New Motor Break-in

[greenjeep]

So the 401 being put in my CJ is a newly rebuilt motor with no miles on it, and I know it is important to carefully break it in for the first 500 miles; the problem is I maybe put 500 miles on it every year! So what should/shouldn't I do to break it in properly? Can I wheel it, or does it need higher RPMs like from town & highway driving?

Sorry if this is a dumb question, but I've never had a brand new vehicle.

 

[H-K]

I think this is a matter of debate/controversy.

This is from a motorcycle site, but if you thumb through it, there's some interesting explanations of the processes that apply to most engines:

http://www.ntnoa.org/enginebreakin.htm

Last motor I broke in was on my BMW motorcycle. The dealer told me to take it easy and baby it and the local non-dealer BMW service gurus told me to do the opposite. They told me to ride it like I stole it.

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

 

[gertsch]

when i rebulid the motor in my truck had some guild lines from a crate motor i did the year before that you do for a intitial break in on the motor so i used them on mine that i rebuilt.

The first step when i first fired it up was time it and then run it up to 2500 rpm in park for fifteen minutes while also checking for leaks and making sure oil pressure was good. After the fifteen minutes i shut it down and changed the oil.

Step 2 I drove it 500 miles being real easy on it and ranging speed on the freeway from 55 to 70 nice and easily and hold it had different speeds.

then after the 500 miles i changed the oil again and started my regular 3000 mile oil changes and it runs great.


But for you wear your lucky to see 500 miles a year you might run into problems unless you can find a place it break it in on a engine dyno or something sorry this is all i no i hope it helped.

 

[Greg]

First thing I'd do is get the right oil. Get a straight weight, like 30w oil, rather than 10w30. Don't use synthetic or semi-syn, just regular oil. Personally, I like Valvoline for engine break ins.

I take the camshaft is new, too? That's the most important part to break in properly. Like mentioned before, get the motor running & keep the engine running just above 2500 RPM for 30 minutes, don't vary the engine speed. It's annoying & loud, but you need to set the pattern on the camshaft & lifters. Keep an eye on your gauges, oil pressure, engine temp, etc.

After you've gotten the cam broken in, drive around the neighborhood for about an hour or so. Be easy on the motor, vary the speed you're driving at. Do a lot of stop & go driving. Again, watch the gauges... keep an eye out for potential problems.

I'd do the same thing for a few more days, easy driving & varying speeds then change the oil & filter. At that point you can run whatever weight you prefer. Once that's over I wouldn't be too concerned about being easy on it... when in doubt, throttle out! The motor will be broken by then, have fun!

 

[mbryson]

First thing I'd do is get the right oil. Get a straight weight, like 30w oil, rather than 10w30. Don't use synthetic or semi-syn, just regular oil. Personally, I like Valvoline for engine break ins.

I take the camshaft is new, too? That's the most important part to break in properly. Like mentioned before, get the motor running & keep the engine running just above 2500 RPM for 30 minutes, don't vary the engine speed. It's annoying & loud, but you need to set the pattern on the camshaft & lifters. Keep an eye on your gauges, oil pressure, engine temp, etc.

After you've gotten the cam broken in, drive around the neighborhood for about an hour or so. Be easy on the motor, vary the speed you're driving at. Do a lot of stop & go driving. Again, watch the gauges... keep an eye out for potential problems.

I'd do the same thing for a few more days, easy driving & varying speeds then change the oil & filter. At that point you can run whatever weight you prefer. Once that's over I wouldn't be too concerned about being easy on it... when in doubt, throttle out! The motor will be broken by then, have fun!

I've only had two NEW motors before and have had good results with the above.

 

[yellowbronco]

Don't listen to all this melarchy Dave!!
Don't even use oil, redline it as much as possible, and pour sand in the crankcase. That'll do.








j/k Don't listen to me, I'm bored

 

[BCGPER]

Pretty much what Greg said is spot on. A couple things I would add is when you first fire it up, let it idle for a minute while you roughly set the ignition timming as guickly as possible, then take it up to the 2000+ RPM. Also, run pure water for coolant. Once your 30 minute cam break in is finished, let the engine cool for about 30 minutes, then dump the water. Pull the lower radiator hose to remove all of it, then refill with quality coolant. I also change the oil and filter at this time, and refill with the straight 30 weight for the first 500 miles.

 

[greenjeep]

Thanks guys, hopefully it all works out ok.