Caring for your diesel

[brooks]

Hi just wanted to put out there that 4WD action had a really interesting article on caring or protecting your diesel engines, mainly directed at the 3L's. They discussed how over throttling can cause over heating in your exhaust and turbo without getting you anywhere quick. They suggested getting an EGT and boost gauge to monitor what's happening inside to help notice temp spikes sooner and more efficiently then just using your normal temp gauge which in a lot of cases can be a bit late once the temp has started to climb, especially in the 2.8L and the 3L which are vulnerable to temp spikes. I have a 2.8L so it really appealed to me as I am in the process of rebuilding the engine as the head cracked, so I decided to replace all internal parts (pistons,rings,bearings,etc) and do the job properly. Obviously they went into lot more detail and and had a few other segestions on how to protect your engines but the EGT and boost gauges were their top two suggestions.

[YNOT]

One of the major causes of early build ZD30 engine failures was PCV (positive crankcase ventilation) oil vapours travelling back up the inlet ducting after engine shut down. This oil mist eventually coats the MAF (Mass Air Flow) sensor causing it to send false readings to the engine computer. It is these false readings from the MAF sensor that often results in the engine over fueling and melting pistons. This is what people refer to as "grenading"
If you have a exhaust gas temperature (EGT or pyro) sensor you will see the temperature rise well above the 550 degrees C (post turbo) recommended maximum, the reason why pyro gauges are so important.

Regular cleaning of the MAF sensor will slow this process down but the best fix is to combine the pyro gauge and MAF sensor cleaning with a catch can or PCV filter. These filter out and collect the oil mist and stop it from coating the sensor.

Blocking the EGR (Exhaust Gas Recirculation) also helps, although it is illegal as you are tampering with an emmissions control device.
The carbon from the recirculated exhaust gases can build up in the inlet system over time and restrict air flow, again resulting in over fueling.

ZD30's have computer controlled turbo boost but at times it does not do a very good job of controlling the boost. At times it pulls the boost right down to allow the EGR to work (pointless if you have blocked the EGR) and at other times can allow boost spikes well past 20 Psi. Although the boost spikes themselves will not hurt the engine they can damage the intercoolers. The end tanks on the standard intercoolers are crimped on and repeated over boosting can loosen the crimping allowing boost to leak out. You will usually see an oil stain (condensed PCV oil mist) around the ends of the intercooler if they are leaking.
Fitting a Dawes and needle valve set up takes boost control away from the computer and lets you set the maximum boost and spool up rate.


The 2.8 (RD28) engines do not have a reputation or history of grenading like the ZD30 but the same principles apply, fit the boost and pyro gauges to keep an eye on what's happening in the engine, fit a PCV filter/catch can to keep oil mist from coating the MAF sensor, block the EGR. All of this combined will ensure the engine gets the maximum amount of air and keep the EGT's as low as possible.

Tony

[brooks]

Thanks heaps for all that info that really helps me.

[teleman]

Wow. This is a great thread and great info from both you guys. Mine is due for a service, and im gonna change the oil and fluids, but after reading this... Definitely changing the air filter and cleaning the MAF and fuel sensor.
Do you guys know how much auto electricians will charge for fitting the gauges?

[YNOT]

Sparky's charge by the hour so it will depend how quick they are. Keep in mind fitting a boost gauge to a ZD30 requires a fitting to be welded/brazed into one of the intercooler pipes and the pyro gauge needs the thermocouple (sensor) fitted into the exhaust, both of these jobs take a bit longer to do so it's not just a straight mount the gauges and wire them up job.

Tony

[nickpeacock36]

Wow. This is a great thread and great info from both you guys. Mine is due for a service, and im gonna change the oil and fluids, but after reading this... Definitely changing the air filter and cleaning the MAF and fuel sensor.
Do you guys know how much auto electricians will charge for fitting the gauges?

Do it yourself mate. I did and consider myself a novice. If you can't weld just get that bit done by a mate who can.

[Leighw85]

Hi just wanted to put out there that 4WD action had a really interesting article on caring or protecting your diesel engines, mainly directed at the 3L's. They discussed how over throttling can cause over heating in your exhaust and turbo without getting you anywhere quick. They suggested getting an EGT and boost gauge to monitor what's happening inside to help notice temp spikes sooner and more efficiently then just using your normal temp gauge which in a lot of cases can be a bit late once the temp has started to climb, especially in the 2.8L and the 3L which are vulnerable to temp spikes. I have a 2.8L so it really appealed to me as I am in the process of rebuilding the engine as the head cracked, so I decided to replace all internal parts (pistons,rings,bearings,etc) and do the job properly. Obviously they went into lot more detail and and had a few other segestions on how to protect your engines but the EGT and boost gauges were their top two suggestions.

Any idea mate of what magazine number this was in? i might of missed the artice

[YNOT]

It was only a few issues back but from memory the article lacked detail.

Tony

[curlyjimbo]

Hey 1st post here,

I've just bought a Patrol with a ZD30. It has the Dawes needle valve, and blocked EGT with a oil catch can with an upgraded intercooler.

The boost is set at 13~14psi, but can sometimes spike at near 20psi.... my question is, how high can I set the maximum boost, with it still being at a safe level?

Cheers,

James

[Skull]

I would say twenty is too much. I had all that and more done to my ZD30 03 minus intercooler. I had mine set for 16 tops which is where you will find you over boost protection. Used to set it off O/B/P in the cold of morning before engine had got to temp. The boost does not need to go any higher than 14-16 ever. You will find with the needle valve controlling spool your engine will have good boost instantly unlike when the computer was managing it. I found that pre Dawes/Needle boost was not there when needed (5-8psi) and coming on strong when I was backing off (13-15psi or higher). Don't go stupid. These lil donks are know for issues related to boost. We do these mods to stabilise and smooth out the boost curv making the car more reliable. Crank it up and you will likely end up with a big old repair bill. My opinion. Good li engine when treated right. ZD30 Reference Doc.... Your new best friend.