The engine is built and waiting to go into my 92 RS. The builder says I should break it in with whatever oil I will run. I want to run a full synthetic as the car will not be driven often. I remember hearing or reading that you should break in with conventional, if you want to run synthetic, it should be added after break in.

The engine has a hyd. roller cam and all parts are new.

 

With a roller cam it doesn't really matter. I'd use conventional. Tune it up quick, and run the ***** off it. Seat them rings!! Engine braking, mid throttle runs, then finally WOT runs.
After 500 miles, change it out to synthetic and leave that for 3000 miles, normal change period after that. But the first time, you're not keeping the oil in there for long, so I wouldn't waste the cash on synthetic.

 

Ask ANYTHING at all about oil, you're going to get every kind of mindless, knowledge-less, experience-less quote of ad drivel or "old wive's tales" hot-rod lore going back 50 or 60 years thrown at you.

Ask it about break-in, you'll get about 5 times as much; notwithstanding that about 95% of that comes from people who have NEVER built an engine AT ALL. Instead they'll tell you something like "my uncle's wife's niece's boyfriends' dad's brother went to a race at the local dirt track once, so he's an expert on cars, and I heard that he says you should always use non-detergent for break-in" or the like. Out of the other 5%, probably no more than 5% of them has ever built more than 5 motors; and if they DIDN'T use synthetic in them, then they'll tell you all about "I used dinosaur juice and mine worked fine"; which is fine, and probably true, but doesn't tell you a damn thing about synthetic. So, apart from spank-off and inexperience and more ad copy and ancient lore, it's even harder to get anything useful.

Then, on top of that, you ask about synthetic. That's the KING-DADDY of all the known universe of subjects you could bring up, that will bring out all the uninformed "I heard it at McDonalds" type of talk about oil, even without introducing the break-in variable.

So you're about to get drowned in uselessness.

Go to an assembly plant, and see what's in new cars. If you don't want to do that, I'll tell you:

It's synthetic.

All of the drivel about "seating the rings" and stuff like that, that you're about to have to listen to, is just that.... drivel.

If it works in brand-new cars with 100,000 mile warranties, it'll work in yours too.

I use synthetic as break-in oil in all the motors I build nowadays that have roller cams in them. Flat-tappet setups are a different matter. But you don't have to worry about that.

Put on your fire suit, zip up your BS coveralls, and prepare for a flame war.

 

Is that why people don't use synthetic to break in, the cash thing? If its not nessicary then I won't do it. No sense in wasting money.

Just read your reply sofa kingdom. I'm not worried about all of the bull that will ensue as a result of my question, I just don't want to hurt the new powerplant. My guy has built hundreds of engines but most of them were back in the day, so I check here from time to time to keep him true, but you know how hard it is to argue with an old drag racer! Besides, he's working for free so usually I let him do as he wants because he does know alot and he has built some baaaaaaad engines. He's got pictures and timeslips to prove it.

 

Maybe it's the money; but I don't think so. I think it's more, fear of the unknown; and the whole voodoo, black magic, and dark arts kind of approach to lubrication. Most people don't understand it, and they adopt an almost religious attitude toward it to keep from straying too far from the straight and narrow.

1st change interval on factory fill fluid is usually the same as a normal oil change interval. 3000 miles or whatever. The thing about a roller setup is, VERY VERY LITTLE metal is shed into the oil, so there's no real need to change it; if of course, the engine is kept clean during building. But even that, you can cure with a filter change. Most everybody gets a bunch of towel lint, pet hair, spider webs, and just miscellaneous dust into a new motor; but that stuff ends up in the filter pretty quick, usually.

So I'd say, go ahead and run synthetic, and change the filter and its quart after 500 to 1000 miles if you want, and then let it go a normal interval.

 

I'll see how long we're going to leave that first oil in there. If he says that we're gonna run it for 3000 miles, I'll go with the synthetic. If he says 500, I'll try to convince him to let me break it in with conventional.

I'll probably run royal purple in it because I've heard good things about it a saw a program that showed their quality control procedure. As an ex-chemistry major, I was impressed. But as you said before, sofakingdom, I know better than to ask the "which is best" question.

 

Depending on which assembly lube he uses to build the motor, chaning the oil shortly after break in is more/less playing in your favor for helping to flush out the sludge this stuff produces. I never used to cut filters after inital break in, but this new group of guys has been doing it relisgiously for years and all tell me that assembly lube really clogs up the filter element.

Just be sure to get a bottle of EOS from a chebbie dealer. This oil addative has a high zinc content which is what your really after to help protect the metal internals during break in. In fact, and even I found this interesting, alot of racers are actually running oil designed for diesel engines since they have high zinc content.

Just my opinion, but 1st fill run dino oil since it's cheap and it's getting drained soon after, that way your saving a few bucks. After that, go full syn and never look back. Dont even know if I'd waste my money on Royal Purple since Mobil 1 does an excellent job protecting internals-and this I can attest to first hand.

 

K dude, I'll check into the mobil 1.