how to properly break in a new car

[2ndclasscitizen]

wut's the difference between breaking in on synthetic and petroleum ?

From reading the Motoman article, I think it's because the synthetic oil doesn't offer enough friction to get the rings to seat, but I'm not 100% on that, I read that article a while ago. But he goes into detail about it.

the question is, what's the best way to get the rings to properly seat, and the window of time that you can do this

Again, by the Motoman article, go hard (but in a deliberate, methodical way) and do it straight away. If you read his article, he goes into a fair bit of deatil.

[charged]

I don't really understand that article, he implys that the cylinders are expertly honed but the piston rings are more of a poorly made after thought. If engines are as well made as he suggests then it shouldn't need to be broken in.

When you rebuild an engine by hand, not on a factory production line, you can match pistons, check ring gaps in the bores to get the optiumum clearances etc. Im pretty sure GM,Ford etc dont do that with their production engines, they are just slapped together so to speak.

[Equinox]

When you rebuild an engine by hand, not on a factory production line, you can match pistons, check ring gaps in the bores to get the optiumum clearances etc. Im pretty sure GM,Ford etc dont do that with their production engines, they are just slapped together so to speak.

and hence the problems that are always popping up for Ford and GM

[charged]

Give an engine some LUV when rebuilding and it will LUV you back

[h00t_h00t]

When you rebuild an engine by hand, not on a factory production line, you can match pistons, check ring gaps in the bores to get the optiumum clearances etc. Im pretty sure GM,Ford etc dont do that with their production engines, they are just slapped together so to speak.

Thats not entirly true, they work out all the clearences on the prototype engine then build all the production ones to that specification. They don't have a miscellaneous piston ring bin full of rings that might fit and just chuck them on regardless.

[KnifeEdge_2K1]

Thats not entirly true, they work out all the clearences on the prototype engine then build all the production ones to that specification. They don't have a miscellaneous piston ring bin full of rings that might fit and just chuck them on regardless.

that's true, but the manufacturing process isn't perfect, you get parts which do differ in size and fit

we're talking about clearances in the hundredths if not htousandths of an inch

[johnelliott24]

It is pretty subjective, but there are some rules.
1) Do not use synthetic oil during breakin.
2) With a solid lifter V8 cam you must run it fast for at least 15 min. to harden the cam lobes. Any other engine I take it easy on so I have a better chance of saving it.
3) With most ring/wall combinations, do load the rings so they seat.
4) Watch for leaks and overheating.
5) Check the timing and mixture immediately after starting.

[mmm_aapls]

The first part of that article states that a ring exerts a small amount of pressure against the piston wall compared to the amount of combustion pressure. Simple physics will tell you that the forces are perpindicular and so are irrelevant.

But I agree with Charger and KnifeEdge that components are sourced from different companys, and are produced within a tolerance specified. So if a piston and a ring where built at the opposit ends of the tolerance then they would not fit as well as a piston and ring made nominal. And you will find that during proto builds, everything is nominal (PPAP process). When full scale productuin starts, it is hard to achieve.

[PerfAdv]

I've had good success breaking in engines by "generally" keeping the revs below 4K (or whatever 2/3rds of redline is for an engine). WOT is fine but no full throttle starts from a standstill. Occasional going over 4k won't kill the engine but I just like to kinda baby new engines.

Use non-synthetic for help in seating rings. This I understand is for increased friction from regular oil. I don't know why then some of the highest performance cars come from the factory with synthetic. After around 5,000 miles make the shift to synthetic.

Break in probably less critical than ever before in automotive history, mainly because of precise manufacturing processes. Still even with tight tolerences the heat cycles of operating temperature and cooldown during the breakin period will harden and strengthen the engine.

So, anything short of beating it to death by driving like you stole won't really harm the engine; why not just be patient and cycle in a new engine so you get an engine that doesn't consume much oil, leak oil, and results in a engine that'll last longer.

[crisis]

This is a pretty interesting article. A lot of it makes sense, but it does beg the question "then why have the factories all specified it differently".

http://www.mototuneusa.com/break_in_secrets.htm

Interesting. I have sent the link to my brother in-law to see what he thinks. I have long heard the theory that if you are going to drive hard you should break in hard. Never properly explained though. Just sounded like wank. When I picked up my last new car I was told to “just drive it like you normally would” which is kind of close.
One of my mates who races just replied to the link and said the guy who built his last motor did the dyno thing. Warmed it up then pulled to 7500rpm first time.

[crisis]

this is all messed up... i'm just going to buy a used car... no worries!

Which is relying on someone else’s ignorance.

[Cyco]

I have long heard the theory that if you are going to drive hard you should break in hard. Never properly explained though. Just sounded like wank. When I picked up my last new car I was told to “just drive it like you normally would” which is kind of close.

According to Ferrari:

A slow break in will produce a tight engine that will struggle to reach redline, but will last a long time. Will also have holes in the power band.

A "drive it like you stole it" will lead to a very fast engine that spins up fast, produces the most power, but eats a lot of oil

A break in that involes some high rev, low load driving and generally taking it easy without holding the same revs the whole time will give a motor that has good power and lasts a long time.

[kigango123]

boring!, i thought you were going to teach me how to hotwire my neigbour's
M3. Oh well

by the way, what would one do if a car was broken in to a way that you didnt like i>e. the prevoius owner was a slow driver now when you drive your car, the power band is all messed up

[Quiggs]

Remove the engine, re-hone the cylinders and put new rings on the pistons. Reinstall engine and break it in how you want. Once the rings are seated, there's no going back.

[magracer]

Remove the engine, re-hone the cylinders and put new rings on the pistons. Reinstall engine and break it in how you want. Once the rings are seated, there's no going back.

I'd say, cane it... it will help you get a good portion of the carbon deposits out and run a little better. If it breaks then you should remove it,...