Thread: Petrol VS diesel?

Modern diesels vs modern petrols is a tad bit different from older models. Although I agree that modern engines can have very good reliability and durability in general they are more prone to failure than their old counterparts.

One of my best mates runs a workshop and I have been helping him out since forever with complex electronics or computer related issues and from our experience there is a difference between old and new. Hell, there is even a significant difference between new as in 0 years old and "new" as in a couple of years back vs say 20+ years ago.

The diesels of yesteryear's are the ones that could do a million K's without a rebuild, the OM617 comes to mind. Those were 70's and 80's engines. Then came the 90's en 00's and some good engines were made, but crap among diesels started to pop up. The VW 2.0tdi's were everywhere by then, very good engine but it did have a few short comings. The same goes for petrol. I'll ignore pre injection engines. The mechanical injection engines were, in general, not that reliable in my experience. Like it's diesels cousins the pumps and what not would wear out but for some reason a lot faster. Then in the 90's we got catalytic converters and lean running engines which did have an effect till we sorted that out. The engines from this era I think are among the most reliable petrol engines in general.

Having said that, a modern diesel engine is chocked to death and although common rail is good for economy I have had to put so much force on stuck injectors that I bent cylinder heads to get them removed. I saw way more engines fail in the mid 200K's with common rail around the 00's then I did with the older diesels before. Especially mercedes. Onto the really new diesels with dpf's and what not, in comparison I see even more of those fail even earlier. Just last month a small ford van with 60K on the clock, failed. It was driven daily for reasonably long distances (courier work between cities, not local traffic)

The shocker for me however is modern petrol engines. They may not have the problem that diesel engines have with EGR and PCV but they have a similar problem. Because "environment" modern petrol engines have started to implement GDI or Gasoline Direct Injection. Since there is no longer clean fuel flowing past the intake valves they no longer get cleaned. The EGR and PCV problem of diesels is coming to petrol as well but not in the form of black goop but a brown-ish hard layer. This causes the intake valves to stick, not close properly and what not causing mayor headache. This year alone we have seen a dozen or so car's with that problem. All of them had done 100K at most. My mate bought a sort of sand blasting device that is filled with walnut shell grit to sandblast the intake port which cleans it without affecting the alluminium.

Also, to reduce internal friction the piston rings have become really loose, combine that with the water thin oil of today and even a few year old honda civic with 60K on the clock uses 1liter per 6k which is acceptable according to the manual but I am not used to honda's using ANY oil whatsoever within their service intervals. Even my 300K+ honda's don't do that. So I'm afraid that in the reliability category really modern petrol engines are not much better than diesels.

All in all the environmental concerns have pushed modern vehicles into the realms of questionable reliability or at least durability which in turn is very polluting since you need to buy a new engine or recycle your car sooner.

Just my experience and 2 cents

Cheers,
-P

Originally Posted by 1nando

Figures aside, modern diesels are frugal, I have no problem with this argument. Modern diesels are also highly tuned, complicated, and require extremely clean diesel fuel to operate. When having this debate regarding petrol v diesel I think of it like this; there's old school diesels which can run on pretty much any diesel quality fuel, there's modern diesels which are a headache waiting to happen and then there's petrol.

I work with heavy vehicles so I love a good diesel, these modern trucks run all day and allow the modern diesel emissions equipment to operate properly... most of the time. Mum and dads who drive these same modern diesels in city stop start traffic are kidding themselves if they think they're reliable compared to old school diesel engines. I can't be bothered ranting further on this particular subject.

I drive a y62 patrol, a petrol guzzling v8 is what most of you think of it as. Yes it drinks double what a modern dual cab drinks but it also has twice the HP, considerably more torque than most and far less s#it hanging of it. There is no egr, dpf, ridiculous high pressure rail system, intercooler, turbo, etc. Around town I'm doing 18-20 and on the highway 11.5-13 depending on hills, wind, vehcile load etc.

I'd put my mortgage on the fact that my NA v8 pertol is twice as relaible as a modern diesel, cheaper to service, and ultimately cheaper to run over 150,000kms. In those kms a good majority of modern diesels will either have egr, dpf, turbo, intercooler, fuel rail issues etc.... and god forbid they actually go remote and get s#it fuel.....then you don't care about liters per hundred but dollars per engine replacement!

Moral of the story, new diesels are not old school diesels and therefore petrol wins due to its simplicity!

Or lower than 11

Originally Posted by 1nando

Thanks for confirming, like I said BS!

I'm a convert. I have always had big petrols. New MR Triton.GLS Premium (ie the heaviest stocker). Mann Hummel Provent 200 catch can is only mod. 5 adults on highway at 80kph yesterday in 6th and it's showing 4.2 litres per 100k...Given how low revs are I believe the gauge. About to do a long trip with the boat on so I will report back. I agree with you about complexity of modern diesels. The little 2.4 Mitsu motor is one of the best of them and puts up huge miles with a catch can to avoid carbon build up. The torque and power with the 6 speed and lighter vehicle means it's quicker than my 4.6 D2 manual. Quiet as a mouse on the highway. Really sweet vehicle. Very comfy seats (They have done a lot of work on this new model).

Cheers

Originally Posted by ozscott

I'm a convert. I have always had big petrols. New MR Triton.GLS Premium (ie the heaviest stocker). Mann Hummel Provent 200 catch can is only mod. 5 adults on highway at 80kph yesterday in 6th and it's showing 4.2 litres per 100k...Given how low revs are I believe the gauge. About to do a long trip with the boat on so I will report back. I agree with you about complexity of modern diesels. The little 2.4 Mitsu motor is one of the best of them and puts up huge miles with a catch can to avoid carbon build up. The torque and power with the 6 speed and lighter vehicle means it's quicker than my 4.6 D2 manual. Quiet as a mouse on the highway. Really sweet vehicle. Very comfy seats (They have done a lot of work on this new model).

Cheers

Good to hear they finally did something about the planks they called seats. If they had been better 20 years ago I would have had a Triton back then.

Tried all iterations since, it had mates with them. And couldn’t handle the seats!

For sure Mike. I agree. I didn't like any of the seats until the MQ and they are good but MR is a step up again. After an hour it still all feels good. I have 4 hours coming up soon so I will.report back.

Cheers

Originally Posted by ozscott

I'm a convert. I have always had big petrols. New MR Triton.GLS Premium (ie the heaviest stocker). Mann Hummel Provent 200 catch can is only mod. 5 adults on highway at 80kph yesterday in 6th and it's showing 4.2 litres per 100k...Given how low revs are I believe the gauge. About to do a long trip with the boat on so I will report back. I agree with you about complexity of modern diesels. The little 2.4 Mitsu motor is one of the best of them and puts up huge miles with a catch can to avoid carbon build up. The torque and power with the 6 speed and lighter vehicle means it's quicker than my 4.6 D2 manual. Quiet as a mouse on the highway. Really sweet vehicle. Very comfy seats (They have done a lot of work on this new model).

Cheers

How big is your boat, It has been my experience that the small 2.5 diesels struggle on hills with large boats.

Trout I agree. If I was still running the Seafarer Vagabond I would have thought twice but for the 750kg 4.5 side console tinny the 2.4 Tdi won't really feel it.

Cheers

Originally Posted by DoubleChevron

2wd twin cab navara. he travels at 90->100km/h usually. But is never in a hurry when towing. The territory used to use 15L/100 towing a smaller caravan. He's always checked fuel economy forever .......... So I believe.

seeya,
Shane L.

I have just come back from a 3000k trip in a twincab Navara 2.5l towing a 1.5t boat and I averaged about 15/16l per 100k's at 85-90kph.
My missus was towing a 2.5t 20' Jayco "Expanda" with a fully loaded 79 series 4.5l v8 and she was averaging the same 15/16l per 100k's.

We did a trip to the Gulf country last year about a 10,00k's round trip and I used my D2a V8 which used about 22/24l per 100k's towing the same boat and at the same speeds.

The big V8 diesel in the 79 series towed much easier than either of the 4WD's I used and the fuel economy was the same as the small Navara engine towing Much less weight and carrying Much less of a load on the tray.