I have a rebuilt engine and transmission I dropped in a couple of weeks ago. I was wondering what is the best oil to use for break-in? I seen comp cams break-in oil on zzp. I've also seen additives. I've read to run it for 30 mins at 2000-2005 rpms then change oil and filter. If this is true after the first oil change do I still need to put break in oil or additives? I don't plan on starting it for another month or so but any input is appreciated.

 

i was told on a fresh motor, use a normal grade oil. not synthetic. as the synthetic is "slicker" or more viscuous. you want the normal oil to some what wear the rings into the cylinder for them to start there own wear pattern and seal properly. im pretty sure the first 30 mins at 2-2500 rpms is to break in the cam. so i would do that, then drop oil. replace with normal grade oil again. and drive for about 1,000 miles. not letting the motor get over 3500rpms. drop oil again. then you should drive it the way you would normally drive it. drive for 2500 to 3k miles again. drop oil. then use what ever oil your normally use, and you should be golden

 

That's for old school, non-roller cams. Modern hydraulic roller setups don't need anything specific done for them. Sure there is some wear-in that takes place in the lifter bores, pushrod cups, etc, but nowhere near to the extent of a flat tappet that slides across the cam lobe.


IMO, there's way too much conflicting info on the web about how to break in a fresh engine build. Some people say to start easy and continue to ramp power up over time. Others say to thrash it right off the bat. I took a more 'middle of the road' approach with mine. I started it once and let it idle for 15-20 seconds just to make sure it wasn't leaking fuel, etc and that everything worked. After a week + in a cold garage, I needed to hear it run anyways to motivate me to make the final push to get everything else buttoned up.

Once I got everything else back together, I started it back up again and got it to operating temperature with idle and low rpm revs. Once it was pretty much up to temp (160+), I took it for a drive after checking again for leaks. I wasn't particularly hard on it, but I did give it up to ~50% throttle. Being that I didn't have my tune dialed in, there was no real way to push it much beyond that anyways (not to mention I had a mechanical issue that was making the throttle a bit sticky, so I didn't want to have it stick at a high throttle opening). I kept the rpm rather low though- I never took it near redline, and can't remember getting even over 4k on the first 5 or so drives.

As I continued to break it in, I tried to vary my driving style without beating on it. I always made sure the engine was up to operating temperature before getting any heavy throttle or high rpm situations. I also made sure to not excessively beat on it- as I worked on my tuning and fixing various swap issues, I started getting to WOT and redline after about 500 miles. However, I was running a decently reduced redline from what my target was and I would roll into WOT vs just stabbing it and shocking the system.

Everything seems to be good so far. The first couple oil changes were a little scary, there was some metal particulate in the oil at first which can be surprising if you're used to just doing normal oil changes on a car with mileage on it. That has all cleared up now. I just ran regular oil with GM EOS in it, nothing real crazy. I wouldn't get too worked up about some strict break-in procedure though- regardless which path you follow, you're going to be violating what another person swears by.

 

Thanks guys lots of great information. I guess everyone has there own method of breaking an engine in. I'll do the common things from what everyone is saying like low rpms and quick oil changes in short intervals I don't think I can't wait 3000 miles before I smash on the pedal I might be able to make the 1000 mark. My monte has been siting since February of 2014. Thanks again hopefully I can start it and drive it by August.