What is the best procedure?

Run conventional oil to normal operating temps and then drain.

Refill (dyno) and run another 500-800 miles

switch to synthetic after that?

any suggestions?

 

New car or new non-factory engine build?

 

For my boosted car here is what I did, change oil at 30 minutes, then again at 1k first two with dyno oil and at 1k switch to Royal Purple, worked great for my boosted setup

 

sorry its a used car..new 383 stroker

 

30 minutes of driving, (spirited driving) or idle?

 

I go a long back, but this has Never me or the engine.
1. drive the engine gently, keeping it under 2K rpms and once your there, Chane the oil and filter and go ahead and take it out on the turnpike for a 100 mile cruse and take the engine up to 2-3 grand RPMS But don't stay at any single like staying a 55 for too long Use up the 100 miles with this raising and lowing the rpm and once you do that, Your finished with the brake-in. I worked for a engine re-builder in Philadelphia and once an engine was finished as far a short block, and we had a electric motor powered rig that you were able to bolt the short to. It had it's pan and oil pump installed and we would bolt a engine to it, turn on the electric motor and go home for the weekend.

Sounds crazy but we put 5 quarts of 10W/30 and let the engine brake it-self in. We had a really large pan under everything so the engine never was with-out oil, but once q came in Monday morning we shut it down pull the magnetic drain plug and cleaner the whole upper engine and in about an hour the engine was in the car, wired up and filled with oil and coolant. I don;t know of anyone who does that other than the Corvette factory who hook up all of the ZO6 engines and run them on natural gas for a shout time to allow it to settle in.

 

Idle only on our initial startup

 

This might get interesting. Breaking-in is mostly just a tradition now but there are lots of different opinions and recommendations still remaining steadfast among many on how it should be done. In recent years most manufacturers have been relaxing break-in recommendations somewhat and most new cars today hardly have a break-in recommendation at all except to try to be a little careful for the first few miles. This is probably meant more to break the owner in to the car more than the car itself or perhaps manufacturers know owners want to break-in a new car whether it needs it or not so they include something in the manual even if it is somewhat vague.

I don't break any of mine in and have not for quite some time now. We used to follow along the lines of some of the recommendations above, varying speed on conventional dino oil for 30 minutes, shut down switch over to synthetic for power runs, etc., but not really anymore. With today's materials, manufacturing methods and surface finishes, parts (good parts) are actually ready to run hard right out of the box. I have built new engines where absolutely every last part including the block was brand new, go to the dyno, warm the oil only and prime oil pressure, cold water, cold engine, start it and go immediately to full power, full load and it will make the most power right then as it will ever make.

I realize there are small engine shops out there where the cylinders might not be perfectly straight and round or the honing might be a little rough and so forth where a break-in procedure might be a good thing but it is possible to build engines today which will not benefit from breaking it in.

 

Thanks guys!

should i just use standard 10w/30 for initial start and break in

 

I would just use whatever you had planned to use during regular service. I might change the first fill sooner and maybe cut the oil filter apart for a look inside. A drainplug with a magnet is a good visual aid to what's going on inside also.

 

Use a good quality dyno 5/30, 10/30, drive normal without steady rpm (vary rpms & load & decel) don't overheat it. Put 10/20/30 miles on it, change oil & filt with same dyno again, check used oil & filt (hopefully it shows no problems) now put 750mi on to get you to the next change with your daily driver synth oil.

 

If you bought a new Corvette the owner's manual doesn't tell you to do that. Says drive with the factory fill until the first scheduled oil change.

 

Drive it like normal, stay alert for temp & pressure readings and visual checks for leaks etc. Have built plenty of engines w/o problems.

 

Don't they do an initial engine break in at the factory? If so, then you should be good to go with normal oil.