Proper SR20DET Break-In
 

Hello all,

While I am aware that this is a VERY controversial topic and has been discussed many many times, I turn to you to find an answer.

I've recently bought a freshly rebuilt SR with all new OEM main/rod bearings, OEM piston rings, cometic valve guide seals, resurfaced head with cometic head gasket, and everything to factory spec. THE BLOCK WAS NOT BORED NOR HONED.

As I purchased the motor, the owner told me the proper way to break it in would be to run it gently for the first 500 miles with non synthetic, change it to whatever oil I choose and I'm good to go. After some research and other saying to "beat the piss out of it" and "drive it how it'll be driven", I'm now torn on what to do.

I didn't put out $$$ for an SR swap to blow it on break in, so any input on the best break in procedure would be very much appreciated. Things such as what you did and the results, people you know who did certain things, etc.

Thank you all again for your input.

Broke I'm my friends KA lightly for the first 500, changed the oil and filter, retorqued the head and manifolds, then drove it like we stole it.

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Thanks for the response. Did you happen to do a compression test afterwards? And how long/well has it lasted since?

Compression tested around 120~ on all 4. Head was warped prior to rebuild and dumped coolant into cylinders 3 and 4. Drove about 5k miles before he pulled it. Was still running when he pulled it. Only reason he pulled it is because he's RB swapping.

Okay, cool. Thank you a ton man.

Drive it like you stole it.

Not but really, I was recommended by 2 reputable shops(Kaizen Motorsports/ Street Faction) to do a few hard pulls. Allows the rings to properly seat. We did this on 2 different motors and worked out perfect. If you need details on how to, PM me.

Thanks for the response. PM sent.


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I always told drive it normally as you would in the city. Drive it brisk, but not all the way to redline. Think lots of hard acceleration and deceleration. Most critical aspect is to not cruise the engine at one rpm, so avoid highway driving as much as you can. On the first fire up and once it's warm, run it for 20mins at 2k rpm and change the oil and filter. It'll clear out the oil/assembly lube that has been sitting in the engine. Change oil (conventional) at 100 miles, 500, 1000, and after that you can change at regular intervals with synthetic if you choose to.

I always break my engines in on the Dyno then change the oil and deliver it to the customer. They get an oil change at 250 miles, 500 miles & 1,000 miles.

Drive it hard. Every new car and especially motorcycles get broken in hard at factories. Also any crate engine you buy is usually thrown on an engine dyno prior to shipping where they run it for hours at various loads.

Also since the SR20det is technically a flat tappet engine you have to run the engine hard on break in or you risk wiping out the cams. The oil rails for the cam shaft do not flow an adequate amount of oil at idle or low RPM, you should at least start the car and have it idle at about 2000 RPM and vary the RPM from 2-3000 and let the car come up to temp. After that set the idle back down and drive it hard, if something is going to break from improper installation it's going to break driving the car hard or soft.

A properly built engine can go from assembly room to the dyno doing 9k pulls in the same day no problem, the theory of soft break ins comes from factory service manuals having to put it in to avoid liability because if they said "So hey in order for everything in the engine to seal correctly we're gonna need you to pull it to redline and do some highway pulls" there'd be even more wrecked mustangs and looped sport bikes than we already have, so instead the factory does all the fun work for you and hands you a book that says "Go easy on it or else" basically to avoid you sliding into the traffic pole down the street.

So from general consensus I'm hearing the best way to get rings to seal is pulls and hard driving. Is there any recommendations for oil? I've heard to get synthetic from some, non synthetic from others, and/or break in additives or oil with zinc in it. What do you guys say?


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20w-50 or SAE 50 synthetic if you don't mind spending the extra cash is much better. Look for oils that specify having added zinc or are advertised as "for flat tappet cams".

Okay cool. Thank you


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If it's turbo'd you want to get into boost to help the rings seal. Although them not honing the cylinders makes me weary of how good of a ring seal you're going to get.


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running it hard will get it as good as it's going to get (if any). Make sure to use NOn Synthetic, non Detergent oils. I've had really good luck with Valvoline VR-1 straight 30 weight after break in switching them to VR1 20W-50

P.S. Proper crankcase ventilation is essential for the best break in.

Okay, so bring it to a full 8 pounds? But stay away from the Redline correct?


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Alright. And the non synthetic and non detergent information should be on the label right?


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Well, 8lbs is less than factory boost even, so sure.


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Okay cool. Thanks

Can hanzbrady stop posting like hes kingshit please, go back to mopping floors at mazworx. Throw some 30 wt break-in oil in the car and monitor your oil pressure, if you need thicker oil then go from there; but don't toss 50 wt in a brand new motor with tight clearances and floor it, thats how you toss rods out the side of your block.

Next, vacuum is what you need to break in a motor, not boost. It just happens that the only real way to get to full vacuum on a turbo motor is to floor the fuck out of it to red line then coast back to idle in gear. Like someone already said though, if you didn't have the cylinders honed I doubt you'll have great results regardless...

Idk, what do I know man I just sell race engines.

Because he clearly has a race engine

I'm a fan of varied load and sensible break in. Hard to monitor things if you're just dogging the shit out of it.
Factory engine are assembled perfectly, every time. People don't have the same means of assembly that multi million dollar facilities have.
Would you rather be monitoring oil pressure, etc while driving around sanely so you will actually notice when something starts going awry, catch it, shut it down, then figure out and fix your issue?
Or would you rather realize your oil pump is weak doing an 8k rpm 1-4 pull and lose oil pressure most likely causing damage beyond what you could "easily" repair?

Thank you for the input on how to break in my motor. If there is an issue with another member please resolve it outside of this thread.

What you're saying makes sense. I will take note of this. Thank you

You don't need a multi million dollar facility. He isn't re inventing the wheel or engineering his race engine program. he needs to follow the instructions in the FSM it's a stock rebuild. Buy some fowler measuring tools, clean everything and go to town. learn from your mistakes, I built my first engine when I was 14 broke it and got it right the second time around.

Break your engine in on a controller environment, beat the shit out of it; also read this article.

http://www.mototuneusa.com/break_in_secrets.htm

Anyone who's searched break in has seen that article.

To each their own, we haven't had a problem with any of the engines we've ever broke in sensibly. And the KA I built at 17 is still in the car, I'd rather play it safe but that's just me. (20k miles and my leak down was dead even 5%)
:2f2f:

Yeah it's a touchy subject for sure, different strokes for different folks I've personally had better success breaking in hard. My Neo VVL is getting broken in on the Dyno, with VR1 30W.

Now this is where I start to get torn. Those who say that since I have completely OEM parts, to do a completely OEM break in. Then again, there are those who explain the mechanics of the piston rings and what they're saying makes sense, even on a motor that's not a race engine.

a slight summary...

Avoid cruising or staying at a steady rpm as much as you can... there's less tension on the rings and can lead to glazing in the bores.

Try not to clutch in while slowing down.. The key is engine braking, decelerating in gear. This provides high vacuum and gives the rings tension... Same with accelerating quickly.

Everything is wearing in, coatings are being worn off, so there is lots of particulate in the oil... lots of sustained high rpms creates heat, and can bake particulate into rotation surfaces, creating gouging or scratches.. not good.

An inertia dyno is super helpful in breaking in obviously, as you can use the drum inertia for sustained engine braking between ramp ups... hub dyno's, and small roller dyno's don't help with engine braking so just focus on the ramp ups.. In my experience, a dyno is the safer choice, and quicker for break-in, as you have more control, with the added benefit that you can dial in your tune at the same time.

Personally, I try to stay away from high boost during initial break in, to ensure the fueling is spot on and not washing the bores from over-rich conditions.

Take with a grain of salt... just my personal observations and experience