1fz break-in procedure?

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May 6, 2011
Davis County, UT
been all over search and mud and have found mainly discussions on oil choice, but little on actually running the engine. I figure a dedicated thread would be nice for me as well as others to come. Here's what I've got so far from research/past experience/common sense, feel free to correct/add:

1. add coolant and burp as much as possible pre-start, and pressurize cooling system (any autoparts store should be able to rent the kit to you for free if you don't have one), inspect for leaks.

2. Before starting, crank engine w/ coil disconnected to prime the oil system (1/4 pressure seems to be appropriate)

3. don't add coolant to engine while running (came across this tip just today, never heard of that before...thoughts? is this just saying don't add cold coolant to a running, hot engine?)

4. Something about letting it get to temp by idle for 10 minutes, holding it at 2500-3000rpm for a few minutes to break-in the cams (this is where I'm fuzzy and most concerned. my cam, ring, timing parts and crank bearings...basically every moving surface is either new or professionally machined and never run before)

5. After 500 miles, change oil. After 1,000 miles, change again and break-in complete

Essentially, I'm wanting to know how a 1fz is broken in at the factory. Plan is to fire it up this afternoon.
Thanks for the help on this awesome forum
Also, I lost a lot of ATF through the rebuild. To replace, get the funnel and add via the dipstick by (I think) running in park for 10 seconds, add. shift to D for 10 seconds, add. Repeat process till you get up to the the fill marks. Does this sound correct?
So this is a full rebuild with new piston rings and freshly bored and honed cylinder bores?
You might inquire of a 'knowledgeable' Toyota mechanic and get his thoughts on whether or not to use a 'break-in' oil on these older style engines.
I used to think it was just hearsay but have read from more than a couple of legitimate sources that 500 miles and you should make several hard passes on the motor to get the rings seated. After that you are good to change out the oil and continue on with your daily routine.
Yep don't baby it, don't hold it at a steady RPM or load for too long, and just go out and drive it. Think about how many new cars are sold every single day and very few are doing anything special.
When I did my rebuild a few years back, I did a lot of research on this both online and talking in-person to some pretty experienced folks. Many very strongly worded opinions out there on this at both ends of the spectrum - at one end drive it hard from the start to the other end that says nothing hard at all for a few thousand miles. I seriously doubt you'll get a scientific consensus here - except for the common one of don't drive it at steady RPMs for extremely long periods.

Some arguments are based on what some mfrs do right at the factory - but is a rebuild where machining is done at a local shop similar to what is done at the GMs/Porsches/Fords factory even in the case where engines are still given a true run in? (It seems actually running new engines under power and true load is relatively rare except in the cases of some lower-volume performance engines).

Other arguments are based on what the factory owner manual says to do and those are typically on the more conservative end.

Interestingly, some of the more surprisingly vocal arguments on this topic come from the piston-driven aircraft engine makers. Are airplane piston engines sufficiently similar to automotive engines? Some may think so, others may disagree based on fuel and lube formulation differences. Both still have pistons with rings going up and down in a cylinder bore that has a certain type of honing pattern. Makes one think, for sure.

Sorry - I know this isn't particularly helpful, but is what I found to be the case.
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Also, I lost a lot of ATF through the rebuild. To replace, get the funnel and add via the dipstick by (I think) running in park for 10 seconds, add. shift to D for 10 seconds, add. Repeat process till you get up to the the fill marks. Does this sound correct?
From my 96 fsm
(a) Check the fluid level.
HINT: Drive the vehicle so that the engine and transmission are at normal operating temperature.
Fluid temp.: 70 − 80°C (158 − 176°F)
Only use the COOL range on the dipstick as a rough reference when the ATF is replaced or the engine does not run.
(1) Park the vehicle on a level surface and set the parking brake.
(2) With the engine idling and the brake pedal depressed, shift the shift lever into all positions from P to L position and return to P position.
(3) Pull out the dipstick and wipe it clean.
(4) Push it back fully into the pipe.
(5) Pull it out and check that the fluid level is in the HOT range. If the level is at the low side, add new fluid.
Fluid type: ATF DEXRON ®II
NOTICE: Do not overfill.
(b) Check the fluid condition. If the fluid smells burnt or is black, replace it
that is awesome, thanks guys. Went to do a test crank and I'm dripping fuel at the filter, looks like I may have forgotten a banjo bolt crush washer...no show today cause my hands will freeze out there
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I reached this last night. Am I safe to drive it hard yet?

When I built my 22R-E (which I would say is pretty similar, just smaller) I ran conventional oil, primed before start, got to temp, held it at 2K rpm for 15 min or so, then drove the piss out of it. Lots of load, varying rpms. Changed the oil at 1K to Rotella T6 and went on. It is by far one of the best running engines you will see (in fact, everyone else I wheel with that has the same engine ask me why mine runs so much better than theirs, even some freshly built motors). That was 8 years ago and it still runs great and doesn't smoke at all even with me abusing it by letting it sit for months at a time and then rudely wheeling the scrap out of it for the weekend haha.
High volume vehicle manufacturers do not break in the engines prior to shipment. They are designed to be assembled and run. The advice in the owner's manual about an early oil change is there to cover the assembly operation where some trash gets into the works.

Rebuilding an engine is no different form building one initially, from the point of view of operation. If the correct number of new, reconditioned or OEM parts, in the correct design configurations (i.e, matching OEM specs) are used, there will be no difference in operation.

To the earlier point about comparing aircraft and terrestrial vehicle engines, yes they are different. Very few requirements for engines that leave the ground are applicable (or necessary) for passenger vehicles.

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