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Just finished an engine rebuild and hopefully will be starting it for the first time by the end of the day as long as the previously working fuel pump comes back to life :(. Anyone know the proper break in procedure for a set of Hastings rings? I know on large trucks it’s generally get on the freeway and drive for a certain number of miles and some have said hold x rpm for x time and you will be fine. What’s everybody’s preferred method?
Thanks, Brennan


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I don't know anything about Hastings Rings. Generally speaking, one theory is to drive it gently, varying the speed but to never run it at high rpm's for 500 - 1000 miles. Another theory is to run it fairly hard right from the get-go to ensure the rings are quickly broken in. Changing the oil & filter after ~ 500 miles seems prudent.

My one point of reference is an MGB I rebuilt a few years ago. I babied it for many miles. At that point it was using about a pint of oil in 500 miles. Then I read about the second method. Figuring I had nothing to lose (and babying it wasn't much fun anyway) I began to thrash it. After a few hundred miles oil consumption dropped to nearly nil and my butt dyno said it had more power. Since then I've rebuilt a couple of engines for my MGA - vintage race car. They get a 20 minute 2500 rpm run to break in the cam/lifters then run hard. Other than leaks (it is an MG...) they use no measurable oil.

see: Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power
 

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Discussion Starter #3
That was the plan originally after watching a few videos of engine break in on a dyno. 2000-2500 rpm for 20 min. But with Alfa you never know sometimes things get weird


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Ring break in is shrouded in myth and mystery. In reality, it is quite simple. To break the rings in they need to be honed against the honing cross hatching you performed on the cylinders before assembly. To be effective this requires the rings to be pressed against the honing cross hatching quite hard, hence the high load school of thought. However, the honing generates a lot of localized heat which can be very damaging to the rings, hence the low rpm low loadiing school of thought. These inherently conflicting requirements provide the answer to the question: how do you break in a new engine? You drive normally, is the answer. You avoid high rpm combined with high load. You avoid low load at low rpm. You avoid very low and very high rpm until the rings are almost seated. You need high rpm towards the end of the process in order to ensure that the no wear ridges develop at the very top and bottom of the cylinder (I.e. at maximum stroke) otherwise the first time you do use the highest rpm the top or bottom set of rings could break from impacting the ridge being in the wrong place.

You must use high load often because only the expanding combustion gas pressure makes the rings seal against the cylinder wall. The ring itself is far too weak to provide the necessary sealing pressure without this effect, or you'd never be able to insert the rings by hand in the first place. Insufficient ring pressure leads to excessive blowby until the rings seat. Continuous inadequate loading prevents the rings from being honed to conform exactly to the cylinder walls. Combustion gas pressure gets behind the compression rings in proper engine operation and presses the rings against the cylinder wall which seals them. Before break in is complete you can expect excessive blowby and excessive oil consumption due to the rings not seating perfectly against the cylinder wall. The bottom set of oil scraper rings are not pressed into the cylinder walls in this manner, they have a circular corrugated spring separating the scraper rings. Those fit tight to begin with because they tend not to break in very much if at all, not enough pressure. They are there to reduce oil film, and consequently oil consumption, as the piston descends by, in effect, squeegeeing the oil film. Those are the rings that get the most damaged by excessive heat during break in from excessive rpm.

So, always, always, always vary rpm and load when breaking in the new rings. Use high rpm occasionally but when you do that ensure that you get out of the throttle as the rpm increases and let the engine spin up under low load. Avoid sharp lifts of the throttle. Avoid lugging (always avoid that though) and make sure you load up the engine frequently as you pass through peak torque rpm. That will seat the rings but not damage them from overheating.

How long does this take? Until the cross hatching is gone. How do you tell it's gone? The engine will feel more powerful (and it will be). It will rev more freely. You will get better fuel consumption and oil consumption should go to virtually zero on a modern engine design. I've noticed on some engines, Alfa, Ford, Mazda and Jaguar that ring seating seems to continue for about 10,000 miles and there is a noticeable improvement in power and fuel consumption at about that mileage if the engine is properly broken in for the first 1,000-2,000 miles.

The newest engines, especially turbos, have very hard compression rings and generally do not need break in nor will they break in. The newest engines are basically ready to run at full load and full rpm right off the dealership driveway.

How do I know I am right? Not only have I successfully broken in about a dozen new car engines that have performed correctly for high mileage with little to no oil consumption after break in I have also used similar techniques, albeit much compressed in time and mileage, to finish breaking in incorrectly broken in used car engines with impressive results in lower oil and fuel consumption and better power. One in particular sticks out: a 1972 Datsun 510 with about 15,000 miles on it I bought from my brother in law who did not know an engine could rev above 4,000 rpm, and still doesn't really. I had to be careful finishing that break in because there was a noticeable resistance to exceeding 4,000 rpm. I suspect the no wear ridges were beginning to form too low and too high in the cylinders (one at each end of the stroke). With patience the engine stopped using oil, improved fuel economy and eventually would rev freely to redline which I estimate was around 6,000 rpm, no tach.
 
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