How do YOU run in that new engine of yours?

[jog5000]

Well, I've just had a "new" engine fitted - new pistons, rings, re-bored etc etc etc, bearings and all.

How do I go about running it in? I dont want to destroy the work that has been done!!

[Demlotcrew]

You need to drive it at vairing engine speeds/loads the only thing that needs to 'bed' in are the piston rings.

Dont poodle around this will give a negative effect.

Andrew

[DRIFTBOY]

I would run it in on a normal non-synthetic oil and avoid wide throttle openings at lower revs.
If the engine feels like it will rev a bit then let it (not bouncing off the limiter everywhere mind).
I've known people say "I don't take it over 4000 rpm when running in" and they floor it up to 4000 in every gear - a nonsense!
I agree with Andrew, don't drive it too gently but don't thrash it too hard yet either.

[Turbo-Brown]

Have a read of what it says in the Haynes manual, it's actually right for once!

You need pressure in the cylinders to get the rings to bed in, and you get lots of pressure from full throttle openings.

Can't remember what the speeds and gears suggested are but as said above, don't let it labour, and don't take the revs too high, but do give it a few full throttle runs!

You've only got a finite time to do this in too in terms of engine hours so look at the book, then go out and do it!