Which is the best way to break-in the engine of a new car?
Many people say drive it easy for first XXX amount of kms.
Others are now saying "drive it hard".

Here's an article that supports the "drive it hard" method with logical explanations and arguments to support the premise.



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

 

I have red-lined mine twice in the first 600 kms, does that count

 

Dino oil in the pan and several full throttle burts....................now drive it like you hate it.
Most / all ring mfg's now agree that breakin em in easy can and will leave you with poor ring seal.

 

Ricks right, don't be too easy on it. I've always used straight 10w oil (this was before they had 5w30) for the 1st 500 miles (800 km) and would do bursts of up to 5500 rpm
thru 2nd & 3rd and then let off, cruise for a bit and give er again.

Would also take it for hour or so cruise up the highway at normal speed and hit it
every so often in 3rd.
this way the engine gets a run a normal operating tempatures and a chance to seat
itself. it's after this that if there's any minor leaks this is usuallly where they'll
show themselves.

after 800 km, drop the oil and filter and put in your desired grade and brand.

 

Well there are always going to be storys on how some one beat the crap out of a new motor and had no probs and other storys were some one took it easy and Boom.
Alot depends on what the motor is and how its built.

Flat tapit cam or roller?
Is it a tight or loose motor?
What kind of rings and bearings?

Stock rebuild u get told to take it easy on it.
But a race motor gets 10 15 mins on dyno change the oil and go for a dyno pull at full power?

Makes u wonder if a 1500k breakin is realy needed or not.
Why baby a 1500 stock rebuild yet they pound the crap out of 15 30 50g motors on a dyno b4 its even in a car.

I say put your new motor in drive it normal for a day change oil drive it normal for a week change oil again then call it good. Just tighten the intake after the frist day and check the header bolts make sure there tight.

Next day spray it.
Worked for me.

 

500 miles break in with mineral oil....

then switch over oil to synthetic..

and drive like u would like to

 

I built mine with 11.5:1 compression,started it for the first time,let it run for 10 minutes,back it out onto the street,then 6000 rpm,all the way up to 4th,sideways,so yes,it depends on who biulds it,and how,i did this one.

 

can you break in a engine with a supercharger on it?

 

had a buddy who builds engines, he says when its all together fire it up,hold the rpm at around 14to1500 rpm for about ten minutes or so,then says take her out and giver crap. After all if everything doesnt seat after the 5 to 10 minute run then it wont seat at all?

 

I've always used straight 10w oil for the 1st 500 miles and do bursts of up to 5500 rpm, after that drive as like as i can.