kim0785b wrote:

Just returned from a 1000 mile trip from London to Edinburgh over the weekend, in all honestly I had major crank anxiety since getting the engine rebuilt 10k miles ago.

A thought got me going on the A1/M1 what is the best Rev to drive at on the motorway, 70mph seems to keep the revs at 1600 rpm but anything above 70mph (overtaking) pushes it to 2000 rpm which I am scared to maintain at that level for anything other than a few seconds.

The usual speed I take is anything between 60-65mph on the slow lane, is there any reference to a torque chart for the SDV6 engine so that I don't find myself over stressing the crank over a prolonged amount of time.....

For years we used to drive to our French home in the D3 and D4. Never even thought about anything. Just added fuel and went, usually traveling fully loaded and at high speed because we were always late!

 New Defender L663 110 SE (known as Noddy!)

Sold Volvo XC90 R-Design (known as Basil)

Sold - D4 HSE (Known as Gerty)

No longer the Old Buses original owner
231,000 miles and counting
05 S manual owned from March 2005
D4 Face lifted
Still original injectors and turbo
V8 Front brakes
BAS Remap, Allisport Intercooler and deCat
EGRs blanked
T-Max split charge
Hanibal Expeedition rack
Prospeed ladder
Duratrac tyres
IID BT
BAS FBH control 

grzesiul wrote:

I drive home 3 times a year avg doing 1279 mile in one go.
On occasion we push the car as much as possible to gain time or use the empty road at night
Car is 9 years old purrs like a kitten and I am not scared of doing around 3000rpm for a while when German autobahn allows it .

get WD extended warranty, although aint cheap I had no issues covering latest issues

they are even more willing to cover stuff in case of car being maintained by same garage

G

Incredible, last time I was on the autobahn was with a W124 at 140mph, sold that at 200,000 miles and the only thing that broke was the wiper motor

I've heard some people use the paddle shifters to try and avoid it from the 2k rpm death zone,

How many DPF regens at 3000 rpm, what was your average mpg? we achieved 35mpg throughout!

disco chris wrote:

Probably not the advice you are looking for but if I were that worried about crank failure I would probably have to sell the car and get something else just so as not to live in that state of anxiety whenever I drove the car.

With regards your question, I don't think it's the RPM so much as how you are loading the engine. If you lug / labour the engine at 1200rpm I believe there will be a lot more stress on the crankshaft than if you're cruising at 2000-3000rpm. So personally I would prefer to use the paddles to avoid the car changing up the gearbox as quickly as possible at lower speeds (when I drive my dad's D4 it seems to want to get to top gear as quickly as possible, and tries to pull from 1200rpm when I accelerate instead of downshifting, which I dislike as it feels like it's lugging the engine more than necessary).

But that's just my opinion. In all I would say try not to worry and enjoy driving your car. In all likelihood it will be just fine.

Chris

Ah thanks Chris! agree, problem is I sort of thrive on anxiety, gets me onto of the maintenance schedule

On a downhill run the rpm are really high!!

grzesiul wrote:

i agree running long hauls on minimal torque is bad for the motor

I bought a disco to get on the long haul

grzesiul wrote:

avg mpg lol ?

only take a look few times not to run out as it is expensive in Germany when stranded on hard shouldedr empty

but all in all we manage 10-11l per 100 roughly fully loaded

G