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Discussion Starter · #1 ·
Hi, a short question...
Anyone has any idea what is the diameter of the outer gear of the N1 oil pump?
I have a set of 77mm Reimax gears but it can't seem to fit my original oil pump which the previous owner claims is a N1 oil pump.
I might also be looking for a N1 oil pump with 77mm diameter gears.
Thanks.
 

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Have a good search here as I'm sure that the information is here already.

I'm pretty sure that the Reimax gearsets for the normal and N1 are different if that helps.
 

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Discussion Starter · #3 ·
From rhdjapan:-
GT-R N1 Oil Pumps originally were sold with Oil Pump Rotors which had an outer rotor diameter of 81mm. In later years of production, Nissan transitioned to the smaller 77mm outer rotor diameter. This is also the size that Nissan currently sell their RB26 Oil Pumps with.
I need someone who has actually changed the gears to verify that rhdjapan is correct.
Having say that, how do we know what diameters are tge gears without opening the pump?
Thanks
 

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Discussion Starter · #4 ·
The gears can't fit my oil pump so I'm assuming it is the older oil pump with 81mm gear.
So if I'm gonna get a new N1 pump, how to tell whether it has 81mm or 77mm gears without opening it?
 

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Hi, a short question...
Anyone has any idea what is the diameter of the outer gear of the N1 oil pump?
I have a set of 77mm Reimax gears but it can't seem to fit my original oil pump which the previous owner claims is a N1 oil pump.
I might also be looking for a N1 oil pump with 77mm diameter gears.
Thanks.
N1 pumps used to be 81mm but Nissan changed the spec to 77mm some time ago. Now I believe all pumps are the same size even std ones. The Nismo is also the same with a steel gear instead of a sintered one.
 

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Nissan in USA are selling genuine N1 pumps for £137 plus postage that I a bargain price and add to that some steel gears will make it the same as a Nismo one so I have been told.
 

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Discussion Starter · #7 ·
Nissan in USA are selling genuine N1 pumps for £137 plus postage that I a bargain price and add to that some steel gears will make it the same as a Nismo one so I have been told.
Yup, thats what I read. I have the gears now, so is looking for a suitable n1 pump. Just want to know how to identify a n1 pump that has 77mm gears...
The gears can't fit my current n1 oil pump which I suspect is the older model
 

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Compare to the Nismo: They are Identical except for the gear material. What would cause the high rate of N1 failures? Poor crank damper and bottom end balance and a weaker sintered gear that is used in the N1 pump. Which is why I think the Reimax gear is the cheaper option to get Nismo performance and save around £150-200 pounds. Flow rates and pressure have been known to be the same as reported on various sites.

Nismo:







Nismo Oil Pump Pictures - GTRPWR Forums

My N1:







Oh and btw, I now have blisters on my hands trying to remove the stupid screws which took an hour because few of them were so tight but I won in the end!:clap:
 

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Discussion Starter · #10 ·
I got my n1 oil pump from from fleabay in the end.
Have not gotten the chance to open it out.
Crossing my fingers that they did not sell me an old stock..
 

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Just order the pump from ebay, not sure why there is so much paranoia about buying from ebay, as long as you are smart and make sure the seller is genuine company who also is available outside of ebay you should be fine.
 
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