Oil pump shim (+) pressure/ bearing clearance

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nj3ndri
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Oil pump shim (+) pressure/ bearing clearance

Post by nj3ndri »

Okay I just bought a OEM oil pump from nissan. Ive seen some people shimming the pump for higher pressure. and making bigger clearance on the bearings. (im guessing a heavier grade of oil is used to compensate)

...I have no idea (I have a basic clue) of how this process goes and how thick the shim should be. (im guessing goes somewhere by the spring)

And what clearances have to be enlarged to.


Anyone have any info on this. Or if its even worth doing.
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cleantune
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Post by cleantune »

I've heard thin shims are best, if at all; like LESS than 0.04" (-Chris28 from Nico).

Personally I have not done any shimming or aftermarket pumps. There is just something about it that seems like it has more probability of doing harm than good. There is an oil pressure relief valve too that will prevent the oil pressure from getting too high.

Also higher pressure can be achieved with a thicker oil, but keep in mind that higher pressures DOESN'T mean better flow, and Flow is what is important.

I have heard that Nismo had a shim that came with their oil pump for the KA's; haven't found what size it is though.

maybe read through this:
viewtopic.php?t=49781&sid=7d45494b10e43 ... f0a4bf349c

...and do an inspection like this first:
http://www.nicoclub.com/archives/ka24e- ... ction.html
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sdaigle240
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Post by sdaigle240 »

i totally agree. the limiting factor in flow is that bypass releif. a higher output pump does equal more flow but if your gonna just hit the by pass earlier then its an inferior setup.
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jholman05
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Post by jholman05 »

So could you shim/de-shim the bypass then relief in order to get more flow/pressure?
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cleantune
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Post by cleantune »

Interesting idea, never thought of doing that. We need to get a hold of someone who works in a hydraulic lab so we can run some tests!

The oil passages in the block may prove to be a limiting factor as well.

Maybe raising oil pressure under idle (minimum oil press) could just be good for idle and cool down?

I wonder if there is any correlation to oil temp and pressure? -like gases heat up when compressed and cool when they expand.
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Post by sdaigle240 »

interesting thought. im fairly sure the releif pressure is a failure safety though. the pumps designed for certain pressures, above X point, damage may occur to the system. ive taken a bunch of fluid dynamics classes so this is just an educated guess. im fairly sure this would be the case for any pump wether its moving sewage or water.

yeah youre right, the problem is fluids are "incompressable" so the ideal gas law doesnt really work. but we know from observations that pressure is a function of temperature.


u know like, at idle:
T=0, P=65
T=160, P=30
T=240, P=14

this is for water.... but somethign like this:
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Post by cleantune »

Reading this made me smile, now were getting somewhere!

So for the water graph above testing a water pump, it looks like density decreases in the system as temperature increases and density increases as pressure increases; is this right?

OP -no worries an answer about what size shim for your oil pump will be produced from all of this. Understanding how and why something works well first, just allows for the best possible solutions for physical application.

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nj3ndri
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Post by nj3ndri »

I was looking through the "Rides" section and noticed on Ramon R's build he listed

Stock oil pump shimmed for higher pressure
Enlarged main and rod bearing clearances

now does this also mean higher revs??
If someone could get a hold of him maybe he has some answers
And I think his build was done at Miami240
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Post by cleantune »

Okay, so just to lay everything out for everyone who may stumble upon this thread: the thing we are talking about "shimming" is the spring for the oil pump pressure relief valve and using a metal disc shim or a metal washer of a diameter that would fit and still allow movement of the piston inside the oil pressure relief valve.

Anyways, Did a goog search an found this; should answer some questions:
http://www.improvedtouring.com/forums/s ... hp?t=16611

"I finally got the new engine fired up. After realizing that I had the oil pressure sending unit wired backwards (I was finding it difficult to believe that it had over 150psi of oil pressure!! ), the motor has about 60psi at a cold idle and pushes up to about 80-85 when reved over 1500RPM... I have about a .020" shim under what I believe is the factory pressure regulator spring...."-Banzai240

"...We did this based on the info from some to start at .040. There was a washer/shim presently in the pump that measured .018 SO adding a .040 to the what I assumed to be a stock washer of .018 placed me at our .060 starting point. Now I think I have tooo much pressure!! After warm up, the pressure jumps to 90+ psi with very little reving (2000 rpm). We have yet to plumb our oil cooler which will be with 10an lines and will require a few 90 degree fittings." -Murphyd

**Just as a side note I have read in more than one place that on average an engine should be getting 10psi per 1000RPM, which may be a good standard for comparison when trying out shims on the oil pressure relief valve.
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Post by jholman05 »

Interesting, so yeah it seems like you could get a bit more pressure by increasing that shim... the question is does the increase in pressure mean you're actually increasing the flow. Or are you really just marginally increasing flow while bumping up pressure.

I have my timing cover off, I may pull that bolt out that holds the pressure relief tensioner spring in and measure my shim.

If I was highly motivated... after I broke my engine in that is at the machine shop I could pull the pan off the car, put another stock shim in (0.018+0.018) and see what the difference in pressure I made.
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2013 - 9.0 Wiseco/Manley, Nismotronic, GT2876R 23psi, Meth, PSM HMIC, 850cc, N62, S15 HLSD, Z32 Spec 3, D21 Fidanza = ??.? @ ??? 440whp/380wtq
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Post by sdaigle240 »

cleantune wrote:Reading this made me smile, now were getting somewhere!

So for the water graph above testing a water pump, it looks like density decreases in the system as temperature increases and density increases as pressure increases; is this right?

OP -no worries an answer about what size shim for your oil pump will be produced from all of this. Understanding how and why something works well first, just allows for the best possible solutions for physical application.

.
yeah just like youd imagin with oil. temp goes up.... viscosity goes down.

if the pressure increases (function of temp - temp decreases) then yes the oil will be more viscous (greater density)

not sure if i can correlate density to viscosity, but im doing it ha!
cleantune wrote:Oka
Anyways, Did a goog search an found this; should answer some questions:
http://www.improvedtouring.com/forums/s ... hp?t=16611
nice read. i think this is why my pressures at 3k are below spec even with 50wt oil. my clearences are .0015" i think stock can be as low as .0001" maybe a half thou across all those bearings is my answer for why im about 10psi low at 3k.
jholman05 wrote:Interesting, so yeah it seems like you could get a bit more pressure by increasing that shim... the question is does the increase in pressure mean you're actually increasing the flow. Or are you really just marginally increasing flow while bumping up pressure.
increasing pump pressure directly increases pump flow.

increasing viscosity to increase pressure does not increawse flow.


i really like the idea of increasing flow but you def have to increase the releiof pressure as well. and at what point is it no longer safe for the mechanics of the pump? im a tad confused... in doing this are you increasing both the output pressure and the relieve pressure?
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Post by jholman05 »

If I'm understanding the FSM correctly you're just increasing the oil pressure regulator pressure (sounds odd putting it like that), and not the oil pressure relief valve. I do not know what the oil pressure relief valve is set at but I would have to think it's much higher than 70psi since that's what the FSM calls for at 3,000 rpm on a warm engine. My dad's KA-T stock S13 motor sees close to 100psi when cold at 3,000 rpm. So to shim the regulator should increase pressure without affecting the failsafe of the relief valve.

Sound right?

Edit - Now that I look back at it, the relief valve is just an oil filter bypass? I was thinking the relief valve would dump the extra oil back into the crank case. Dang.

Image

Just a blown up portion of that screen shot ^

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Image

Image
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2012 - S14 KA, Nismotronic, GTi-R T28 12psi, Meth, PSM HMIC, DW550cc, N62, S15 HLSD, Spec 3, Fidanza = 12.4 @ 110
2013 - 9.0 Wiseco/Manley, Nismotronic, GT2876R 23psi, Meth, PSM HMIC, 850cc, N62, S15 HLSD, Z32 Spec 3, D21 Fidanza = ??.? @ ??? 440whp/380wtq
YouTube Channel -> http://goo.gl/MZ5EE
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sdaigle240
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Post by sdaigle240 »

see... there is two seperate releifs.

one is a filter releif. if the pressure through the filter is too much it by passes it so you motor gets enough oil... despite not being filterd.


then there is a pump safety releif. this is when the pressure gets so high the pump could actually break. so they picked a pressure witha big safety margin im sure. on BITOG they say typical pressure release for a motor reving to ~7k would be in the range of 75-90. now i believe its still possible for your gauge to read higher than that as your fathers KA sees. i think the releif does its own thing by passing oil when it goes above the spring pressure, howevey you may still have higher pressure than the releif at your gauge sensor.

lets get hypothetical...
so if you increase pump pressure (increases flow), thats great. but say your now hitting the pump by pass at 4500 instead of 6000. now at 4500 your flow is actually less than an un shimmed pump not hitting bypass! so... unfortunately we dont knwo the by pass pressure, i cant find it anywhere. but i do know if you were to increase the pump pressure by X% then the relief pressure should increase by the same precent....... in theory lol

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nj3ndri
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Post by nj3ndri »

in a way..im getting lost ..getting a little too advanced for me lolol
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Re: Oil pump shim (+) pressure/ bearing clearance

Post by 1SikS13 »

good topic, i bought a new oem pump and it seems to read on the low side on my gauge.
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