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Old 5th May 2019, 09:22   #31
grivas
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Originally Posted by macafee2 View Post
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!.

Last edited by grivas; 5th May 2019 at 09:24.. Reason: additional info
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Old 5th May 2019, 20:38   #32
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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...
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Old 6th May 2019, 09:59   #33
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Quote:
Originally Posted by minimutly View Post
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!.
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Old 6th May 2019, 12:26   #34
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No - I actually mean low tolerances as in a a low number after the +/-. This is correct terminology.

You seem to be mixing up tolerance, precision and accuracy!

Refs. for your perusal

https://www.keyence.com/ss/products/...sic/tolerance/

https://labwrite.ncsu.edu/Experiment...yprecision.htm
No confusion !!!

I spent five years as an apprentice toolmaker for an aircraft company.

I was trained to use every tool and machine in the workshop and manufactured parts to a tolerance of a tenth of a thou.


I call you and raise you £50.00---------
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Old 6th May 2019, 12:32   #35
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This is never going to occur in a modern engine. The machining tolerances are very low.
By the way, where did you get this information ???


From your own practical experience or only that of others.

Just curious, that's all.----
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Old 6th May 2019, 13:36   #36
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Ford Focus users manual recommends the following:-
I quote"Don't drive too fast for first 1000 miles. Vary speed frequently and change up through gears early. Do not labour the engine."
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Old 7th May 2019, 06:15   #37
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Originally Posted by COLVERT View Post
No confusion !!!

I spent five years as an apprentice toolmaker for an aircraft company.

I was trained to use every tool and machine in the workshop and manufactured parts to a tolerance of a tenth of a thou.

I call you and raise you £50.00---------
In which case, you have no excuse for getting it wrong, do you?

Besides - only five years - you really should have completed the apprenticeship.

Quote:
Originally Posted by COLVERT View Post
By the way, where did you get this information ???


From your own practical experience or only that of others.

Just curious, that's all.----
From the experience of experts like yourself!

How many new car engines do you know about that have seized as a result of localised hotspots?

Last edited by MSS; 7th May 2019 at 06:19..
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Old 7th May 2019, 09:49   #38
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Originally Posted by COLVERT View Post
I was trained to use every tool and machine in the workshop and manufactured parts to a tolerance of a tenth of a thou.
This reminds me of when my dad worked at Firth Browns. He said that the Germans sent them a wire that was the thinnest they'd ever seen. So dads workshop drilled a hole down the middle and sent it back.
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Old 8th May 2019, 12:59   #39
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In which case, you have no excuse for getting it wrong, do you?

Besides - only five years - you really should have completed the apprenticeship.



From the experience of experts like yourself!

How many new car engines do you know about that have seized as a result of localised hotspots?
I did complete the apprenticeship------it's called LIFE.---


I'm very glad to see you do take on board the things I say. Lol.
More power to your Gillhoolie.---
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Old 8th May 2019, 23:52   #40
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Let's face it, modern computer controlled equipment works to far closer tolerances and at higher honing speeds, lasers quality and accuracy check all parts automatically, so the engine of a modern, cheap mass produced car needs little of the care that 60's and 70's engines needed. Bores and crank/con rod bearings in those days, could easily hot spot if worked hard before the roughness of the machining had been honed smooth by the normal movement of the parts, and allowing the oil to permeate the microporous surfaces. Working a tight, new engine too hard would overheat the high spots, causing localised melting, heat distortion and partial (and occasionally complete) seizure of the engine.
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