Motor Break-in after rebuild.
 

guy seems to have the method down........



Now this is how you break in a brand new Engine.



https://www.facebook.com/reel/7901321999959698

That's exactly how I handled the break-in of my 930's engine after I finished it.

_

When I rebuilt my 3L (Alusil cylinders), Bruce Anderson told me to fire it up and drive it like I stole it. Worked great.

I've read several things that said that to break in a motor you want smooth, low-load high revs, and variability of revs, so don't hold steady at 6000rpm, but vary between 2500 and 6000. Don't run 6k in 6th gear, keep the revs up in low gears, first and second. But also, don't break in a motor that's a high revving motor while keeping the revs below 2k all of the time.

Low load will not seat the rings effectively. You need high cylinder pressures to do that. Like Supe says, "drive it like you stole it". And yes, absolutely, vary the revs as much as possible. Engine braking from high revs help seat the rings as well. On the gas hard, off the gas. Don't baby it, but don't abuse it either.

Initial start-up with new cams and rockers (or lifters) is very important as well. The mating faces need to be burnished in to one another. Low revs kill cams on initial start-up, so keep it spinning at at least 3,000 rpm or so for ten to fifteen minutes. Do this stationary, without driving it, because if you drive it, the revs will need to drop at various points along your drive.

Back to the video - never saw the point in displays like this. O.k., it has lots of power. Good for him. Many cars do. Let's see him really drive this contraption, on the drag strip (the only place it has any hope) and see what he can do. Oh, and paint your goddamned truck - the rat rod b.s. has worn out its welcome.

While you're at it, get off my lawn... ;)

Correct...don't hold rpms steady. But don't baby the engine. Create as much combustion chamber pressure and heat as you can. Compression rings have a bevel on the inside edge of the ring, facing upward, for the purpose of using combustion chamber pressure to force the ring outward and against the cylinder wall. This, plus heat, can cause the ring and cylinder wall to mate together perfectly. This is your goal at new engine startup.

What Jeff said.