Are you doing your own build if you are I am pretty sure the most important thing is priming properly using paste and if new cam I would follow the cam manufacturer break in guidelines with any good break in oil if they dont rec one. Also on a fresh build most important was cam second main bearings so usually after quick run complying with your crank and cam break in if instructions ,if not I would put no load on engine and then swap oil after no more than 20 min and then run a dino oil with varying load and rpm staying below 4k for few hundred miles to let rings cut cyl and not develop hot spots then switch to whatever your gonna run for another 500 to 1k.What method(s) have you used to break-in your built motor(s)?
What oil type(s) did you use?
Varied opinions and no consensus found but I would appreciate feedback. Please include: build / motor type / oil type and viscosity if possible.
I would follow my builder's recommendation to a tee. If you don't trust what he wants you to do, you probably don't trust the motor he just built . That said, old days used to be conventional oil for break-in but I don't see that going on now. Factory motors have not been doing that for a long time.
I'd be asking oil brand, if he cares, how many miles before oil change, and if he wants you to do anything specific in the break-in procedure. Honestly who cares what a bunch of us forum people think - the builder is the guy you need to trust. It's kind of like, you just had surgery and ... well ... who do you want to tell you what's needed post op? It'd be the surgeon.
Good luck with the break-in!
How did you drive it for the first 500 miles?
I actually just switched to 30 right bio syn and had internal battle of 40 or 30. Everything I have read says the 30 will protect better cause of greater flow and that most important is film strength. I agree with our tight tolerances a 30 may be way to go and only at track I think will I run a 40 weight not sure yet .it is scary for such a simple thing when we invest so much in our cars and I am not even built ,hoping to keep it that way for a while to lolI just used typical luqi molly 5w30
Start car got it up to temp changed oil. After that did a 500 mile break in and changed the oil again. Did a couple of pulls and changed the oil one more time.
Just pulled the eng apart to do headstuds and decided to check everything and the bearings still look new after about 2k miles and a dozen of dyno pulls @ 30psi.
The clearance between the crank and main bearings are very tight on these engines for some reason. I wouldn't go any higher then 5w30 on break in. AMS oil makes a good break in oil if you want to use a true brake in oil but frequent oil changes at first will work the same.
Don't be alarm by some metal flakes on first couple of oil changes