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N1 Oil Pump - Epic Fail

Rezlo

By Rezlo,
in Engines & Forced Induction

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Marko R1
Marko R1

fuel cut explains the massive flames that gtr's shoot out on the limiter - most gtr's u will see in japan run this way. so my guess is that fuel cut is acceptable but not sure if its better or worse t

zebra
zebra

errr....might want to re-read what you just wrote Marko. No fuel = no flames

JonnoHR31
JonnoHR31

same shit for an oil pump, engine is still stopping and starting in the same way. the only difference would be between different ecu's, for example, a stocker rb30e ecu cuts fuel to all cylinders when

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2rismo Grand Master

2rismo

Posted
Posted
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.

Similar to mine on the RB25 and very effective. Good job.

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bubba Grand Master

bubba

Posted
Posted
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.

So the excessive clearance is to account for a wide variety of tolerances.. can the excessive clearance be reduced? if you were going to use a collar, would it be better to have one machined to suit your individual pump gears? and what would be the minimum clearance required for thermal expansion?

Sorry for all the Q's.. it's getting to crunch time with my engine and I need to find a clear path :)

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Fastrotor Proficient

Fastrotor

Posted
Posted

Just something i've though about too, why cant there be some sort of silicon damping between the pump and crank... ie like a silicon 'shim' so to speak to take up the slack and also damp the harmonics ??? I guess the worry would be it failing in time and the slack comes back, but hell, if theres that much slack already ..... ?...

Gary

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  • 7 months later...
Simonster Proficient

Simonster

Posted
Posted
was it a new pump?

Yes it was.

Am thinking of just fitting a standard RB30 pump and balancer, mine is a street car and will never see the track.

I have an RB25 using the standard water & oil pump and balancer with 430rwhp for almost 5 years without any issue and it see a decent amount of track time.

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double overhead sun visors Community Regular

double overhead sun visors

Posted
Posted

I had an N1 fail, don't know if it was the cause or part of the fail chain that went down. But now have a NITTO and have heard good things about them... Contact Croyden and get their advice on NITTO, they have an interesting story on how tuff they are.

They are a good price, flow well and have forged internals....

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Duncan Grand Master

Duncan

Posted
Posted

was the n1 pump the cause or the symtom of the failure?

anyway, I run a nitto pump now, it has survived 3 rebuilds with just a clean and re-assembly. It provides a little too much pressure per rev until the releif valve opens but that is better than less. If you fit one make sure you run oil restrictors to the head and turbos

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Simonster Proficient

Simonster

Posted
Posted

Thanks guys, yet to pull the engine out to see what's left. Hoping it has screwed anything else, thinking i noticed it as it happened but i'll find out soon enough.

Yes was thinking nitto as well.

What are your thoughts on standard pumps? Is there any info on their failure rate compared to others. I do note that all N1 failures have aftermarket balancers and i'm not suggesting they are at fault, just interesting.

A very good friend of mine runs a 25/30 with VL oil pump and standard balancer- makes 500+hp. He gives that thing curry and limiter bounces it regularly with no issues.

That's a pretty good accolade Duncan! Is there potential to alter the spring so it relieves a little earlier to have it produce close to standard pump outputs?

Cheers

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rad100 Grand Master

rad100

Posted
Posted

how would the aftermarket balancer affect the pump? u would think it would help with the harmonics and not cause as many vibrations?

i would also think that with the rotation of the pump and excessive vibrations plus oil running through is what would kill it?

explain why the aftermarket balancer would affect it?

cheers

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Duncan Grand Master

Duncan

Posted
Posted
how would the aftermarket balancer affect the pump? u would think it would help with the harmonics and not cause as many vibrations?

I would expect the exact opposite....why would a small aftermarket manufacturer be able to make something that manages complex harmonics better than Nissan's engineers?

Most factory balancers might be rubbish due to age, but at least you know they were designed and researched for that exact use.

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Dobz Experienced

Dobz

Posted
Posted

I was just looking at page 7 and rezlo had pics up of his broken n1 pump. It's not hard to see why the are prone to failure, the outer gear wall thickness from the root of the tooth to the outer diameter is paper thin and the sharp radius at the base of each tooth is a definate stress piont. Has anyone considered it could be the outer gear failing causing it to jam and break the inner? Being sintered iron doesn't help matters either.

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R31Nismoid Grand Master

R31Nismoid

Posted
Posted
I would expect the exact opposite....why would a small aftermarket manufacturer be able to make something that manages complex harmonics better than Nissan's engineers?

Most factory balancers might be rubbish due to age, but at least you know they were designed and researched for that exact use.

Interesting point isn't it?

I can't think of more than one Racepace car that has killed a N1 pump - all using the stock Nissan balancer and so on.

All circuit driven... Must be something in the water down here :)

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