Oil Viscosity
 

What weight oil would be correct for brake in and then for after break in for a blown bbc?

I allways use a strait wieght oil for brake in because of what is in a multi wieght is not good with high heat,like where the rings run on a fresh hone. 30w warmed a little is before the first start is good.If it's a flat tappet cam a racing oil should be used.That what works for me.Bill

Depends how loose the motor is? I run 60 weight valvoline racing oil plus some marvel mystery oil in my blown injected bbc

I don't know what the tolerances are for the mains and rod bearings, but I can find out seeing as how the engine isn't totally assembled yet. Is there any guide lines I could use? Thanks.

Oil
 

Brad Penn makes a Brake in Oil.It has Loads of the GOODIES that a Fresh Motor NEEDS!!!
Later
G 8)

Re: Oil
 

x2
Penn Grade 1 for break in at $6/qt and like BBChevy said it's got lots of "zippitydodaday" in it. Only 30 wt but breaking in a flat tappet cam you won't be under 2000 rpm anyway.
If possible, run reduced ratio lifters or remove inner valve springs during break in. This is one of my personal streadfast rules.
Good luck, Dave

Lucas also makes a good "Break In" additive also. Part # 10063 which cantains Zinc. Can also be used in each oil change too.

TS1955

That's good to know about the Lucas product. They are readily available around here where Penn isn't.

agreed that main and rod clearance should dictate weight of oil. comp cams has a break in oil additive toooooo