Ok so this was my take on My Break In... I did it in 3 phases: ( I did this based on some of the GM engineer interviews talking about the complexity of this engine and all its parts)

Phase 1: First 500 miles... No hard acceleration, no cruise control...My preference was to use Z mode (where it stays in V8 all the time) and My mode (where V4 pops up all the time).. but mostly Z mode easy driving and upshifting Z mode if rev's stayed high cruising.

Phase 2: Next 500 miles....Mixed between Z mode and My mode with some manual shifting with rev's up to 5000 RPM, only used cruise to see if it works....short time. Man does she pull strong at that upper end.

Now with 1175 miles on it.....just enjoying ALL she has to offer....WHAT A DREAM MACHINE....I have to pinch myself every time I see her in the garage and start her up.

Share how you guys Broke your C8 in....the New guys I'm sure would love to hear.

 

I’m definitely going to use your phase 1. Seems that’s the way it should be done. All cylinders equal. Hopefully here within two weeks.

 

Thanks for your thoughts.

My plan is to have all eight cylinders operating for the first 500 miles.

 

I get mine in 2 months and definitely want all 8 cylinders running, z mode does that?

 

Z mode keeps the engine in V8 mode just like it does in Track mode.

 

Thank you

 

Thanks for this post, very helpful.

 

Thanks guys....it's what's worked for me. g

 

Good info about the 8 cylinders in Z mode, thanks!

 

Kept it out of V4 mode and used the suggested max rpm for the 1st 500 miles. Mostly was in Manual Mode. Followed non aggressive braking as well. After 500 miles got close to redline a few times to provide max stress to valve springs! IF one was going to break wanted to be close to home! Also to have fun and let it deaccelerate from high rpm in gear (bit more oil drawn up on cylinder walls.)

C8 is now 8 months old. Have been driving in Z MODE Power Set to Track (MRC in Sport) much of the time in our rural area. Took the Interstate once, use back roads the 20 miles into town. Apply brakes aggressively periodically as it's fun and keeps a uniform layer of my low dust Carbotech ceramic pads on the rotors! That avoids low speed low brake pressure squeal. Many 0 to 70 runs as I have to merge into an often crowded 4 lane divided highway at the end of my rural road from a stop sign. Lots of traffic going and coming from Myrtle Beach this time of year!

Been using My Mode as well letting it go into V4 Mode and more than 5th and 6th gear, which is all Z MODE Power set to Track will allow (it's won't go into V4 Mode and only goes into 6th >~72 mph.) Engine runs great and although my C8 was in the valve spring failure window- no issues.

 

I think you guys are overthinking this a little. I ran my car in sport or tour for the first 500 miles. Didn't go above 4000 rpm. No cruise control and no hard starts or stops. After 500 miles, everything was fair game.

 

I used Z mode exclusively for the first 500 miles with power set to track. I wanted all 8 cylinders to break in the same. For the next 500 I used my mode when on the highway. Don't know if the V4 mode requires any break-in, maybe someone can shed some light.

 

There is a large population out there that will say you missed the op to set your rings and your HP and oil consumption might suffer. But your car your break in ! I have seen Chevy breaking in their mega dollar endurance racing engines and they definitely set the rings repeatedly. They may have been thrashed on a dyno prior but same idea!

 

^^^
Hmm, if you're referring to the "drive it like you stole it crowd,” “not a knowledgeable population!!”

Particularly the folks following the lnternet motorcycle engine info, that reads like "drive it like you stole it stuff." One thing to break and engine in when it's on a dyno and no trans gears, brakes etc to "break-in." Also the cylinder hone is a big factor. Was a good article about the special hone used on NHRA ProStock engines. It was special to gain some extra hp NOT longevity or to avoid oil burring! BTW, those are the most sophisticated NA 500 cid engines where there is no blower or power adders to make hp. Have to live with simple atmospheric pressure. All the National event times are within fractions, so any extra few hp is very critical. Quoting: "Modern Pro Stock engines (500 cid) make upwards of 1,500+hp and can cost upwards of $100,000."

Yep anybody can make ~11,000 hp with nitromethane and a huge blower. They all use about the same parts, just replace often!

The key is a ProStock Engine only has to last a few runs before parts replacement and a rebuild. Like when we worked with the Petty NASCAR team and Dale Inman said, when I asked about the durability of their 000 oil (or some such oil designation) "Does fine for the 500 miles we need!"

FWIW, the 502/502 BB Chevy Crate engine I built for my street rod has similar recommended break-in procedures as the C8. Just done with non synthetic oil and changed several times before that 500 miles. Block is the same as that used for inboard marine engines as are the forged crank and other internal components. CNC ported cylinder heads and manifold are made by Edelbrock with GM name!

 

The mega dollar racing engines are hand built, and don't have to last for 100,000 miles. Different strokes.

That large population thinks they know more than GM's engineers, but have no science or data to back up their nonsense.

Oh, and you don't need to use Z mode to keep the engine in V8 mode. Put the transmission into manual and it stays in V8, too.

 

I think this having to set the rings is a hold over from the engines of yesteryear when tolerances weren’t anywhere close to what they are today. If you watch the Jay Leno video on the C8 convertible, Tadge Juechter pretty much admits the break-in is for the rear end.

 

Yep today's machining and finish hones are designed for Synthetic oil and no more loose sand etc. The metal finishes are carefully controlled so minimum ring setting time is required.

Big difference in racing engines! Those pistons and rings are designed for reduce friction, i.e. more hp.

Typical racing pistons use low tension rings for less friction. The ring tension needed to assure combustion pressure stays where needed, above the piston rings, is controlled though the use of gas ports drilled into the ring land going behind the rings. That provides the pressure needed ONLY when the combustion pressure is high. It pushes the rings to the cylinder wall probably only 15% of the 4 stroke cycle NOT 100%.

Racing rings are significantly narrower for less surface area in contact with the cylinder wall for less friction. To stop the pressure from leaving through the normal butt ring gaps as used on the C8 and almost all car engines, racing engines may use a step joint. All just costs money and assembly time. Ring life is NOT 50,000+ miles, nor need it be!

 

What are your thoughts on oil change/s ? Tom

 

^^^^
Since your question follows my post, this is my "thought."

I'm an old timer so thought changing oil early was a good thing to do.

For my early 2014 C7 Z51 (built September 2013) with a dry sump I changed oil at ~1500 miles because it made me "feel better!" NOTE that was 13 months BEFORE GM issued the bulletin that said change oil in Dry Sumps (NOT WET SUMPS) at 500 miles. It had zero to do with engine wear etc. It was their problem because of curing silicone engine seals "possibly" depleting the antifoam agent in all oil and that foam "might" flow into the air intake tube through a hose with the burped air from the dry sump tank! That "might" cause oil to run into the air filter and drip on the ground "if the engine is operated at sustained high speeds." I put the words in bold quotes BUT those are GM's might, possible, sustained high speed words in the bulletin!

For my 2017 Grand Sport followed the GM recommendation of change at 500 miles ONLY for that possibility of oil foam causing oil to drip on the floor!

For my C8 will have the dealer change oil and filters when the OLM says to, which will be in 12 months (first time ever in any of my 6 Corvettes as always did my own!) At the same time he'll change the DCT filter. That will be with about 4000 miles as that is what I'll have on the C8 in 12 months when the OLM will say change Oil and filter.

 

I just hammered it ......