break inning a rebuilt engine

[crazygogo]

what is the proper way to break in an rebuilt engine? does warming up the oil 1st help?

[SilverXJ]

Yes, pre warming the oil won't hurt. Follow the cam manufactures recommend break in method first. Usually 2000 rpm with some rpm variations for 20-30 minutes. The piston rings will be mostly broken in after that but it won't hurt to go ahead and run the ring break in procedure. Usually some 3/4 throttle runs with coast downs in a lower gear.

[crazygogo]

so leave it in 1st gear? when breaking in the rings?

[Muad'Dib]

You don't have to leave it in 1st, but definitely downshift or put it in 1-2 so the engine will act as an engine brake. This helps break in the rings. I was so weird about this I would do it randomly during the first 300 miles or so... I also didn't let it idle for too long I would always fluctuate the RPM's during that 300 mile period. I was nuts but my Stroker hasn't had any issues.

[crazygogo]

how many miles should i do this for 300 or 600 miles? this is my 1st jeep engine i am rebuilding. and i don't wanna frakin break it in WRONG!

[Muad'Dib]

I would do it until the first extended oil change after the break-in.. which is usually between 300 and 500 miles depending on who you ask.

The biggest thing to worry about is the cam break-in. RPM fluctuations for 30 minutes typically between 2000-3000 RPM's.

1.) Fresh Oil in engine
2.) Break cam in using RPM fluctuation procedure.
3.) Change Oil
4.) Drive it like you stole it \ Engine Brake \ Don't let it idle for extended periods \ Seat Rings.
5.) Change oil again between 300-500 miles.
6.) Enjoy and change oil after this on regular 3 month intervals.
7.) OPTIONAL Switch to Synthetic when you feel comfortable with doing so.

[crazygogo]

Thats much easier to follow and btw when you mean drive it like you stole it.. Beat on it for the 1st few hundred miles? and i love how you put things in steps.. thank you

[Muad'Dib]

Don't feel like you have to baby it... just drive it like you would any other day.

[SilverXJ]

Don't baby it and don't beat on it. Drive it like normal, depending on your driving style. If you drive like a granny don't drive that way. Don't lug the engine. If you are going up a hill and you aren't gaining speed or gradually gaining speed make it down shift and rev higher. Don't think "this is a new engine and I need to be careful". What you want is pressure on the rings for them to seat.

[crazygogo]

understood and 10-4 good and thank you SilverXJ for the more detail way to drive the new engine