Engine Break-in After Rebuild

[AnotherArchitect]

On my last thread, (smoke and misfire), we found that the piston ring was broken, which lead to an engine rebuild. I must note, the engine bores were not scratched or anything, thus, no sleeve was necessary.

There seems to be a lot of misconception about engine break-in (specifically after a rebuild).

This dude seems to know his stuff https://youtu.be/MlmHOMm9gow

My mechanic seemed pretty sure of his method; "turn the car on after putting it back together, leave it for an hour or so to make sure there are no leaks and drive it moderately for about 500 km (300 miles or so)

Just wanted to get some advice on the break-in. Things are good for now, been driving the car moderately, not leaving to idle for too long etc. I've been trying to get through the rev ranges (under 3500 rpm) and not drive at one speed the whole time. is 500 km too little or too much?

Any advice would be appreciated!

[apexit4]

I'd assume following the break in procedure for when the car was new wouldnt be too far off from what you should do in your current situation. The owners manual should have all those details.

That being said, I've never done an engine rebuild myself so I could be wrong.

[apexit4]

Found the E70 X5 owners manual online. Here's the page on the breaking-in period.

[mitch808]

Most engine builders want you to drive the car, like how you want it to perform.

After an initial warm up, oil change, you can pretty much beat on it. This would seat the rings to how your engine is to be driven.

Most OEM's are taking a 1000+ mile easy break-in.

AMG puts the engine on a dyno, and drives it on a virtual racetrack at WOT at roughly 0 miles.

That said, the best break-in procedure, is the one recommended by the engine builder that is offering a warranty on his labor.

[yco]

500km is ok to be safe.. if there is no leaks big part is done though..
if i were you, i d gradually increase the max rev after 500km and use the whole rev band after 750km.. starting with lower gears like 1-2 max revs and then use the other ones up to max rev.. keep an eye on the oil temp.. it shouldnt exceed 100c until you start to push.. higher oil temps can be an indicator for problems at that period..

Originally Posted by mitch808

Most engine builders want you to drive the car, like how you want it to perform.

After an initial warm up, oil change, you can pretty much beat on it. This would seat the rings to how your engine is to be driven.

Most OEM's are taking a 1000+ mile easy break-in.

AMG puts the engine on a dyno, and drives it on a virtual racetrack at WOT at roughly 0 miles.

That said, the best break-in procedure, is the one recommended by the engine builder that is offering a warranty on his labor.

actually yes they do dyno the engine but there is a break-in period still cause they dont test only the horsepower on those tests.. there can be exceptions for AMG GT for example but i d still go easy on first 500-1000km.. i had a GLS 63 last year for 3 days and the car was at 120km.. had a huge sticker on front shield explaining what not to do until 1000km.. engine is a metal to metal thing it needs some time.. and its safer to be at lower revs in that period..

[Autobacs]

For a racing crate engine but I would go by this:

-Drive car for 200-300 miles carefully, still no full throttle. Vary the RPM (do not get on the
highway and set the cruise control).
-Remove oil filter, cut open and inspect for metal contamination.
-At this point you can also replace the break-in oil with synthetic Amsoil of the appropriate
weight.
-Your new engine should now be ready for final tuning and full throttle operation

[laselvasurf]

After I had my S63 rebuilt by Ghassan I did about 1000 miles of low stress varied driving, then did an oil change and started to increase load over the next 2000 miles to the point of working it hard. I then did another oil change and have driven it hard since.

Here's the break in procedure ghassan recommends: https://www.ghassanautomotive.com/bl...k-in-procedure