The RB26DETT oil pump is driven off the front of the crank, and early cranks differ from later ones. Check yours before you choose a pump.
Early R32 cars
Tomei's fitting manual says Nissan lengthened the oil pump drive on the RB crank in August 1991, at the R32 minor change, to reduce the load on it. Nitto calls the earlier cranks "short snout" cranks and says the short drive was largely responsible for the premature wear and failure of many standard oil pumps. Check your crank before you choose a pump.
Crank collars and pump options
Nitto's RB flat drive crank collar, which Nitto calls its extended crank collar, gives the pump's inner gear a longer drive surface to grip. It is made from 709 high-tensile steel and locks on with M6 grub screws. Nitto's fitting guide has the crank snout machined and the collar fitted with an interference fit, so the crank has to come out of the engine. Nitto's sine drive pump is the other option: an 11-tooth drive Nitto designed as an alternative to splines and flat drives, used only with Nitto's RB sine drive oil pump collar. Whichever you choose, buy a pump and collar that match.
Nitto RB flat drive crank collar | Nitto flat drive oil pump | Nitto sine drive oil pump | Nitto oil pump alignment tool | Tomei oil pump | RB26DETT parts
Which oil pump?
Each pump below is listed for the R32, R33 and R34 GT-R RB26DETT.
| Pump | Drive and gears | Check |
|---|---|---|
| Nissan N1 oil pump | Genuine Nissan N1 pump | No flow figure from Nissan. Check your crank before ordering. |
| HKS uprated oil pump | Larger SCM435 rotor, thicker at the drive contact area | Relief pressure is set with an outer shim. HKS says the alternator has to come off to adjust it. |
| Tomei high performance oil pump | Larger SCM435 chromoly gears | Tomei says it doesn't fit the pre-August 1991 crank and recommends the later Nissan crank, 12200-05U03. |
| Nitto flat drive oil pump | Flat drive, larger EN26 billet steel gears | Nitto recommends its RB flat drive crank collar with this pump. |
| Nitto sine drive oil pump | 11-tooth sine drive, EN26 billet steel gears | Needs Nitto's RB sine drive oil pump collar. |
Nissan N1 oil pump | HKS uprated oil pump | Nitto RB sine drive oil pump collar | Nissan OEM RB oil pump | Nitto billet oil pump
RB26 oil pumps: the makers' own figures
Every figure here comes from the maker, from its website, its fitting manual or an archived copy of its own web page, apart from the standard pump's oil pressure, which comes from Nissan's workshop manual (see below). Makers don't all test the same way or at the same rpm, so treat them as a guide.
| Pump | Maker's flow figure | Gears | Drive and crank | At Epic GTR |
|---|---|---|---|---|
| Standard Nissan RB26 | 47 L/min at 6,000 rpm (Tomei; 46.7 in Tomei's manual). HKS gives 42 to 47 L/min | Sintered alloy, 11.0 mm wide | Drive lengthened in August 1991, Tomei says | Yes |
| Nissan N1 | No figure from Nissan | No figure from Nissan | Genuine Nissan | Yes |
| HKS uprated (15003-AN001) | 65 L/min at 6,000 rpm | SCM435, 88 mm outer diameter, 12.4 mm wide | Thicker drive contact area. Adjustable relief pressure | Yes |
| Tomei high performance (193035) | 56 L/min at 6,000 rpm | SCM435 chromoly, larger diameter | Not for the pre-August 1991 crank. Tomei recommends crank 12200-05U03 | Yes |
| Nitto flat drive (NIT-OIL-RB26) | 64.8 L/min at 7,000 rpm (factory pump 46.5), from Nitto's published figures for the earlier version of this pump | EN26 billet steel, larger than standard | Flat drive. Nitto recommends its RB flat drive crank collar | Yes |
| Nitto sine drive (NIT-OIL-RB26SINE) | Not published by Nitto | EN26 billet steel | 11-tooth sine drive. Needs Nitto's RB sine drive oil pump collar | Yes |
| Nitto externally adjustable 7075 billet (NIT-OIL-BILLETRB) | Not published by Nitto | EN26 billet steel, billet 7075 housing | Sine drive only. Needs Nitto's RB sine drive oil pump collar | Yes |
| NISMO (15010-RR580) | The same as the genuine pump, NISMO says | Stronger gears, used in Super Taikyu racing | Not stated | No |
| Reimax Gr.A (15010-ATA01) | About 40% more theoretical output than genuine. No L/min figure published | SCM440H, 85 mm outer diameter (genuine 77 mm), 12 mm wide (genuine 11 mm) | Not stated | No |
| Reimax capacity up rotor kit (A1510-AA077 / A1510-AA081) | About 10% more theoretical output than genuine, and no change to the regulated pressure, Reimax says. No L/min figure published | SCM440H, 12 mm wide, 77 or 81 mm outer to suit your pump | Fits the genuine pump with Reimax's cover, no machining | No |
"No" in the "At Epic GTR" column means Epic GTR doesn't list that part, so there is no product link.
Nissan OEM RB oil pump | Nissan OEM N1 oil pump | HKS uprated oil pump | Tomei high performance oil pump | Nitto flat drive oil pump | Nitto sine drive oil pump | Nitto billet oil pump | Nitto RB flat drive crank collar | Nitto RB sine drive oil pump collar
Standard RB26 oil pump: the makers' figures
| Item | Standard RB26 pump | Given by |
|---|---|---|
| Flow at 6,000 rpm | 47 L/min (46.7 in Tomei's manual). HKS gives 42 to 47 L/min | Tomei, HKS |
| Flow at 7,000 rpm | 46.5 L/min | Nitto (archived Nitto web page) |
| Oil pressure, warm engine (oil at 80°C) | Approx. 1.5 kg/cm² at idle, approx. 3 at 2,000 rpm, approx. 4.6 at 6,000 rpm | Nissan's R32 engine workshop manual |
| Gear material | Sintered alloy | Tomei, HKS, Reimax |
| Gear width | 11.0 mm | HKS, Reimax |
| Outer gear diameter | 81 mm, says HKS. Reimax says genuine outer rotors come in 77 mm and 81 mm, so check yours | HKS, Reimax |
| Gear teeth | 12 and 13 | HKS |
| Oil pressure adjustment | None | HKS |
| Crank drive | Lengthened in August 1991, at the R32 minor change | Tomei |
What the flow numbers mean. Tomei and HKS both put the standard RB26 pump at about 47 L/min at 6,000 rpm, and HKS gives a range of 42 to 47. HKS quotes 65 L/min for its uprated pump and Tomei 56 L/min, both at 6,000 rpm. Reimax quotes its pumps as a percentage over the genuine pump rather than in litres. Nitto's published figures for the earlier version of its flat drive pump are 64.8 L/min against the factory pump's 46.5, but at 7,000 rpm, not 6,000, so they can't be compared directly with the Tomei and HKS figures.
Why more flow isn't the whole story. Tomei recommends a larger-capacity sump with its pump. It also fits the factory sump, but Tomei says to check the oil level. A bigger pump does nothing for a short drive either: Tomei says its pump doesn't fit the pre-August 1991 crank, and Nitto recommends its crank collar with its flat drive pump. Sort out the drive first, then pick the flow.
Adjusting oil pressure. HKS says the relief pressure on its pump is set with an outer shim and can be changed without removing the sump, but the alternator has to come off. Tomei's pump adjusts through an external regulator plug, also without removing the sump. Nitto's billet pump has an externally adjustable valve. Nitto's RB Oil Pump Note says the relief valve on its pump cracks off at approx 120 psi, or approx 75 psi with the inner spring removed.
Tomei's 1.5 mm oil gallery orifice (standard 2.0 mm) limits the oil sent to the cylinder head, and Nitto makes RB oil gallery restrictors in 1.1, 1.3 and 1.5 mm and a blank.
Tomei 1.5 mm oil gallery orifice | Nitto RB oil gallery restrictor
Nitto oil pump: Nitto's published figures
Nitto published these flow figures, in litres a minute, for its NIT-OIL-RB26 pump on its earlier website. They are for the earlier version of the pump: Nitto has since redesigned its oil passages, and the figures are no longer on Nitto's current website. Nitto measured at 7,000 rpm, where Tomei and HKS quote 6,000 rpm, so the figures can't be compared directly. Nitto gives no oil temperature or oil grade.
| Engine speed | Factory pump | Nitto pump |
|---|---|---|
| 750 rpm | 4.6 | 6.5 |
| 2,200 rpm | 15.3 | 20.2 |
| 7,000 rpm | 46.5 | 64.8 |
Nitto's current RB Oil Pump Note says the pump's pressure relief valve crack-off pressure is set to approx 120 psi with both springs fitted. With the inner spring removed, it drops to approx 75 psi. Nitto gives no rpm for these figures. Nitto publishes no flow or pressure figures for its sine drive or billet pumps.
Sources: Nitto's earlier RB oil pump page (archived copy) | Nitto RB Oil Pump Note (PDF)
Tomei oil pump: oil pressure by rpm
Tomei's fitting manual for its 193035 pump gives these oil pressure reference figures, in kgf/cm². Tomei measured them on a standard BNR34 RB26DETT with WAKO'S 4C-R 15W-50 oil and the standard sump. Tomei says they are a reference only and vary with the oil used and the weather. The pressure is changed by swapping the springs and shims in the external regulator plug.
| Engine speed | Double spring (Tomei's factory preset) | Single spring | Single spring + 1 shim | Single spring + 2 shims | Single spring + 3 shims |
|---|---|---|---|---|---|
| 3,000 rpm | 6.27 | 4.68 | 4.82 | 4.96 | 5.10 |
| 3,500 rpm | 6.40 | 4.90 | 5.02 | 5.16 | 5.28 |
| 4,000 rpm | 6.58 | 5.20 | 5.34 | 5.48 | 5.62 |
| 4,500 rpm | 6.77 | 5.47 | 5.53 | 5.59 | 5.65 |
| 5,000 rpm | 6.86 | 5.54 | 5.63 | 5.73 | 5.82 |
| 5,500 rpm | 6.73 | 5.63 | 5.71 | 5.79 | 5.87 |
| 6,000 rpm | 6.65 | 5.49 | 5.61 | 5.74 | 5.86 |
| 6,500 rpm | 6.51 | 5.34 | 5.41 | 5.48 | 5.48 |
| 7,000 rpm | 6.30 | 5.12 | 5.22 | 5.33 | 5.43 |
| 7,500 rpm | 6.22 | 5.01 | 5.13 | 5.26 | 5.38 |
| Idle (1,000 rpm), cold, just after starting | 5.7 to 6.3 | 3.9 to 4.5 | 4.6 to 5.2 | 4.9 to 5.6 | 5.4 to 6.1 |
| Idle (1,000 rpm), warm, oil at 70°C or above | 3.0 to 3.5 | 3.0 to 3.5 | 3.0 to 3.5 | 3.0 to 3.5 | 3.0 to 3.5 |
Standard RB26 oil pump: Nissan's workshop manual figures
Nissan's R32 engine workshop manual gives these oil pressure figures for the RB26DETT, in kg/cm², checked on a warm engine with the oil at 80°C. Nissan doesn't host the manual on its own website. These figures are cross-referenced: several separately hosted copies of the manual all give the same figures.
| Engine speed | Oil pressure (kg/cm²) |
|---|---|
| Idle | Approx. 1.5 |
| 2,000 rpm | Approx. 3 |
| 6,000 rpm | Approx. 4.6 |
These are Nissan's workshop check figures for a warm engine. They aren't from the same test as the figures other makers give for their own pumps, so don't compare them directly.
Source: Nissan's R32 engine workshop manual.
Related guides
FAQ
Why is the early R32 crank different?
Tomei says Nissan lengthened the crank's oil pump drive in August 1991, at the R32 minor change. Earlier cranks have the shorter drive, which Nitto calls the "short snout", so check your crank before you buy a pump.
Can I fit a crank collar with the engine in the car?
No. The collar needs machining with the crank out.
Why do RB26 oil pump gears crack?
Tomei and HKS say the standard pump's sintered gears can break at high rpm, and Nitto says the short drive on early cranks wore out and destroyed many standard pumps. The makers' answers are stronger gears and a longer drive: the later crank, Nitto's flat drive collar, or Nitto's sine drive pump and collar.
Which RB26 oil pump should I buy?
Start with your crank. Tomei says its pump doesn't fit the pre-August 1991 crank, Nitto recommends its flat drive collar with its flat drive pump, and Nitto's sine drive and billet pumps need its sine drive collar. Then compare the makers' figures above.
How much oil does a standard RB26 oil pump flow?
Tomei gives 47 litres a minute at 6,000 rpm (46.7 in its fitting manual), and HKS gives 42 to 47. HKS quotes 65 litres a minute for its uprated pump and Tomei 56, both at 6,000 rpm.
Does a bigger RB26 oil pump need a bigger sump?
Tomei recommends a larger-capacity sump with its pump. It also fits the factory sump, but Tomei says to check the oil level. Speak to Epic GTR about the parts that suit your build.
Can I adjust an RB26 oil pump's pressure?
The standard pump has no adjustment, HKS says. HKS's pump is set with an outer shim, with the alternator off, and Tomei's has an external regulator plug. Neither needs the sump removed. Nitto's billet pump has an externally adjustable valve.
What oil pressure does the Tomei RB26 oil pump give?
With its factory preset double spring, Tomei's fitting manual gives 6.27 kgf/cm² at 3,000 rpm, 6.65 at 6,000 rpm and 6.22 at 7,500 rpm, and 3.0 to 3.5 at a warm idle (1,000 rpm, oil at 70°C or above). Tomei measured these on a standard BNR34 engine with 15W-50 oil and the standard sump, and says they are a reference only and vary with the oil and the weather.