Proper rebuilt motor break-in?

[jonathan909]

What is best practice now that this thing is back together?  EJ25S with new bearings and rings, everything else as it was.

[idosubaru]

Based on GD's comments in the past I think it's minimal. Bearings don't require it and those stock rings are very forgiving. Chrome rings are a different story I believe. 

 

On 11/6/2018 at 4:50 PM, GeneralDisorder said:

The rings are lapped perfectly cylindrical and smooth in a tool steel tube at the time of manufacture. They virtually do not require any seating. What little "break in" takes place is kept to an absolute minimum by ensuring the rings are smooth and the walls have a finished plateau surface devoid of any raised wear points. The top ring is a steel nitrided ring and virtually requires no "seating". Secondary compression/oil control is cast iron and these will seat easily with no honing at all. Indeed the Subaru rings are so thin that honing the cylinder is likely to overheat the rings and cause them to lose their spring tension resulting in WORSE compression. Also the wear materials and impregnated honing grit will tear up your bearings and shorten engine life as they mix with the oil and end up through the whole engine. 

Show me a mirror finish in a used Subaru bore and I'll show you a block that needs to be bored oversized due to excessive wear. 

There are NO cases where a flex hone is a suitable answer. If the bores have so much wear that all the cross hatching (which are the valley's of the plateau finish) is gone, the bore is SHOT and no amount of honing will bring it back. It would require a rebore to the next piston oversize, and the last step in that process is a proper diamond finish plateau hone. 

I can produce references from the 80's that were already stating not to hone cylinders on a rebuild unless absolutely necessary if you want to achieve quickest seating and highest ultimate compression. Piston ring manufacturing, and engine manufacturing tolerances eliminated the need for honing on rebuilds back in the 1980's. Things have only got better since then. 

The reality is - if the bore isn't good enough to run - you need to bore it out to the next piston size. 

And more important than the cylinders BY FAR, is the line hone. After 100k the line hone takes on all the shape and appeal of an elderly bag lady. With the #2/3/4 main's having sometimes three times the allowable oil clearance. 

And the best reason of all - I build Subaru engines FOR A LIVING. I do this every day and we build everything from stock to engines making well over 600 crank horsepower. I haven't honed a cylinder wall in 15 years and not a single engine uses oil or has failed to properly seat the rings. And they seat FAST. It has been (wisely) said that on the first revolution of the engine the rings are wearing in - on the second they are wearing out. I will typically do a 100 mile break-in and then we go full-throttle. My engines always exhibit perfect, uniform compression, and the oil changes show no wear materials. The first oil change at 500 miles ALWAYS shows ZERO oil consumption. 

Oh yeah - and it isn't opinion. It's FACT. Once you have done this as many times as I have - it's not an opinion anymore. I speak from VAST experience. 

GD

 

 

On 8/5/2018 at 11:29 PM, GeneralDisorder said:

Cylinder pressure seats rings. Ring manufacturers recommend 2/3 throttle and varied engine speeds. Honestly I typically go WOT after about 50 miles of 2/3 throttle, and closed throttle coasting. 

There is NO break in for bearings. There should not be any contact on bearing surfaces EVER.

GD

[jonathan909]

I remember this - in fact, it may have been from a thread that I started, since I came here after not getting what I thought were clear/consistent answers about honing on other fora.

Fwiw, I'm not using Subaru rings, though Rock's invoice states Japan as COO for this set (and, curiously, Israel for the bearings).

So in real terms, what does that translate to?  Keep it under 3K for those first 50 miles, then back to normal?

 

Edited April 9, 2021 by jonathan909

[1 Lucky Texan]

I've read similar 'aggressive' break-in stuff from some motorcycle rebuilders. Something about the inner champfer on rings and cylinder pressure being necessary for 'seating' them properly.

[Mike104]

"on the first revolution of the engine the rings are wearing in - on the second they are wearing out"

Best thing I read today! 

[idosubaru]

14 hours ago, jonathan909 said:

I remember this - in fact, it may have been from a thread that I started, since I came here after not getting what I thought were clear/consistent answers about honing on other fora.

Fwiw, I'm not using Subaru rings, though Rock's invoice states Japan as COO for this set (and, curiously, Israel for the bearings).

So in real terms, what does that translate to?  Keep it under 3K for those first 50 miles, then back to normal?

 

I’d do what he said above:

“Ring manufacturers recommend 2/3 throttle and varied engine speeds. Honestly I typically go WOT after about 50 miles of 2/3 throttle, and closed throttle coasting”.

I’d do that for 100 miles then 500 mile oil change.  

Those rock auto rings aren’t much different than stock and won’t be an upgraded $$$$ material needing special attention. 

if they are decent quality and required a specific break they’d have instructions.

 

 

[1 Lucky Texan]

yeah, an accelerated oil change or 2 might be a good idea in case  a little fuel blows by.

 

I guess synthetic oil is ok? Cars ship out with it new from the factory so, I guess the old timers were wrong about insisting 'dino' oil be used for break-in.

[jonathan909]

On the oil change:  That's the plan, and as much because that'll help flush whatever bits of the old bearing metal remain in the passages.

I tell ya, I had the block run through the washer at a local engine shop and I scrubbed the oil pan first in my cleaning tank, then in the kitchen sink with soap and water, and then ran it through the dishwasher - and there were still teeny little specks of metal in there that I could wipe off with my finger.  It was exactly like the bad old days when strippers didn't get arrested for physical contact with the customers and though you could wash off the whipping cream you'd keep finding glitter in your beard no matter how many damn showers you took... at least, that's what I heard from other guys...

Edited April 9, 2021 by jonathan909

[GeneralDisorder]

We don't break them in at all anymore. Now that we have a chassis dyno in the facility we run them about 10 miles on the dyno (after several heat cycles during start up testing) and then we tune them at WOT and hand the keys to the customer. We do this with break in oil in them and ask the customer return in 500 to 1000 miles for the first oil change. We give no stipulations on how they should be driven other than they should not be timid with it. 

There's no "break in" on a new car from the dealer is there? Why should my engines be any different if they are built to the same or better quality? 

GD

Edited April 11, 2021 by GeneralDisorder

[jonathan909]

1 hour ago, GeneralDisorder said:

There's no "break in" on a new car from the dealer is there? Why should my engines be any different if they are built to the same or better quality?

Honestly, how would I know?  I've never bought a new car in my life.

[GeneralDisorder]

2 hours ago, jonathan909 said:

Honestly, how would I know?  I've never bought a new car in my life.

Me either. But common sense would say that if you have *never* heard of someone not adhering to the new car break in procedure and thus causing some kind of failure or voiding some kind of warranty then clearly there isn't one. With millions of cars sold annually there would be a LOT of problems if a specific break in procedure were required on the part of the consumer. 

GD

[jonathan909]

True dat.

[1 Lucky Texan]

4 hours ago, GeneralDisorder said:

We don't break them in at all anymore. Now that we have a chassis dyno in the facility we run them about 10 miles on the dyno (after several heat cycles during start up testing) and then we tune them at WOT and hand the keys to the customer. We do this with break in oil in them and ask the customer return in 500 to 1000 miles for the first oil change. We give no stipulations on how they should be driven other than they should not be timid with it. 

There's no "break in" on a new car from the dealer is there? Why should my engines be any different if they are built to the same or better quality? 

GD

 

What goes in for 'break in' oil?

[GeneralDisorder]

Amsoil Break-In oil:

https://www.amsoil.com/p/break-in-oil-sae-30--brk/

GD

[jonathan909]

At least I can get that stuff here - I wanted to get a couple of cans of their MP HD (on your recommendation) and found it's not sold in Soviet Canuckistan.  Had to smuggle 'em in from Montana two summers ago.