Thread: 101 original lump vs a Diesel alternative

Yeah I think although the Isuzu has lots of grunt (apparently) it chews gearboxes quicker than you can say where's my wallet!
I think that there are some land rover diesel options that have been proven, that should do the job.
It's a pity that we don't have the diesel p38 lump here that was a 3.something or other I believe.


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A non turbo Isuzu pulls no harder than a 3.5 loaded or not.
TDI pulls no harder than the 3.5 loaded or not.
The 3.5 has a working rev range of 500rpm to 5000rpm(and sometimes more)
A diesel has a working rev range of 500 to 4000rpm
4.6 rover eight is a direct bolt in fit, no enginneering and is no heavier than a 3.5 and low cost.
I note the Isuzu turbo in the army Perentie in time gives the transfercase a hard time.
Fairely overdrive wouldnt be possible on a powerful diesel.
4.7 diff ratio if used with a Diesel, will gear up the low range and spread the high range ratios further apart and make you rev the diesel harder between gear changes in the diesel narrower rev range.
Transfer high ratio change alone will not be enough with 5.56 diff ratios.
To fit a diesel the transfercase cannnot be moved rearwards or forwards due to tailshaft issuses, so any gearbox change or longer engine change will require moving the engine and radiator forward and chopping of the fan tunnel and the gearshift and engine cover always ends up much higher and much changed.
Steering and brakes on a 101 are OK for its time and original design for army convoy speeds...........all would need a rethink.
101 hubs are different from other rover vehicles as is its steering box.


I am just pointing out facts.
One of the things I like about the 101 is its flexiable motor especially in top gear where it will pull smoothly from 20mph though to 75mph and is happy to do it.
How much noise is that diesel going to make a few inches away from the driver?
How much is this going to cost with engineering ?

Would have been better off buying a ex rural fire service dual cabin Mazda 4x4 or Mitsubishi with a diesel with good brakes, steering and fit what ever body you need.........the jap trucks will not ride any worse and you will be able to hear the radio too .
Ron

TDI motor in a 101 ?
Less reliable than the 3.5?
Will need the pommie bell housing from Zeus and the TDI will work better on a 5 speed box than a 4 speed.
The TDI will go no better and it has to be worked alot more gearbox wise to keep it happy as there is little below 1800 rpm and the 4 speed box is not as slick as the 5 speed boxes the TDI is usually mated too.
The five speed boxes are all longer than the 4 speed......remember the 101s special short bellhousing.
The five speed R380 is interesting though a 101s remote gearshift too as the the throw is very, very much shorter and it is alittle harder to find the gear, the R380 box works best with its standard gearchange set up.
The LT95 gearbox and transfercase combination is one of rovers strongest.
Of all the land rovers I have driven the 101 is the one where they almost got it perfectly right for its designed application.

Originally Posted by isuzurover

The 3.9 isn't that much heavier than a V8. IME the front springs on a 101FC are quitre stiff (though haven't calculated it).

I understood that the 3.9 diesel is almost double the weight of 3.5 V8.

I am basing my comments on the experience of others who have replaced the original engine with heavier engines. Yes the front springs are stiff but compared to the unladen rear, quite loaded up. I know from my own vehicle that the front does not need much more weight up front.

I am not sure there is any real advantage performance wise in going to an older diesel. I have seen vehicles with a 300tdi and a Mazda diesel and there is no real performance improvement and not the improvement in fuel consumption that would be expected.

I think a 4.6 properly setup on gas would be the go.

Garry

Originally Posted by garrycol

I understood that the 3.9 diesel is almost double the weight of 3.5 V8.

I am basing my comments on the experience of others who have replaced the original engine with heavier engines. Yes the front springs are stiff but compared to the unladen rear, quite loaded up. I know from my own vehicle that the front does not need much more weight up front.

I am not sure there is any real advantage performance wise in going to an older diesel. I have seen vehicles with a 300tdi and a Mazda diesel and there is no real performance improvement and not the improvement in fuel consumption that would be expected.

I think a 4.6 properly setup on gas would be the go.

Garry

One word "range"

Originally Posted by garrycol

I understood that the 3.9 diesel is almost double the weight of 3.5 V8.

I am basing my comments on the experience of others who have replaced the original engine with heavier engines. Yes the front springs are stiff but compared to the unladen rear, quite loaded up. I know from my own vehicle that the front does not need much more weight up front.

I am not sure there is any real advantage performance wise in going to an older diesel. I have seen vehicles with a 300tdi and a Mazda diesel and there is no real performance improvement and not the improvement in fuel consumption that would be expected.

I think a 4.6 properly setup on gas would be the go.

Garry

The rover 3.5 V8 is ~200 kg dry with ancillaries.
A 4BD1T is 330 kg dry with ancillaries.

The 4BD1T has the best fuel economy in its class. I am not sure what you mean by an "older" diesel? It was used until the mid 90's.

You have to be kidding about the 4.6... Why not just convert it to a jet turbine if you want to throw away fuel... Do you bottle and compress your own farts to refuel in the middle of the canning or the gunbarrel????


101ron - as for all your posts. Most are just trivial matters. If a HS2.8 and a Chev 6.X have been fitted, then a 4BD1T can be fitted. T-case upgrades to mil-spec are available. The ratios can be made to work in a perentie 6x6 with 7.50s and 4.7s, so 9.00s and 5.57s would be fine.

Lardy - the 4BD1T would be far better than any LR engine option. The gearbox would be fine, but an Isuzu 6-speed and LT230 would be a good option, and can be made compact enough.





...no, wait, you are of course all correct... a 4BD1T is "old" and outdated (compared to a 101), and a carb 3.5L petrol v8 cannot be improved upon...

Thanks gents,
This is the constructive forum of my peers I was looking for, this has been very helpful, and all aspects will be investigated and assessed upon their merits.
I have to say has no one thought of (if we are going off land rover engine plant territory) the 4.2 pooooootrol lump pulls like puffing billy all day everyday, you really can't knock the early patrol lump for basic bullet proof longevity, draw back being its a bloody long old donk again like the Isuzu offering, but the body weight is similar and I think the chassis is of similar length to a 101 any thoughts?


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The nissan should be easier on the drive line than a 4 pot Isuzu, if you were going to do this it would be silly not to improve performance with a turbo diesel 4.2(standard 4.2 nissan non turbo would be no improvement)
I notice most people who support the diesel side of things have not owned a 101with overdrive for a long period.
Lardy, do some miles in your 101 with standard motor and get to know it well.
Overdrive is number one to cruising speed and fuel burn on a 101 with standard motor
Then make your decision
If the speed with overdrive is kept at 80 kph or less at the vehicles aerodynamic best speed and the overdrive keeping the rover 3.5 at it most efficent 2000rpm the fuel burn is supprizingly very good.
Aero dynamics on the 101 play a much bigger part than people realise diesel or not and it is usually only where a petrol motor needs to use full power the fuel burn becomes greatly different.
Work a petrol engine at the right revs and load and you will be supprized.
.