Break-in period

[SacraMaro]

OP,

I think that you should baby the engine and car at least until 1500 miles. Break-in period also counts for the suspension and wearing in brakes... and other vital parts. I personally bought my 1SS with 67 miles on it and followed the instructions to a "T". I have had no problems. The LS7 is an amazing piece of tech. Break it in gentle, then give it hell. 2 cents

[soulsea]

This is the predicament I find myself in ...

The Z/28 isn't my DD and I've been swamped with work lately, as a result since I bought her 16 days ago I've only had a chance to put 170 soft miles on her ... soft as in I think I've been to 4000rpm but once and never past it.

The thing is I have a track day booked on Nov. 21st, and at this rate I'll be lucky to have 500 miles on her by then. So even though I'm a novice track driver (I bought the Z to learn) who will likely never push her to her real limits, I am super apprehensive about tracking her with such low miles.

I've been really looking forward to it but now I dunno if I should cancel or not. :/

Thoughts?

[90503]

My $.02....

I wouldn't think if any of the break-in parameters were violated that it would mean your car is doomed....lol

....Varying the speed and rpms seems to be the most prudent for the rings and safely street driving and keeping the rpm below 4k?...(not sure if that's in the Z/28 break in or not)....

I would suggest that the break-in period suggested in the manual is a good middle ground to drive safely, break in the engine, and get it in for a look-see by a mechanic before it is put to hard use....

As far as tracking it....man, that's a tough one....Personally, I would wait....If you really want to track it, make time to put some break-in miles on it....Might be worth the peace of mind in the long run....Good luck....

[tahoeacr]

Have you done any track days at all?

[kartracer]

Having done and instructed at countless track days I would give you the green light on attending, but with the following caveats...

1) Get 500 miles on the car
2) Short shift during the track day(under 5000rpm)

I give the green light because experience tells me that you will NOT be doing threshold braking or cornering at the limit of adhesion during your first day. What you will do is learn the basics of "the line", and begin to get an understanding of the "friction circle".

All of this will be done well below the limits of the car so revving it out wont be necessary at all. The car has plenty of grunt to shift it at 4500-4800 rpm and still be gaining more than enough velocity to make most any corner a braking event at a novice level.

So go have fun and don't worry about it. Plus it'll be a good opportunity to really bed in your brakes.

[soulsea]

Originally Posted by tahoeacr

Have you done any track days at all?

20yrs ago when I lived in the UK a friend gave me a two day lesson package at Silverstone ... but it's so long ago the answer is really no. I mean I understand braking points, apexes, accelerating through corners, and a few other basics, but no real on track experience to speak of.

Originally Posted by kartracer

Having done and instructed at countless track days I would give you the green light on attending, but with the following caveats...

1) Get 500 miles on the car
2) Short shift during the track day(under 5000rpm)

I give the green light because experience tells me that you will NOT be doing threshold braking or cornering at the limit of adhesion during your first day. What you will do is learn the basics of "the line", and begin to get an understanding of the "friction circle".

All of this will be done well below the limits of the car so revving it out wont be necessary at all. The car has plenty of grunt to shift it at 4500-4800 rpm and still be gaining more than enough velocity to make most any corner a braking event at a novice level.

So go have fun and don't worry about it. Plus it'll be a good opportunity to really bed in your brakes.

Thanks k, that sounds like good advice and take it all on board. My mind is a little more at ease and I'm almose positive I will be going.

[tahoeacr]

Originally Posted by kartracer

Having done and instructed at countless track days I would give you the green light on attending, but with the following caveats...

1) Get 500 miles on the car
2) Short shift during the track day(under 5000rpm)

I give the green light because experience tells me that you will NOT be doing threshold braking or cornering at the limit of adhesion during your first day. What you will do is learn the basics of "the line", and begin to get an understanding of the "friction circle".

All of this will be done well below the limits of the car so revving it out wont be necessary at all. The car has plenty of grunt to shift it at 4500-4800 rpm and still be gaining more than enough velocity to make most any corner a braking event at a novice level.

So go have fun and don't worry about it. Plus it'll be a good opportunity to really bed in your brakes.

2nd

Let me predict the newest member to get the "track bug" will be Soulsea.
You drove Silverstone. Now Watkins Glen and Road America, maybe even Daytona will be on your list by the end of November. Then I see a road trip under the term "vacation" to the West coast. Infineon, Laguna Seca. Yeh, your going to be hook. Should have bought a Prius. Never seen one of those on the track.

[soulsea]

I was actually also planning to take an extensive course at Spring Mountain next time I'm in Vegas ... but obviously not in the Z.

For now Roebling Rd race track will have to sufice as it's the nearest road course to me.

[Snidely Whiplash]

Originally Posted by tahoeacr

My take on this is adhere to the manual if you intend to keep and run this car 100k+ miles.

The hard break in side:
If you are only interested in fast lap times, break it in hard. You will probably pull it apart and build the engine anyways.
Engines I've broke in hard always seem to rev quicker and run better. Have I ever had them long enough to check durability? No.

Factory break in:
These engines are set up with a 3 micron bigger piston than bore.
Enough said for me.
Engine builders set up clearances for short to no break as track time is a premium(at least the ones I know). No team has time to drive 1,500 miles before testing on the track. Ferrari Challenge engines are broke in at the factory. They recommend replacement at 9K kilometers. So, a Z/28 break in is 25% of a 458's engine life. I suspect that GM engineers along with designing the Z/28 to be fast also had 100k mi lifespan in mind.

Oil change 500 mile have analysis done. 1,000 mile have analysis done then decide if going to 1,500 for the next. I suspect these engines will be a little cleaner than most.

As far as warranty, screw that. I trust no manufacture warranty. Been screwed enough to know its my bill and they may or may not pay it depending on how the planets aline and how many claims they have had ect., ect.

I seriously doubt the car is built to go 100k before rebuilding drivetrain/suspension.
I had a friend in 'Nam that had his folks order a 1969 ZL1. It was sold with no warranty and though it had a VIN, you had to sign a document that you were going to race it and not drive it on the street. BWAHAHAHA

[backtotintops]

Whiplash...I like your sig line but it's not true...the glue guys have more fun http://youtu.be/tSggEhvfi9U

[Russell James]

Originally Posted by andig

Gents - What is the consensus on breaking in the car?

I have now covered just over 500 gentle miles, i.e. No aggressive accelerating, max 4000 revs/80mph.

Would you now start to gradually "put your foot in" or wait until the 1500 mile point as the handbook suggests?

Also, when would you recommend doing the first oil change?

Thanks

Andy

I pull the drain plug 10 minutes after buying the car. Not to drain the oil, but to put in a magnetic drain plug. Then at around 1500ish, change the oil, trans, diff.. putting better than OE in all. With the Z, you'll also want to bed in the brakes and put in a good Dot 4 like Motul.

Break in wise... You never hammer brand new ring and pinion gears. So the drive it like you stole it off the showroom floor peep... good luck with that. Gee, wonder why so many people complain of diff problems and gear whine. And yes, there will be plenty of people that get away with it. That doesn't mean it was the right thing to do, means it was well built and they got lucky. Being unlucky might be an engine with some parts on the tight side, such as valve stem to guide clearance, piston to cyl, rod side clearance... When you're dealing with mass production, you're dealing with variation. Have a friend in powertrain development, he always tells me when they xplode one on the dyno, often root causes to tight parts galling. That same engine broken in with moderate loads would have been fine.

Just an opinion, and they will vary. When in doubt, go middle ground. Nothing wrong with moderate loads until you get to 1000 ish, then give it some blasts... around 1500ish, change the fluids. No limits from then on.

[BlackinBlack]

Originally Posted by Russell James

I pull the drain plug 10 minutes after buying the car. Not to drain the oil, but to put in a magnetic drain plug. Then at around 1500ish, change the oil, trans, diff.. putting better than OE in all. With the Z, you'll also want to bed in the brakes and put in a good Dot 4 like Motul.

Break in wise... You never hammer brand new ring and pinion gears. So the drive it like you stole it off the showroom floor peep... good luck with that. Gee, wonder why so many people complain of diff problems and gear whine. And yes, there will be plenty of people that get away with it. That doesn't mean it was the right thing to do, means it was well built and they got lucky. Being unlucky might be an engine with some parts on the tight side, such as valve stem to guide clearance, piston to cyl, rod side clearance... When you're dealing with mass production, you're dealing with variation. Have a friend in powertrain development, he always tells me when they xplode one on the dyno, often root causes to tight parts galling. That same engine broken in with moderate loads would have been fine.

Just an opinion, and they will vary. When in doubt, go middle ground. Nothing wrong with moderate loads until you get to 1000 ish, then give it some blasts... around 1500ish, change the fluids. No limits from then on.

This is great advice.

The drive it hard for ring break in is bullsh!t. Modern cars are built to very different than car built years ago. Bore finish, ring material, tolerances and even piston material is different. Ever wonder why they do not use forged pistons in so many modern cars? Google search "forged piston slap".

http://ls1tech.com/forums/generation...-engineer.html

Even the HIPO LS7 uses hypereutectic pistons for this very reason.

That being said tolerances are a bunch tighter and ring material is designed different than race rings. So the rules are different. Race car rules are not equal to street cars. I had a motor built by a NASCAR engine builder (modifieds, sprints, etc for one of my older cars. It was a very high end build with a 9000 RPM redline, solid roller cam, custom stroker crank, rods, pistons, etc. I had an insane amount of money in the motor. This professional engine builder told me to break in the motor as it was setup with street tolerances so I could get 50,000 miles between rebuilds. (It was a 345 CID small block ford that at 8Lbs of boost made 700 HP at the crank back in 1997. With the max 26 lbs of boost power was going to be 1000+ but I never ran it that hard.)

BTW the motor never had any blow by and I follow a similar break in procedure. (His was under 5K for 700 miles but that was based on this specific motor build.) For the race motors he did not require a break in but most were run in on the engine dyno which was a mini break in and also were rebuilt a few times each season.

[andig]

Originally Posted by BlackinBlack

This is great advice.

The drive it hard for ring break in is bullsh!t. Modern cars are built to very different than car built years ago. Bore finish, ring material, tolerances and even piston material is different. Ever wonder why they do not use forged pistons in so many modern cars? Google search "forged piston slap".

http://ls1tech.com/forums/generation...-engineer.html

Even the HIPO LS7 uses hypereutectic pistons for this very reason.

That being said tolerances are a bunch tighter and ring material is designed different than race rings. So the rules are different. Race car rules are not equal to street cars. I had a motor built by a NASCAR engine builder (modifieds, sprints, etc for one of my older cars. It was a very high end build with a 9000 RPM redline, solid roller cam, custom stroker crank, rods, pistons, etc. I had an insane amount of money in the motor. This professional engine builder told me to break in the motor as it was setup with street tolerances so I could get 50,000 miles between rebuilds. (It was a 345 CID small block ford that at 8Lbs of boost made 700 HP at the crank back in 1997. With the max 26 lbs of boost power was going to be 1000+ but I never ran it that hard.)

BTW the motor never had any blow by and I follow a similar break in procedure. (His was under 5K for 700 miles but that was based on this specific motor build.) For the race motors he did not require a break in but most were run in on the engine dyno which was a mini break in and also were rebuilt a few times each season.

Great advice gents - thanks.
I am up to 750 miles now and pretty much stayed under 4000 rpm and no lugging of the engine.
Should be fully run in, in a couple of more weeks and then I will see what she can do after changing out the fluids.

Thanks

Andy

[RockerBox]

I know with sportbikes that the break-in procedure is just for liability reasons. They don't want a newbie hammering the throttle the first day they have it.