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Y2KGUII ZD Wgn
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Discussion Starter #21
I'm not convinced piston design had much if anything to do with it, that design has been around a long time and on many vehicles that don't grenade, materials and specification parameters, yes that was a big issue (as I said in the beginning). My grenade was rebuilt with improved piston quality but same design.

I think we are starting to discuss the very borders of the classic grenade now with injector issues.

I have a set of pistons out the back from a recent Peugeot diesel and man I cannot believe how light they are and they have graphite impregnated pressure faces. Whereas in the old days the quality of the components was the key, the cost of the component has been the governing factor for a long time and even the best get is wrong sometimes.
 

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Not that matters, but i had to speak out: my personal opinion....Grenade term should be switched to EGR-desaster.

Let's think how many blown engines had pistons no. 1 and no. 2 destroyed....very few compared to the engines that had issues with no.3 but especially with no. 4....That damned no. 4....the most isolated....in the back...with all the heat. An extra "help" provided by EGR valve and you have the perfect recipe for how to kill an engine. The crap is injected un-even, so cyl. no 4 takes most of it.

The MAF and the ridiculous blow-by filtering beneath the rocker cover are just aditional factors....my humble opinion. After blocking the EGR we all saw a EGT dropdown, smoother engine and an overall performance improovment.

PS. I really dont think ZD30 has a bad design, i think it's quite a good engine, but you have to understand the basics. For me, this forum was the A.B.C in understanding how a diesel engine works and particulary made me understand the ZD30.
 

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nissan patrol gr
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I'm not convinced piston design had much if anything to do with it, that design has been around a long time and on many vehicles that don't grenade, materials and specification parameters, yes that was a big issue (as I said in the beginning). My grenade was rebuilt with improved piston quality but same design.

I think we are starting to discuss the very borders of the classic grenade now with injector issues.

I have a set of pistons out the back from a recent Peugeot diesel and man I cannot believe how light they are and they have graphite impregnated pressure faces. Whereas in the old days the quality of the components was the key, the cost of the component has been the governing factor for a long time and even the best get is wrong sometimes.
Gu2, lol, and this avatar?
hahaha, I think that tweety (piolín in spanish) is more "macho men"

Cheers



 

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Y2KGUII ZD Wgn
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Discussion Starter #24 (Edited)
Not that matters, but i had to speak out: my personal opinion....Grenade term should be switched to EGR-desaster.

Let's think how many blown engines had pistons no. 1 and no. 2 destroyed....very few compared to the engines that had issues with no.3 but especially with no. 4....That damned no. 4....the most isolated....in the back...with all the heat. An extra "help" provided by EGR valve and you have the perfect recipe for how to kill an engine. The crap is injected un-even, so cyl. no 4 takes most of it.

The MAF and the ridiculous blow-by filtering beneath the rocker cover are just aditional factors....my humble opinion. After blocking the EGR we all saw a EGT dropdown, smoother engine and an overall performance improovment.

PS. I really dont think ZD30 has a bad design, i think it's quite a good engine, but you have to understand the basics. For me, this forum was the A.B.C in understanding how a diesel engine works and particulary made me understand the ZD30.
Not convinced that the EGR played a major role in the grenade effect but it was a contributing factor hence it's inclusion in NADS, the back cylinders on a lot of mass produced vehicles have, at best, a slight disadvantage over the front cylinders due to air movement.

I also don't think the engine is a bad design, top of it's class for the time, but I still believe material specifications played a huge part in the "grenade".



Bloody quote pane won't work again...... but did for Daemonus??????

(Quote)"Gu2, lol, and this avatar?
hahaha, I think that tweety (piolín in spanish) is more "macho men"

Cheers"(Quote)

Now you've hurt my very sensitive feelings............ :hmm: :shock: :p :coffee:
 

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Not convinced that the EGR played a major role in the grenade effect but it was a contributing factor hence it's inclusion in NADS, the back cylinders on a lot of mass produced vehicles have, at best, a slight disadvantage over the front cylinders due to air movement.

I also don't think the engine is a bad design, top of it's class for the time, but I still believe material specifications played a huge part in the "grenade".



Bloody quote pane won't work again...... but did for Daemonus??????

(Quote)"Gu2, lol, and this avatar?
hahaha, I think that tweety (piolín in spanish) is more "macho men"

Cheers"(Quote)

Now you've hurt my very sensitive feelings............ :hmm: :shock: :p :coffee:
Very true about the last pistons getting hotter on a lot of cars but more to do with the coolant being too hot to heat sink by the time it gets back there. Opel fitted an extra water pump to the Omega 3.0 V6 back in the 90s for the same reason and then the police put a third on for when the cars idles for a long period.

Cummins have also had the same issue but it was self made when they had coolant lines running in the valley of their V16s amongst the turbos and exhausts.
 

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To me it seems as a mixture of items which NADS refer to: EGR, exhaust gas mixing with oil from crankcase = blocked air intakes, turbo curve, broken/leaky intercooler, ceramic glow plug missing tips, low oil in the first series, faulty MAF. Each of this has a small part of the unpredictable destructive process.
 

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i wasn't going to jump on the bandwagon and getting in to this topic again but i think we sometimes need to go back to logical thinking,most 4x4 diesel owners today drive them very hard,i was driving on a trip the other week and some guy in a toyota landcruiser passed me on the motorway,he had a long (possibly 12x5) long double axle tralier on tow,he passed me out and i was allready doing 80,he had the tralier fully laden with all sorts of crap.. now what engine could put up with that??

i think sometimes we need to realise what is the maximum speed to drive while towing,i know i drive always with 3tonnes at maximum 60mph,but the road needs to be level,if i have any inclines i have no issue staying in 4th gear,let the gearbox do the work and not the engine.

anyway,100k seems to be the magic number on early models,a reliable production engine needs to be tested intinsively,and they are,they leave the factory ready and fully reliable.

now if any modern day production engine can clock up say 80k then there is no reason why that engine can't do 700k's .... as with any engine and whatever it's used in,something has to make the engine sick,we can all day long blame engine parts and whatever else anchored on the engine but remember that engine was reliable up to x amount of miles so what went wrong and why at this milage now... ?

i think a lot of it is how the engine is looked after,a lot of people just expect too much from them simple as,and as what is been said on this very thread,i think majority of it is heat damage.

when you add a tralier with 3tonnes onboard like i do everyday well then my pistons need to be able to withstand that weight also,i think keeping the speed down is vital to keeping EGT'S and engine at it's safe limits,i know it's common sense but people just do push them too hard.

ok i'm not saying that this is going to be always the main cause,but it could be a lot of the time.
 

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Dan, I think we are mostly talking about the engine, not about a sort of unconscious being between the driver chair and steering wheel :coffee:
 

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I would also like to add to this post.

I highly recommend changing your injectors after 250-300k as well, my 2001 ZD30 with full nads including the glow plug timer, was rebuilt at 292k at 295k i blew a hole threw the 4th piston which has lead back to an injector failure.
I have an EGT gauge, boost gauge and water temp gauge that showed very low temperatures, EGT was at 280-300 degrees when it failed and my water temp was sitting on 85 degrees.
My UAFC also showed no MAF voltage issues which could contribute to this problem.

Heres a couple of photos of the damage.



 

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Hmmmm Seems i was right the other night when i mentioned chit injectors on FB... I'll have to find these fresh pics and see what other comments have been posted.
 

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Downside of diesel compared to petrol. An injector failing open will kill any Diesel engine, as over fueling increases the temp, unlike petrol which does the opposite.

The old post above about people driving any Diesel engines too hard or towing to much, I think this is mainly an Australian issue. All the 4x4s get crappy Diesel engines here. Put a duramax or Cummins that all the yank mobiles get and they'll work hard day in day out.
 

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I would also like to add to this post.

I highly recommend changing your injectors after 250-300k as well, my 2001 ZD30 with full nads including the glow plug timer, was rebuilt at 292k at 295k i blew a hole threw the 4th piston which has lead back to an injector failure.
I have an EGT gauge, boost gauge and water temp gauge that showed very low temperatures, EGT was at 280-300 degrees when it failed and my water temp was sitting on 85 degrees.
My UAFC also showed no MAF voltage issues which could contribute to this problem.

Heres a couple of photos of the damage.
Shiz that sucks man, only 3000 km after the rebuild. Is there any come back on the engine re-builder?

I think I will definitely be insisting on new injectors then.
 

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Shiz that sucks man, only 3000 km after the rebuild. Is there any come back on the engine re-builder?

I think I will definitely be insisting on new injectors then.
Doubt there will if it was the owners decision yo skimp on new/ servicing the injectors and fuel pump.

In this case i would only warrent my workmanship and from the pic it is clearly a injector failure.

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If stocky is who i think he is im fairly sure it was only the head he replaced wasnt a full rebuild

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Doubt there will if it was the owners decision yo skimp on new/ servicing the injectors and fuel pump.

In this case i would only warrent my workmanship and from the pic it is clearly a injector failure.
If stocky us wo i think he is im fairly sure it was only the head he replaced wasnt a full rebuild
Yep still would suck. Also confirms to me that I should do a full and thorough job on my motor and not just the head.
 

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Y2KGUII ZD Wgn
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Discussion Starter #37
Shiz that sucks man, only 3000 km after the rebuild. Is there any come back on the engine re-builder?

I think I will definitely be insisting on new injectors then.
3000K??? over the years I've seen and heard of some dodgy "rebuilds" that have dropped their bundle very quickly (mostly because someone is bodgying it up to sell), but 3000k? that's got to be a record.
 

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If stocky is who i think he is im fairly sure it was only the head he replaced wasnt a full rebuild

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Believe the bottom end had already had a rebuild prior to stocky buying it.
 

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Believe the bottom end had already had a rebuild prior to stocky buying it.
Looking at the photos that would make sense, the bore and piston tops are clean and new. Piston is marked with 0.05 oversize. Can see the square shape, which I assume is a ceramic heat coating over the top and into the chamber.

Still it is crazy that just a faulty injector can destroy a new piston in that way. I gather it is over fueling that cylinder so temps in the piston crown combustion chamber area are extreme.
 

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Looking at the photos that would make sense, the bore and piston tops are clean and new. Piston is marked with 0.05 oversize. Can see the square shape, which I assume is a ceramic heat coating over the top and into the chamber.

Still it is crazy that just a faulty injector can destroy a new piston in that way. I gather it is over fueling that cylinder so temps in the piston crown combustion chamber area are extreme.
See it every now and then in the heavy industry.
One port on the injector nozzel can erode or become damaged, and squirt a fuel stream at the piston.

Have seen a fair few holes burnt through liners also.
Must say i do love to see a bit of carnage and im in the right industry to see lots it would seem.

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