ZfirstVette

This was dated this morning, but not sure if it's new news. I don't have a Z06, just happen to see this. http://carbuying.jalopnik.com/chevro...ter-1724296112

FAsnakes

Not new and not really news. .

gsgold

It never hurts to put out this type of critical info even if its repetitive. I'm getting my oil changed this Tuesday. I have 803 miles on my Z and I really did follow the break in period.....and it was temping to jump on the gas.....it is one fantastic car.

CaryBob

Bearmans, one of the engine builders at the plant has made some excellent posts that explained in detail the reason for the 500-mile oil change. To quote him:

... The reason that the oil needs to be changed is because we use RTV to seal the front cover, the rear cover & the oil pan. Until the RTV cures it releases gases that contaminates the oil & causes the oil to froth. By replacing the oil at 500 miles, the RTV is cured and the contaminated oil is removed & replaced with new 5W-30 Mobil1.

Mr. Gizmo

Bignasty took his white c7z right to the strip brand new from the dealer. He ran 10.3's.

Break 'em in hard they go faster and last longer

davepl

In 1952 your Mom might have done so in order to compensate for chrome rings or some other super-hard ring package. But modern machining has made the "break it in hard, runs hard" thing nonsense for 20+ years.

I took my Mustang to the track with no miles, but that was a Mustang. Be nice to your LT4.

Tripleblk6spd

Your on point, but the fact is, if it was bad to run it hard out of the gate, do you really think GM would let you? I have been building modern race engines for years... I "break them in" on the Dyno once the cooling system has bled itself. Never had an issue. If it's going to break, all the "break in" is going to do is prolong the inevitable. I would rather have it break with fewer miles than more.

davepl

I break them in on the dyno too, but if yours is anything like ours, it cycles both load and RPM over a wide range for about 30 minutes (which also breaks in flat tappet cams nicely). That's probably nicer than most people treat them!

The only part I disagree with is that any failure was inevitable and merely delayed by breakin. After all, you can wipe a cam lobe (flat) with bad breakin, whereas that tappet might last 200K otherwise. Not the best example, but it serves as an exception that proves the rule (or whatever cliche fits here).

FWIW though, the engine and rear end are the only things that GM says "require" a breakin, and my rear end went at 500 miles after what I thought was a great breakin period!

bearmans

Here is another post that I made about why following the break-in process is important. Also, answering other questions about rumors.
Barry


1) That at 500 miles, the horsepower of Z06 motor increases. This makes sense to me because it 500 miles, as you know, we no longer have a 4000 RPM limit, as it can now go to 6500 RPM. And, as the formula which I learned in high school, says that horse power goes up to 5278 RPM (I think), that part of the rumor make sense, that is the Z06 is power increases at 500 miles solely because of our being allowed to rev our motors higher. While I do not agree, and of course can be dead wrong, this part of the first rumor says that GM still does not allow us the full 650 HP at 500 miles.

2) The second rumor I heard today, makes absolutely no sense to me, but who knows, maybe it is true. That rumor is that GM wants us to be "break-in respectful" of our LT4's, and they have consequently programmed into the ECM, that only when reaching 1000 miles, does the motor make even more power, as it only then makes its full 650 HP at 1,000 miles.


Here is the response from GM engineering...

The rumors your friend asked you about are completely untrue. A brand new LT4 will make just as much power as a well broken in LT4, though we strongly recommend that an owner be respectful of the machinery and perform a nice break-in for the first 500 miles before using all the power and engine speed range of the engine. The reason is that the main and rod bearings need a bit of time to wear-in to the mating parts, in particular the crankshaft journals. All freshly machined surfaces have peak and valleys if viewed under a microscope. The break-in period allows the bearings and journals to “bed-in” which improves the bearing mating surfaces for maximum durability. In essence the mocroscopic high spots wear down to the mating surfaces so the mating surfaces are nice and smooth relative to each other. Years ago we used lead in our bearing formulations and lead was very forgiving to “touch” conditions that can occur with newly machined parts. Since lead was eliminated for environmental reasons we went to new materials and poly coatings. These work quite well but are not as forgiving as lead is. As a result the break-in period is a bit more important with the new bearing materials. This is why we stress the 500 mile break-in period should be adhered to and the owner should refrain from WOT and high engine speed. The break-in recommendation is detailed in the owner’s manual. As for GM restricting power during the break-in period that is simply not true. Full power is available from day one, though a smart customer won’t drive the car like he stole it until the engine is broken in.

Again, FOLLOW YOUR OWNERS MANUAL FOR ALL BREAK-IN PROCESSES!!!

Detroit Steel

always a good reminder. Thought the front page would think so too...
https://www.corvetteforum.com/articl...ed-z06-engine/

brianinvegas

Chevrolet certainly has NOT told this new owner to change the oil at 500 miles. I can't find it in the owners manual. And Findlay Chevy never said a thing about it. I only have 750 miles on the odometer so maybe I head over there on Saturday.

BLEKVET

Standard practice. Any new high performance engine - run it hard to 4000 rpm max, frequently. Get it under load hard and often. Run up a few hills. Change the oil at 500 and 1000 miles.

Mr. Gizmo

This is the most ridiculous thing I have ever heard. GM should be able to find an RTV provider that makes a product that doesn't need time to cure so it doesn't release gases that contaminate the oil causing it to froth.

Owners of 80 to 100k 650 horsepower cars are driving around with frothing oil full of air bubbles for the first 500 miles. This is just dumb. if they can;t find an RTV, -- hell use a gasket.

R50THC5

One would think, considering the Z06 cost, that the first oil change is on the dealer. Oh yea, the new GM. In fairness, I have had the sales rep pay the first oil change regardless of the type of car purchased.

CaryBob

You have a misinformed dealer. GM pays for it. The 500-mile oil change is free. Plus four more; you get two free oil changes a year for two years.

vette6799

Given the choice of listening to anecdotal data or old wives' tales on CF or what you hear from GM engineering about the correct way to break-in the car they designed, I think I'd listen to GM engineering.

Mr. Gizmo

to the contrary in the old days -- up through the early 80's it was break them in easy. From the mid eighty's until 3 or 4 years ago it didn't make a difference. Now it seems to have gone back to the old days or at least for the Lt4 --