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Old 08-02-2015, 07:29 PM   #1
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Default Nismo Oil Pressure Spring Set...What to expect.

A few years ago I purchased a set of oil pressure springs from Nissan Motorsports for my green autoX truck. Today I felt the energy to tackle installing them.

First off many thanks to Shawn Pritchard of Destiny Racing, he is the Datsun guru. You know you are good when you are caring for the late Paul Newman's old race cars. Shawn taught me all I needed to know to be able to experiment until I was happy. He is a good friend!

Things you will need to consider.
1) How hog-wild is your motor?
2) Are you actually abusing it enough to warrant changing anything? If it's stock and it's taking you to work and back then I would say this article won't be needed for your engine.
3) Drifter? Autocrosser? Rallycrosser? Drag Racer? Yeh this might help you.

I can tell you this much right off the bat...using both inner and outer Nismo springs will gain you well over 80psi at 4000rpm. That's 20 more psi than a real track-only Datsun race prepped engine uses. Stock the KA24e wants to see between 65-70psi at 3200rpm.

***If you have not installed an oil psi gauge in place of the idiot light you will want to do that before continuing anything in the article.***

80+psi is overkill!!! You'll pop a gasket at those pressures unless you have built the motor around that.

*OEM (on the right) vs. Nismo Inner and Outer Springs (both on the left)
*Also pictured is the cap you need to remove from the pump along with two washers that measured .463" in diameter which are also an option for adjusting pressure.

You start out as with any other under vehicle project, on good ramps or using jack stands.

1)Remove the lower splash shield...easy!

2)Look for the oil pump. It is located on the intake side of the block behind the alternator. There you will find a large bolt head (I used a 24mm wrench but I think it is actually 22mm). Loosen that bolt and remove it using caution that a little bit of oil and the spring will be wanting to come out of that hole.

So now what? You have the spring out in your hand and you are trying to decide what combination will give you the desired oil psi that your engine requires.

Based on my experimenting this is the guideline I came up with.
*Bear in mind that if you are running an external oil cooler or your engine is tired your readings might be different and may require further experimenting with different spring and washer combinations.

Stock (One OEM Spring)
-Idle with 15w40 = 15psi hot
-4000RPM= 65psi

Nismo (both springs)
-Idle w/ 15w40 = 22psi
-4000RPM= 80+psi maxed out gauge
-Ran strong and oil pressure response was instant.

*Both Nismo Springs

Half and Half = (OEM Outer/ Nismo Inner)
-Idle w/ 15w40= 20 PSI
-4000RPM= Never checked, oil was pegging 80+psi at 2000RPM

Old Datsunhead Setup (OEM with stacked washers)
-Idle w/ 15w40= 18-19PSI
-4000RPM= 75psi peak.
-Oil pressure response not as quick as it was with both Nismo springs but the benefit was no longer pegging the oil gauge. Good Idle psi.

*These are the washers given to me to use by a Datsun guru friend of mine. They measure .463" outside diameter. They go between the cap and the spring. Each washer will increase oil pressure by 5psi.

Large Nismo Outer Spring Only
-Idle w/ 15w40= 10psi (very slow to get to this with some engine noise)
-4000RPM= 40psi max
-Instantly I knew this was not good so I only ran it for a moment to get actual numbers then shut it down.

I did not run the tiny inner spring by itself. Even though the Nismo catalog says this is possible I did not feel comfortable after seeing the results of the large spring only. Running them as a pair makes the most sense but not for a stock motor.

Final setup I went with was the old Datsunhead setup. While not as quick on the draw as the dual spring setup it still gives good pressure both on and off-idle. Luckily these Nismo springs cost me very little back when I bought them.

If after reading this you feel the need to play around with this here are the Nismo part numbers for the springs.

15133-E4620= Inner Spring
15133-22010= Outer Spring

KA24e engines already share the same oil pump as the turbo ZX so no mods are needed to use these springs.

Always use caution and common sense when working on vehicles of any kind. My numbers are merely a guideline and your results can vary.

Thanks for looking!

And don't forget the coffee!
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IG@ rainmaker_d21

Last edited by Foul_Mouth; 08-02-2015 at 07:59 PM.
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