[wnyzl11le]

I was on the net this morning found this from Chevy about breakin figured I would share. https://my.chevrolet.com/content/dam...tion-guide.pdf

[Gritesh]

800kms without exceeding 4000 rpm.



This ones gunna be tough I'll admit

[wnyzl11le]

Originally Posted by Gritesh

800kms without exceeding 4000 rpm.



This ones gunna be tough I'll admit

Sure is.

[Alain]

Shoot, I didn't realize that not exceeding 4,000 RPM was only up to the 500 mile mark !!!

I went all the way to 1400 miles last summer without going over 4,000 RPM before having to put the car away !!!

I can't wait to get it over 4,000 RPM as soon as it comes out of storage.

[mlee]

Originally Posted by Alain

Shoot, I didn't realize that not exceeding 4,000 RPM was only up to the 500 mile mark !!!

I went all the way to 1400 miles last summer without going over 4,000 RPM before having to put the car away !!!

I can't wait to get it over 4,000 RPM as soon as it comes out of storage.

ha ha... same here, but I got my break-in miles on in the 1st 3 days.

this is a great reference for track alignment settings too.

[hawk02]

Originally Posted by Gritesh

800kms without exceeding 4000 rpm.



This ones gunna be tough I'll admit

Cry me a river.

At least GM has reduced much of the break-in miles from what they were in the 2017 owners manual.

Keeping my car under 80 mph and not being able to drive at a constant speed for 1500 miles was not a pleasant experience.

[rlarsen462]

Most of this seems counterintuitive to my experience from when I used to build motors. I always had better compression and oil loss results when I broke motors in hard especially the first 50 miles with lots of varied RPM and engine breaking. Really gets the rings seated during that early critical time when they can still wear into the cylinder crosshatch. Arbitrary RPM limits never made much technical sense to me other than not bouncing it off the rev limiter. However constant RPM and low throttle load is definitely not ideal for the first 500 or so.

[Ryephile]

Originally Posted by rlarsen462

Most of this seems counterintuitive to my experience from when I used to build motors. I always had better compression and oil loss results when I broke motors in hard especially the first 50 miles with lots of varied RPM and engine breaking. Really gets the rings seated during that early critical time when they can still wear into the cylinder crosshatch. Arbitrary RPM limits never made much technical sense to me other than not bouncing it off the rev limiter. However constant RPM and low throttle load is definitely not ideal for the first 500 or so.

+1, thank goodness for another guy with some actual experience.

The owners manual wasn't written by the powertrain engineers in the best interest of excellent ring seating, it was written to give the OEM the best possible legal advantage with a warranty claim.

[rlarsen462]

Originally Posted by Ryephile

+1, thank goodness for another guy with some actual experience.

The owners manual wasn't written by the powertrain engineers in the best interest of excellent ring seating, it was written to give the OEM the best possible legal advantage with a warranty claim.

Also for reference I was building strung out turbo 4 bangers which I guarantee were dealing with higher compression and putting out more HP/cylinder and HP/L than the LT4. Motors run in hard (obviously turn the boost down, we would run the boost control wide open so we'd get maybe 10-12 psi instead of the 30-40 the turbo could build here at altitude) would always look better when we tore them down than a motor that spent too much time on the highway at constant RPM in the first 100 miles or so. Way less oil consumption too, even with forged pistons (which expand and contract more than cast).

You've GOT to get those rings properly seated and your window to do so is pretty small. Also I used to run dino oil instead of synthetic for break in but I believe modern synthetics don't prevent good break-in the way older ones did.

That being said I'm fully aware these limits are put in there for OEM warranty reasons (and to some extent to let people unaccustomed to big HP RWD cars some time to adjust before they go hooning off and killing themselves right off the lot), so it's really up to you what you want to do. We are talking about relatively minimal differences in the grand scheme. If you make a few less psi compression per cylinder and use 0.5 qt more oil per 3000 miles most people won't care.

[Ryephile]

Thank you for sharing your insight.

[Apexslayer]

Originally Posted by wnyzl11le

I was on the net this morning found this from Chevy about breakin figured I would share. https://my.chevrolet.com/content/dam...tion-guide.pdf

Thanks for posting - all of this is in the users manual. Chevy did a great job detailing break in and track prep!

[Scottyz]

Originally Posted by rlarsen462

Most of this seems counterintuitive to my experience from when I used to build motors. I always had better compression and oil loss results when I broke motors in hard especially the first 50 miles with lots of varied RPM and engine breaking. Really gets the rings seated during that early critical time when they can still wear into the cylinder crosshatch. Arbitrary RPM limits never made much technical sense to me other than not bouncing it off the rev limiter. However constant RPM and low throttle load is definitely not ideal for the first 500 or so.

Never ever did we, my dad brother and I, have ANY sort of mercy on ANY car we owned. From pretty much minute number 1 outside the dealer parking lot we beat out cars relentlessly. Literally.

And guess what......they were all super fast for what they were. No blown engines or transmissions either. Take my word for it, consistent top speed drives were normal for me. Not run it up to top speed!!!!
Run it at top speed till the exit where I get off. 20 minutes, 30 minutes, 1.5 hours, whatever..... I just made sure my oil and fuel was up. Oil changes I did frequently cause we were burning the oil. EVEN WITH OIL COOLERS ON A COUPLE CARS!!!!! The oil at times after 2500 Kms was almost lumpy.

My mom is shitting her pants right now. She found out I bought the car. My dad is giddy. My mom is well aware of the way I am. Sometimes we can’t grow out of it. She’s afraid I’m gonna kill myself in it. I can’t blame her.

[Scottyz]

You've GOT to get those rings properly seated and your window to do so is pretty small. Also I used to run dino oil instead of synthetic for break in but I believe modern synthetics don't prevent good break-in the way older ones did.


100% agree. Even burning the oil in the cars we drove, not burning as in blue smoke but burning as in overheating it..... if we pulled an engine from a vehicle, like the time we sucked in a throttle blade during a nitrous run, they always looked really clean. Always.

[kropscamaro16]

lol shit i was on the freeway doing 120mph my first night i picked up my car


crazy how quiet and smooth new cars are at high speeds i didnt even realize i was going that fast lol