RB26 oil system

[Armanio]

The reimax gears have the same geometry as the oem gears, just different metallurgy. They make gears for both the normal and n1 pumps. I have the restrictor installed with the Oem pump and reimax gears.

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I know the full reimax pump moves a ton more oil than OE, you say the 81mm reimax gears are the same gear ratio as OE? I thought they were a higher gear ratio as well as SCM material, 11 vs 12 teeth making just the reimax gears in the stock housing have higher oil output plus the safety of a stronger material. Correct me if I'm wrong.


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[PurpleStreak]

You're right about the geometry, I stand corrected. Not sure about the flow difference, nothing I could find advertised anyway

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[tommytomatoes]

Just installed all new:

Reimax gears 77mm into an N1 pump. Made sure to loctite the bolts going back in. Used vice grips on the base of the screwdriver shaft to get good leverage on them.
Also recently installed the Tomei oil restrictor provided with the head gasket kit. Personally I think for me anything else would be overkill.

[FRRACER]

Did you check the clearance between the inner gear and the collar? Reimax gears have excessive play which is not good at all for the sake of reliability.

[240zdan]

Why do you say that? If anything I think MORE clearance would be more reliable. And heres why:

We all know the rb26 crank flexes at high hp/high rpm situations. With crank nose flex and tightly clearance oil pump gear you put possible strain on the gear. Whats worse, a bunch of strain on an oil pump gear from a crank that doesn't give a crap about what its driving or a sloppy fit between the gear and the drive which could have no ill effect whatsoever?
Reimax gears have been proven in group A cars and I have yet to see a failure online from the excessive clearences they run.
Just because they are a sloppy fit doesn't mean they are bad, they put the effort into creating an upgrade, I am sure they would make the clearences super tight if they deemed it necessary.

This also brings up another question. Perhaps Nissan shortened the crank drive on r32 motors to minimize the damaged caused by crank nose runout on the oil pump at high rpms? Maybe they knew there was an issue, and tried this as a last resort to improve reliability before the model went into production?

Perhaps the issue here is crank harmonics? A bad damper, improperley balanced rotating assembly, or even a line bored block that is putting unecessary strain on an oil pump could be the leading cause of failure.

For what its worth, I pulled my oil pump due to low oil pressure that got worse and worse. I ordered a set of reimax gears. When I pulled the pump I discovered loose backplate screws. I threw the reimax gears in just because, but could have easily reused the OEM gears. They showed little wear, and I drove the car hard... but avoided the limiter as much as possible (400whp). I never installed a crank collar, as I felt it wouldn't solve anything. I would never attempt to tighten the clearences between the crank and pump... this is just plain stupid to me.


I laugh when I see .002" clearence collars made for sale. One hard rev and youre oil pump gears are crying.

Ultimatley, the flat drive system is flawed regardless, but common sense and paying attention to your motor and oil pressure will yield reliable results.

[240zdan]

Why do you say that? If anything I think MORE clearance would be more reliable. And heres why:

We all know the rb26 crank flexes at high hp/high rpm situations. With crank nose flex and tightly clearance oil pump gear you put massive strains on the gear. Whats worse: a bunch of unwanted load on an oil pump gear thats tightly clearenced to a flexing crank or a sloppy fit between the gear and the drive which could have no ill effect whatsoever?
Reimax gears have been proven in group A cars and I have yet to see a failure online from the excessive clearences they run.
Just because they are a sloppy fit doesn't mean they are bad, they put the effort into creating an upgrade, I am sure they would make the clearences super tight if they deemed it necessary.

Obviously the drive system used is poorly designed, but perhaps Reimax thought a stronger billet gear, as well as a loose fit, woudl provide a reliable solution to the problem. Again, a company that goes to the effort of making upgrades such as these does everything for a REASON.

This also brings up another question. Perhaps Nissan shortened the crank drive on r32 motors to minimize the damaged caused by crank nose runout on the oil pump at high rpms? Maybe they knew there was an issue, and tried this as a last resort to improve reliability before the model went into production?

Perhaps the issue here is crank harmonics? A bad damper, improperley balanced rotating assembly, or even a line bored block that is putting unecessary strain on an oil pump could be the leading cause of failure.

For what its worth, I pulled my oil pump due to low oil pressure that got worse and worse. I ordered a set of reimax gears. When I pulled the pump I discovered loose backplate screws. I threw the reimax gears in just because, but could have easily reused the OEM gears. They showed little wear, and I drove the car hard... but avoided the limiter as much as possible (400whp). I never installed a crank collar, as I felt it wasn't necessary with the stronger oil pump gears.


I laugh when I see .002" clearence collars made for sale. One hard rev and youre oil pump gears are crying.

Ultimatley, the flat drive system is flawed regardless, but common sense and paying attention to your motor and oil pressure will yield reliable results.

Tightening up the clearence is NOT the solution. A wide drive IMO is also NOT the solution. Plenty of gears being split by wide drives. I strongly believe the issue is due to crank flex or misalignment of some type on the oil pump gears putting unnecessary strain on the inner gear.

[240zdan]

Take a look at this pic. Its quite obvious the crank nose was running out, as seen by the evident wear on the wide drive on one side. As a matter of fact, we can almost see some heat build up there. This cant be good.

[240zdan]

Here's something to think about. When the crank nose if flexing at high hp/rpms, which drive do you think would cause more damage to an oil pump gear? Add a tightly fitting collar to the equation, with minimal clearence. I am not saying narrow drives are better then wider ones, they both suck. But perhaps Nissan was scrounging up a way to fix the issue, but nothing improved. I can almost certainly say they didnt shorten the drive for NO reason...