Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum - View Single Post - How long do you have to break in a freshly built motor??

sd8ted · 03-06-2008, 11:15 PM

When I rebuilt my motor, for the first 500 miles I stayed below 4500rpms. And changed my oil after that then I was good to go. This is what I did personally, however different people have different opinions. Rebuilding with forged rods/pistons etc was an expensive process so I went with the safer route.

There are other ways I've read about, one involving running your car kind of hard after it starts up and warms up fully. The rings seat within the first 20 or so miles, if that. And by running your car hard seats them with a nice seal, as the pressure of the gas in the combustion chamber is what seals the rings.

Here's a SITE that tells about the hard/fast break in method. Goodluck!

03-06-2008, 11:15 PM	#7
sd8ted Leaky Injector Join Date: Nov 2005 Location: Greenville, SC Posts: 72 Trader Rating: (0)	When I rebuilt my motor, for the first 500 miles I stayed below 4500rpms. And changed my oil after that then I was good to go. This is what I did personally, however different people have different opinions. Rebuilding with forged rods/pistons etc was an expensive process so I went with the safer route. There are other ways I've read about, one involving running your car kind of hard after it starts up and warms up fully. The rings seat within the first 20 or so miles, if that. And by running your car hard seats them with a nice seal, as the pressure of the gas in the combustion chamber is what seals the rings. Here's a SITE that tells about the hard/fast break in method. Goodluck!