How many miles to break in new rod/main bearings?

OmgAwd · 10-31-2008

My new main and rod bearings have about 80 miles on them now and I have yet to beat on the car. What is the usual break in period?

Info-
Eagle Rods
Clevite race series .50 oversized main and rod bearings
Brand new oil pump
13G at 16psi

**Goat Blower** · 10-31-2008

You've done plenty, let 'er rip. That is assuming you changed the oil at 20 miles, if not, do it now and you're good to go.

joesushi · 11-06-2008

You never need to be EASY on an engine. The point of rebuilding engines is to replace seals, correct loose tolerances, and get more compression from seating new rings properly(arguably the most important part). You seat rings properly by throttling up in rpms and letting off (keeping it in gear) revving down creating vacuum, and flexing the rings up. Then do the opposite and create a little boost and flex the rings down. Your freshly honed cylinder walls will sand away at your rings creating the best possible compression.

My engine runs great after beating it like a wife since day 1 and thats about 10k miles. My first rebuild.

**Shane@DBPerformance** · 11-06-2008

You break in rings and the cylinder walls, not really bearings. If the rings don't seat well within the first 50 miles, then they might not ever. You normally want to change your oil a couple times in the first 100 miles.

**JET** · 11-06-2008

Yeah, there is no break in for bearings, since they don't actually touch anything. I agree with the above. I am nice for the first few miles, then progressively get more aggressive. Vary the throttle like Joe said and change the oil at 20 miles and 100 miles, then I do 1,000 then it is good after that.

OmgAwd · 11-07-2008

What sushi said is true and I did that. I already changed the oil and everything is working great. Thanks.

brando · 11-07-2008

yea you should let the motoe get through one heat cycle then change the oil gettinbg all the contaminent's out. the change it at 500 and 1000 then the normal 2500-3000. seating the ring's is the most important part of a rebuild though. put your car in 2nd or 3rd gear and go from 2500-45/5000 about 15 time's. .durring the process you will feel you car picking up a little bit of power intill the cylinders start to glaze over. if you dont do this you will have constant blow by in your cylinders