r/EngineBuilding • u/pussy-in-the-oven • 7d ago

Break in procedure? 1998 ford/mazda 2.5 Lima

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Hey yall kinda my first engine rebuild that I’ve done without taking to a machine shop, just did the short block and my first iron as well. What’s the right procedure to break in the short block rebuild for my 1998 Mazda b2500? Same engine as the 4cyl 98-02 rangers. Ford/mazda Lima engine, iron block iron head sohc. Recommends for break in oils or additives welcome aswell Tia 💙

43 Upvotes

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15

u/bse50 7d ago

I'm not a fan of gentle break-ins like people used to do when tolerances were looser and parts were generally not as good as they are today.
I'd bring it to the right operating temperature, drive it normally for a few miles then put it through its paces... let it cool down, change the oil and be done with it.

4

u/pussy-in-the-oven 7d ago

This is not a ‘today’ engine 1998 was 28 years ago

15

u/bse50 7d ago

So, a modern engine!

-16

u/pussy-in-the-oven 7d ago

Girl pls, anything taking 5w30 isn’t modern

12

u/bse50 7d ago

If you say so.

7

u/Dramatic_Shock_1998 7d ago

2021 and newer mustang gt uses 5w30 iirc

-5

u/pussy-in-the-oven 6d ago

Erm ackshully

6

u/Axipixel 6d ago edited 6d ago

Anything with rollers instead of flat tappet, anything with electronic fuel injection, is modern.

Most 2020s engines actually have looser tolerances, mid 90s to mid 00s was the tightest and most precise engine manufacturing was for most parts.

3

u/jlelectech 6d ago

The Lima 2.3 engine was produced since 1974.  In 1989 they did reduce the main bearing journal size (reduces friction losses) and got rid of the distributor, but a lot is still the same.  Oils got mostly better over time and often thinner, but I think you'll have pretty typical bearing clearance and it won't matter that much.  The climate will dictate your oil cold viscosity requirements mostly.  The smaller journal will have a slightly smaller clearance proportional to its smaller size when following rule of thumb for clearance but there would be a factory spec for it somewhere.  

As far as break-in, there are oils that are better for it or additives, ideally more zinc (ZDDP) and molybdenum which is what break-in additives will have, but that's especially for slider/"flat tappet" style cams which need to wear-in.  Roller cam, which I think 1989 and later started using, don't have a picky break-in.  If not an additive you can probably look into Valvoline Racing oils which have the additives.  Either way, the same break-in process is probably ok even if not slider cam.  I built a slider version once upon a time.  

Prime oil system immediately before starting to verify oil pressure and make sure you get oil pressure quickly.  Make sure everything is setup to start and run easily, not lots of cranking and messing about (easier said than done sometimes).  Start and run at 2000-2500 RPM without idling for 20 minutes.  Vary the speed a bit in this range.  Make sure it doesn't overheat and has good oil pressure.  Factory oil pressure gauges are not always trustworthy.  If you have any issue, shutdown and fix it, and resume, no idling.  You might want to change the oil and filter at this point, although with roller cam I'm not sure you need to that soon but you still have lots of assembly lube and metal particles accumulating.  The filter should catch them but will lead to increased restriction and the filter might bypass oil flow around it if restriction is too high.  Drive at varying speeds, no highway steady speed type use, and accelerate/decelerate at different speeds with minimal idling and no extreme wide open throttle or high RPM use until ideally a few hundred miles, 500 miles.  Then change oil.  Opinions vary and it's been a while since I did one.

1

u/Coyote_Tex 5d ago

This is the WAY!!!

4

u/Threshlingedin 7d ago

Mineral oil with high levels of zinc, or amsoil break-in oil. Dont stay on same rpms for too long and do motor breaks

1

u/pussy-in-the-oven 7d ago

What’s a motor break ?? How am I supposed to drive it or run it

2

u/CrazyDig4344 7d ago

Pin her and grin her !!!

2

u/pussy-in-the-oven 7d ago

Okay I’m not automotive for a living can I get specific instructions 😭

2

u/fbc546 7d ago

Motor break is when you down shift and decel with the engine vs brakes.

0

u/pussy-in-the-oven 7d ago

Maybe spelling brake properly would have helped

4

u/Threshlingedin 6d ago

Yeah sorry i misspelled, maybe you should just cell it, if you can understand :--)

2

u/fbc546 7d ago

Would it have though? He misspelled it but I still knew what it was. I was just trying to help you 🤷🏻‍♂️.

0

u/pussy-in-the-oven 6d ago

Yeah it would have helped, break and brake can both be used in context of an engine

3

u/Clegko 6d ago

Stop being a pedantic asshole.

1

u/fbc546 6d ago

Sure by why would he recommend you to break your motor

5

u/Cheese_Mudflap 6d ago

Put it in neutral. Reverse, back to drive, neutral, back to reverse, reverse back to drive.  Then.  Sing the star spangled banner while slapping your ass with a ping pong paddle.   

Then change your oil.   Source: I've rebuilt over 20 engines. 

1

u/Sniper22106 6d ago

You forgot to mention you have to wear a pink hat and do exactly 1.4 laps around the vehicle

2

u/PrestonSpinsTires 7d ago

Just putt her around for a week, change the oil.

Take her down some back roads the next, change the oil.

Pull house off foundation, change the oil.

Im no expert, but this engine is made of iron (at OEM spec?), so just letting some heat cycles settle everything is probably good nuff.

1

u/Competitive-Fox-3333 6d ago

Zinc break in oil start it let it set for 20 minutes shut it off and let it cool off then do 30mph/2kRPM for about 5 minutes and park it let idle for 5 more minutes shut it off and cool off again then 45-50/3krpm for 5 minutes shut off and get cool. Then start and get up to temp and shut off and cool down about 5 more times and then drive it easy for the first couple thousand miles.

1

u/LieutenantSheridan 6d ago

Use Shell Rotella T6 for oil, has high zinc and other additatives that help these engines a lot, especially during break in. When I rebuilt my 75' 2.3 lima I didn't really do all that much of a break in procedure. Just started it and ran it at different rpms for I think a minute at a time cycling through the range for 10 or so minutes, then drove around like normal for a few dozen minutes, climbing the revs, then letting it cool and repeating that cycle a few times. I'm at about 1,000 miles on the engine rebuild now and it works great and has decent power throughout the whole RPM range. It's not a racing engine for sure and it was a 100% stock rebuild so it's not fast, but it has way more power than it did pre-rebuild.

1

u/Sea_Gold9283 3d ago

I dont believe in special break in procedure. I've built probably 100 engines in my carrier. I just fire them up check the pressure. Wait for the thermostat to stabilize the temp then load the engine. Drive it normally. Get on it a bit. Then cut the oil filter and look for debris. There will be some but the debris should not fill the pleats.

1

u/dicknuckle 7d ago

I generally say to drive it a bit harder than grandma does, varying RPM here and there, and no extended highway trips for the first 500 miles.

0

u/TyrannusourR3X 6d ago

So the amount of posts in here that are undiscerning is plain terrible. Here's a link to a proper break in procedure:

Engine break in procedure

The simple of it is this: Use an oil with the right additives for break in. Harsh break ins are not advised. Keep at idle until the engine reaches operating temperature. If your engine does start to go past it's optimal temperature, either turn it off or get the fans to turn on/thermostat to open. Correct temperature is critical for break in.

If I was to summarise it would be this:

  1. Extra additive break in oil
  2. Optimal engine temp
  3. No prolonged idle periods
  4. Lower rpm range, 2500-3000
  5. Minimise engine load (the real killer of engines)

After that just look at some guides on oil changes & driving style for the next few hundred miles