Initial breakin of new crate engine

1934chevycoupe

Veteran Member
Mar 12, 2013
326
Harleysville, Pa
So got hooked on Hot Rod Engine Masters on cable, and one of the shows this weekend was about using a dyno to breakin a new engine. I have a GMPP LS3 w/ the hot cam, which apparently is not all that hot. Anyway, one thing they mentioned was that if you're going to install coated headers, that you should initially install old headers or manifolds to breakin the engine, and then install your coated headers after everything is all adjusted and running right. Otherwise, you nay have bubbles in the coating or i guess they turn an ugly color. The engine came w/ manifolds i can put on, and i'm not sure if you'd run a short pipe and maybe run it into some mufflers or not. I know the neighbors would go for the mufflers. Anyone here start off w/ a new LS never run, and hooked up to your shiny new headers for the initial breakin? Experiences? Thanks
 

biker

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Gold Member
Dec 7, 2014
5,067
Canada
Depending on the coating, traditional break-in flat tappet cam engine can easily overheat headers, especially if jetting and timing aren't dialed in. No airflow to them sitting still. A dyno room will have a big fan blowing on the engine.
The LS is a roller cam engine, and you don't need to break it in the same way. If you are tuning the fuel/ignition mapping, you can do that in short bursts without sustained rpm.
Once you get a safe tune, you can run it up to temp on the road, drive around and let the rings seat in to their cylinders. The headers will have good airflow.
 

badazz81z28

Veteran Member
May 4, 2001
22,124
Alabama
On a brand new LS engine, you are seating the piston rings. They come with specific instructions for loading the engine for break-in. High quality coatings will not bubble or burn off. Your engine is going to produce way hotter exhaust temps beating on it than engine break in. You should see my stainless headers....the road course living at 6-7K RPMS has made them change colors.
 

sandlapper

Veteran Member
Oct 9, 2020
1,460
SE CSA
As for excessive noise ...
Without mufflers, your neighbors might well remember you in the same light as ya do that blitzed Casanova who sharted his britches at poolside buffet.
Planning on stayin' long, Caz?

Quite true; bad tune will permanently wreck that purdy coating ... learn to live w/ black & routine $1.99 spray bomb touchups.

fwiw, here's GM install guide for LS3 crate; includes break-in procedure. Take note of its LS oil prime.
https://www.chevrolet.com/content/d...s/01-images/ls3-efi-crate-engine-19419862.pdf
 

G72Zed

Veteran Member
Sep 8, 2015
4,072
Canada
Be it LS based or other brands, for a fresh build's first "start-up" and break in, if your timing is within reason right from the first fire, meaning not being overly retarded, and the fuel ratio close, or on the fat/safe side, you will have no problems with "boiling or bubbling" a quality applied header coating.

As badazz81z28 mentioned, since you are roller, you are focusing on attaining the best ring seal possible, and that takes a certain procedure, best done on an engine dyno due to the controlled environment.

You are also breaking in the roller wheels, pushrod tips on both ends as well along with rocker contact points, my build partner and I use certain oils to make this happen quickly, but follow GM's recommendation for oil to avoid any warranty issues should they arise.

Biker makes a very good point as well when breaking in a new engine, especially when flat tappet cams are involved, you have 2 scenarios that must be addressed at the same time. Big fan (s) on, timing set and AFR's in the range.

I have tuned many "new" engines on the dyno that had brand new coated headers, none of them ever boiled.

One of the more difficult "break ins" I was involved in was a large cube pump gas HEMI, custom built dual carbs on a semi rise tunnel ram, new $2,000 coated headers, and a solid FT cam!!!

FWIW, here's a pick of "day 2" on the final tune...changed the clear hoses to black braided from the valve cover oil separators to the rear intake plenum, and dialed in the final AFR's with the K&N air filters installed, we only lost 10hp or so, owner will never feel the difference from 740 to 730 hp.

As you see by the pic, the headers look like they just come out of the box.

HEMI.jpg
 

1934chevycoupe

Veteran Member
Mar 12, 2013
326
Harleysville, Pa
ok. All that sounds good. Not pulling the engine for a dyno breakin, but was going to take it to a tuner after running, so will talk to them, and may let them breakin and tune at the same time. Thanks guys
 

1934chevycoupe

Veteran Member
Mar 12, 2013
326
Harleysville, Pa
As for excessive noise ...
Without mufflers, your neighbors might well remember you in the same light as ya do that blitzed Casanova who sharted his britches at poolside buffet.
Planning on stayin' long, Caz?

Quite true; bad tune will permanently wreck that purdy coating ... learn to live w/ black & routine $1.99 spray bomb touchups.

fwiw, here's GM install guide for LS3 crate; includes break-in procedure. Take note of its LS oil prime.
https://www.chevrolet.com/content/d...s/01-images/ls3-efi-crate-engine-19419862.pdf
my manual is a little different on the breakin. where above says to prime the engine w/ some type of preluber, my manual says to remove power to the engine control module, and use the starter to spin the engine and build oil pressure. i think using some type of preluber to build pressure would be the better way.
 

1934chevycoupe

Veteran Member
Mar 12, 2013
326
Harleysville, Pa
So on another note, and i'm sure it's been discussed at length, my manual says to use Mobil 1 5w-30. Got it. Just read a Hot Rod article and they're using Lucas breakin oil for breakin on a LS3. I know breakin oil usually is high in zinc additives for flat tappet cams, is there any benefit for a roller cam engine to use breakin oil? Manual has me changing O&F after breakin and after 500 miles.
 

biker

Veteran Member
Gold Member
Dec 7, 2014
5,067
Canada
I would have no trouble with 5w30 conventional oil for break in on a roller cam engine. Nice and light flows/pumps immediately. Remember the purpose of break in is to allow moving parts to wear in nicely together. Nice light conventional oil allows that and carries the byproducts to the filter for trapping.
I would guess break-in oil is pretty light too, but while the extra slipperiness is good to keep flat tappet lifters and cam alive, it may not be ideal for pistons and rings if not needed.

I would think the most important part is what you already mentioned. Dump the oil 2 or 3 times early in the life of the engine to flush out metal byproducts.

Edit: I see you said Mobil 1 5w30. Synthetic I assume. Well, if that's what GM wants....I'd stick to it. Their engineers know their stuff. And I imagine synthetic might deal better with the localized heat generated by new parts rubbing together. Heat you won't see on a coolant temp gauge.
 

G72Zed

Veteran Member
Sep 8, 2015
4,072
Canada
Sometimes it's what the break in oil does "NOT" have in the add pack. The more aggressive the engine/valvetrain the more the need for a break in oil formulation. And as the ring package and bore finishes get pushed and fine "tuned" the more focus on ring seal sets in.

Making 75-100 hp per cylinder N/A is the norm these days in many builds, not having every cylinder seal up kills the program real quick.

Your engine is mild, and I would follow GM's recommendations to the T. They know the ring pack, materials, and bore finishes, and the particles that will be floating in the oil's film as well, hence the reason for the O&F after break in, and after 500 miles.

I have done a filter change half way through a break in session, filters are cheap, cut the filter apart to make sure everything is going OK, take pics and document as well. Filter media will tell the story, pending on micron rating.

Good luck with the break in.
 




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