Break in oil, new short block

[demasrv]

I'm almost done replacing my small block. Do I need to use engine break-in oil? I'm in Indiana so it's pretty damn cold right now, so the prospect of using a heavier weight oil doesn't seem right. I know these engines have pretty tight clearances too.

My initial thought was to run break-in oil for the first 50-100 miles, change it out for 0w20, then change the oil again at 1k miles. All while following the manual's break-in procedure (under 4k, vary rpms).


Thoughts?


EDIT: I meant to post this in the Engine technical topic forum. Whoops.

[humfrz]

Oh, I'd suggest you just put some 0w20 in it and run it for a few thousand miles, then change it.

[chipmunk]

Unless you are extremely confident of your RTV application skills, I'd say dropping the oil pan to check for RTV debris is going to be more important than break-in oil, esp after a rebuild.

But to the original question, I used 0W-20 full synthetic. Changed oil within 1500 miles, and then again around 4000 miles, and then every 5500-6000 miles. Mobil 1 0W-20, sometimes 5W-30.

[JohnH]

i changed my factory oil and filter at 1000km. All motorbikes do this, so I figured it was a good idea.

I broke it in properly "motoman" style. it works on every engine I've built or seen built.

when I changed it, I went with a quality synthetic 5w30. I'm not running 0 weight oil in a performance car. Nor will it ever be driven in cold weather.

[TommyW]

IAG specifies break in oil for 1,500 miles to keep their warranty intact. 50, 500 changes then synthetic at 1,500