break-in oil

I just had the 4.0L rebuilt in the jeep, the mechanic put in Valvoline 50 wt. race oil with break-in lube added. I've got about 800 miles on the build, the mech. put 360 of that on it himself. I'm ready to change the oil for the first change.

My question is what would be the next step oil and filter?

some type of oil for flat tappet engines.

i use rotella synthetic 15-40 and a wix or napa gold filter on my 89 with 245k miles.

do a search here as the topic of which oil to be used has been rather beat to death.

X2 -- please search. Many extensive threads exist with many opinions. Search "oil" or "ZPPD".

50W oil with Break in additive? HUH?

I am not aware that anyone even did kind of thing anymore, I sure don't.

Well, at this pont, it's either right or it's not.
Put in what the MFR calls for unless your engine rebuilder suggests otherwise.

-Ron

In a nutshell, you want oil for a flat tappet engine, higher ZDDP levels, in the Mobil-1 line only the green top 'high mileage' stuff makes it, it is marked 'high mileage' and comes in 10W30 which is what the 4.0 pretty much runs on. The same with all the other brands, most have what they either call 'high milege' or 'classic car' or something like that, like they could not just have made it simple and put 'recommended for older flat tappet engines'. or 'contains higher levels of ZDDP to prevent cam ware on older type motors'...

back to out finishing my new radiator install...

I don't know exactly why he used 50 wt. oil, but I wasn't real sure about some of his work. I went ahead and stayed with Valvoline 10w-40 conventional oil. Would 30 be better? I did a search before I posted, but wasn't coming up withan answer.

Straight weight is not better anymore for anything. Synthetic oil with 5W-XX or 10W-xx gets the oil circulating through the engine the best for start-up protection. Then you have the issues of the ZDDP. And we can post on this as much as we want, but you have to form your own opinions. As much as I like my answer to this issue, there are many other opinions, and you need to figure yours out. Many people on this forum love the rotella 15W-40. My opinion is that it is too thick at start-up. You have to figure it out yourself. These forums are more a place for gathering information. There is no definitive answer. http://www.naxja.org/forum/showthread.php?t=995799&highlight=ZDDP

My engine builder gave me 6 quarts of 25wt pennzoil racing oil when i picked the motor up, he told me to drive it like I stole it for the first 1k then change it out for whatever I wanted to run. He gave me a 2 year 24k warranty with the engine as well. Hudson or "Hud" as we all know him around here is probably the best engine builder in SW VA, too bad he retired last year and closed up shop. He was our local 258/4.0 expert. That 4.0 now has 35k after the rebuild and is running better now than it did when the Jeep was bought new by my Dad in 1990.

I run 10-30 Rotella in all 5 of my XJ's