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MG Midget and Sprite Technical - Engine break in theories

In a separate thread regarding oil consumption on a new engine, there were several differing opinions on how to break in a new engine. My method has been to run it hard from the gitgo.

As to why, see this: http://mototuneusa.com/break_in_secrets.htm

Specifically, see articles 11,23 24, 25, 26.

What do you think?

--Jack
JM Morris

I was gentle for 200 miles, thrashed it after that, then retourqued head after 500 miles (ARP bolts). I've been happy ever after since then. I'm not recommending this, it's just what I did.
Gary & Gaps

That was the advice i got and followed...treat it like a red headed step child from the start....in fact ive heard here to run the 1st few miles in 3 rd gear just to add some pressure load to the engine

What you want to avoid is babying it... Doing so causes the clys to glaze making oil blow by... and thats Never a good thing.

Prop
Prop

Don't be too gentle. Bed the cam/s in for 15 minutes or so at 2000plus rpm. Switch off to sort any niggling leaks do not idle. Set fuel and ignition if appropriate then use car. May I suggest normal ( reasonable) driving not Molly Coddling. As Prop says some thrash in low gears is good. Why some thrash? The ring sealing pressures will be highest at peak torque when the engine is at its most effecient in terms of cylinder filling....give it some peak torque to bed the rings. Why not thrash in high gears? Damage occurs when heat builds up faster than it can be rejected. New engines will have higher friction in bores till properly bedded. Respect that and the engine should give good service. Ignition and fuelling must be good too.

Peter
P Burgess

Not with an A series, but some years ago when I had company cars, I used to get a new one every 2 1/2 years. the cars had to be collected from Preston where our office was and I would drive non stop to South Kent at 70 or there about (would hate to say 70+) all my cars ran better than other people who had a similar model and used it locally never doing a long run when they first got the car. Drive it like its going to driven for the rest of its life. Never had a problem with any of the cars.
Mike
Mike J Pearson

I fear I must have been misundestood in an earlier.
So I shall try and explane my driving in method.

-first start run for 15/20 minutes at +2000rpm to bed in the cam.
-switch off check for leaks etc
-adjust valves set ignition properly and setup carbs better.
- take it for a long (300+mile) night drive going to 60% of the rev limit.
using the gears to avoid labouring the engine (with labouring I mean pulling hard from low rpm in a high gear)
not staying at one constant rpm for long only shutting it down for fuel (for car and driver)
-then change the oil and filter.
-then drive it for an other 700 miles.
not driving for shorter periods than 30minutes
over time slightly increasing max rpm from 60% to 80%
-change oil and filter
-then drive it like you stole it!

When running in there is no crime to accelerate quickly when using the gears like they are suppose to.

Just don't load up the car with people and go driving it up hill in 4th from 1500 rpm and then try to accelerate.

This is only based on old engines as I have never had a modern car ;)
Onno K

I read that link about caning the engine from right away. Says the first 20 miles are it for the window to seal the rings to the bores. Interesting.

Anybody think that can apply to our old A series engines?
Lawrence Slater

I don't think so.

Just to throw an other in the mix
http://www.calverst.com/main.htm
Go to Calvers corner engine running in procedure
Onno K

This thread was discussed between 30/11/2011 and 02/12/2011

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