Break-in

[jayb53guy]

A ton of great info here, thanks!

[BigBoyBlue]

Originally Posted by Lonny Doyle

Before dismissing GM's break in period I would suggest doing some research as to why it was recommended.

I do feel like it would be beneficial for GM to give customers a reason for break in besides "because we say so".

I have been in the racing industry for many years as a machinist, engine builder, head porter, R&D and Driver and I will do a 1500 mile break in period.

There are a lot of new components in a car sliding together that need to have a break in period. A good example are rear end gears.

When you set up a new set of rear end gears there is a break in period that should be followed. A new set of gears will always run hotter than a set after break in. This is because when the teeth of the gears are ground there are microscopic peaks and valleys. Until these peaks are worn down to form a plateau for the oil, the gear teeth can make contact with each other instead maintaining an oil film between them. This is what causes the heat.

This is also true with piston and cylinders. Cylinders are honed leaving a cross hatch than needs to be worn down to form a plateau for the oil. This why a new engine may use a little oil at first. The rings are riding on top of the peaks.

If you break the engine slowly these peaks come off as very small particles that are too small to cause any small scratches that are in line with piston travel. If you take your brand new engine and put a lot of load on it, it can cause several problems, one is that you can put enough side load on the piston to cause these peaks to make contact with the dry film lubricant that is applied to the piston skirts and wear it away prematurely.

Another is the peaks left on the cylinders from honing can break of in slightly larger particles that cause scaring of the cylinders in the same direction of travel which makes the cylinders not seal quite as well.

Also with more contact there is more heat which causes the cylinder to distort to a slightly different shape than it will after it is properly broken in. This means your rings first have to seat them selves to a cylinder that was running abnormal temperatures in odd places and then wear to fit the cylinder that has eventually plateaued.

Engine bearings are coated with a material that smooths to match the slight imperfection of the cranks. Even though a crank is ground to very close tolerances they are not perfect. They also need to run long enough to plateau the high spots so when it is under a load it has a nice surface to keep a film of oil between the bearings and the crank. When an engine is machined they machine them very straight, but when you warm them up they do not expand the same all over. This can cause the main bores to not stay perfectly inline with each other. This causes the crank bearings to be a little tight in some places. Allowing the bearing to break in slowly again creates smaller particles that tend to leave the bearings smoother.

You also should never run an engine hard until it has completely warmed up. All of these components are broken in in a warmed up condition and that is when they are the strongest.

I know that it is unlikely that anyone will have a problem if they decide not to break in there cars as recommended by GM but it is only about 30 hours of driving. Take a road trip up through the mountains and it will be done before you know it.

Is it worth the risk?

Good stuff, sir. You sold me.

I purchased my car new with 173 miles on it. I cringe to think about how it was driven during those miles. Then again, most people would be scared to drive this beast really hard until they were used to it.

Either way, assuming my car was abused for the first 173, babied for the next 1300 miles, do you think I'd have a problem? My rear end does make that clunk sound when reversing out of my driveway in the morning and turning the wheel very wide.

[blessedhellride]

Originally Posted by BigBoyBlue

Good stuff, sir. You sold me.

I purchased my car new with 173 miles on it. I cringe to think about how it was driven during those miles. Then again, most people would be scared to drive this beast really hard until they were used to it.

Either way, assuming my car was abused for the first 173, babied for the next 1300 miles, do you think I'd have a problem? My rear end does make that clunk sound when reversing out of my driveway in the morning and turning the wheel very wide.

No, I think it will be fine, I think its all precautionary. On top of that you are protected via gm powertrain warranty.

[OldScoolCamaro]

...synthetic fluids everywhere, what say you about friction inhibition and break in? The skinny is....driver awareness. This car can kill you,.. in 10 seconds or less. There has been nothing associated with any wear, break in, or anything else, from any source....anywhere. Even the manufacturer...other than a nebulus recommendation. Nothing has been documented or articulated on the issue beyond that since it's inception, not a peep, .....at all. One can't strap the car on and drive it like they did in the video..., with the marketing terminology as advertised....without great risk. Remember back in the day when they watered down the HP for insurance purposes.

[TigerFA]

Originally Posted by adamgl

They're not going to void your warranty for going 6000 rpm in the first 1500 miles. Go easy and vary speed for 50 - 200 miles then break it in hard if you want the max potential from you motor.
Just don't abuse it.

Really, has any 5th gen not went over 4,000 rpm for the first 1500 miles?

Nope but not redline, from 4k on that thing goes like crazy....

[2012-1822]

Check out post 81 on fourth page to see what Scott has to say about it here:
http://www.camaro5.com/forums/showth...=295112&page=4

[427vette]

I have been purchasing GM muscle cars of all sorts, types, and eras since 1967, along with many car club friends.

I've seen the pocket protector guys with notebooks and nerves and the wild men that lit them up and drove them hard from day one. I am some where in between.

What I do know is in the end it made no difference. I have 700 miles on my ZL1 and after 500 mi. I drive it as I please. So far I haven't had any problems I read about on this site. If you can't enjoy it might as well sell it.

[2doorrocket]

Originally Posted by Sven59

Be careful violating the break-in period, I believe that the Chevy Service department can tell if you violated some of their rules and could void your warranty.

They cannot void your warranty there is something called the Magnusson moss act. It's very hard for the dealership to determine that you've done anything to it. Once a CEL is thrown the vehicle will take a snapshot at that exact moment and documents everything, speed and what not, that is all they can use to determine whether they are going to cover or deny a warranty claim.

For example: There was a case on my ZL1 for a weird problem that was throttle and crank case ventilation related, I somehow I don't know how slipped at the track and it traction control kicked in and I heard a knock and it blew the dipstick out. The report said 85 mph and a pretty high G's figure. GM still covered it, but the parts were really cheap, crank case breather tube and stuff. Plus they didn't even think twice about the air intake and the exhaust on the car.

But hey that's just a friendly reminder of the consumer protection laws out there.

[Front Runner]

Originally Posted by Lonny Doyle

Before dismissing GM's break in period I would suggest doing some research as to why it was recommended.

I do feel like it would be beneficial for GM to give customers a reason for break in besides "because we say so".

I have been in the racing industry for many years as a machinist, engine builder, head porter, R&D and Driver and I will do a 1500 mile break in period.

There are a lot of new components in a car sliding together that need to have a break in period. A good example are rear end gears.

When you set up a new set of rear end gears there is a break in period that should be followed. A new set of gears will always run hotter than a set after break in. This is because when the teeth of the gears are ground there are microscopic peaks and valleys. Until these peaks are worn down to form a plateau for the oil, the gear teeth can make contact with each other instead maintaining an oil film between them. This is what causes the heat.

This is also true with piston and cylinders. Cylinders are honed leaving a cross hatch than needs to be worn down to form a plateau for the oil. This why a new engine may use a little oil at first. The rings are riding on top of the peaks.

If you break the engine slowly these peaks come off as very small particles that are too small to cause any small scratches that are in line with piston travel. If you take your brand new engine and put a lot of load on it, it can cause several problems, one is that you can put enough side load on the piston to cause these peaks to make contact with the dry film lubricant that is applied to the piston skirts and wear it away prematurely.

Another is the peaks left on the cylinders from honing can break of in slightly larger particles that cause scaring of the cylinders in the same direction of travel which makes the cylinders not seal quite as well.

Also with more contact there is more heat which causes the cylinder to distort to a slightly different shape than it will after it is properly broken in. This means your rings first have to seat them selves to a cylinder that was running abnormal temperatures in odd places and then wear to fit the cylinder that has eventually plateaued.

Engine bearings are coated with a material that smooths to match the slight imperfection of the cranks. Even though a crank is ground to very close tolerances they are not perfect. They also need to run long enough to plateau the high spots so when it is under a load it has a nice surface to keep a film of oil between the bearings and the crank. When an engine is machined they machine them very straight, but when you warm them up they do not expand the same all over. This can cause the main bores to not stay perfectly inline with each other. This causes the crank bearings to be a little tight in some places. Allowing the bearing to break in slowly again creates smaller particles that tend to leave the bearings smoother.

You also should never run an engine hard until it has completely warmed up. All of these components are broken in in a warmed up condition and that is when they are the strongest.

I know that it is unlikely that anyone will have a problem if they decide not to break in there cars as recommended by GM but it is only about 30 hours of driving. Take a road trip up through the mountains and it will be done before you know it.

Is it worth the risk?

Sounds good to me!

[crzy1racing]

Mine made it 22 miles before it hit the limiter and 140 mph. Opps it has 30 miles on it now.

[Sven59]

I followed the break-in.