EGR ZD30

Engines and Engine Systems
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Tony
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Re: EGR ZD30

Post by Tony » 06 Sep 2014 21:06

Josh, I bought my "Troll with 118 000 km on the clock just over 6 years ago, and am now sitting on just over 200 000 km's. I recently had big issues with the engine, and ended up reboring and redoing the entire engine. When all this work was being done, I noticed that the EGR had been blocked already (I don't know at what mileage) so I can't comment on the changes / or benefts of doing it. All I can say is that I have done 80 odd thousand km's myself, and my issues had nothing to do with the EGR being blocked - I don't think.

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Re: EGR ZD30

Post by JoshJ » 07 Sep 2014 11:09

Thanx for your reply Tony. I read the thread on your Troll. Sorry to hear about that. They way I see it at this stage, is That it does not influence the engine directly when it comes to reliability. Some guys have done it and some not and there Trols are still going strong.
One thing that is clear, is that if you change something it has further or other impacts and those have impacts of there own. When you close of the EGR you must tend to the turbo boost, cause it increases boost on a engine that already suffers from over boosting. Over boosting can cause in return engine failure problems. For example, car goes in limp mode when coasting due to over boosting. You put foot to increase power for an uphill or overtaking, nothing happens so you push the peddle more, in return overfeuling the engine. Do this for long periods and whamm, motor gone. Or un noticed damage accrue and as time goes it deteriorates up until it breaks down.

Photos iIve seen on the inter web of EGR related stuff looks bad. I'm no pro but diesel exhaust gas is full of oily gunck. Hence the reason why you'll never need to replace a diesels exhaust because it has burnt or rusted through. It gets lined with insolation with every kilo you drive. Now with EGR you put that gunck into a space where it is supposed to by clean and pure for effective combustion. Its like taking the stuff from once own exhaust and putting it in once mouth. Phew :lol:
Help me out if I've got this wrong. This must with time block things on your intake system.

Then, the purer the fuel mix the greater the combustion. The greater the combustion, the greater the power. And heat and speed is the after math. A diesel engine can barely burn all its fuel as is, that's why they smoke. Why disrupt the combustion even more by adding used outlet gas to the mix.

What i do know is that i was blessed enough to have a Troll from new, i have the opportunity to treat it right from new. So i want to do the right things right. I don't want to make any drastic changes to a already fragile system. And i don't want to strip things that are major like heads and pumps and turbo's and manifolds unless its absolutely necessary. Once you do this things are never the same.

Thats my thoughts thus far. Help me if i sit die pot mis. All i know of Trolls I learned through reading you ouws posts on this forum.
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Joshua

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Re: EGR ZD30

Post by JoshJ » 07 Sep 2014 11:44

Tony,
I see its about for years since the rebuilt. How is your Troll doing? Do still have the EGR blocked off. Any other engine mods that you feel add value?
Sorry for asking. But the forum is like reading a reality story. I miss the after math reports. I'm always interrested in knowing what happened after that dreadfull day, once the problem is solved. ( You did give some feedback, thanx for that.)
Was the lemon worth the sqeeuze? Sorry for putting al this to you. But its jst a general trend that i pic up. Once the guys find the problem and the "solution" you don't hear of it again. I sometimes wonder if the repair was effective and solved the problem for good. And so on.
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Joshua

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Re: EGR ZD30

Post by Tony » 07 Sep 2014 20:29

Josh, the rebuild only was completed November '13 and I ran the "new" engine in over December / January this year. In Feb, the oil was changed and the 3" downpipe was added. Since then, I have done a good 8500 trouble free km's which is helping the family regain trust in the car! I do have one niggly, and that is the EGT temp, i'm finding it climbs way too high on any uphills. So I am trying to get to the bottom of this problem - but apart from this, the engine is running beautifully.

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Re: EGR ZD30

Post by Kagiso II » 07 Sep 2014 21:32

Hi Josj .. what is the EGT readings uphill .. and what normal>?
Do you keep it in high on up hills ? I found with AGAROB that the EGT tem came down as soos as i hit the "Overdrive" button .. but I dont think your's have that old time g/box . or does it ??
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Re: EGR ZD30

Post by Stefan » 08 Sep 2014 11:46

JoshJ wrote:Thanks Peter and Stefan.
This is a very interesting read. Stefan the fact that you have done so many k's does carry a lot of weight. Plus I enjoy your sense of humour :rolling:

Do you also have the overboost problem? My trol is pap in 5th gear. And overtaking is dreadful. 1st,2nd,3rd gear no problem very strong and punchy. Get on the open road and nothing. You can't even full it pulling in 5th. It just keeps the 110km. If you want more you must wait for a downhill. Is this it? Or is there more?
I am going to Namibia in December. I'll be towing a trailer. And i am all ready dreading the idea of driving 7000k's with a car that can hardly cope with 110k's a hour when its empty. Maybe I'm just expecting to much from the kar.

What mods have you done stefan?
Hi Josh,

The following is no longer 'standard' on my Patrol:
> 33" cooper STT's
> Aftermarket intercooler & oil catch-can
> Frans installed a Uni-chip to resolve an under-fueling issue that was caused by replacing the faulty can-bus module on the injector pump - boost performance is set to normal (i.e. 0.4 to 0.9 bar boost)

If definitely sounds like there is a problem on your car. Like many guys have suggested, I would also recommend that you take your car to a reputable dyno-shop.

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Re: EGR ZD30

Post by JoshJ » 08 Sep 2014 21:04

Tony,
Thanx for the reply. I'm no machanic but I see you bord the piston sleeves. I had a Oom that was a diesel mac and I once heard him tel a guy that if you go to oversize the engine will run warmer and will over heat quickly because of the wall thickness that is reduced between the ports and the sleeves. But you only mention EGT so not sure how that can effect it.
Then, i have been reading a lot about the EGR on the google. And it was very interesting stuff. You have not said that your egr is still blocked off after the overhaul. Maybe its worth a check.
If it is not blocked off and the radiator that cools the recycle gas is blocked or partialy blocked from the gunk, it can cause the hot air to go into the intake at higher temps. Causing higher EGT temps.

Oom Mac,
Are you refering to Tony. I don't have temp problems that I know of. And mine is manual. :thumbup:

Stefan,
Thanx for the feedback. I got the Troll back from SWAMBO so i've been driving it for a few days on roads I usually travel. And find that she performs much beter after the VNT was adjusted. Pulls in 5th up to 140km/h with not much efford. So the Trolls doing beter. She still had it when I made the adjustment. And I could only test it for a short drive, then had to give it back :lol: . But driving it everyday now I can say that there is defenet improvement.
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Regards,
Joshua

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Re: EGR ZD30

Post by JoshJ » 08 Sep 2014 21:26

I read alot of stuff on EGR last night and there is defenitly more advantages blocking it of than not doing it. On diesels. I pasred a piece from wiki that l found might be an adding factor to the ZD30 failure. Acidic oil.


"By feeding the lower oxygen exhaust gas into the intake, diesel EGR systems lower combustion temperature, reducing emissions of NOx. This makes combustion less efficient, compromising economy and power. The normally "dry" intake system of a diesel engine is now subject to fouling from soot, unburned fuel and oil in the EGR bleed, which has little effect on airflow, however, when combined with oil vapor from a PCV system, can cause buildup of sticky tar in the intake manifold and valves. It can also cause problems with components such as swirl flaps, where fitted. Diesel EGR also increases soot production, though this was masked in the US by the simultaneous introduction of diesel particulate filters.[9] EGR systems can also add abrasive contaminants and increase engine oil acidity, which in turn can reduce engine longevity.[10]

Though engine manufacturers have refused to release details of the effect of EGR on fuel economy, the EPA regulations of 2002 that led to the introduction of cooled EGR were associated with a 3% drop in engine efficiency, bucking a trend of a .5% a year increase.[11]"

Environment forced ideas like EGR. To control the EGR they use 2 methods. The VNT turbo and electronic control. The VNT turbo close the vains via vacume thats commanded by the ECU. This reduces turbo pressure to go lower than exhaust pressure, allowing the egr valve to open and letting the recycled exhuast gas in. If you dont reduce the turbo pressure the gas cannot enter because its over powered by the turbo air pressure.
Thought I'd share. :mytwocents:
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Regards,
Joshua

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