Neo Oil Pump Question

[kitto]

There is also another issue that is well overlooked that myself and a friend are currently working out.

The issue is most of these after market crank collars have too much tolerance between the collar and the inner gear drive surface. Its believed this is causing the inner gear to violently move around inside the housing and crack itself and or the outer gear.

This is a known issue which is found here;

http://forums.gtrcanada.com/gt-r-tech/46419-reimax-collar-clearances-pics.html

There was a guy making collars that had a better tolerance but he no longer does them.

It seems like you almost need a custom collar to suit which type of gears you have.

My friend had bought a brand new N1 pump and the pump actually failed on idle. Now we believe the pump had actually cracked while at higher RPM but it just let go when the engine was at idle.

The second pump he put in was an RB25DET pump with billet gears. The tolerance was so loose that the pump gears that were moving around all over the place actually cracked the pump housing and caused oil to leak externally. He thought it was the front main seal. But close inspection revealed a cracked housing.

[bubba]

^^ and that is why I had my machinist weld up the snout of the crank and machine it back to suit my gears

Some people don't like it but if done properly it's fine, works for us in a few engines and one is making 580awhp and gets regularly abused with 8500rpm limiter launches (different oil pump to me though).

Oh and NEW balancers!

[Moodles2]

With that link, those clearances were only checked while cold. The metal will have expanded at operating temperature, so heating up the metal to operating temp and then checking the clearances would make it more clear.

[bubba]

Dissimilar metals too.. as for what clearance to run I left that up to the machinist as he has far more experience with these things than I do!

The key though is, finding a good machinist

[kitto]

With that link, those clearances were only checked while cold. The metal will have expanded at operating temperature, so heating up the metal to operating temp and then checking the clearances would make it more clear.

Yes of course this needs to be taken into consideration.

Its hard to work out exactly how much tolerance you need on them when cold.

[Stephen Thorpe]

Hi everyone, sorry for revisiting this old thread but it is the only one that had activity on it when I did a search for the Oil Pump Part Number I need.

My Oil Pump has failed and according to Nissan it is 150105L800 for a 1997 RB25DET.

So it seems that the N1 Pump is interchangeable with this part Number and it is better because it has hardened gears inside the pump and is less likely to fail.

Think the N1 updated part number is 1501024U01 (according to the Net) but I have no idea if this will fit the same way.

Any ideas... ?

From what I understand it needs a Crankshaft Collar to work properly as there appears to be excessive clearance but if the collar is too large it could cause the pump to crack.

So for a daily driver, pretty much standard, do you guys think it might be safer to go to the standard item?

It makes similar pressure and flow I am presuming and I don't need to worry about Thermal Expansion of a Crankshaft Collar ?

Cheers

Stephen

[GTSBoy]

N1 should go straight on. Neos came with them from factory. The problem is that old original N1 pumps are good things, and at least for a while, the later manufactured (all for spares) ones were shit.

[Walfers]

Where would you buy one from? Taarks list them as rb26 compatible but not 25 neo...

[GTSBoy]

I don't know if I would buy one, given what I said about later manufactured ones having a bad reputation for shitness. But if I were to buy one, the usual suspects that get trotted out would be Amayama, RHDJapan, etc.