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N1 Oil Pump - Epic Fail


Rezlo

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prob cost more than man on the moon for a 1-off too :blink:

I coudnt imagine it costing more than a new oil pump. Personally i think its rediculous to have to spend over $1000 for a decent oil pump. Here in the states i dont any stock style oil pump costing anywhere near $1000 but the RB ones. Its a F'ing rip off.

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Is it possible to take the N1 Pump apart and take the old gear to a machine shop and have a new stronger gear made?

Yeah you could. (Machine work in the states is alot cheaper than in Aus.... and if he drives a 240sx, he's american)

I thought it was done just outside Area 51. Haha

Ha ha ha ha ha ahh a.... it was shot in a sound studio in Navada. Apparently in the movie you can see the light from a door being opened off stage.

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  • 1 month later...

i didnt read every letter of all the previous posts, however, I have a FJ20 engine in my ride which dont have the best oil pump in the world from factory in them either. When i built my engine i used a BDG external oil pump. Its a single stage belt driven unit with a mounting bracket off the side of the engine to mount it and a plate with a spline welded onto it bolted to the front of the harmonic balancer. We machined off the 3rd pulley from the balancer and bolted the plate there in its place. The pump was $960 and then once the internal pump was deleted, it was a matter of tapping a fitting into the block and making up a pickup in the sump the suit. Base pressure and peak pressure can be set very easily via an allen key adjuster and spring selection.

Maybe worth considering... just a thought.

Please ignore the control arm chop. It has been boxed in and strengthened since these pics.

IMG_0002.jpg

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Just throwing my own little bit of fuel on the fire. I happened to have a N1 pump sitting around waiting to go back on my RB24 when it's done. I also happened to have a RB20 crank with a JUN collar installed that came out of my engine before it went to the builder. Took a little vid just to show the amount of play between the two. I also mic'd the two and came up with 0.22mm of clearance between the flats. Seems a bit excessive to me. I personally don't think it's a material issue as much as a design issue. And it's not just a pump design issue but, an entire oiling system design issue. I would bet that while not all of the N1 failures happen during heavy acceleration or cornering that the initial damage that leads to the failures did. I think that any kind of cavitation in the pump do to the oil sloshing to the back or side of the pan could cause extra resistance on the outside gear or even momentary seizure. This coupled with a loose fitting drive I would think would be enough to break the gears. I also think that has something to do with why Sydneykid prolly hasn't seen the failures that most have. If you do everything to keep the sump from ever sucking air this isn't an issue at all. When my engine gets back I'll have to fit the N1 drive gear to the R33 crank that's in it now and see if there's a difference. And just so it's clear, I'm not championing any pump or pump fix here. I'm just suggesting a cause to the problem.

th_pumpdrive.jpg

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I've got two sets of the JPC steel gears here for an RB30 and RB25/30 I'm currently doing. I can snap some photos if you're interested. They fit an N1 housing, not a standard 25/26 pump. I've only had one in well over 50 N1 pumps break but that's one too many and the steel gears are cheap insurance.

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Just throwing my own little bit of fuel on the fire. I happened to have a N1 pump sitting around waiting to go back on my RB24 when it's done. I also happened to have a RB20 crank with a JUN collar installed that came out of my engine before it went to the builder. Took a little vid just to show the amount of play between the two. I also mic'd the two and came up with 0.22mm of clearance between the flats. Seems a bit excessive to me. I personally don't think it's a material issue as much as a design issue. And it's not just a pump design issue but, an entire oiling system design issue. I would bet that while not all of the N1 failures happen during heavy acceleration or cornering that the initial damage that leads to the failures did. I think that any kind of cavitation in the pump do to the oil sloshing to the back or side of the pan could cause extra resistance on the outside gear or even momentary seizure. This coupled with a loose fitting drive I would think would be enough to break the gears. I also think that has something to do with why Sydneykid prolly hasn't seen the failures that most have. If you do everything to keep the sump from ever sucking air this isn't an issue at all. When my engine gets back I'll have to fit the N1 drive gear to the R33 crank that's in it now and see if there's a difference. And just so it's clear, I'm not championing any pump or pump fix here. I'm just suggesting a cause to the problem.

th_pumpdrive.jpg

This excessive clearance is something I was alluding to several pages ago.

I'm still waiting on my splined gears but if that doesn't come through, as opposed to using the collar that I have sitting here, I am thinking of having the snout built up then machined back to suit my specific N1 gears.

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bubba - that is a lot of play, cant belive that!

i just wonder whether this clearance is required though for heat expansion...greg, what are your thoughts on this? do you recall how much play my pump has with the customer collar you made for it?

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i also noticed that the clearance between pump gear and crank was high...

what i dont understand is why nissan use two flat surfaces to drive the pump so all the force is put on two small areas. surely a hexagonal shape or similar would have worked much more effectively

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bubba - that is a lot of play, cant belive that!

i just wonder whether this clearance is required though for heat expansion...greg, what are your thoughts on this? do you recall how much play my pump has with the customer collar you made for it?

If heat expansion was an issue wouldn't the timing gear be prone to failure when the engine reached operating temperature?

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it was $960 for the pump and then the price of a custom sump, mine was around $300 from memory as the engine builder did the whole engine including the sump. Then some braided line and a mounting bracket, the belt and modification to the crank snout. Around 2k in total i think. I dont have much of an idea what a new aftermarket high flow internal pump costs for an RB, but i thought 2k for a big oil setup was pretty good.

G

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bubba - that is a lot of play, cant belive that!

i just wonder whether this clearance is required though for heat expansion...greg, what are your thoughts on this? do you recall how much play my pump has with the customer collar you made for it?

They need clearance to allow for manufacturing tolerances where the centreline of the crank can be not quite concentric with the centreline of the pump gear, I made yours a little tighter Marko because I sat the pump on and checked where it was running before I made the collar. The clearance isn't a problem. The standard rb25/26 gears don't break and they run the same. SR20's, CA18's, Toyota 4AG's, Hondas and others run the same drive setup and rarely have problems. Nissan TB48 engines have a similar problem when they're pushed. I think it's just down to the material used. Powdered metal is used for a lot of parts that are hard to machine cheaply, almost all oil pump gears are made the same way. To mill an N1 outer gear you'd need to use a <2mm diameter cutter which just isn't workable for that type of job.

I don't know why Nissan made the N1 pump with a smaller diameter outer gear which makes everything a little thinner and easier to break. I just fitted a set of the JPC gears to an N1 housing and they are good, same side clearance as factory and about .001" more clearance between the gears. The engine is from a hillclimb/circuit car still running the hydraulic tappets so I didn't want to go for a bigger pump.

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The engine is from a hillclimb/circuit car still running the hydraulic tappets so I didn't want to go for a bigger pump.

Hey there Greg.

Interesting that you wrote this as it brings up a question I've wanted to ask. I am about to buy a Tomei Pump for 'insurance' that my current N1 Pump doesn't break - however I wonder what are the disadvantages (if any) of having the larger pump besides its price.

I have a winged 9Litre Performance Metalcraft sump. People talk about the Tomei 'running the sump dry' but this makes no sense to me unless they are running massive pressure... if the pressure is adjusted on Tomei to a similar pressure of the N1, then (given the same motor) the flow should be near identical should it not? ie the Tomei will bypass all the extra flow straight back to the sump? And if so, is this a problem?

Long ago I looked at replacing the N1 gears with the Reimax ones. The reason I bought the N1 in the first place was because the RB26 already seems to suffer from too much oil going to the head (so everyone puts restrictors in). So there didn't seem to be any point going to the higher volume pumps given the clearances that are run.

So is the only real reason to put a Tomei in for the strength of its gears? And for the fact that is has this '3 gear' design which might be a little more forgiving on any crank wobble? Or is it actually "better" to run an N1 size pump with Reimax (or JPC etc) gears for strength.. Lets forget price for a moment, lets just say you could buy either for the same price:

1. Tomei with the pressure kept down (and hence less oil pumped to the head)

2. N1 with very strong gears.

(guys this is not a N1 vs Tomei or Nitto or JUN question - just a question of High Pressure/Volume vs 'needs' of the engine I guess)

Thoughts?

Edited by R32 TT
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