I've read posts on this site for quite a while and have thoroughly enjoyed the education provided here. This is one I've been searching for and haven't been able to find in any of the forums yet. I am at the tail end of a motor rebuild, complete, that began in May. You have to respect the financial limitations.....lol I've upgraded some of the internals and hope to produce around 400 HP when it's back on the road again.
My question is, what is best practice for breaking in a new motor? Lots of information on the web, half of which contradicts the other half, some for tractors, some for semis, not a lot for the 7.3. My stock motor lasted 450,000 miles and was getting 18 mpg until I pulled the motor. Any advice, suggestions, or other posts on the forums regarding this would be greatly appreciated.

Thanks!

 

Dang.....160 views on this post about what's the best way to break in a brand new completely rebuilt motor.....and not a single reply. Wow.

 

Sorry man, I am not sure on a whole new motor. I only of a few on here that have done that. Here is a bump so hopefully One of them will see the thread and help

 

Thanks for the bump! Much appreciated!
I've seen a few posts about people getting newly rebuilt motors for their trucks but I can't recall what they did to break them in afterwards and now I'm not able to find the posts. I lot like the reason I have 6 different 10 mm wrenches.....never can find one when I need one so I go buy another one....lol
I have faith. There are some 7.3 geniuses on this site. Someone will feel sorry for my goofy *** and help out.....lol

 

I hooked up a tank with oil in it to an oil pressure port, pushed air in it and primed the system first. Then started it. Ran the motor at varying rpms for 30ish minutes. I then dropped the oil to get most of the assembly lubes out and also pulled the injectors while it was still hot and re torqued the heads. Up to you if you want to go through that, it was required with mine as I had my heads oringed. I suggest it, but it's not a lot of fun. Put a new crush washer on the injectors, re assembled. New oil and filter, ready to go. It is suggested to not put a lot of boost through a fresh motor without orings on the heads for about 5k miles to let the head gaskets "settle in" with a good seal. If you're fairly stock shouldn't be a problem.

 

To add, if you do springs I know there is a heat up and cool down initial run to help them set.

With gassers, they recommend the first 500 to be smooth and not really pushing it. I think logic would say to give it a few hundred miles, maybe a good long run or two in there to get the air out, before you start pushing it.

After all that work I would think you’d want to take it easy for a bit!

 

Clean oil and variation in RPM is something I have ALWAYS read.

 

As with all engines I have re built, make sure the RPM's vary and do forced engine braking (if stick, down shift gears and let the engine rpms rise, if auto manually down shift from OD- D-2-1 a few times after the engine has warmed up) this method has worked great at 500-1000 miles change oil and let her rip. My engine on my truck has absolutely 0 blow by fumes and its got 25k on her since the rebuild.

 

Thanks for the responses!


I should have added more info about my motor. It honestly never occurred to me that the break in might be different with different components. The basic laundry list for the motor is: Gearhead Stage 1 Cam, Comp Cam 910 Springs, Complete Ford Rebuild kit (Pistons, Piston Rings, Wrist Pins, Cam Bearings, Rod Bearings, Main Bearings, etc), Stock Forged Rods, Rosewood 160 / 30 Injectors, KC300x 63/70 Turbo, Smith Brothers Push Rods, ARP Main Studs, Arp Rod Bolts (Stock Head Bolts, I figured it would be a lot easier to do the internals with ARP for now and upgrade to the ARP head studs after the motor is together.), Jelibuilt tunes on a PHP Hydra, complete head job, and the entire rotating assemble, including the flywheel, balanced. Goal is to end up around 400 hp with low EGT's and extreme longevity (Trying to get at least 500,000 miles out of this motor....and good gas mileage (around 20 MPG would be great!)....lol


The other part of the equation is truck use. It's primarily a daily driver with little, if any towing or hauling. My work truck that I haul materials and tools around in (maybe2,000 lbs max) Pretty light stuff...


The few videos I've seen about breaking in a motor on the tube say to put the motor under a fairly heavy load (70% to 80% of max) almost as soon as it;s initially started, to help seat the rings.And that it might take as long as a year or more to fully break one in. I'm open to any ideas or experiences though. Again, Thanks for the feedback!

 

The only time you might bite your nails is when braking in a flat tapped lifters/cam, i have wiped a cam before cause i didn't use oil with high content of ZDDP aka brake in oil.