N1 Oil Pump - Epic Fail

[proengines]

The difference between the nissan drive and a spline drive is like the difference between tightening a bolt with an open ender on a hex head compared to a 12 point socket on a 12 point head, massive difference in the torque you can apply before the head rounds off.

Mike, I was thinking of a collar fitted just the same way as you fit a regular one, press fit and locking screws directly to the crank. Same way as my collars, Jun ones and even the dodgy cheap ones being sold now that look like the flats are machined with an angle grinder.

[unique1]

for the cost of setting up an external pump i would not waste my time with any jap brand pumps, they are up around 2k now and the external pump setup isnt gonna cost that much if you source the parts yourself, and its alot simplier than people like to make out

I am leaving my built motor on a stand until i sort out my dry sump setup now, i dont want to risk it any longer with the Jun pump, its only done a few thousand km's but still the cost of replacing cranks and rods, etc is not worth risking.

[Rezlo]

There is nothing wrong with the pump drive setup as used on RB's. If this was such a bad design the SR20's would also grenade

[bigmikespec]

Mike, I was thinking of a collar fitted just the same way as you fit a regular one, press fit and locking screws directly to the crank. Same way as my collars, Jun ones and even the dodgy cheap ones being sold now that look like the flats are machined with an angle grinder.

Yes I understand. It is just a terrible design in all honestly, regardless of how long it is, it's just a plain fail on Nissans behalf.

In that case it would be silly not to go a involute spline or similar, just need to get the fit right. I have seen splines fail a few ways, but it just comes down to good design and manufacture.

I agree with "unique1" save the f**king about and go external pump/wet sump.

Mike

[Marko R1]

^ that is how i understand it, failure occurs between the oil pump drive & outside edge of crank collar

[Sydneykid]

I don't think anyone is saying that every N1 pump is going to fail, more that the chances of a failure are higher than with other pumps.

As for it being a build problem, that would imply Nissan can't build their own motors.... I'm sure I've posted this before, but this was my N1 pump off an 8,000km old R34 N1 motor that barely ever saw limiter or "hard driving":

To me, that points towards either poor grade materials used in the pump, or Nissan not knowing how to build their own N1 spec motors. I'd say the former is more likely...

That looks like excessive clearance, hammer marks, followed by cracking.

How's the flanges on the crank collar?

If they are worn it won't matter what pump you use, it will still get hammered.

Cheers

Gary

[bigmikespec]

Gary, yes any clearance and they will flog out in no time, like a keyway, spline or whatever!

From what "proengines" said I gather the collars are press fit and if they are then there should be nothing really to worry about. However, I wont be taking the chance when it comes to solving oil issues on my GTR.

Mike

[Sydneykid]

Gary, yes any clearance and they will flog out in no time, like a keyway, spline or whatever!

From what "proengines" said I gather the collars are press fit and if they are then there should be nothing really to worry about. However, I wont be taking the chance when it comes to solving oil issues on my GTR.

Mike

We have used Greg's collars on quite a few engines, warm up the collar (in the oven), cool down the crank (in the fridge), push on and they lock up nicely with the temperatures equalised. Grub screws only a safeguard really. It's not the collar to crank clearance that's the worry, it's the collar OD to oil pump flange clearance that needs measuring. Greg's collars are a nice snug fit, ID and OD, never had a problem with excessive clearance. Maybe another reason why, like Duncan, we haven't had any issues with N1 oil pumps over 10 years of using them.

Cheers

Gary

[Swiper the Fox]

I always recommend using a Nitto collar when using the Nitto pumps. They are machined to match the pump drive perfectly. I even fit the collar when using an R33 crank if there is any signs of wear.

Edited August 20, 2009 by DiRTgarage

[Marko R1]

We have used Greg's collars on quite a few engines, warm up the collar (in the oven), cool down the crank (in the fridge), push on and they lock up nicely with the temperatures equalised. Grub screws only a safeguard really. It's not the collar to crank clearance that's the worry, it's the collar OD to oil pump flange clearance that needs measuring. Greg's collars are a nice snug fit, ID and OD, never had a problem with excessive clearance. Maybe another reason why, like Duncan, we haven't had any issues with N1 oil pumps over 10 years of using them.

Cheers

Gary

hey greg - that n1 pump which recently failed, was that running 1 of your crank collars

[Brockas]

That looks like excessive clearance, hammer marks, followed by cracking.

How's the flanges on the crank collar?

If they are worn it won't matter what pump you use, it will still get hammered.

Cheers

Gary

Gary, it was an R34 N1 motor, there was no collar.

I agree with excessive clearance, but as I said, this is how it came straight from Nissan.... less than impressed.

[Rezlo]

Would I use or sell another N1 oil pump?

NO!

Bloody obvious why the N1 pumps fail, the narrowest area of the lobe is right on the contact flat edge where it contacts.

Lucky big ends and mains still look like brand new and there is no other dammage.

Will change bearings as safety obviously.

[ezy_09s]

I think a splined drive like the 2jz one below would be a better option

,as the failures seem to be common..cracking where the flats are machined on the gears.

[Rezlo]

I think a splined drive like the 2jz one below would be a better option

,as the failures seem to be common..cracking where the flats are machined on the gears.

If the flat pump drive setup was a bad design the SR20 would destroy oil pumps as well, yet they can run to 8500rpm all day every day on a stock oil pump,

To add to that, Harmonic damper to protect your oil pump? tell me how if a 700hp RB25 with stock harmonic damper has such bad harmonics, enough to crack and oil pump, how is it that the main bearings still look like brand new? hell they dont even look like the motor has ever ran and she has over 20 000km's since I built it.

I am chalking N1 pump drama down to either poor quality control (in material and/or manufacturing) or poor material spec

[R31Nismoid]

They are a I4. Not a longer I6.

Taking a wild stab here but a I4 is not going to have the crank movement a I6 has, especially due to weight and so on.

Nor are the forces/pressures there especially if hitting limiters and so on with all that extra spinning around.

[Rezlo]

Torsional vibration and harmonics are generaly worse in an I4 due to firing order and cyl sequence, also one of the reasons most I4's have ballance shafts to try help NVH

Large crank movement = toasted bearings, SR20's run main bearings pretty easy if not 100% dead on ballance when running over 400wkw yet dont break oil pumps running a near identical drive setup & dimensions to the RB... Rb on the other hand comes out with bearings looking like brand new yet oil pump is scrap metal, The RB pump is driven not even 3-4mm from No:1 main bearing, pump gets damaged from movement but bearing isnt touched?

There is no way to have rotational vibration / whip without it running out of center.

[Duncan]

....as the failures seem to be common..cracking where the flats are machined on the gears....

not all of them, mine howed no signs of wear at the crank but still cracked the outer gear in 3 places. Probable cause was crap running through the fine clearance of the pump causing it to crack.

Its clear that the fit between the crank and pump drive need to be checked for correct fit before use

[bigmikespec]

Yes Rezlo an inline 6 is dynamically balanced, so no issue there.

It would be good to see the design of the SR next to the RB and compare. The RB does deliver more power and torque, it may be that the flat pump drive for the SR is "adequate" (as s**t as it is) and Nissan cut corners doing the same with the RB.

[proengines]

hey greg - that n1 pump which recently failed, was that running 1 of your crank collars

nope

[Scooby]

nope

someone else's?