I know your not supposed to run synthetic during engine break in so I used Royal Purple Break in oil for engine break in. I have a roller cam so I don't really need to break the cam in but i did do a 30 minute break in to get the rings seated. I also had the engine dyno tuned so it has 5-6 dyno runs to around 5500-6000rpm. Then i drove it on street for like 30-40 miles.
The oil was dirty so i changed the oil on Sunday but went to Joe Gibbs HR-4 full synthetic oil. I thought it would be ok because i thought the rings would be seated by now. I hope the rings have seated because i don't want engine blow-by...
what do you guys think?

 

You've already broken one of the cardinal rules for a new engine by putting it on a dyno before it's broken in. But it sounds like you're lucky, and it's still together. Why worry about oil type now?
New engines wont completely seat the rings until you've got about 500 miles on them, and dyno trips shouldn't be done until the rings seat, or you may find they never do seat. Now it's just waiting to see if the new engine burns oil once it's got a few thousand miles on it.
Breaking in a new engine involves running it at various speeds and using compression occasionally to slow down. Never run it to max rpm's or keep it at one speed for long periods of time.

 

that was after 30 minutes of cam break in though. and I've heard of people breaking their engine in on a dyno

 

Breaking an engine in on the dyno is a very good thing, if you do it right. Making passes to see how much HP it can make is not breaking it in correctly. Breaking in on a dyno is just like it would be in a car. Run it up and down, don't hold it at high rpm's and don't hold it at any rpm for long periods.
And with a roller cam you don't need any breakin time for the cam.

 

that was after a 30 minute break in though..and yeah i know i don't need to break in the cam but did it to help make sure the rings seat.i've heard that new moly rings can seat within an hour or so..man i hope mine have and don't have blow-by later on, that will suck.

 

Don't know where you heard that from, but rings take a lot longer than that to seat, even regular iron ones. There's nothing wrong with breaking the engine in on a dyno, as long as it was done right. Hopefully, the guys doing it knew what they were doing. The best way to break an engine in is by driving it, not terribly hard, and definitely not easy. What seats the rings to the cylinder walls is gas pressure pushing out from behind the rings. You'll only get that from putting the engine under a load, which is why it's also not a good idea to run a new engine even slightly in the garage. The first runs of the engine are the most critical. Basically with a new engine, you want to start it, take it on the road and run it. Or in your case, the dyno, then the road. Once the engine has twenty miles or so on it, change the oil, still using conventional oil. Believe it or not, as "clean" as your new engine was, your oil will have contaminates from break in lube, the metal that the rings shaved off the rough cut cylinder walls, etc. And as you saw, your oil was dirty after your 30-40 miles. Then after the next 1,500 miles or so, change your oil again, and go crazy with synthetic if you want to. Chances are your engine will be ok, time will tell. So to answer your question, yes, too soon for synthetic!

 

i drove the car like 20 miles today. should i drain the synthetic and put conventional back in until a little later?
maybe i will do a compression test to see if the rings didn't seat and are causing blow-by..

 

Did I use that darn invisible ink again on my last post?

 

lol huh?

 

Yeah, that and my last sentence answered his initial question if it's too soon for synthetic. That's why I was wondering, maybe he didn't see any of it?