I just finished installing my forged engine and was wanting to know whats the best way to break it in? how many miles until it is broken in? What mileage should i change my oil before i reach the break in point? thanks

I bought the royal purple first start break in oil and started it let it idle for like 10 minutes held it at 2000 for 10 minutes or whatever my cam box said to break my cams in and then changed the oil and ran crappy reg oil for 500 miles changed it again and ran reg cheap oil for 1000 then put castrol gtx reg oil in it and ran the DOG shit outta it...i was on 5 lbs until the castrol gtx was in and it never seen more then 3500 rpms... more information on ur build would help tell you how to break it in..cuz if your injectors are huge and your running rich your gonna wash the rings out and they might not seat....

From Corbin's engine rebuild write-up (http://2gnt.com/index.php?d=A%20Proper%20Rebuild):



Double check every bolt and connection. Fill up all of the fluids. Keep the car on engine stands. Now, fire the engine up. It might cough a little, but let it run. If you have an oil pressure gauge, look at it. You will likely see the oil pressure start at 75 psi and drop down to 25 psi as the engine warms up. While this is happening, look everywhere for leaks. You are looking for coolant, oil, exhaust, anything. If you have a really major leak, shut the engine off too fix it. If it is minor, you should probably just let it go for now. It might seal up as the engine warms up. You should keep running back to the cockpit to check out the gauges. If you have a boost gauge, check the vaccum. It will likely be in the 16-20 in-Hg range. If you have an air/fuel gauge, make sure the O2 sensor starts to cycle after a minute or so. After the engine has fully warmed up and run for 15 to 20 minutes, shut it off. Drain the oil and change the filter. This should remove any loose debris that might have made its way into the system during the build. If you have a turbo with an internal wastegate, you may choose to remove the actuator before driving the car. This will keep you from building any boost. Start the engine again and let it fully warm up. Find an empty stretch of road and do a 30 to 50 mph run and compression brake back down to 30 mph. Keep the car in the lowest gear that will keep you below 4k RPM max. Keep the car in the low gear during the compression braking to pull a lot of vacuum. Do this repeatedly for the next 20 miles. Now, drive in stop and go traffic for the next 200 miles. Stay off the interstate. Use your gears and vary the engine RPM when cruising, still keeping under 4k RPM. Compression brake when possible. Don't lug the engine in a high gear. When you hit 220 miles, change the oil and filter again. Use cheap dino oil again. Do the same stop and go traffic crap until you hit 620 total miles. Just change the oil this time (cheap dino oil). Do the stop and go traffic thing again, but mix in some highway cruising if you have to. When you hit 1,020 miles, change your plugs and do a compression test. If everything looks good, you can put the wastegate actuator back on (but keep the boost low). Change the oil and filter again with cheap dino oil. Drive in mixed stop and go traffic and interstate cruising until you hit 1,520 total miles. Now, you can change the oil and filter with full synthetic or whatever you would normally use. If everything seems to be running well, you are free to drive the car how you want now. Full boost, rev limit, whatever it was built to handle. Have fun and keep it between the lines!

i think corbin's break in is a little excessive/overrated, but ensures complete engine break in. i just:

1. idle for 20 mintues, change oil/filter
2. drive 500 miles, change oil/filter
3. drive 1000 miles, change oil
4. drive 3000 miles, change oil/filter

wow i didnt think it would take so long to break in lol. I guess it will be a while before ill be going to the track. oh yeah and its wiseco 8:8:1 with eagle rods. i have stock injectors with the 12:1 FMU and 255 walbro until break in then ill be going to SFMU with 440's and 15-18 psi. thanks for the help guys.

Hehe, ah yes, how to break in. I have a process, but I'm not telling because its such a huge topic of consternation...er conversation.

Do a google search on motoman's way to break in the engine and you will find it close to mine (just not quite as aggressive). Basically my thought process is that the biggest area of "break-in" is in the cylinders. That area is (generally) mostly broken in within the first 100 miles (though I have seen rings not totally seat until 800 miles (for whatever reason I do not know).

But I've said too much already, just watch for fluids and signs/sounds that don't fit and good luck.

Oh yeah, one more thing (because you have forged pistons) you should always warm it up before taking off.

lol. so true mark. I've read up and seen comparisons on pistons, piston rings, cylinderwalls, etc on various methods of breakin. Oddly enough, the cleanest afterwards pics are from the engine that was broken in with beatn the shit out of the motor. lol

Originally posted by bullettdsm
Hehe, ah yes, how to break in. I have a process, but I'm not telling because its such a huge topic of consternation...er conversation. Do a google search on motoman's way to break in the engine and you will find it close to mine (just not quite as aggressive).

Not quite as aggressive? :wary

1. Make sure everything is connected and tight.
2. Make sure you've got all your fluids topped off.
3. Roll the car into the street in front of the house/shop/workspace.
4. Start the car, bring the revs to red line and dump the clutch.
5. Rev limiters scare piston rings into their place.