[BanditT/A]

Hey guys,
What do you all think of this engine break-in procedure versus the "take it easy" break-in? Is this guy crazy or does he have a good point?


http://www.mototuneusa.com/break_in_secrets.htm

[machine shop tom]

It's not as crazy as it seems. As he said, with the modern techniques of honing (torque plates, plateau honing), moly rings, etc., it really doesn't take long for the rings to seat. Im a little skeptical about the need for the rings to "forced against the cylinder wall", but the rings are already seated by the time the cam is broken in. The business about accelerating and decelerating iss nothing new; ring manufacturers have been advising that for years. It simply loads the rings the way they need to be loaded to seat onto the cylinder. I personally would take is easy for a couple of hundred miles or so just so the bearings conform to the crank, etc., but a long break-in time is mainly to insure that everything is ok.

[k-star]

I run all my motors on a test stand before they leave my shop. I have found that the leak down after running them on the stand is always a little better then when the motor is new. But if i leak it again after it's in the car and has a few miles on it the percentages get even better. So there is some merit in the loading the motor deal to get the rings to seal. As far as things breaking... If they are going to break at 7000 rpm's its going to happen if you got 5 miles or 500 miles on it...... I personally take it easy for a few miles 20-50 before i spank it like a 4year old in wal-mart!!!!!!!!

Keith

[Jmark]

One question I have on the article. Its stated that the rings need to seat completely around the cylinder wall.
How I understand that statement:
Once seated, the rings will stay in that position from then on and will not rotate around the piston as time goes on. ( if the rings moves, the "seat" will not be the same, as the wall is not perfect and the ring has moved.)

Is this correct thinking? Do the rings stay in the same place or do they move?

Mark

[k-star]

What i have found is that the rings will rotate. I have not done any in depth research on this. I have had times where i took apart a motor that was only run a few minutes or a few miles and have found that the rings are not where i put them while assembling the motor. The oil ring will move as a unit. The gaps of the expander and the rails will stay in the same relationship to each other but the whole package will rotate some. It seams to me that the oil ring moves the least..... The 2 compression rings seam to rotate more. I don't know that there is some set amount or any thing like that.

A correctly finished Cylinder bore is real close to being round and straight. Most modern machining will get them within .0001" round and straight. So the ring does not need to conform to the bore as far as being out of round. I think the seating of the ring has to do with the finishes on the bore and the ring (plateau)

Keith