Engine running in?

[m_jermyn]

With my engine nearing completion it has me thinking what is the best method of running it in?

I have done a little research and it seems if you ask 10 different people you get 10 different answers. So whats it to be?

From what I understand its important to bed the rings into the hone on the bore as if you dont you will glaze it and the engine will consume alot of oil.

So what do you recommend?

Mike

[maxfield]

Get on a motorway in a high gear, accelerate from low revs and then letting off and letting the engine brake. Keep doing this and build up the revs. This is what's usually advised.

I'm sure someone else will better explain it than me.

[DanThe]

Maxfield is right for the rings, you need to do this as soon as possible just stay away from the high end of the rpm scale, cheap mineral oil for this then change it after 100 miles or so with the filter, run the bearings in on mineral oil too

[daimlerman]

I kept to 2000rpm for the first 250 miles,then built up to 2500rpm over the next 250,then changed oil and filter.
Built up engine speed over several thousand miles,never letting the engine labour.
Changed oil and filter again at 3000 miles.

Now at 40k+ miles,the oil and filter is changed as soon as the last green light goes out.It drops it's oil level by less than a quarter of the distance between the full and fill me marks on the dipstick over the time the oil is in the engine.
Like most M20's,there is an oil stain on the drive where it is usually parked!

I use 10/40 semi-synthetic oil bought by the 25ltr barrel from Witham Oil and Grease Ltd,a local oil supplier.

[mrLEE30]

put cheap oil in , failry hard driving for 100 miles after a good warm up (not idling) and never sat at one rpm for too long i.e up and down allowing engine braking, after 100 miles dump the oil and filter, replace with good stuff, retorque everything and enjoy a nice loose motor with plenty of power.

this is option 2 out of 10!

[Turbo-Brown]

You need load (not labouring the engine) and then vacuum. You also need a warm engine and cheap mineral oil.

Warm the engine by starting, checking for leaks, then driving to a quiet dual carriage way.

You load the rings by giving it full throttle from say 30mph in 3rd up to say 50mph.

You then get vacuum by just taking your foot off the accelerator pedal and coasting letting engine braking bring you back down to 30mph.

The vacuum pull oil up between the piston and bore and washes away any remnants of the honing process.

Do this maybe 7 or 8 times and then change the oil. If you don't change the oil, all that microscopic crap that you've contaminated the oil with is just washing round your new engine.

You have maybe 20 mins to run an engine in properly.

You can't run bearings in, only rings and bores.

Once you've done your oil and filter change, you've done all you can so don't piss about with nambying the engine for hundreds of miles

[StuBeeDoo]

My system is similar to Daimlerman's.

No more than 3k rpm for the first 100 miles, then increase in 500rpm steps every 100 miles until you get to 500 miles. Then change the oil and filter and drive normally. Plus, as TurboBrown says, don't labour the engine while it's running-in.

Another alternative I used many years ago with rebuilt engines was drive it gently for the first 100 miles then change the oil, thrash it within an inch of its life for 500 and change the oil again, then drive it normally.

I've never had any problem with either system.

[m_jermyn]

Pretty much everything you guys have said is what I have read...

[CaesarBob]

No-ones mentioned the one that did the rounds a few years ago that said; thrash it to within an inch of it's life, straight out the box. Don't think anyone was brave enough to try it!

[StuBeeDoo]

Pretty much everything you guys have said is what I have read...

Good, aren't we Mike??