Thoughts on engines these days

[Teleman191]

So this is just a general question aimed all of us who drive 4cyl diesel.

I was an owner of a grenadine Zd30 and must say over all my web searches and mechanic advice, there is no real clear cut answer, rather a few things contribute to the end result.

One of the issues that came up time and time again was the engine being too small for the patrol. What I want everyone's opinion on is do you think this is a true statement or are you a believer in technology? Take for example the pathfinder weighing about 200 - 300 less then the trol, but has a smaller engine. Also the new amaroc with an even smaller engine.

I'm not really a tech head but I understand Diesel engines enough to diagnose problems if there are any, but with the issues early gu patrols had, I can't see longevity in the amaroc. OR should we embrace technology and trust these new wiz bang oilers ?

 

[jimmy_jay89]

with diesels the more power you required ment that you will need a larger capacity engine

take the 4.2L when it was released it was powerful and reliable when size mattered it was great it had the pull, and the ability to speed up a car reasonably quickly
Now however, the 4.2 is a antiquated pos..

with modern diesels, the same power can be obtained from a smaller engine

the zd30 is more than enough to push the pootrol and the d22

the yd25 is one of the smallest diesels available in current utes but its also the most powerful and stable

the new v6 and the 5cyl diesels are also making a comeback but are producing far less hp/Nm per Litre/cyl than the 4cyls
the 2.5 is about 400Nm
the v6 is 550
the v6 (in a jeep) is 525
the 5cyl ranger is about 480ish
hell even the v8 in the cruiser is under powered at only around 500

so to answer the question.... while the older diesels have longevity on their side, they cant compete (which is why nissan replaced the 4.2 with the 3)

the easiest way to see this is

the 4.2 produced about 100kw at 350Nm
the 3L about 97 at 350
and the 2.5 about 147kw at 400Nm
or the v6 3L about 170kw at 550Nm

 

[Krankin]

But....the fact still is....

THERE IS NO SUBSTITUTE FOR CUBIC INCHES...PERIOD!!!!

 

[Geoff3DMN]

But....the fact still is....

THERE IS NO SUBSTITUTE FOR CUBIC INCHES...PERIOD!!!!

There's no reason you can't take a big engine and supercharge it or turbocharge it though and at some point the engine can't be increased any more because it won't fit in the vehicle.

So... I guess that means that the ideal engine for a Navarra is a twin turbo V8

 

[tweak'e]

euro makes some great small high powered diesels.
a lot of it is down to the tech used. nissan tends to use the cheaper tech.

the big problem is that owners/mechanics/fuel companies/etc are used to commercial based diesels that will run fine on crap fuel. small high tech engines will never run well or reliable if you feed them crap. untill fuel co start delivery quality product and mechanics stop dragging their knuckles you will always get problems.

 

[Krankin]

True....

Now apply that high tech to a larger engine and you will have more power and better reliability
The shit fuel... Well what can we do??

 

[gadgets]

so to answer the question.... while the older diesels have longevity on their side, they cant compete (which is why nissan replaced the 4.2 with the 3)


I was under the impression that Nissan only dropped the 4.2 in the patrol because it could not pass European emission laws?

 

[gadgets]

To me owning a diesel should mean good fuel economy for a big car and a long life for the engine, only time will tell what kind of run the newer diesel motors will get.

 

[tweak'e]

yes main reason for new engines is to comply with the new emission laws.

don't forget one reason not to have big engine and big power is the limits of the driveline. these days one major part of getting good fuel economy is to use lighter running gear to keep weight down.
eg some cars have pathetic towing ratings due to the light gearbox which can't handle it.

also there is marketing and tax. in some countries engines over 2.5 litres get taxed more which is why euro navaras are generally the 2.5 litre models.

 

[180degrees]

someone mentioned the V8 cruiser being low powered.

Can I just point out there is a huge difference between having peak torque from 1200rpm right through the rev range vs having a tiny engine that only makes peak torque at 2000rpm or higher and then tapers off again after like 750rpm.

any cruiser or trol in 4.2TD or the 4.5 V8 cruiser will happily pull a big weight around, cubes vs high tech small engine I know what I would rather.

btw OP I could be wrong but the ZD30 in patrol fails because they have like 4psi boost thanks to the ECU when cruising on the highway and apparently the ECU injects far to much fuel in for the amount of oxygen which leads to them burning holes in pistons.

 

[gadgets]

also there is marketing and tax. in some countries engines over 2.5 litres get taxed more which is why euro navaras are generally the 2.5 litre models.

Yes, very true, I think alot of these countries are now changing the system to an emission based one, example, the more emissions your car produces the higher the tax you pay.

 

[Krankin]

there's that horrible word again.......TAX

 

[gadgets]

there's that horrible word again.......TAX

Well, that's what its all really about isn't it ?

 

[tweak'e]

yeah unfortunately so.
now some cities have green tax ie you have to have a certain emission car to be able to go into the city at all. 4.2 patrols are banned !

 

[Teleman191]

New diesel rav 4, max towing 550kg brakes or not braked. NOT a typo.
I read that this is because Toyota has not used this engine in a climate like aus. Also another new high tech one, dualis diesel, a 1.6l producing 114 and 320nm. Don't quote me on those figures though, but all this stuff is I think more appealing then big 4.2 and 5.0 v8. (At the moment) but will they stand the test of time?

 

[180degrees]

I was going to post the rav4 diesel specs in the jokes section when it came out, but I am not that harsh, I could end up driving a gutlux soon

dunno how you could want a smaller engine listen to this v8 cruiser and tell me it doesn't stir something in the pants http://www.youtube.com/watch?v=z5JJXLlI3Ao they get like 11-12L per 100km to which is not far off the 4cyl utes.

 

[ben85]

I think the saying goes "there's no replacement for displacement!"

But....the fact still is....

THERE IS NO SUBSTITUTE FOR CUBIC INCHES...PERIOD!!!!

i'd rather have a something like a 4L turbo diesel in the nav if i had the choice.
the 3l feels like it works pretty hard at times. a bigger engine that doesnt have to work as hard I would expect to last longer in the end.

bigger is better as far as i'm concearned.

 

[Old.Tony]

If I recall there was a fundamental difference between the GU30 in the Patrol and the almost-same engine used in the Navara.

The reason for burning holes in the pistons was that Nissan run 'em hot to produce the power that they get - and it was usually #3 piston that would melt, mostly because the turbo was bolted to the back (just after #4) so the heat from #1 and #2 would add to #3 and just make things worse. Might be something in the water jacket too - but Nissan solved it by introducing a squirt pump that sprayed oil onto the underside of the piston crown as the piston descended. This was the engine introduced to the Navara - which allowed them to crank it up even higher!

In order to produce power you can do several things. You can squeeze more beans out of a small motor (increase temp, increase boost) but you'll do this at the expense of longevity. The alternative is to use a bigger motor - per unit capacity you're producing less power, and per unit capacity there's less strain on all of the components.

More cubes = more power for a reason. The little 2.4L V8 engines they run in F1s could never haul my van to Uluru and back despite it developing over 500hp (at 19,000rpm). Next year's F1 engines will be a bigger surprise - 1.6L turbocharged V6 with rpm limited to 15,000 and using energy recovery technology. These engines wouldn't survive the warranty period of our cars!

 

[tweak'e]

If I recall there was a fundamental difference between the GU30 in the Patrol and the almost-same engine used in the Navara.

The reason for burning holes in the pistons was that Nissan run 'em hot to produce the power that they get - and it was usually #3 piston that would melt, mostly because the turbo was bolted to the back (just after #4) so the heat from #1 and #2 would add to #3 and just make things worse. Might be something in the water jacket too - but Nissan solved it by introducing a squirt pump that sprayed oil onto the underside of the piston crown as the piston descended. This was the engine introduced to the Navara - which allowed them to crank it up even higher!

sorry but none of thats true.
they all have oil squirter's and they never ran hot to make power.

nissan screwed up the piston design, the increase in oil was a bandaid.
patrols have issues with the turbo/egr control system which causes the boost to drop to 4psi while maintaining the same fueling. hence high egt's.

intake clogging with egr soot, lack of oil cooling in hot climates, the maf only control system, variable turbo vanes sticking, etc are all contributing factors.

 

[180degrees]

yea so in actuality the original renault design is not exactly a bad one just Nissan thinking they know better and bolting on all this unnecessary crap to it, should of just put the D22 variant in the trol, not like 6kw and >40nm are going to be all that noticeable, I have had half a tonne of wood in the back of mine and didn't even know it was there so its not like the motor wouldn't cope with the extra weight.