rebuilt engine, amsoil full synthetic for breakin?

I've also read that. However, you aren't breaking in a new engine, so you may want to begin with the synthetic straight off. In a rebuild, I think the only parts you would be concerned about would be the rings. If you re-sleeved the cylinders and installed new rings, then you might want to use natural oil to get the rings to seat more quickly. I think ("Danger, Will Robinson!") that if you installed new rings but did not sleeve the cylinders, you would be fine going with synthetic immediately.

Congrats on the rebuild! Please keep us posted on your next steps and any issues.

Well I figure if M1 sync come from the factory in a new Viper and Vett it aint gona hurt your little motor none

BMWs, like a lot of cars, come with synthetic from the factory.

Continental and Lycoming recommend mineral oil for break-in of aircraft engines.

Wonder why? Air cooling (actually "oil" cooling) perhaps?

Was not long ago, dino oil for 15000 miles then switch to synthetic.
Its all opinion now. I dont see any gain in using it considering expense and service intervals. Longer service equals longer neglect. Im not pointing fingers here in OTT, but i have seen the results of not taking the time do do periodic inspections. That synthetic wont save you when leaks develop.

Yeah!

People are buying into the mileage "computer" analysis on oil changes here and abroad as a way to save the climate. BMW suggests initial oil intervals of up to 15,000 mi are OK.

How about saving the motor and allowing it to operate the most efficient over the longest period of time and having each motor live as long a life as possible before it needs to go to a recycler and be replaced?

My 4Runner, for example, has 160K on the clock and the motor burns zero oil and emits only 1/4 of the allowed pollutants at each emissions test. From all indications, its just getting broken in.

My wife got soooo pissed at the idiotic "cash for clunkers" program we had here in the States a few years back. Many were perfectly good cars that needed a little TLC. How much environmental damage was caused by having to replace those vehicles? They weren't "clunkers." The program was a clunker.

In my opinion, the frequency of oil changes affects the longevity of an engine more than the oil used. I have a company-provided 2003 F150 4x4 with a small V8. It has 307,000 miles on it and doesn't use oil. The engine sounds like it did the day I got it. No special oils have been used, just have it changed every 3,500-4,000 miles at the nearby "wash-n-lube".

I've always used Rotella 15-40 in my diesels. No engine problems at all. My jeep grand Cherokee has 183k on it. I use Quaker State 10-30 in it. Never any engine problems. I think the key to engine life is regular maintenance schedules.

I had a 1983 Nissan Maxima with a diesel in it. Bought it in 1985 with about 18,000 miles on it.

I changed the oil filter with one from the dealership one time. It took a contortionist monkey to change it, and it cost $19.00 back then.

I then added a Frantz Oil filter. Changed the filter about every two weeks because I was driving 400-800 miles a week.

Sold the care, still running fine, with 360,000 miles on it.

Oh, I used John Deere 50-Plus oil. And the Frantz used toilet paper rolls, which I bought a a restaurant supply by the case.

Now lets argue about toilet paper filters!!!!

Warning lights- put an aircraft landing light with a red lens on wood processor oil sensor and powered it through a relay. Broad daylight and that 4" lamp is blinding. Need something like that in the wife's car.

Frequency of oil change is the key. Read a story of a garage keeper that changed oil every 2000 miles. At 100,000 he tore it down and no ridges and cross-hatch was cleary visible.

I knew people that bought new vehicles, never changed oil til just before traded in. The mentality was dont spend a dime unless absolutely necessary. Next owners problem.

Well, I'll bite. My 1998, Dakota had synthetic in it at 2,000mi. It did not break in until almost 70,000 miles. Break in defined as an increase in fuel economy AND power. We had a Van with a carbureted 318 (same engine as the Dakota) that my father ran on Dino oil until he saw the increase then switched to synthetic. It broke in at 13,000 miles.

I had believed the 'synthetic from the start' crowd and changed my first change at 2K. Looking back, that was a mistake. It cost me more in fuel and oil changes. Also, big mistake going to platinum plugs, gave my poor ol' 318 fits I thought were other issues. Cost me more for the plugs, wires, dist caps, rotors, coil, valve work, etc. Switched back to good ol' Copper plugs and all the issues vanished.

So, I've found the more traditional approach to be more effective for me, at least on the larger engines. I'll stick with regular oil until break in and then switch to synthetic on big motors.

Now, if you pay attention to the factory specs, even on those expensive BMW's, the engines are factory broke in so you don't need to start with dino oil at all, according to the factory. So take it for what you like. I took it at face value and my 2007 Caliber has had synthetic in it from the first change. Then again, at 1.8L it's so weak I wouldn't notice a break in change! Does get great gas mileage though.

General advise has been that if you rebuild an engine with a flat tappet lifters and put in a new cam and lifters, you should use a break in oil designed for this purpose. It will contain more so called impurities like zinc which aid in lubrication and insure you don't flatten the camshaft lobes. Most, if not all, new engines in automobiles use roller lifters/roller cams that don't require the extra break in protection. There are several oils designed as break in oils for older motor rebuilds, Royal Purple makes a good one as do others.