In about a week or 2 I will be picking up my 2013 gs. It’s a long story but I am having a brand new factory LS3 put in. This is my first time having a brand new engine in my vehicle so I am wondering how I should go about breaking in the new ls3?

 

You will probably hear a lot of different opinions from don’t go over 15 mph to the drive it like you stole it recommendation. I would say let it heat cycle and cool down on short highway drives, easy no load driving at first and progressively a bit more aggressive throttle inputs. Stay away from high coolant temps. An oil and filter change early on won’t hurt. More too come from others I’m sure.

 

I just had a ls3 crate put in my car, what I did was heat cycle it first, 20 min running, then let it cool, 3 times, using Joe Gibbs LS break in oil, drove it easy not going above 5k rpm after heat cycle, constantly changing rpm, occasionally I did wot to 5k rpm, 2nd gear wot to 5k, let it coast down staying in 2nd, 3rd, gear wot to 5k, let it coast, 4th wot to 5k, let it coast, did that 3-4 times randomly along with normal driving, don't let the rpm's sit, no cruise control whatsoever... I personally did this for 200 miles, changed my break in oil at 200, added new break in oil, then still varied rpm's but took it up to 6k rpm a couple times, drove more aggressive, still wot and coasting occasionally til about 800 miles, changed oil again to Joe Gibbs LS30 oil and drove it how I wanted...my engine has around 2000 miles now, been to track and drive it pretty hard, runs flawless.. will change oil again at 2500 miles, then back to normal intervals in changing oil.

 

No short drives at first, heat cycle the engine up and down and oil change at 500? I'd stay under redline for a while but wouldn't completely baby it. Then change at 1000 and you can start normal oil change intervals. Nothing to worry about.

 

GodofClutch,
This is from GM crate motor instructions from my LS7

Start-up and Break-in Procedures: Safety first, if the vehicle is on the ground, be sure the park brake is set, the wheels are chocked and the car cannot fall into gear. Verify everything is installed properly and nothing was missed.

1. This engine assembly needs to be filled with oil. After installing the engine, ensure the crankcase has been filled with the appropriate motor oil to the recommended oil fill level on the dipstick. These crate engines require a special oil meeting DEXOS1 - 5W30. Also check and fill as required any other necessary fluids such as coolant, power steering fluid, etc.
2. This engine MUST be primed with oil before starting. The use of Kent-Moore engine preluber kit J45299 is the preferred process for priming. Note: A constant and continuous flow of clean engine oil is required in order to properly prime the engine. Be sure to use approved engine oil, as specified.
3. Start the engine and listen for any unusual noises. If no unusual noises are noted, run the engine at approximately 1000 RPM until normal operating temperature is reached.
4. When possible, you should always allow the engine to warm up prior to driving. It is a good practice to allow the oil sump and water temperature to reach 180°F before towing heavy loads or performing hard acceleration runs.
5. The engine should be driven at varying loads and conditions for the first 30 miles or one hour without wide open throttle (WOT) or sustained high RPM accelerations.
6. Run five or six medium throttle (50%) accelerations to about 4000 RPM and back to idle (0% throttle) in gear.
7. Run two or three hard throttle (WOT 100%) accelerations to about 4000 RPM and back to idle (0% throttle) in gear.
8. Change the oil and filter. Replace the oil per the specification in step 1, and replace the filter with a new UPF48R AC Delco oil filter. Inspect the oil and the oil filter for any foreign particles to ensure that the engine is functioning properly.
9. Drive the next 500 miles (12 to 15 engine hours) under normal conditions. Do not run the engine at its maximum rated engine speed. Also, do not expose the engine to extended periods of high load.
10. Change the oil and filter. Again, inspect the oil and oil filter for any foreign particles to ensure that the engine is functioning properly.

 

Follow GMs instructions if its real important to you.
First 50 mi get the rings seated dont baby it nor beat on it. Dump oil and progressively have more fun

I woulndt worry about it really. Lots of failures are the owners fault by showing off, revving the pee out of it (esp cold) donuts etc. There is simply no benefit to babying things for 500 miles 1975 has come and gone.

 

I build my engines and start em up go to the highway to tune em at wide open throttle for a few times and fine tune drive ability as well when all done go back change the oil and head for the dyno to find tune at wot that’s my brake in procedure and that’s what I build them for.

 

Yep.....this right here! ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Start up, drive to the highway, rev/accelerate and coast a few times......take it back to the garage (maybe 30 to 50 miles of driving), change the oil......and done!

The only thing that matters with a HR valvetrain is seating the rings. Everything else is just BS.

KW

 

I cant stress as the above instructions state. Prime that engine. I cant stress how important it is and how many times I replaced new engines due to people not priming the new engine properly.

 

When first start a new engine I bring it life to idle never gas up check for leaks underneath and inside engine bay all the while engine remains in idle I now be checking coolant level oil pressure, for leaks coming to running temperature all been good is ready for the road and whatever Is I want to do.

I used to prime my engines many years ago but now all is different mixing 50% Castrol GTX 10 w 30 and 50% Lucas non Synthetic oil Stabilizer so I don’t need to worry about priming cause that stuff clings and stays in place I use it on all bearings both Pushrod ends and rockers so when I’m done my engine is ready for me and scared for no-thing.