A question for PROFESSIONAL engine builders

[swampbuggy]

This question is not intended to start a debate (although it might and that would be ok). It is not intended to start an argument. It is simply to find out how you gentlemen who wish to participate in this topic approach the objective. I am attempting to learn the proper or best way to do this.
So one has assembled an engine with" all new" top quality parts, lets assume it is a S.B.C. with solid roller cam. ALL clearances have been checked extremely close. The CYLINDER BORES are perfectly finished to compliment our .9mm/.9mm/2mm ring package in a 4.185" hole. The engine is on the DYNO, oiling system is primed, timing light is ready to dial in ignition timing. The engine fires up sounds ok, we have good oil pressure, we quickly check ignition timing (it is a crank triggered system) so it is probably real close, assuming it is close enough--------------------HOW (or) what do you do as the dyno operator to maximize the rings sealing up to the cylinder walls??? Thanks in advance for any replys, Mark H.

[SRS_Chris]

Here's how I do mine...
- Consecutive full throttle pulls until the power curves lay on top of themselves. Once the power repeats, rings are seated. Power should increase with each pull. If it is going the other way (decreasing) something is terribly wrong.
- I use an acceleration rate of 200 rpm/second.
- Keep a close eye (and ear) on engine vitals, including O2 readings if available. Address any issues before going any further.
- I start with a peak rpm about 2k lower than I expect peak to occur and creep up onto peak with each consecutive pull. I feel that it is important to keep pulling through the peak torque range (even on first pull), because this is where peak cylinder pressure occurs. It's the cylinder pressure that will force the rings into the cylinder walls.

That's how I do it, but I am sure others will have their own method(s).

[blykins]

I'd say we all do it pretty much the same way.

We get the engine up to operating temperature (differs on application), then make a short pull to make sure the carb is right, no issues, etc. The following pulls are to peak hp rpm.

As Chris noted, you will see the power go up on the first 2-3 pulls and then it will start to level off when the rings are seated.

[Walter R. Malik]

Note to the OP ... The ONLY difference between a PROFESSIONAL and a gifted AMATEUR has nothing to do with talent but, simply that the professional gets paid and possibly does it for a living.

That said ... a series of loaded short pulls, (only 500 rpm range or so), works well and also allows enough between time for one to see that everything else on the set-up is within where you want it to be.
The more often the engine is loaded, the less time it will take.

[Frankshaft]

This question is not intended to start a debate (although it might and that would be ok). It is not intended to start an argument. It is simply to find out how you gentlemen who wish to participate in this topic approach the objective. I am attempting to learn the proper or best way to do this.
So one has assembled an engine with" all new" top quality parts, lets assume it is a S.B.C. with solid roller cam. ALL clearances have been checked extremely close. The CYLINDER BORES are perfectly finished to compliment our .9mm/.9mm/2mm ring package in a 4.185" hole. The engine is on the DYNO, oiling system is primed, timing light is ready to dial in ignition timing. The engine fires up sounds ok, we have good oil pressure, we quickly check ignition timing (it is a crank triggered system) so it is probably real close, assuming it is close enough--------------------HOW (or) what do you do as the dyno operator to maximize the rings sealing up to the cylinder walls??? Thanks in advance for any replys, Mark H.

Run the engine until the oil is up to temp, varying the throttle a bit, and load a bit. Shut off engine. Pull valve covers, check lash, reinstall valve covers. Fire up engine, verify starting timing point, and do a light pull. Depending on engine, say, 4500-6500. Make a back up pull, and let her eat. Rings should be in by then if hone was right, or close. The days of rings "breaking" in for 500 miles is pretty much non existent these days. Pre lapped rings, honing methods figured out and adjusted for application, etc. I always use dino oil though for the break in, and dyno session. Sometimes we will drain the break in oil and fill it with whatever oil will be run, and make a few pulls to see if there is any power.

[David Redszus]

My recommendation is to follow the GM Motorsports engine break-in procedure.

To ensure accuracy and repeatability, SAE J-1349 dyno procedures and settings should be used.

But in fact, every engine builder has their own test procedures they believe in.

[engineguyBill]

Rings should be in by then if hone was right, or close. The days of rings "breaking" in for 500 miles is pretty much non existent these days. Pre lapped rings, honing methods figured out and adjusted for application, etc. I always use dino oil though for the break in, and dyno session.

As stated above, modern, quality piston rings are lapped at the factory and will seat almost immediately - as long as the cylinders are prepared properly. Cylinder wall finish is very important and a torque plate should be used on any high performance/racing build. Non-synthetic engine oil is typically recommended for initial engine start-up/break-in.

I don't think that you will find much argument concerning this subject . . . . . .

[tpepmeie]

My recommendation is to follow the GM Motorsports engine break-in

David, is that procedure in the public domain? I’ve not come across it.

[tenxal]

When breaking a flat tappet engine in on the dyno, the engine will change tone as the rings seal up.

[randy331]

Note to the OP ... The ONLY difference between a PROFESSIONAL and a gifted AMATEUR has nothing to do with talent but, simply that the professional gets paid and possibly does it for a living.

Guess I can't post my opinion since I am just a hobbyist.

LOL

Randy

[modok]

It surely would depend on the rings and honing. Thin pre-lapped rings and a plateau hone, should be ready to go right from the start. More old fashioned/conventional rings, I'd expect the procedure would be more like the instructions I see for industrial engines. Still want to put some load on the engine right away, but not 100% load, perhaps 50% for a few pulls, then bring up the load gradually. How gradually....I don't know.

[MELWAY]

Here's how I do mine...
- Consecutive full throttle pulls until the power curves lay on top of themselves. Once the power repeats, rings are seated. Power should increase with each pull. If it is going the other way (decreasing) something is terribly wrong.
- I use an acceleration rate of 200 rpm/second.
- Keep a close eye (and ear) on engine vitals, including O2 readings if available. Address any issues before going any further.
- I start with a peak rpm about 2k lower than I expect peak to occur and creep up onto peak with each consecutive pull. I feel that it is important to keep pulling through the peak torque range (even on first pull), because this is where peak cylinder pressure occurs. It's the cylinder pressure that will force the rings into the cylinder walls.

That's how I do it, but I am sure others will have their own method(s).

That probably works on 80% of engine. But is a good way to hurt a highly strung drag engine
I like to start them up straight to 3000rpm. As soon as it gets some temp put about 80-100ft lb on it for 10 min vary rpm a little make sure it's not too Rick or lean. Or pipes glowing red
Them do tappet filter check.
Then some short 1000rpm pulls at 600rpm/sec and tune from there

[user-17438]

I usually vary the load and rpm until the temp comes up. Make a pull, check lash. Let it rip. Depending on who prepped the cylinders, or assembled the engine has an effect on rings breaking in.
Usually the guys that dunk the pistons and rings in moly are the ones that I see take forever. If they are properly prepped. By the first or second pull they should be set.

[swampbuggy]

Thanks a lot folks for all of the replies. I was thinking along these lines----I do not understand everything about the modern finishes given to the cylinder walls, i will rely on my machinist/engine builder/dyno operator for getting it correct. I have been thinking about how much attention to, and striving to get the finish on the cylinder walls JUST right, then after the engine is started and running the crosshatch or whatever one wishes to call it begins to change ever so slightly with every second. So i was really interested to see how many of you folks believed that it was IMPORTANT to get some load on the engine quickly ?? thanks again Mark H. Oh thanks Walter for giving us amateurs a little credit LOL !!

[rustbucket79]

I’ll throw in how I was taught. Up to 3000 (how quick depends on if it’s a flat tapped or not ) Get some load on it, say 25 to 60 pounds depending on the engine size and get a good half hour on it. May have to divide the time up if the engine oil gets too hot. Let cool overnight if possible, then another 20 to 30 minutes varying load and RPM to say 50% of the engine’s capacity. Check lash/set base timing and proceed with the pulls.

Naturally, timing is addressed quickly after the engine fires, and mixtures/air fuel/exhaust temps are monitored closely and corrections are made as required during that first hour.