What does everyone recommend for breaking in a rebuilt engines. I've seen quite a few opinions on line but wanted to see what the j-body scene thinks.

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

I know a few people have said to use the procedure at this site. Thoughts?





"You can only feed them semen for so long before their legs fall off."

I go with the drive it like you stole it method. Beat the hell out of it and back. Every motor we have ever built or installed has been done this way and they are all still running to this day and running well. seat the rings and go with it.

I plan to break mine in....like I stole it.




PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO

although my dad firmly believes in what these two above do i just cant bring myself to do that to a brand new engine LOL.

there is no right way or wrong way to do this honestly. its just whatever you prefer. engine break in procedure is done differently by everybody and their brother.

this is my way...

basically, i drive a new engine calmly for the first 50-100 miles so i can diagnose any issues that may arise (and not cause any more if something IS wrong). then i change the oil and proceed to go out and do small burst pulls in a lower gear, up and down letting the engine decelerate the car. this seats the rings nicely. after that its balls to the wall.

as for the bearings, by the time you are done assembling an engine with all the rotation you should be doing, turning it after each bearing install they are usually pretty good. especially if you check oil pressure and crank the engine over with the starter on the stand/bench before you install it.



M45/OS crank/2.4 snout. It's nice to be injected but I love being blown!

My engines have always been broken in with a turbo and therefore I cannot "beat them".

I go with the method Brad said - go easy on it the first 100-200 miles while seeing how everything is running, ensuring no leaks, no odd noises, nothing out of the ordinary... I monitor oil pressure at this time with a snap-on gauge and make sure everything is where I expect it. I get oil readings from multiple sources.

After that I bring the car up to speed on the highway and do a lot of "deceleration" runs to seat the rings...

At the 600 mile (1000 km) mark the oil is drained and inspected, replaced with the oil of my choice and a new filter and once again oil pressure is observed cold and hot at idle and driving.

If everything meets my satisfaction it is time to boost it.

ALL of my engines were broken in on stock injectors and stock tune to take out any variables... I do realize that cams and a new static compression ratio changes the tune requirements drastically but frankly I won't take chances for that first little while and I go easy for that reason. i'd rather have a wompy tune to drive around on during break in rather than be washing the cylinders down trying to figure out the proper injector constant on initial startup. Once I have done that first oil change it is time to swap the injectors and get the tune base-lined.

Now - if I was breaking in an engine that was N/A and was carb'd or came with an ECM packaged that was mated to the engine then I would do the beat the hell out of it break-in.

Ideally I'd prefer an engine to get broken in on an engine dyno/stand... when I build the engine for my 81 Firebird I plan to do just that, including dialing in the carb. Then all I have to do is dump it in the car and ride.

-Chris-



-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...