mcoss

GUIDE STATUS - IN DRAFT.

Please check back for the full guide after I update this status.

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Howdy all. Just reserving this thread so that I can post an easy to follow, step by step guide to installing the Nissan Anti Detonation mods for all to use.
I'm just gathering all of the photos from my camera, taking some new photos and updating the parts and price list.


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The Nissan Patrol 3L di engine can have a few modifications to make it more reliable and avoid the dreaded 'grenade'. This thread is not here to debate the reliability of the engine, or compare it to the 4.2 or petrol variants, its here as an easy to follow guide for anyone interested in doing the modifications.

I have done these modifications to about 10 GU patrols now, and while I'm not a qualified mechanic I reakon I have it down pat. Many thanks to Chaz for teaching me.

Any advice on this thread is just that - advice. I am not a mechanic so if in doubt ask first!

WHAT IS NADS?

NADS or Nissan Anti Detonation is a series of simple modifications that can be done to the di zd30 engine and exhaust to avoid the well documented issues with piston and engine damage.
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WHY SHOULD I INSTALL NADS? (Short version)

There are 5 root causes for the zd30 engine failures.

1. Exhaust Gas Reticulation Valve (EGR). This valve recycles inert (but very dirty) exhaust gas back into the inlet manifold in an effort to reduce emissions. However the blank gunk deposited creates restrictions in the inlet manifold causing hot spots and starvation to mainly number 2 and 3 cylinders. See the install section for photos.

2. Oil Starvation. When the early engines came out, Nissan recommended that it only required 6 or so litres of oil. After a while they noticed many failures and "fixed" the problem by recalling the Patrols to shorten the dipstick. The correct amount of oil for the Di ZD30 is 8.3 Litres.
The modified length of the dipstick is (edit)cm

3. Overboosting. The ECU on the early GU patrols doesnt control the boost very well. The GU patrol has a Garratt VNT (Variable Nozzle Turbo). The way this works is - the pitch of the blades of the turbo are changed to create more boost at lower exhaust pressure. Think about how a turbo prop planes engine works. At a constant rev range the power (or thrust) can be increased, decreased or even reversed by changing the pitch of the blades. Like a fan!. The ECU has a pretty big job on its hands trying to control boost at the best of times - different engine revs, different load, the EGR opening and closing (which increases boost in the inlet manifold, after the turbo that the ECU doesnt know about). Nissan introduced an overboost sensor to try and over come this. It basically measures the boost (in the intercooler) and if it stays over a certain psi (it seems different for many sampled patrols) if puts the car into limp mode. You will know if you have limp mode if you are driving along, and all of a sudden if feels like you have no power. If you release the accellerator and reapply, it resets. Very annoying!

4. High EGT (Exhaust Gas Temperature). The Diesel engine is made to work. Good torque at low revs so you dont have to rev its guts out to get power. Its one of the reasons it is so fuel efficient compared to petrol engines) as a lot of the power is rquired just to get your 3T car moving! Obviously for the engine to run you need fuel and air and the combination of these can determine the temperature of the exhaust. Over fuelling or underboosting are common causes of high EGT. Why should i care about EGT? Well, at certain temperatures metals change caracteristics. They can get weaker (causing failure) or even melt! If your exhaust is glowing hot, think about how the pistons, cylinders, manifolds, oil and turbo are feeling!

5. Dirty or faulty MAF sensor. The MAF (Mass Airflow Sensor) is a small device located just after the air filter which measures the volume, speed and temperature of the incoming air. If the sensor is faulty, the ECU can over or under fuel the engine, causing high EGT and failure.
A common issue with MAF sensors is that they get oil on them. This is caused by the Crank Case Ventilation hose feeding back into the air inlet, just after the air filter. If you have a look on top of your engine, you will see the pipe coming from the top most part of the engine, it goes to the air inlet next to the passenger side battery. Oil mist causes the MAF to give incorrect readings. Regularly cleaning your MAF sensor, and fitting a good qulity catch can will certainly help. Its a simple thing that can be done relativly quickly. See the how to section for details.

WHAT PARTS ARE NEEDED? WHERE DO I GET THEM?

If you have read this far, you are probably keen to learn about what is included in "the mods" - Well here they are!



What - Boost Gauge
Why - Monitor what your turbo is doing. Easy to install, do it first.
Where- Get a good boost gauge. It is the foundation of knowing what your engine is doing. myPatrol4x4.com.au vendors section (when it appears), Ebay, Patrol4x4.com vendors section or even your localauto parts shop. Dont get the el cheapo one - you will find yourself replacing it soon enough. I have a Garratt Boost Gauge. You dont need one that goes into vaccuum.. mine does but it doesnt really matter.



What - EGT Gauge
Why - Monitor your Exhaust Gas Temperature. This is just as important as the boost gauge. You will be impressed with the feedback it gives you about your driving style!
Where - As above. I have a Auber digital gauge. I prefer the instant accurate feedback from the LCD display, but others prefer an analouge dial.



What - EGR "Shim"
Why - *CAUTION* Blocking your EGR is probably not legal in your state. EGR's can "Fail closed" . Blocking hte EGR not only helps to keep your inlet manifold and oil clean, it helps you to control the boost that your turbo is producing.
Where - myPatrol4x4.com.au vendors section (when it appears), Patrol4x4.com vendors section, or make one up yourself




What - Dawes Valve
Why - A Dawes valve sets the upper boost limit.
Where - http://3barracing.com sell them, as does some local 4x4 shops (at a outrageously inflated price, Shame!) If you have time get it direct from Darren Dawes at 3 bar racing - it might take 3 weeks but it might teach the local shops a lesson for being so greedy. We can also organise a group buy - post interest in the other section!



What - Needle Valve
Why - A needle valve controls the spool up rate of the turbo once we take away the ECU's control. "Spool Up" is the rate of increase of boost from the turbo. Too fast and you might get limp mode, too slow and you will lose power and have high EGT
Where - Dependable Distributors in SA is where i got my Italian Needle valve.



What - Catch Can
Why - To filter the crank case ventilation pipe, keeping the MAF sensor and intercooler clean.
Where - The Provent 200 is a great option, seems to work very well. Some people choose to buy cheaper catch cans with varied success in catching the oil mist. Have a look on ebay, or http://www.westernfilters.com.au - the kit comes with most needed things.

What - Exhaust upgrade
Why - Having a less restrictive exhaust improves performance, and lowers EGT
Where - Most exhaust shops can knock something up, but i preferred to spend a bit extra and get a 2 3/4" Beudesert mandrel bent exhaust. The Catalytic Converter is 200ccm and it makes an impressive difference.

Other Items that are not high priority, but make life better

What - Intercooler upgrade
Why - The standard Nissan intercooler has crimped ends. They will leak over time, its a common problem.. If this is happening to yours, you may notice black stains on the fins near the ends, or an unexplained loss of boost. Neither are good for your engine
Where - If your wallet is bulging and you have 10 weeks up your sleeve to wait grab a Cross Country intercooler. ASETurbo are just down the road, they are cheaper and normally have them in stock. They also come with all new pipes and a fan. A few other places also recore intercoolers on ebay etc. When mine dies, ill go the ASE i think..

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WHERE DO I START?

So you have decided to go for it! Congratulations! It might seem daunting at first, but if we break it into chunks and take the time to learn what we are doing and why, it will make it a great learning experiance.

Here is the order of how i would go about it... In the next post ill start to describe, in plain english with photos, how to eat this elephant!

1. Fit Boost Gauge.
2. Fit EGT Gauge
3. Fit Catch Can
4. Fit boost control

In between each step i encourage you to DRIVE THE CAR and observe how each change makes a difference, more on that to follow..