Nissan RB30 Engine Guide

Chandler Stark

Meet Chandler

Chandler is an automotive expert with over a decade of experience working on and modifying cars. A couple of his favorites were his heavily modded 2016 Subaru WRX and his current 2020 VW Golf GTI. He’s also a big fan of American Muscle and automotive history. Chandler’s passion and knowledge of the automotive industry help him deliver high-quality, insightful content to TuningPro readers.

The Nissan RB engine family is one most heralded engine series in recent history, and a perfect example is the 3 liter inline-six RB30 engine. It might not be as popular as its smaller displacement siblings, the RB25DET and RB26DETT, but the RB30 is still a very capable tuner motor.

This guide will cover everything you need to know about the RB30 engine. We’ll look briefly at the engine’s history, before digging into the technical specs, car applications, engine specs, common engine problems, and most importantly, performance and mods.

But first, let’s enjoy this beautiful modified RB30DET running a Garrett GT4294R turbo at 39 PSI, making more than 800 horsepower.

RB30 engine
Credit: Fullboost/Youtube

Nissan RB30 Engine History

Nissan first unleashed the RB30 engine in 1986 as the naturally aspirated RB30E, mainly for use in the Australian market. They put the RB30E inside several trims of the Skyline, where it made 153 horsepower and 186 lb-ft of torque. In 1988, Nissan put a high performance version of the RB30E inside the Skyline GTS1, with horsepower increased to 176.

The following year in 1989, Nissan released another high performance version of the RB30E inside the Skyline GTS2. The GTS2 made 190 horsepower and 200 lb-ft of torque. still naturally aspirated.

Production only lasted for the Skylines in Australia until 1990, but continued for another two years for the South African market until 1992. Nissan only released a naturally aspirated RB30 engine, and there was both a carbureted and fuel injected version. There was a turbocharged version, the RB30ET, but that was only released by Holden.

Technical Engine Specifications

EngineRB30 S/E/ET
Model Years1986-1999
Displacement3.0 L (2,962 cc)
AspirationNatural; Turbocharged (T)
Compression Ratio9.0; 7.8:1 (turbo)
Bore and Stroke86 mm x 85 mm
Valve Train12 Valve SOHC, 2 valve/cyl
Fuel SystemCarbureted (S); Fuel Injected (E)
Head/Block MaterialAluminum, Cast Iron
Horsepower Output153-201 horsepower
Torque Output186-218 lb-ft of torque

Car Applications

  • 1986–1988 Holden Commodore VL (RB30E & RB30ET)
  • 1986–1990 Nissan Skyline (RB30E)
    • Skyline GX
    • Skyline GXE
    • Skyline Silhouette
    • Skyline Ti
    • Skyline Executive
    • Skyline GTS1 (1988)
    • Skyline GTS2 (1989)
    • Skyline 3.0 SGLi (1987-1992)
  • 1989–1999 Nissan Patrol ST30 (RB30S)

Engine Design Basics

The RB30 is a 3.0 L inline-six motor. Nissan and Holden created three variants of the RB30; the RB30S, RB30E, and RB30ET. The RB engine code can be broken down as follows; RB – “RB” engine series; 30 – 3.0 L of displacement; S – Carburetor; E – Fuel Injection; T – Turbocharger. The RB30S is carbureted, the RB30E has electronic fuel injection, and the RB30ET has fuel injection and a turbocharger. Nissan released the RB30S and RB30E, but only Holden produced the RB30ET.

The block for all Nissan RB30 engines has a bore and stroke of 86 mm x 85 mm, and is cast iron while the head is cast aluminum alloy. There are two different RB30 engine blocks, the series 1 and series 2. The only difference between the two, is the series 2 blocks are set up to accept turbochargers, because they are already tapped for water and oil feed lines. Otherwise, the blocks are the same. All Skylines and VL Commodore turbos had the Series 2 blocks regardless of whether or not they had a turbo.

The valve train for all engine variants is a single overhead camshaft (SOHC) with 2 valves/cylinder. Versions that had fuel injection utilized Nissan’s new Electronic Concentrated Control System (ECCS) intake manifold – similar to the RB20. They also used a 12v electrical system, which was also new at the time. The ignition system is a single coil system with a distributor and uses a drive-by-cable setup for the throttle body.

RB30E horsepower figures

The naturally aspirated and carbureted RB30S was rated for 134 horsepower and 165 lb-ft of torque. The RB30E inside the standard Skylines was rated slightly higher, at 157 horsepower and 186 lb-ft of torque. The RB30E inside the Skyline GTS1 and Skyline GTS2 made 176 horsepower and 188 lb-ft of torque (GTS1), and 190 horsepower and 200 lb-ft of torque (GTS2). This increase was due to different camshafts, higher-flowing exhausts, and new ECU programming.

The RB30ET Turbo

The RB30ET differed from the standard RB30E in several ways. Compression on the naturally aspirated RB30E/S was 9.0:1, while the RB30ET was lower at 7.8:1 to accommodate boost. The RB30ET had larger 250cc injectors (190 cc for RB30E), and also got stronger connecting rods, piston cooling oil jets, a larger oil pump, different camshaft, new intake and exhaust manifolds, and obviously, a Garrett T3 turbocharger – but without an intercooler.

The RB30ET bumped up power over the standard RB30E, making 201 horsepower and 218 lb-ft of torque. This might not sound like a ton in an age when 300 horsepower is considered entry-level, but in the mid-to-late 1980s it was very respectable.

The RB30DE and RB30DET Engines

While the RB30DE and RB30DET engines are popular in the aftermarket community, they are actually hybrid motors and were never released by Nissan. The D in the engine code stands for dual overhead camshaft (DOHC). This is accomplished by fitting an RB25DE or RB26DETT cylinder head and or turbo to a standard RB30E/T block. The RB25DET is not typically used.

The DOHC cylinder head and twin-cam setup allows for improved performance, fuel economy, and horsepower. It changes the compression ratio to around 8.2:1, which makes it very boost-friendly, and turns the RB30DE/T into a 24-valve engine. One of the most famous RB30DE and RB30DET engines was produced by famed Japanese tuner TommyKaira for use in the M30 Skyline. This version actually used a RB20DET head, and made 240 horsepower.

Common Problems and Reliability

Like the rest of the RB series, the RB30 is known to be able to take some serious mileage. Nissan built these engines to make it past 400,000 km (250,000 mi) without breaking a sweat, and they are capable of that and then some. There have even been some owners plowing past 400,000 miles on their RB30-powered cars. In addition, Nissan used the RB block as the basis for the RD six-cylinder diesel engine, which should give you an indication of its stoutness.

The main thing to keep in mind is timely and proper maintenance are critical. As we’ll get into, the RB series all have documented oiling issues. Making sure proper oil changes are done every 3-5,000 miles is incredibly important.

The timing belt is also known to be a weakness on the RB engines and should be changed every 60,000 miles at the most. The RB30 IS an interference motor, so a broken timing belt can have serious – and expensive – repercussions. On interference engines, when the timing belt breaks the valves do not fully close, which means the piston will run into the valve as it hits top dead center, which will usually bend or break the valve.

RB30ET Crank Collar and Oiling Issues

The two big problems on the RB30 relate to the oiling system and crank collar. This isn’t specific to just the RB30 series, as the RB20/25/26 also have noted issues with the oil pump and oiling systems. They all suffer from this issue (early RB26 only).

Oil Control System Issue and Fix

The issue with oil control on the RB30 is that in the upper RPM range the oil pump pushes too much oil into the cylinder head. This leads to clusters of oil pooling on top of the head and not draining back down into the oil pan. The problem is exacerbated by insufficiently sized oil return passages.

The oil pooling on top of the head can lead to oil starvation issues, especially when on the track. Worst case scenario is oil ends up coming out of the cam breathers and into the inlet system, taking it away from the rotating assembly which needs it.

Fixing the oil control problems takes five steps. First, you want to block off the rear oil feed gallery to prevent excess oil from flowing into the head. Second, you want to add a restrictor to the open oil gallery to control the oil flow to the head better. Third, you’ll want to run an external oil line from the head to the sump for better drainage from the head. This Head Oil Drain Kit from Franklin Performance is made for the RB series.

Fourth, you’ll want to machine out the oil return galleries by 1mm for better drainage. Finally, you’ll want to machine around the galleries so they can take in the oil better (and thus drain it quicker). Additionally, after you have taken these steps, you can also run a larger sump and oil pump to increase oiling. For very high horsepower builds, a dry sump is the ultimate solution.

Here is an excellent guide with a more detailed step-by-step process to solve the problem. The guide also covers the below issue with the crank collar.

Crank Collar Issue and Fix

The problem with the RB30 crank collar is that the part of the crank’s snout that touches the oil pump drive is too small and wears easily. Both the pump and the crank can become damaged, resulting in the oil pump gear cracking and breaking and a complete loss of oil pressure.

The issue is exacerbated by repeated high RPM engagement, and as you can imagine, no oil pressure at high RPM means big problems. This is probably the most common issue on the RB30.

To fix the problem the stock crank collar needs to be machined off and a replacement put on that allows for more engagement of the inner oil pump gear. Here is an RB30 crank collar from Franklin Performance.

Apart from these two main issues, as long as adequate maintenance is kept up, the RB30 series will run for lots of miles.

VL Commodore Flaw

While this isn’t so much an engine flaw as much as it is a design flaw, it does affect the RB30ET inside the Holden VL Commodore. Due to the design of the Commodore’s nose, the header tank on the radiator is lower than normal. While it’s typically not a problem, if you are refilling your radiator and don’t sufficiently bleed all of the air from the system you can potentially cause air locks and hot spots, leading to serious damage.

Skylines, which did not have a drooping nose, did not suffer from this issue because the radiators were located high enough. While this isn’t a huge issue and can be avoided by correctly bleeding the coolant system, it’s still worth mentioning.

RB30 Performance Upgrades

From the factory, the RB30E makes 157 horsepower and 186 lb-ft of torque, and the RB30ET makes 201 horsepower and 218 lb-ft of torque. Especially by today’s standards, these are pretty low power figures. Luckily, the RB30 absolutely loves to take on upgrades. Many people are running 300 and 400+ horsepower RB30 powered vehicles, with the top builds cracking north of 800 horsepower.

For those that have the RB30S, you can convert it to electronic fuel injection, but it’s neither an easy or quick modification. If you have an RB30S and you’re looking for more power, you’ll want to start shopping for a bigger carb. If you really want to make north of 200 horsepower, we recommend starting with the RB30E or RB30ET.

How to build the RB30DET

If you want to make any reasonable power on the RB30 you are going to need forced induction. So, your first consideration for an RB30 build is going to be the block you are using. If you already have the RB30ET then you are in luck, if not, you’ll want to make sure you are using a Series 2 RB30E block. As mentioned earlier, the series 2 blocks already have oil and water feeds tapped, making them turbo-ready. You can machine a series 1 block to series 2 specifications, but obviously it’s more timely and more expensive.

If you are converting the RB30E to a turbo, you’ll also need a new intake manifold and new exhaust manifold. If you can source them from a VL Commodore those obviously work, if not you can go custom/aftermarket.

Your next step is going to be adding the turbo. The RB30ET stock turbo is a Garrett T3 that is capable of about 225 horsepower max. For many budget builds, people have been known to use the RB25 T28 turbo running 7-8 PSI of boost for around 250 horsepower. If you’re looking for a little more power, a 3076 or 3540 with an .82 rear housing are good upgrades for the 350+ horsepower range.

At this point, you still have an RB30ET, so now you want to swap on a twin-cam DOHC cylinder head from the RB25DE or RB26DETT. These heads breathe much better and the twin-cam setup allows for better tuning for both low and top-end power. Here is a RB30 twin-cam swap guide you can use as a reference.

Nissan RB30 Legacy

Overall, while it might not get the attention of its smaller displacement RB2X cousins, the RB30 is still a very stout engine. Nissan built the RB30 for reliability, which is clearly evidenced by the massive amount of mileage they can take before biting the dust. It’s not uncommon to put more than 250,000 miles (400,000 km) on one without having to do any major rebuilds.

Whether you’re looking at the naturally aspirated or turbocharged versions, the RB30 is a unique piece of history. It’s not going to wow you with your jaw-dropping power from the factory, but instead it focuses on sheer efficiency and reliability, and it does so very well. But, if you really want, the RB30 is capable of some startling power numbers, just look at these 700 horsepower RB30-powered Skylines.

What experience do you have with an RB30-powered car?

Let us know about your Skyline, Commodore, or Patrol in the comments below, and let us know your build plans!


Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *