Thread: Eny meny miney mo which diesel motors the go

Originally Posted by Blknight.aus

lets just skip the whole rudolph diesel and his peanut oil fired engines and go straight to my favorite engines the 2.25 series landrover diesel and petrol engine. why? because the 2 are so close to identical that in many respects they are. Crank, block, rods, pistons, flywheel, cooling system and valve gear are identical, they are so close that if you took a diesel engine, plugged the glow plug holes, tapped the injector holes, did some machining to the combustion chamber, added a carby + sparkplugs, hoicked the injector pump dropped in a dizzy and a coil and viola, one ex diesel come petrol 2.25 series engine.

did they share the same crank or ws the diesel forged?

now you'd think that with so much in common that the engines would last the same but they dont.

and heres one example why.

hands up all of you series diesefaster you wear the engine out The petrol's got more power to give and it generally gets asked to give it.

Just on that consideration in the real world the diesel will outlast a petrol engine. However in lab conditions if you made all things equal both engines would wear out at the same rate.


some other things that make a difference.

diesel fuel is a lubricant, if you diluted the engine oil with a liter of diesel you'd do less damage than if you tipped in a liter of petrol (youd also be less likely to blow your self up from hot combusion gasses igniting the engine oil)l owners, what happens on a cold day just after you start it and you try to make it do some work?

It stalls

not modern diesels....

so even tho the engines are identical (well more or less) due to the nature of the beast the diesel generally gets treated nicer than the petrol (well the older ones that started the whole diesels last longer thing anyway)

not the point being made...look at most old diesels, they had stronger blocks, forged cranks insted of cast, and produced less power than ther petrol eqivenlent..


diesels arent so fussy on fuel air ratios, If they run too rich they speed up and the govenor winds it back if they run too lean well they almost always run lean if they do carbon up they tend to run a little better due to the increased compression giving a better light off of the fuel charge unless a valve sticks in which case that pot makes no power untill it clears itself or you do something to fix it. If a petrol carbons up from rich running it can cause pinging and hot spot run on, Run it lean and you can burn out the valves and pit the pistons.

over fuel a diesel and the EGT's go up....not so good

Timings important on both more so on the diesel as if its too far wrong it just wont run but the petrol will struggle on Im unconvinced as to which is going to cause the most damage by running with off timing.

it should also be indicated that for this its assumed that there are no defects in the metals or the making of the engines. Once you start including these things all bets are off. And this is ONLY about the old school engines not these new ally headed things.

my point exactly, the newer diesels arent as over engineered as they use to be AND they are doing more work/cc normally under forced induction which brings more stresses with it....there are developing more power higher in the rev range, thus getting driven harder as alot have turbo lag like the 300tdi...combined with not a low enough first gear for trucks this size.

Serg

I've got a 300 Tdi and a 3.0TD L322 RR.LR's are made for the world,they don't suit every ones needs or desires,thats what the aftermarket trade is for.The original post was about the life of a Tdi and wether it should be replaced,my answer is no but if the owner wants too based on the failure of your Tdi thats his choice. Pat

Originally Posted by uninformed

my point exactly, the newer diesels arent as over engineered as they use to be AND they are doing more work/cc normally under forced induction which brings more stresses with it....there are developing more power higher in the rev range, thus getting driven harder as alot have turbo lag like the 300tdi...combined with not a low enough first gear for trucks this size.

Serg

call me pedantic but 90% of the dead engines I get to play with have died because someone didnt do the right thing at some point

the bottom end of the tdi is essentially the same as the 2.25 series donk. even the td5 has similarities AND both are still made from good ole cast iron.

so long as you leave it the hell alone all landy diesels are over-engineered for what they are ment to do when you start playing with the power output your putting things at risk.

on the series you can use either crank in either engine Fozzys running a petrol crank and its now a diesel and since that donk came out of bug 2.0 then went into kermit and now runs in fozzy I have no idea how many Ks that donk did before it was transplanted into bug 2.0 the crank is now also ground undersize running oversize bearings... I know how many K's Ive tortured that donk over.


the stalling while cold still applies to modern diesels the concept is the same but you get more assistance from your electronic control to stop it it still happens tho.

Most older diesels are petrol blocks or close relatives to petrol blocks. the same applies to new diesels, the chev 6.8l v8 turbo diesel block is shock horror stun amaze the same block as the 6.8l supercharged v8 but with a different timing gear setup so it can drive the injector pump.

on the cooling issue...

If i can take a half assed rebuilt 2.25 over recycled series diesel run it to 135 in the top tank and still not blow it apart even with a dodgy who knows how old radiator from a petrol engine (and its not even the full arid conditions radiator) I think the cooling system is more than adequate and if you manage to actually cook up ANY landrover thats had even semi close to decent attention paid to the cooling system then you have no vehicular sympathy and what your driving has every right to spit the dummy at you.


on the overfuelling issue... if your diesel is overfueling then something is wrong with it....

IF you set it at a given set of RPMS and it overfuels the governor will wind it back. IF you mess with that and you overfuel the engine to try and make more power out of it you'll kill it and thats not a new thing... ITs been known about since the ICE was invented....

the southern cross maintenance manuals used to have a cautionary warning about it for their stationary engines.

as for the point not being made the point I was trying to make was, I thought, definatley made and driven home, Diesels have the reputation of lasting longer than petrols because they used to and not because of any magic of engineering but becuase of the nature of the engines, old diesels dont like cold running and in order to specifically eliminate the odds of specifically manufactured as petrol or diesel engine I used an engine block that does both and your comment does little to disprove my statements rather it reiterates them.

Sumating your statement, The diesels were made tougher and made less power so they lasted longer. OR to reword it. Old diesel engines outlasted their petrol brethren

if turbo lag and low off boost power is a problem for you, perhaps learning to drive the vehicle as it was designed to be driven as opposed to tweaking the nipples out of it so that it performs how you want it to instead of as it was designed to do.

you also fail to make mention of the benefits of modern metallurgy, engineering and machining processes nor do you appear to take into account anywhere (nor has anyone else from what I've read of this thread) that cars are now made down to a cost and not up to a standard. Sure I can spec you a landrover engine that is a sub 3l Turbo Diesel, makes more power and torque than the stock naturally aspirated 4.4l V8 and will do over 1M Km, will function correctly in 60+ degree ambient temperatures and down to -60 as well as being able to run on anything from sweet light crude through to AvTur But...


are you prepared to pay for it?

Originally Posted by Blknight.aus

Most older diesels are petrol blocks or close relatives to petrol blocks. the same applies to new diesels, the chev 6.8l v8 turbo diesel block is shock horror stun amaze the same block as the 6.8l supercharged v8 but with a different timing gear setup so it can drive the injector pump.

6,8l supercharged chev V8's and turbo diesels hey, interesting...........

the one they use in the humvee, available in both petrol and diesel models...

both are crap... (mainly cause I cant afford to put Either in any car Im going to own.... and dont want to take the risk of cooking one in the comparatively tiny engine bay of a deefer/disco I also couldnt keep the fuel up to either of the thirsty buggers)

It might be the 6.5l...

(googling............)

I will stand corrected it is the 6.5 that is the same the 6.8 is an overbored block for the petrol heads at this stage...

the petrol block predates the diesel the initial version being in a 1960's oldsmobile and a later version as the (I think) the l78 for corvette.

advertised as 394+ 396 cubic inches for the petrols (oldsmobile + vette versions) and 395 for the blazer diesel (earliest diesel version I could find) and the hummer listed it at 6.5l but I didnt find a cubic inches variation.

WOW, I thought people got upset about spelling in forums,

Originally Posted by PAT303

I've got a 300 Tdi and a 3.0TD L322 RR.LR's are made for the world,they don't suit every ones needs or desires,thats what the aftermarket trade is for.The original post was about the life of a Tdi and wether it should be replaced,my answer is no but if the owner wants too based on the failure of your Tdi thats his choice. Pat

Pat
my inquiry was about the longevity and economy as in $ long term of the various diesel motors that commonly go into Defenders. I was wanting to understand if I bought a 2.8 TGV would it last longer being a larger capacity improved designed, or for the money I would pay out would I get any long term benifits over the 300 Tdi. Of cause a brand new everything on it motor is appealing considering a 300tdi is almost as costly.
So there are three choices the 300 Tdi (standard), the (high purchase price)TGV 2.8 and the bone ratterling isuzu. For long trips it seems the isuzu loses out as the noise levels go against it
Guys motors fail for sure we all know that, some sooner than others, some cost more to maintain over thier life too, I am not sure which one is going to be the best bet option long term. For instance is a isuzu cheaper to maintain than a 300 Tdi etc. Or is the outlay of a 2,8 TGV lead its self to being a more economical motor long term because its all new.
Great discussion open for comments

Originally Posted by garryseries3

For long trips it seems the isuzu loses out as the noise levels go against it

Methinks you need some more experience with these motors before you cast judgement.
Of the three vehicles I own (japanese petrol car, japanese diesel car and Isuzu powered rangie) the rangie is the road trip vehicle of choice.