How to run in a new diesel engine?

Pew_Pew_Pew_Lasers!

There's absolutely no need to run any new engine in. Just do as you should with anything else - don't exceed silly RPM until the engine is warm.

dampdaveski

I prefer the company rep style of running in, nail the noisy pedal to the floor and use the clutch as a brake , only joking honest

cyclonebri1

Pew_Pew_Pew_Lasers! wrote: »

There's absolutely no need to run any new engine in. Just do as you should with anything else - don't exceed silly RPM until the engine is warm.

And buy a new engine at 3 years old, or sell the car to some unsuspecting plank.

Yes we all know that modern engines are produced to finer internal tolerance and finish so that they require less running in, but if an extra can of oil and replacement filter gives me the peace of mind of knowing I am taking the best possible car of MY engine, I will continue to due that.

Also it's not the revs that actually matter, it's the load you place on the engine, avoiding labouring is more important, ie change down earlier to keep the engine spinning more freely.

And don't forget, you are not just running in the engine, the gearbox and all the drivetrain components need time to bed in, brakes included

AdrianHi

cyclonebri1 wrote: »

Adrian, that special oil is simply mineral oil, it allows more wear than is strictly neccessary. If synthetic oil is used from new it can actually prevent an engine from bedding in, check out BMW's research on this;)

Regular mineral oil?
That surprises me. On of the benefits of a synthesided oil aka "full synthetic oil" is it's higher carbonising (coking) temperature which serves to prevent carbon build up on hot fast moving components like turbo chargers improving reliability.
Diesels run cooler than petrols, perhaps cool enough.

cyclonebri1

AdrianHi wrote: »

Regular mineral oil?
That surprises me. On of the benefits of a synthesided oil aka "full synthetic oil" is it's higher carbonising (coking) temperature which serves to prevent carbon build up on hot fast moving components like turbo chargers improving reliability.
Diesels run cooler than petrols, perhaps cool enough.

Actually I could have over simplified it, the advice generally given is to use a quality mineral oil. Synthetics simply do not allow a rapid enough bedding in of the engine components, ie, they do their job too well :TThe key phase however is never put synthetic oil in a brand new engine

epninety

AdrianHi wrote: »

Regular mineral oil?
That surprises me. On of the benefits of a synthesided oil aka "full synthetic oil" is it's higher carbonising (coking) temperature which serves to prevent carbon build up on hot fast moving components like turbo chargers improving reliability.
Diesels run cooler than petrols, perhaps cool enough.

The problem is that high quality running oils (such as quality fully synthetic) don't allow the cylinder bores and piston rings to fully bed together, because they don't allow enough abrasion. Instead the bore ends up with a highly polished surface which doesn't allow the piston rings to seal properly. This means an increase in 'blow by', the leakage of compression from the combustion chamber to the sump, which reduces power and polutes the engine oil, as well as increasing sump pressure which may cause oil seals and breathers to weep oil.

A decent 'running in' oil has the right combinations of additives to deal with marginally increased wear for a low mileage, without compromising the long term life of the engine. The last brand new engine I installed ran with the supplied bedding-in oil for a few hundred miles before it's first change. That has covered 100k miles now and consumes no significant amount of oil between 6k changes, despite having worked hard .

The main reason for occasional high revs during running in is to ensure the pistons travel the last fraction of a thou up the bore at the top of the stroke (and also to encourage the piston rings not to stick in their grooves). I regard this as good practice for the entire life of any engine, even once a week or a month will be enough. It ensures the wear ridge at the top of the bore cannot foul the piston rings at high RPM.

I once bought a GTi that had a reasonable mileage, but only ever driven like a shopping car. A few weeks of enthusiastic driving was sufficient to damage the top rings and oil consumption and smoke went through the roof. Never happened on any of the other (5 or 6) cars with the same engine that I had dealings with, including those which were owned by boys racers and ragged sensless at every opportunity. (The cause was broken piston rings, of course)

cyclonebri1

epninety wrote: »

The problem is that high quality running oils (such as quality fully synthetic) don't allow the cylinder bores and piston rings to fully bed together, because they don't allow enough abrasion. Instead the bore ends up with a highly polished surface which doesn't allow the piston rings to seal properly. This means an increase in 'blow by', the leakage of compression from the combustion chamber to the sump, which reduces power and polutes the engine oil, as well as increasing sump pressure which may cause oil seals and breathers to weep oil.

A decent 'running in' oil has the right combinations of additives to deal with marginally increased wear for a low mileage, without compromising the long term life of the engine. The last brand new engine I installed ran with the supplied bedding-in oil for a few hundred miles before it's first change. That has covered 100k miles now and consumes no significant amount of oil between 6k changes, despite having worked hard .

The main reason for occasional high revs during running in is to ensure the pistons travel the last fraction of a thou up the bore at the top of the stroke (and also to encourage the piston rings not to stick in their grooves). I regard this as good practice for the entire life of any engine, even once a week or a month will be enough. It ensures the wear ridge at the top of the bore cannot foul the piston rings at high RPM.

I once bought a GTi that had a reasonable mileage, but only ever driven like a shopping car. A few weeks of enthusiastic driving was sufficient to damage the top rings and oil consumption and smoke went through the roof. Never happened on any of the other (5 or 6) cars with the same engine that I had dealings with, including those which were owned by boys racers and ragged sensless at every opportunity. (The cause was broken piston rings, of course)

Bang on fellow, just had an ache in my keyboard finger or I would ha........

Flearoy

I run pretty old cars due to fiscal constraints, and one thing that is almost guaranteed to make me run a mile is when a car is touted as being especially 'low mileage'. In what gear were those miles done you might ask?

cyclonebri1

Flearoy wrote: »

I run pretty old cars due to fiscal constraints, and one thing that is almost guaranteed to make me run a mile is when a car is touted as being especially 'low mileage'. In what gear were those miles done you might ask?

Once a friend brought me a car, 8 years old, actually a Mk1 Astra GTE 8valve. Proper hot hatch in it's day. Real low mileage car, 26,000 miles. Problem was this car had been owned from new by an old lad, Gord knows why, that had never driven it out of the village, used a few miles per week to pick up pension and groceries etc.

It looked fantastic, but when he got it on the road it had zilch perfomance and did more miles per gallon of petrol than oil.

I stripped this for him, and I've never seen anything like it before or since.

The inlet manifold was half blocked with carbon. The combustion chambers were probably reduced in volumn by 1/2. All pistons had several broken and siezed piston rings. The bores were absolutely worn out, probably due to the car never running "off choke".

We did resurect it, and it was finally a fantastic car, but oh what an example of how to screw an engine,