How long for a break-in period for a new motor?

[95CobraMike]

built a new 306 with rings and bearings, wondering how long break-in period i need to do before "normal" driving
thanks

 

[Grn92LX]

Click this link and follow Barry R's response. You're broken in now Just come home and change the oil and drive it as you normally would. Just check for leaks and odd noises before you take it out.


http://bbs.hardcore50.com/vbulletin/showthread.php?t=12510&highlight=engine+break

 

[Pokageek]

They told me to take it at variable speeds until 1k so I figured that was the definition of "break-in." They also said don't change over to synthetic until 1k miles or so. I am at 450 miles now and run it hard on occasion. No problems.

 

[Grn92LX]

Who is "they"? I switched to synthetic @ 500 miles which was fine after I asked Mark O'neal From probe/chp.

 

[95CobraMike]

whats wrong with synthetic oil right away?

 

[BlueOvalStangGT]

Something about glazing cylinder walls?

 

[Pokageek]

They meaning the engine manufacturer (precision engine out of Texas)

 

[HUNTED]

Your engine is broke in after 30 mins of start up. Either the rings are gunna seat or they arent. When you have your block bored they glaze the walls of the block in order to break the glaze you have to run a non synthic oil to do so

 

[Rootus]

Your engine is broke in after 30 mins of start up. Either the rings are gunna seat or they arent. When you have your block bored they glaze the walls of the block in order to break the glaze you have to run a non synthic oil to do so

+1

 

[wytstang]

Hunted is correct.

 

[95CobraMike]

sweet action so when i first started my engine i had regular oil in it.... i started the engine, warmed it up reved it up a few times (to 3k) ket it idle for a while and then shut it off and drained the oil and put in synthetic, its been about 300 miles since and it hasnt seen even 1 pound of boost yet.... so all that taking it easy for nothing

 

[Redsnk95]

As the racers say, after you back if off the trailer its broke in. In all reality I do initial crank-up on dyno oil, to help the bearings. After that back to Royal Purple.

Troy

 

[Grn92LX]

sweet action so when i first started my engine i had regular oil in it.... i started the engine, warmed it up reved it up a few times (to 3k) ket it idle for a while and then shut it off and drained the oil and put in synthetic, its been about 300 miles since and it hasnt seen even 1 pound of boost yet.... so all that taking it easy for nothing

Thats incorrect. You really needed to go out once the cars running/driveable and put a load on it. Too late now though.

 

[ROLLIN5.0]

The regular oil is supposed to break the glaze from honing, so that the rings can properly seat. That is quickly accomplished by putting a load on the pistons. If you are at 400+ miles, break-in is way back in the rearview, where you can hardly see it. Go ahead and drive it like you stole it, and run whatever oil you were planning to switch too. It amazes me how many engine builders give bunk instructions on how to break it in.
Brandon

 

[95CobraMike]

so the consensus is that you have to take it out for a drive and put it under load before it is ready for synthetic?