Hi guys --

Been trying to stick to the overall break-in rules: varying throttle, no cruise, progressively increasing revs (up to short forays into the 6's now). Car's up to 300 miles.

I have a work trip coming up that will take me through to the 600 mile mark. but, it's mostly highway.

Any tips? Should I just shift bewteen 5 and 6 every so often, and vary from 60-80? Any harm if I cruise?

Thanks

 

Took mine on a 350 mile trip a couple of days after delivery, most all highway miles.

I kept it in 6th gear, and varied my RPM's within a 1,000 rpm range every few miles.

That was 14,000 miles ago...

 

The primary concerns during break in is excessive heat build up and harmonic vibrations. So the highway by itself is not a problem as long as you consider these problems. So avoid high speed when working the engine hard (hill climbing, racing, pulling a trailer (if anyone did that witha 8), etc.) and vary your speed. So my feeling is to try to stay below 80, 75 would be best, and occasionally lower or raise your speed a few MPH. Downshifting to 5th will lower the engine load, but also cause higher revs and breakin friction heat will go up, so I would only do that for short times.

My 8 only had ~1000 miles on it when I drove from Atlanta to Miami. Mainly ran at 75-80. 80 was only 4,000 rpm, so not too bad. I now have 5500 miles on it and have had no problems.

Biggest concern is DON'T Abuse your engine during the break in.

 

just passed the first 600 miles, now i'm dying to get the juice out hahaha

 

I varied RPM & speed. Mostly highway miles (commute) during break-in. I was one (the only) that allowed mine to idle 45 min the first morning I had it home (picked up with 3 or 5 miles)
to your question: I varied the RPM by using 4th, 5th & 6th at speeds of 60-75 while limiting RPMs to 4500 IIRC.

 

I'm at 1300 miles now, and I still feel like I'm abusing it if I make it beep.

 

Highway miles are not as good as mixed driving for breaking it in. I wouldn't count the miles as 600 more like 200. I also wouldn't go over 65 and vary the speed between 55 and 65 every 10 min. In short it is a pain to break it in on the highway. I always try to keep my first 1000 around town. All my cars and trucks have gone well over 150,000 with no problem and have never burned oil. My younger brother just waits for my cars or trucks. He has my 1993 Ranger 4.0 with 192,000. I asked him if he wanted my 97 Honda with 179,000 but he said no.

 

Don't obsess over break in - just take it easy, stay away from the upper end of the tach, vary your cruising rpm's a little bit, and you'll be fine. Remember, the engine's only got three moving parts...

I did notice the transmission loosend up noticeably during the first 1000 miles so. Now it's still precise but there's less friction going thru the gates.