I just recently had my engine rebuilt, its a 4.9 straight six and i didnt get any information from the company that i had do the rebuild and everything so im not sure what to do to break it in? i was told that it is very important to break in a new camshaft correctly and obviously not to beat on it for a while.

 

hi if it was mine i would use marvel mystery oil. in the gas and oil.the cam will break in in 30 min. at 2500 rpm this rpm is to oil the cam enough.and when going down hill back off the gas this pulls oil around the rings to help them seat and seal. it might smoke but it will stop when it seals.run it at diffrent rpms. change the oil and filter at 500 miles.and good luck

 

Some of the newer oils don't have enough zince for flat tappet cams so you might want to use some Diesel rated oil like Rotella for break in. If you can, try to prime the oiling system. Usual method is to drive the oil pump with a drill and shaft down in the distributor hole.

Run in the engine for 30 minutes like the guy said before you drive off. You might also want to retorque the heads after it cools down.

Plan a nice medium length road trip, say 100+ miles round trip. Speed up and slow down, don't keep a constant speed. Let the engine do some braking on downhills.

When you get home you might change the oil and filter. Or at least do it at 500 or 1000 miles. After things are seated you can use whatever oil you want. Oil choice depends on how you machined the cylinders, what kind of rings and personal choice. But like I said start with a diesel oil to protect the cam during run in.

Good Luck,

Jim Henderson

 

+1 on the 500-1000 mile oil change/break in period. Marvel mystery oil or a comparable additive isn't a bad idea either.

But I will suggest just running the cheapest oil you can find. It's not going to make it to a standard oil change interval anyway, and if something should go wrong during the break in period you didn't waste the money on a good oil. The only exception would be if you want to run synthetic versus conventional.

 

start with a diesel grade oil like Rotella or Delo 15w40. run a good quality filter like a wix, puralator or motorcraft.

dont run any other type of oil till 3000miles.

 

This is the procedure we always used when breaking in a flat tappet motor:

1. Rotella, Delco, or similar oil, as mentioned above the new oils do not contain the zinc or more specifically "ZDDP"( Zinc Dialkyl Dithio Phosphate) that flat tappet cams need. Also the diesel oils are better at resisting breakdown.
2. A good filter, on fords hard to beat the motorcraft filter
3. run engine, with fan in front of radiator for 20min between 1800 and 2000 rpm (steady rpms), watch temp, DO NOT allow to overheat, keep plenty of air moving thru the radiator with fans.
4. shut it off and walk away until the next day
5. the next day, fresh oil change, finish tuning motor in if needed (timing, carb, etc)
6. drive 200-300 miles, no heavy loads on engine, varying engine speed, do not exceed 55mph or 3000rpm
7. change oil, next 400 miles, light loads allowed, still vary engine speeds, rpms up to 4000 max
8. at 700-800 miles you are good to go, give it a fresh oil change again, using rotella, delco or similar, if you are insisting on using regular car oil, use a ZDDP additive in the oil.

Also, do NOT go adding Marvel's, Brake Fluid, or any one of a dozen things you see people suggesting to dump in the oil. All you will do is dilute the oil down from what it had to begin with in the additive package and run the risk of having problems down the road. If you add anything, use a quality break in additive. Comp Cam, Crower, Red Line, Trick Flow and others all make quality break in additives that will not dilute the oil down and will add to the package with ZDDP, etc to help protect the motor during initial run in.

 

DO NOT RUN SYNTHETIC in a freshly rebuilt engine, unless you want to replace the cam. Synthetics do not have enough zinc in them, and you will literally run the lobes off your new cam in 3-500 miles