Engine break in advise….

E28 technical advice asked and given! Troubleshooting, modifications and more.
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Posts: 309
Joined: May 26, 2013 3:24 AM
Location: Fayetteville, Ga

Engine break in advise….

Post by 5timesturbo »

Well, after installing the new pistons and turbo…..I want som advise on how to go about breaking in the engine. I wanna set the rings but I don’t wanna keep going into boost or high pressure to do . I’m hearing a dyno isn’t necessary. What are some advise from the group. Any advise is appreciated
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Re: Engine break in advise….

Post by Preyupy »

My recomendation is to start it and get it up to 1500-2000 rpm fairly quickly. Check for leaks and check basic ignition timing and mixture if you have a wide band O2 sensor. Get it up to full temp running the RPM between 1500-3000. I would let it cool down, maybe check valve lash and look for leaks and check oil level and coolant level ( once it has cooled down. I usually do this 2-3 times then take it for a drive, don’t be afraid to put it under load but I would keep it out of boost for the first 20-30 miles. Then just drive it normally without leaning on it too hard for maybe 100 miles. If the rings are not seated by now they never will be. Start leaning on it harder but watch for detonation and lean or overly rich mixtures. I’m not one for long drawn out break in procedures. Just pay very close attention and slowly work up to full load and RPM over maybe 200-300 miles.

Race engines on the dyno usually get 2-3 heat cycles, and about 2 hours of break in time before we lean into them HARD.
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Re: Engine break in advise….

Post by euroshark90 »

Use regular 30w motor oil. No synthetic oils with friction modifiers. Run the engine at 1500 RPM for 20 mins and bring up to temperature. Once the 20 mins are up, shut the engine off and drain the motor oil while still hot.
I do that to get as much assembly lube and fine metal shavings out of the engine during initial break in.
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Re: Engine break in advise….

Post by turbodan »

Break in is the most important time to run the right oil. Many will say use the cheapest, crappiest conventional oil you can find. This is inexplicable unless the idea is simply to use it to flush the engine out. I would recommend using something like VR-1 20w50, with it's ample concentrations of EP additives, to ensure that no galling or scoring occurs while your valvetrain is burnishing and breaking in. Mobil 1 15w50 is a good option too. Basically use the same oil you would use at any point in the engine's life, something of the appropriate viscosity with the right additive package.

For the first start, blip the throttle a few times to rev it between 1500 and 2000 RPM. Vary the load and RPM for the first few minutes. This can be done in neutral, no need to take it on the road although you can if it's fully buttoned up and driveable. I would warm it up this way and check for leaks, once the thermostat opens you can shut it down and let it cool off. Check fluid levels again and take it out for a drive.

The owners manual offers excellent advice, I would follow a similar program. Avoid high revs for the first few hundred miles. Ease into it. Boost in itself isn't a problem, most of the load in an engine is from reciprocating mass, though full throttle and hard accel should be avoided. Keep the revs below 4000 for the first 500 miles, then perhaps 5000 for the next 500 miles. After 1000 miles or so I'd say you're about there, though if you can get to 1500 without getting wild it certainly wouldn't hurt.
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Re: Engine break in advise….

Post by EuroShark »

I agonized over this during my first rebuild and eventually settled on the "break it in how you're going to drive it" approach. Not too aggressive right off the bat, but not too gentle either. Too little engine speed can be a detriment to the mating process between the rings and the cylinders, and too much engine speed can scorch the rings while they are still wearing in. This process begins as soon as the engine starts running and the bulk of the material is removed in the first few miles, which is why it's important to get the engine moving and load up the rings. Accelerating and decelerating (engine braking) without spending much time idling or at a steady engine speed is the key, since you're loading up the rings in both directions, so to speak.

On the first start I check for leaks, make sure the cooling system is full, and get the car moving. For the first 20-30 miles or so I try to keep engine speed under 3000rpm. After that I try to observe a ~5000rpm limit for the next couple hundred miles or so. By that point if the rings aren't broken in, something probably went wrong during the rebuild. Then I'll change the oil and drive it however I feel like. Hasn't failed me yet.

I still run conventional break-in oils, mostly because they are inexpensive. Rotella T4 is a safe choice, or something like Motul or Driven break-in oil if you can find it for a decent price. I've never tried anything fancy on the rings or cylinders. I just wipe the bores with cheap ATF and give the rings and skirts a little regular engine oil.
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Re: Engine break in advise….

Post by austin8753 »

i always use quality motor oil with great zinc content, especially on a fresh/reconditioned engine. drive it like you would normally, except no hard acceleration or hard deceleration (and i personally don't take it past 4k) for the first 1000 miles.

change the oil at 1000 miles and inspect the oil and filter. if nothing looks amiss, you're golden. go beat it it like it owes you lunch money, if you feel comfortable. my mentor always did stuff this way and so have i; worked great so far. just my $.02...

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