food nd cars

After the rebuild I ran valvoline 10w-50 for about 20 miles, drained it and replaced it with 5w-30 joe gibbs break in oil. I now have about 500 miles and I am going to change the oil next week before I hit the dyno. Should I stick with 10w-30 conventional for awhile longer? or is it time to use 5w30 mobil 1 synthetic?

myk

iTrader: (4)

It's my understanding that after motors are broken in it's o.k. to use synthetic oil. I've only heard not to use synthetic during break-in; I'm sure you know that synthetic oil would prevent the rings from breaking in and sealing properly. If you're sure your motor is broken in I don't see a problem with synthetic...

food nd cars

Anyone else?

lt1-xjs

The factory fill on Vettes was Mobile 1 5w30, They had 0 miles. So it looks like to me they were broken in on Mobil 1. People have different opinions on engine break in period. 500 miles should be more than sufficient.

LSXNV

iTrader: (1)

Break in is more for flat tappet cams and less for rings. You would have been fine switching to synthetic after your initial oil change. Your rings usually seat very quickly.