat up allowing a lot of the oil to escape before reaching the top end. This is where the pressure reading is taken. 10 psi of oil pressure at the top end is plenty. Once the oil exits the rocker shafts its no longer under pressure anyway.
 
Good luck findin one. Lots of people show them in stock but they are nowhere to be found since MP has discontinued them.
 
Just an FYI. changing the spring will have no effect on low rpm oil pressure. The spring will just change/limit the max oil pressure, if the oil pump is capable of developing enough pressure.
A quick way to determine if the pump is capable:
Cold engine: bring up the rpm till the oil pressure hits max. Note this pressure. Then let the engine oil warm up to normal operating temp. Raise the rpm, again, and see if it will reach the same pressure. It will probably take more rpm.
If you cannot reach the same oil pressure, changing the spring will have no effect on max oil pressure.
 
Charrlie_S said:
Just an FYI. changing the spring will have no effect on low rpm oil pressure. The spring will just change/limit the max oil pressure, if the oil pump is capable of developing enough pressure.
A quick way to determine if the pump is capable:
Cold engine: bring up the rpm till the oil pressure hits max. Note this pressure. Then let the engine oil warm up to normal operating temp. Raise the rpm, again, and see if it will reach the same pressure. It will probably take more rpm.
If you cannot reach the same oil pressure, changing the spring will have no effect on max oil pressure.
Click to expand...

I will try this , thanks
 
As Charlie said the high pressure spring only limits top end pressure. Won't do squat for idle pressure. Why don't you try 10w40 or 15w 40? I wouldn't be surprised to see it increase 5-8 psi
 
Rusty, What is the oil pressure at 1,000- 2,000- 3,000 rpm etc? If the hot pressure is at least 10 psi per 1,000 rpm, up to about 50 psi. I wouldn't worry about it. It would be fine. Too much oil pressure can be bad, also. I run mostly slant sixes, and we have found that high volume oil pumps and high pressure destroy the pump gear, and cam gear.

Lower oil pressure (within limits) helps fuel economy, and power. I did a test one time with a slant six legal Z/SA car. switched between 10-30 oil and straight 30 oil, at the track. 3 runs with 10-30, 3 runs with 30, then 3 more runs with 10-30. Car ran an average of 1 tenth of a second quicker in the 1/4 mile with 10-30. This is why most new cars use 5-30, or 0-30 oil.
 
Charrlie_S said:
Rusty, What is the oil pressure at 1,000- 2,000- 3,000 rpm etc? If the hot pressure is at least 10 psi per 1,000 rpm, up to about 50 psi. I wouldn't worry about it. It would be fine. Too much oil pressure can be bad, also. I run mostly slant sixes, and we have found that high volume oil pumps and high pressure destroy the pump gear, and cam gear.

Lower oil pressure (within limits) helps fuel economy, and power. I did a test one time with a slant six legal Z/SA car. switched between 10-30 oil and straight 30 oil, at the track. 3 runs with 10-30, 3 runs with 30, then 3 more runs with 10-30. Car ran an average of 1 tenth of a second quicker in the 1/4 mile with 10-30. This is why most new cars use 5-30, or 0-30 oil.
Click to expand...

x2
 
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