Best engine break-in procedure?

[Slow Car Sport Mode]

Again, while this particular instance could be construed (in my case) to a Sunwest 2.5L SOHC EJ251 "Enhanced short block" https://sunwestautoinc.com/product/subaru-ej25-short-block-2-5l-sohc-1999-2005/ mated to some Subaru Reconditioned Non-EGR heads that should be for it, and with Six Star Revised MLS gaskets for the mating of...

These heads have been reconditioned and were sold through a Subaru Dealer in Denver CO ,I purchased the inventory of a now out of business repair shop and these were among the parts. I contacted the dealer and they were able to give me a basic description of what gets done to the heads. Cam seals included, installer must set valve lash and put sealant under rocker plate.

hot tank cleaned and inspected, pressure tested
deck resurfaced
new stems, guides, valves, and seals
milled to .0015" for straightness
3 angle grind of valves and vacuum tested

Here are the s/n's on the heads and other markings on each head for reference only and does not effect compatibility

#1 584500 AS 004 7-1B
#2 980518 Q1 013 6B

I am not the original purchaser so I have no way to warrant the items, sold as-is please be sure to inspect pictures as these are non returnable, I think these are non egr heads but not completely sure

And of course, all new timing belt kit and other gaskets ready to go... - I have not yet viewed the information Sunwest has sent over about "how best to break it in." I thought I'd ask here. @Trav has given me a great lead on two 10W-40 mineral and high zinc break-in oils to run.. however, I still have questions (and again, if this is for "all engines" cool, please specify in your reply

1. How long to run break-in oil for?
(Preliminary research seems to suggest 100 to 200 miles "should be okay," yay or nay?)

2. How to drive during break in? Everything I have heard says to me moderate/hard on the throttle and do a lot of letting the engine coast down to speed, keeping an eye on temperature or maybe short runs (again, how long? Speeds? Highway, like an hour blast varying it like 65 to 90 for short times one way then letting it sit, or two hours of same, moderate to high RPMs.. how???? Highway cruising speed can easily be about 80 and a little faster than that sometimes. Would that be a good environment? Or not maintain same speed...)

3. Engine break-in oils help specifically with optimal ring sealing for highest compression, moreso than a regular "non synthetic" oil which this board has essentially taught me doesn't quite exist? Group 1, 2, 3, 4, 5 or Roman numerals thereof, every other thread seems to touch on this......

4. See questions 3, it's worth it to buy that oil and run it for.. ~200 miles, or how long, see question 1?

5. Any engine break-in oil that isn't a 10W-40?

6. Is it OK to use an xW-30 (like, more than likely, HPL No VII 5W-30) after using break in oil? I'll have the Fumoto valve on...

7. When is the engine broken in, when can normal oil be used?

@Trav recommended me one of these two: (so I'm inclined to purchase one of these two. I have a new catalytic converter ready to go, as well, since the old one has been flooded with coolant

https://a.co/d/9FrTCOE

Driven Racing Oil 03706 Driven Racing Oil BR40 Conventional Break-In Motor Oil | Summit Racing

Free Shipping - Driven Racing Oil BR40 Conventional Break-In Motor Oil with qualifying orders of $109. Shop Engine Oil at Summit Racing.

www.summitracing.com

 

[Zee09]

I can't wait for the bizarre wisdom soon to appear here

 

[Skippy722]

Chrysler recommends the following. Did exactly that, engine seems happy at 42k and so far has not burnt a drop of oil, even during break in.

“Drive moderately during the first 300 miles (500 km). After the initial 60 miles (100 km), speeds up to 50 or 55 mph (80 or 90 km/h) are desirable.
While cruising, brief full-throttle acceleration within the limits of local traffic laws contributes to a good break-in. Wide-open throttle acceleration in low gear can be detrimental and should be avoided.”

WOT at low gear just seems to result in tire smoke but also showed me the limited slip differential was working as intended

 

[Slow Car Sport Mode]

Dedicated license plate thread.

I love the Choose Life plates too. The ones for reasonable prices I’ve been picking up. Hopefully I can get one from all states that offer them. Something very important to me. :) :love: I love all your plates Blake. Trying to head back home and grab them vintage players dad said I can have.

bobistheoilguy.com

Can't post PDFs (??? Always wondered about that. SDSs are PDFs too usually) but. Sunwest sent me this about Engine Break-In and of course I treat BITOG as superior to the people that made the engine/car, since it is all a CAFE conspiracy that rules the world like the Stonecutters and therefore manufacturers etc are not to be believed:

(Playing Springsteen "Glory days" as I think about this upcoming in a few weeks when I get to break this in. I got the Michael Jackson "Thriller" Popcorn GIF in mind as well although that shouldn't come up lol... this thread is about engine break-in..)

 

[TiGeo]

I can't wait for the bizarre wisdom soon to appear here

 

[Slow Car Sport Mode]

View attachment 169573

I'm so curious. I want to get it right...

 

[cptbarkey]

Any 5w30 will do fine after the "best" voodoo magic break in procedures.

I noticed you didnt mention an oil filter. What's your plan for that?

 

[Slow Car Sport Mode]

Any 5w30 will do fine after the "best" voodoo magic break in procedures.

I noticed you didnt mention an oil filter. What's your plan for that?

Ahh, sorry about that. The last surviving one is a Supertech MP9688. (All this stuff is going over there Friday when the Short Block comes in. Thank you, Sunwest Engines in Washington State.)

I'm putting that Prestone stuff BACK in boxes (I've given away about 75% of my stash. Still have about a literally ton left, at least I know how much now. Just divide 2000 by 9 since each weighs a little more than 9 pounds) and I'm going with the Subaru coolant in the other thread discussed....

Pictured is:
- My Central Tools 6429 24" Precision Straight Edge so they can run it to make one more time that these heads and block mating surface are FLAT. They should be.......
- Aisin TKF-010 Timing Belt Water Pump kit because I'm just not into Gates and this is OE... Thanks Toyota........
- Cylinder Head #1
- Cylinder Head #2
- Supertech MP9688
- Permanent Ultra Grey to re-seal the oil pan (again. Previous $500 junkyard engine had MISSING SCREWS on it, I'm telling ya, NO MORE JUNKYARD ENGINES FOR ME....)
- A COMPLETE timing cover with ALL SCREWS and NO CRACKS (amazing condition. A rarity)
- New Motor Mounts
- the tall box is a. ~$200 Catalytic Converter, since coolant was basically in the old one like a plumbing pipe to a sink when the sink is full.
- New NGK Blue Spark Plug wires. The NGK Ruthenium HX out of old engine may be OK.. I'm running out of money here.
The Subaru coolant and Master Engine Reseal Kit from Subaru is on the way. I'm throwing THOSE head gaskets IN THE GARBAGE.

Have I left anything out for what they will need, minus whatever will come off the old engine?

 

[SwampSurvivor]

Put oil in
Start car
Drive

 

[cptbarkey]

Good choice on the oil filter. no need to go fancy for a few break in changes.

The https://sunwestautoinc.com/product/subaru-ej25-short-block-2-5l-sohc-1999-2005/
description says short block, but the rest of it refers to a long block. I'm confused but it sounds like you have that sorted with the additional parts needed. I was confused why you listed a reseal kit but now it makes sense.

 

[DuckRyder]

Is that guy really using a cheek poker on an aluminum head at about 1:04?

Follow their procedure, it is a little over the top but whatever.

Break in is probably mainly predicted on the ring pack and cylinder finish and they don't tell you what that is, probably plain rings based on the break-in listed.

Suppose you could go down the rabbit hole of what "NPR Teflon coated, Hyper-Eutectic Pistons and rings" actually means. BTW Hyper pistons are fairly intolerant of abuse, make sure the timing is set properly and no chance of preignition or detonation.

 

[Astro14]

No. 2 - I wouldn’t do what you’re saying. Avoid hard driving. No full throttle. No high speed. Vary the load, vary RPM, but do it moderately. That’s gently for you.

A few hundred miles and change the oil. Done.

 

[Trav]

You can also pre-lube these engines with a pressure tank just before mounting the alternator and firing the engine by attaching the tank hose to the oil pressure switch port. I use a gauge that goes into that location that included an idiot light and loud beeper if you loose pressure. All you need is an adapter 1/4 NPT the tank hose and most gauges use to 1/4 BSP Subaru OE pressure switch threads.

Cranking it with no fuel or spark works okay, putting your foot to the floor and cranking it I believe will not work on your earlier model with a cable throttle body so pull either the crank sensor wire or ECM fuse.
That is a good short block but it is old school honed (that is a good thing) not plateau honed meaning it needs to be broke in properly. Modern new car break in procedures do not apply to this type of cylinder finish. DO NOT use synthetic oils for 3-5K I go 5K you can create a oil burner, you want cylinder wear to occur so the rings are well seated. Fuel economy will be significantly lower and the automatic transmission with do a lot more shifting due to the tight engine making the engine feel slow, this is normal during this period.

Proper filling of the cooling system is critical on these, vacuum filling is best, if you cant vacuum fill it fill it through the upper hose, it fills the block and heads from the top, the thermostat is on the bottom so filling it at the cap does not work very well, remove the small diameter hose on the throttle body and continue to fill until coolant comes out of that hose then reconnect it. Connect the top hose to the radiator and now fill through the cap. Forget the fancy funnels these engine will not work that way and overheat possibly damaging the engine, the engine most be full before firing.

I did my Outback XT engine last year, the way I broke it in (and the previous one as well) will drive the armchair experts wild but this is it.
Filled with sump with Valvoline 10w30 and half a bottle of Redline break in additive, fired the engine, ran it at 2000 rpm for 20 min and dumped the oil. Changed the oil and filter used the same Valvoline oil and the other half of the break in oil and drove it at lower rpm for 100 miles and dumped it again. I then used another filter and the Motul 10w40 for 1000 miles 2x and finally the Motul again to 5K.
At that point I installed a Valvomax, Tokyo Roki filter and Mobil 1 ESP 5w30. Always pre fill the filters on these.
It is a lot of oil to use and a bit of a PITA but it was worth it, the engine uses no measurable oil and is smooth as glass.

 

[TCL]

Bang it off the redline!

 

[Zee09]

Bang it off the redline!

In reverse...............

 

[Dave Hess]

Get it repaired and drive it another 200K miles.

 

[wpod]

Drive it gently until it is warmed up, then drive it how ever you are going to drive it. Break in oil is a marketing scam.

 

[wpod]

Filled with sump with Valvoline 10w30 and half a bottle of Redline break in additive, fired the engine, ran it at 2000 rpm for 20 min and dumped the oil. Changed the oil and filter used the same Valvoline oil and the other half of the break in oil and drove it at lower rpm for 100 miles and dumped it again. I then used another filter and the Motul 10w40 for 1000 miles 2x and finally the Motul again to 5K.
At that point I installed a Valvomax, Tokyo Roki filter and Mobil 1 ESP 5w30. Always pre fill the filters on these.
It is a lot of oil to use and a bit of a PITA but it was worth it, the engine uses no measurable oil and is smooth as glass.

What does running the engine at 2000rpm for 20 minutes achieve? The engine will break in what ever oil is used.

 

[Passport1]

I put a reman Volvo redblock 2.3 in my 940 twenty-one years ago. Replaced lots of the ancillary bits and pieces like hoses, radiator, engine mounts, filled it with conventional Pennzoil 10W-30 and drove off. Changed the oil and filter at 600 miles. Engine still runs perfectly now at about 140K miles. Burns zero oil.

 

[Astro14]

What does running the engine at 2000rpm for 20 minutes achieve? The engine will break in what ever oil is used.

It breaks in the cam and lifters. This is an absolute must.

Every cam manufacturer requires it. Their warranty is void if you fail to do it.

It is a critical step.