RB30 Facts, Figures and Helpful Hints

[mudnut]

Engine Bay.

The RB30 engine bay layout is very similar to the TD42 and TB42 engines, but there are some differences.

Drivers side.

1. Windscreen wiper motor..............7. Fuel filter.

2. Brake master cylinder..................8. Tacho signal resistor.

3. Clutch master cylinder................. 9. Ignition coil.

4. Air filter housing........................ 10. Window washer bottle.

5. Relay cover plate....................... 11. Top radiator hose.

6. Battery Earth / -ve terminal........ 12. Air conditioner sight glass.

[mudnut]

Engine Bay. Passenger Side.


1. Air intake Pre Heat................5. Radiator over flow bottle.

2. Power steering reservoir.........6. Distributor.

3. Oil filler cap.........................7. Timing belt cover.

4. Air intake dust separator........8. Radiator filler cap.

[mudnut]

Bleeding air from the cooling system.

After an engine coolant change out, or repair where the coolant has been drained, the air in the system must be removed.

This is to ensure that there is sufficient coolant for the system to operate properly and to eliminate the risk of creating an air lock you must bleed system with the heater controls set to hot.


The first picture shows a bleed point situated in the top of the aluminium casting where the top radiator hose is attached to the engine. The second picture is of a funnel I have made using an old radiator cap, a rubber grommet, some copper tube, a rubber shocker bush, a plastic bottle, hose clamp and rubber washer.

Another way is to tape the bottle neck to the radiator filler. ( When doing this, you must open the overflow bottle and raise the hoses up above the filler or the bottle may be over filled).

This is to allow the air in the system to bubble out without blurting coolant every where while the engine is running. You must run the engine until the thermostat opens, to make sure air is not trapped in the block.

After bleeding the system, it is a good idea to take the vehicle for a short drive, wait for it to cool down and check the coolant level again.

[mudnut]

Exhaust Gas Recycling Valve. (EGR)

The EGR valve is part of the Emissions and Engine control system. The valve is located on the rear of the intake manifold. Its job is to allow spent exhaust gasses to enter the inlet manifold. This reduces the combustion temperature and limits the amount Nitrous Oxides produced by the engine.

The following problems may be caused by a malfunctioning EGR: Running rough at Idle. Hesitation under acceleration. Poor fuel economy.

One problem my EGR had, was that the metal pipe which runs from the rear of the exhaust manifold to the valve, was cracked. This was only found after the exhaust manifold was removed to get it machined. It was causing fumes to enter the cabin, but only when the engine was under heavy acceleration, so was almost impossible to detect.

The factory fitted Exhaust Manifold Studs on the RB30 also had a tendency to crack. This will sometimes let exhaust fumes to enter the cabin too.

Cracked studs and a leaking exhaust gasket can also cause a loud ticking or noise similar to that caused by worn valve lifters.

To check the exhaust manifold properly, the metal shroud must be removed.

[mudnut]

Timing and Fuel.

After having the head off the engine, it is essential to get the engine tuned properly.

This is because after machining the head, the compression ratio is slightly changed.

I had set the timing to factory specification (A sticker on the tappet cover has the correct information), after the head gasket was replaced, and the engine was making a "pinging" noise (detonation) under acceleration. Detonation can cause engine damage.

I then retarded the timing by 4 degrees, at which point the pinging noise disappeared. On taking the patrol to get Dyno-Tuned, the engine was still found to be detonating (timing still too far advanced). The mechanic was able to retard the timing a further 8 degrees at which point the engine was still achieving maximum torque. (Stock standard configuration: 73.5 rear wheel Kilowatts).

He recommended only using 91 RON petrol for everyday use (commuting) and switching to 95 RON for towing and off road use.

[mudnut]

Running LPG and Dual Fuel.

There are many threads dealing with problems from running Dual Fuel.

I will try and deal with some commonly asked questions.

Tuning for LPG

I asked Alitis007 ( a very knowledgeable forum member) for timing, spark plug gaps specifications for a dual fuel RB30. This is his answer:

"Timing is a bit fiddly because you need to find the happy medium between both fuels. Reason being that lpg has a higher octane rating than petrol so you need to advance (timing) slowly and drive the car and make sure it doesn't ping on either fuel.

Don't alter the factory plug gap because that could cause a miss fire, you could put in a colder plug as lpg burns hotter, but if your motor burns oil using a cold plug is not ideal.

The heat range of a plug is written in its part number, higher the number colder the heat range, as is other information like size, length, type and some other information irrelevant for now.

As a example a BPR6E is colder than a BPR5E. Changing the heat range more than one number is not ideal either because you can severely alter the exhaust gas emissions of the car and possibly cause engine damage or premature failure.

Without tools like a gas analyser that's all the information I can help you with."

[mudnut]

LPG. Missfiring, rough idle and rough running.

A dual fuel engine has its own set of factors which may cause problems to deal with. First, and foremost, the ignition system needs to be in excellent condition to handle both fuels.

Running constantly on LPG, for long periods of time can cause some components in the carburettor to dry out and become unserviceable.

If after checking for vacuum leaks, faulty ignition components, freeing up any sticking carby linkages and running a carby cleaner in the petrol, the problem still persists, you have a few options.

You can do a carby kit change out, replace the carby with an aftermarket unit, or get it reconditioned. Once the problem has been fixed it is a good idea to start the engine on petrol, then switch to lpg, at least once a day. This will ensure that the carby components will be kept in working order.

The quality of the gas conversion plays a big part in how the engine will perform. I have found that some (not many) of the mechanics that do the gas conversion can sometimes use of inferior wiring connectors (scotch locks and cheap lugs), and also they may run poorly routed wiring and heater hoses.

Some mechanics also use pliers instead of proper lug crimpers when doing the conversion. This can cause high resistance joints and/or intermittent faults, and might also be a factor in making the engine backfire, which, in turn can cause more problems.

Routing of the electrical wiring over sharp metal, near the exhaust, or not securing the wiring properly may also result in short circuiting or open circuits. Also wiring that is under tension, has a knot in it or is flexing constantly can become open circuit. Sometimes it a can also be the cause of an intermittent fault.

Loose or poor quality spade lugs can develop a film of carbon under them. Although they may look okay it is a good idea to check them and use a pair of pliers to tighten them.

The cab heater hoses are often used to supply hot water to warm the mixer and prevent it from icing up and starving the engine of gas.

The use of "Y" pieces instead of "T" pieces at the junctions where the mixer heating circuit is piggybacked to the vehicle's heater is recommended, because they prevent cavitation, which may result in poor water circulation.

I have also seen problems caused by metal filings or swarf from the gas piping or from the service station get lodged in the gas components, such as solenoids.

There has also been a few cases where the solenoids and control components have failed.


The Diaphragm in the gas mixer can "go slack" over time, too so the mixture may need to be adjusted. As Alitis said in the above post: It is hard to tune for LPG, without the correct equipment.

I also recommend getting a LPG specialist to tune the engine

Some relevant threads;

http://www.nissanpatrol.com.au/forum...t=idle+mixture

http://www.nissanpatrol.com.au/forum...t=idle+mixture

This is a scotch lock. An easy way to join wires, but they sometimes fail, especially if subjected to moisture and vibration.
I strongly recommend soldering all joints and then sealing them with heat shrink or brush on electrical tape.

[GQ TANK]

Missfiring, rough idle and rough running

This can also be caused by the a loose carby. in the base of the carby there are 3 screws that join the butterfly assembly to the rest of the carby, they can come loose (especially if you are using a impco carby mixer) - as they have a lot of top loading on the carby.

To detect remove the air cleaner, try moving the top of the caby - any movement you have this issue.

To fix - remove the air cleaner - remove the 4 mounting bolta at the base of the carby, flip the carby and tighten the 3 large screws.

While you have the carby out and if you don't live in cold climate consider doing the carby heat mod for a little bit of extra power - remove the honey comb element.

Note:- the Loose carby issue affects the RB30s and TB42s - I have had it occur on both motors

[mudnut]

Have a look at some of the horsepower figures here http://en.wikipedia.org/wiki/Nissan_RB_engine

An interesting read for those that would love to modify their RB30.

From the 73.5 rear wheel KW readings I got on the dyno, it also shows that the drive train takes almost a third of the power the stock engine produced.

[Nissan cedric]

Hello mudnut... Ta for the effort. It has certainly lead me to consider. I have a fumes in the cabin and my fuel is 17.5L x 100 K's. So I will give this a big look at. Also is there a vacuum gauge that can be fitted and view that would assist re fuel usage. Again thank you for your effort. Perhaps we could have a dedicated RB30 site or sub site. Please keep the information coming. Regards Nissan Cedric