running in an engine, is it a myth?

[macafee2]

when I was a teenager someone once said to me about running in an engine, run in fast, always fast. Is this a myth?
I was also told run an engine in gently.... handbooks used to say similar

Race engines, I think they get thrashed from day 1 which fits with run in fast, always fast but they have a short life


macafee2

[Daveluck]

Originally Posted by macafee2

when I was a teenager someone once said to me about running in an engine, run in fast, always fast. Is this a myth?
I was also told run an engine in gently.... handbooks used to say similar

Race engines, I think they get thrashed from day 1 which fits with run in fast, always fast but they have a short life


macafee2

Blimey....
Please Pass - Running In.

I had a couple of those signs in the back window back when. So always slowly ( or as slow as a hormonal teenager with a pretty girl in the passenger seat and a 2.0s Capri could drive )

Ahhhh...happy days.

[KWIL]

It used to be, not to exceed 2000 rpm, always gentle acceleration and first oil + filter change at 500 miles.

[roverbarmy]

I remember the signs "Running in please pass" and the ones "Running out please push"!
My old dad used to shout "No mechanical sympathy"

when anything was being thrashed.

[COLVERT]

Too many variables for a quick reply.
Maker--materials used--factory tolerances--etc, etc the list goes on and on.

Generally though take it easy for the first 1,000 miles or so if you want long life.

Those racing engines last only a few months.---

[macafee2]

but what about run in fast always fast, is it true or rubbish?

macafee2

[MSS]

Originally Posted by COLVERT

Too many variables for a quick reply.
Maker--materials used--factory tolerances--etc, etc the list goes on and on.

Generally though take it easy for the first 1,000 miles or so if you want long life.

Those racing engines last only a few months.---

Agreed.


Also, change the engine oil after the first 1000 miles in order to remove the suspended particles resulting from the running in process.

[grivas]

Originally Posted by macafee2

when I was a teenager someone once said to me about running in an engine, run in fast, always fast. Is this a myth?
I was also told run an engine in gently.... handbooks used to say similar

Race engines, I think they get thrashed from day 1 which fits with run in fast, always fast but they have a short life


macafee2

A new car should be driven sensibly initially, without revving the hell out of it, making use of the gears as intended and breaking correctly, then follow the manufacturer's guidance for service. That is it!.

race engines are for winning races, they are stripped down at the end of each race and each component is examined under the microscope!.

[minimutly]

Really? Only the money no issue, no engine rules formula. Most people racing couldn't afford rebuilds after each meeting, let alone each race.
Running in for one of my race engines would be as many warm up cycles as you could get in, wide ranging rpms, no idling (does more damage than anything), check everything possible - leaks, tightness etc, drop the oil and filter, replace then away.
Rebuild when it had an issue.
Now, if this were a BDG or similar for a customer, the builder would life it, in hours, a bit like you describe above. But that would be because the potential cost of a failure would be many times the cost of a rebuild. I guess what I'm saying is the rules are there are no rules...

[grivas]

Originally Posted by minimutly

Really? Only the money no issue, no engine rules formula. Most people racing couldn't afford rebuilds after each meeting, let alone each race.
Running in for one of my race engines would be as many warm up cycles as you could get in, wide ranging rpms, no idling (does more damage than anything), check everything possible - leaks, tightness etc, drop the oil and filter, replace then away.
Rebuild when it had an issue.
Now, if this were a BDG or similar for a customer, the builder would life it, in hours, a bit like you describe above. But that would be because the potential cost of a failure would be many times the cost of a rebuild. I guess what I'm saying is the rules are there are no rules...

I was referring to F1 racing, where the engineers would want to check how components are affected in the prevailing conditions of the race!.