how to break in a rebuilt engine

[ghostuss]

Just wondering, how to break in a completely built KA turbo engine. Lowered compression, forged piston, rods, and all the goodies. Exactly how would you break it in? I was told a few ways. First way on a dyno, with 2 hour 1/3 rpm, 2 hours 2/3 rpm, and 2 hours of full rpm. Then I was told to run it without turbo kit and take it easy for a few thousand miles then turbo. Then again I was told it would run like shit without turbo stuff since it's a lowered compression engine.

[orion::S14]

It'll run fine...8.5:1 will be ~6 less HP than a stock KA at 9.5 compression.

I'd put it all together, run it with no boost, but varying load and RPM for ~250 miles, and make sure it's all OK.

Change oil a few times in those first 250 miles...

Then run it like hell.

From what I've read, it takes cylinder pressure to force the rings out against the cylinder walls and "break in"...so if you baby it...that won't happen.

Bearings require no break in, seals require no break in...only thing you need to be concerned with is the rings sealing.

- Brian

[ledzeppelin240]

Wrong...Well not really, but what I would do is:

First set your base timing, Prime the engine. Then you will want to run it for about 20 minutes at 1500-2000RPM, making sure you have correct oil pressure and so that the cam can be broken in. For breaking in the rings you never want to drive at a constant speed. And you also want high vacuum conditions. Rings are prelapped during manufacturing and they say that they will seat in a very short period of time. But 2000 to 3000miles would be safe as a break in period. Don't drive at a constant speed. Change your oil at 500miles. Do not allow the engine to idle too long. WOT should be avoided.

If I missed something point it out.

The first few minutes a critical to the life on an engine. Anyone can rebuild and engine but the real difference is how well it is done will determine how long it lasts.

[RBS14]

Guess everyone has their own opinions.

However, I've heard from multiple people that I respect highly (and some top engine builders in Japan) that you want to drive the shit out of it like you are never gonna drive it again. HARD. This makes sure the rings seal. Babying an engine with a fresh rebuild can result in the rings never sealing. Also, it's important to note that all car manufacturers run fresh engines to redline multiple times for testing to ensure nothing is wrong, and to seat rings. So DO NOT baby it. Also, multiple thousand mile break in periods are bullshit. Drive it like hell for a hundred miles, throw your tubo on and have fun.

[ghostuss]

lol now who Do I trust? completely different inputs...

[infinitexsound]

im with rbs14...

high rpm to break in cams.. for couple hours.. then take it out to do figure 8 for awhile slowly then gradually increase in speed... and drive it on the street but a little more agressive.. then change oil and drive it some more...

[Rezlo]

Guess everyone has their own opinions.

However, I've heard from multiple people that I respect highly (and some top engine builders in Japan) that you want to drive the shit out of it like you are never gonna drive it again. HARD. This makes sure the rings seal. Babying an engine with a fresh rebuild can result in the rings never sealing. Also, it's important to note that all car manufacturers run fresh engines to redline multiple times for testing to ensure nothing is wrong, and to seat rings. So DO NOT baby it. Also, multiple thousand mile break in periods are bullshit. Drive it like hell for a hundred miles, throw your tubo on and have fun.
EXACTLY

Ive been building engines from 600Chp mitsu V6's (sohc Origionaly NA) to 1500Chp 2JZ's and all our muscle car stuff which includes a 2400whp 600 cubic inch wedge in our copany Dodge Avenger door slammer.

You run your fresh motor for 10 minutes odd to make sure there is no air locks in the cooling and the oil presure is right and no leaks, then beat the shit out of it, WOT to red line then release and let it slow down under full vacume to suck the micro particles out, first change at 30 minutes of running, 2nd change at 3 hours/400miles MINERAL oil, beat the hell out of it!!! then drive normaly, change your oil to synthetic ONLY after 8-10 000miles or the rings still wont be fully bedded in.

Ive seen engines get to 80-100k without rings bedding in, you need to apply presure to the rings by going WOT for them to seat and it has to be done ASAP before the freash hone swirls wear off!!!

One thing to NEVER forget especialy in NA to Boost builds, your top ring gap must be around 7 thou for turbo and 8-9 thou for Turbo&Nitrous per inch of bore width in normal rings, hardend chrome/teflon inpregnated need a slightly different ring gap but they are extreemly rare, run the 2nd ring about 15% smaller gap than top, and run your oil rings SLIGHLY (+/- 5-8%) wider than stock spec

If you dont gap your rings wide enough they will butt under high Temps and crack the top of the ring land off.

[Jeff240sx]

I'm with RBS14. Drive the hell out of it.
Make sure that when you turn the key, everything will work. You don't want to be turning on/off and cranking alot. After that, run for a few minutes to ensure everything works, then drive it like you would normally. If the motor falls apart, it would have after the babying session. If the motor holds up, it's good like you wouldn't believe.

My motor.. with 10k miles and 8.5:1 CR is at 160-160-160-152.
-Jeff

[sepulchral]

drive it slow for like 1k miles and check oil, all fluids, oil pressure, etc then you should be ok

[dunno]

EXACTLY

Ive been building engines from 600Chp mitsu V6's (sohc Origionaly NA) to 1500Chp 2JZ's and all our muscle car stuff which includes a 2400whp 600 cubic inch wedge in our copany Dodge Avenger door slammer.

You run your fresh motor for 10 minutes odd to make sure there is no air locks in the cooling and the oil presure is right and no leaks, then beat the shit out of it, WOT to red line then release and let it slow down under full vacume to suck the micro particles out, first change at 30 minutes of running, 2nd change at 3 hours/400miles MINERAL oil, beat the hell out of it!!! then drive normaly, change your oil to synthetic ONLY after 8-10 000miles or the rings still wont be fully bedded in.

Ive seen engines get to 80-100k without rings bedding in, you need to apply presure to the rings by going WOT for them to seat and it has to be done ASAP before the freash hone swirls wear off!!!

One thing to NEVER forget especialy in NA to Boost builds, your top ring gap must be around 7 thou for turbo and 8-9 thou for Turbo&Nitrous per inch of bore width in normal rings, hardend chrome/teflon inpregnated need a slightly different ring gap but they are extreemly rare, run the 2nd ring about 15% smaller gap than top, and run your oil rings SLIGHLY (+/- 5-8%) wider than stock spec

If you dont gap your rings wide enough they will butt under high Temps and crack the top of the ring land off.

This would be the man to listen to.

[S14DB]

Rape dat Biatch!!!

[Var]

i was wondering the same thing. It makes sense that you would have to beat on it, because how else would race engine get broken in? It's not like they can take it easy for a thousand miles, then race it.

But what abut the break in period for the cams? I've heard you need to run a fast idle for an extended period of time to break in BRAND NEW cams.

[ghostuss]

This would be the man to listen to.
I know... Taking notes as we speak.

[kingsol]

since when were you going turbo? better give me a ride this summer

[HolyShiznit]

I talked to Ivan at PhatKA-T and he suggests and does the "no break in" break in. He has done this to all of his cars and customers cars, and since his supra's make 1500ish hp and his KA-T made 640....I think he knows what he is doing. Also I dunno about the cam thing because Ivan swaps cams all the time to test them and from what I read he doesn't hold them at high RPM for long periods of time but I could be wrong. *shrug* I think the old thinking of babying a fresh motor is BS and shouldn't be paid attention to. Fiznat on NICO drove his for 20 miles to make sure everything was hooked up right and then he took it to the dyno immediately and made 430rwhp.

[Jeff240sx]

i was wondering the same thing. It makes sense that you would have to beat on it, because how else would race engine get broken in? It's not like they can take it easy for a thousand miles, then race it.

But what abut the break in period for the cams? I've heard you need to run a fast idle for an extended period of time to break in BRAND NEW cams.

New cams have their own break in. And if a new motor (like mine) has new cams installed, it's break-in supercedes the motor's. 2-3 different RPM levels for prolonged intervals (10-15 minutes) and an immediate oil change. That's what thrust me into the "hell.. might as well beat it in now" mindset.
-Jeff

[SochBAT]

OK so i was at an AM/PM with my friend and we were discussing what we read on this post about driving the hell out of the motor to make sure the rings sit. A guy standing close to us said whoever told us that was complete bull. U never want to break in a new motor that way.. He said depends on what kind rings u use. Said that some kinds of rings sit as soon as u turn the key. he also said that he builds race engines so he should know..I didnt pay much attention to him cause i didnt want to agrue about the wisdom of the forun members..but can someone clarify what different kinds of rings are there, and do they require different break in metheods and periods?

[Jeff240sx]

Don't know.. but I know 20 guys that "build race engines". Including myself. Engine break in is also very widely discussed, and if you ask 100 people, you'll get 75 different answers. Few people will say the exact same thing. Engine break in to some people is a religion. They have a belief because their pappy told them the way his pappy told him. You can't change a belief, and argueing against these people is futile.
However, in the past 30 years, there have been so many technological advances that people refuse to assimilate or don't know about. Like when you HAD to rebuild a car at 100K miles. Now cars go 250K with little maintenance. Ask alot of '89 owners. Or, when you HAD to change your oil at 3000 miles. Then it started to go back up, and Quickie-Lubes brought that number back down. Mobil1 is good for 15K+. It protects better at 10K miles than dino oil does when it's fresh. Rings are no longer made of a lead-alloy alone. Thinking used to be that rings had to be as rigid as possible to force the rings into the cylinder sleeve. Now, moly-coated iron rings are pretty much standard, and steel rings are growing in popularity. These new rings have emphasis on flexability and function, allowing softer rings to do the same job better. The placement of these rings have changed immensely, resulting in better sealing properties.
Building a Mopar 383 vs. a technologically advanced import motor are very different. A musclecar motor I'd never recommend a rape-ride for break-in. Everything is different.
For a 240sx.. 100% recommend a beat-in.
-Jeff

[BLT123]

Worked with a brazillian tuner once - basically the steps above (running it till hell brakes loose) apply. After you tune it though, stay away from above 5000rpm for 1000km. Then come back and do another round of tuning after that. :)

[RBS14]

Like Jeff said, there are a few different types of rings.

The most important thing to note is that moly rings last the longest, but take longer/more effort to seal. With moly rings, you REALLY need to beat the shit out of it.

[SochBAT]

thank you guys..IM gonna print this up and go find that guy..friggen lamo

[S14DB]

OK so i was at an AM/PM with my friend and we were discussing what we read on this post about driving the hell out of the motor to make sure the rings sit. A guy standing close to us said whoever told us that was complete bull. U never want to break in a new motor that way.. He said depends on what kind rings u use. Said that some kinds of rings sit as soon as u turn the key. he also said that he builds race engines so he should know..I didnt pay much attention to him cause i didnt want to agrue about the wisdom of the forun members..but can someone clarify what different kinds of rings are there, and do they require different break in metheods and periods?
Sounds like a high class ricer to me.

[Rezlo]

One thing i should have mentioned in my post above,

ONLY rev it up or put it under load when its at opperating temp, NEVER beat on a cold motor new or old...

Best to never let new technology engines still and idle to warm up, start it, let it run for a few seconds for the oil presure to stabilize then drive it, keep the rpm's fairly low (under 3000rpm) and keep it at light loads till you are at opperating temprature and your oil presure starts to drop (those with oil press gauges will know what im talking about)

RIGHT after rebuild let the engine idle to opperating temp while checking for leaks twice (let it cool down completely between each round)

Cam's are tricky, but 95% of what you hear in the US is from old V8 builders, remember we dont use solid or flat lifters, our valve train is about 1000 times less energy absorbing than old V8's thus creat less heat which is a direct result of friction. When putting new cams in always lube them REAL well with cam break in lube, that will normaly keep them quite safe for the first 10-20 minutes which is the most vital for them

I did a write up on my website, http://www.rezlo.com/Pages/6G72/6g72.htm
its all on my old toy's 6G72 Mitsu NA 3L but it has a lot of info on building and breaking in newer motors that might help some,

[ledzeppelin240]

Hmm...Yeah WOT with it will seal the rings for sure after the initial startup and break in. It all makes sense...I can't wait till my KA24ET is done, I really want to know how well my cylinder head is going to work. On a side note has anyone here done "extensive" cylinder head work??

[tgm]

If you want a slower engine but one that will last longer break it in easy, if you want a faster engine that will not last as long run the shit out of it.

[Jeff240sx]

If you want a slower engine but one that will last longer break it in easy, if you want a faster engine that will not last as long run the shit out of it.

Myth. A break in is about sealing the rings. The speed you do it depends on what materials your piston/rings/cylinders are made of, and how well you prepped everything. Engine break in used to determine how long your car lasted.. but now you can buy a 5000 mile SRT-4 that's smoked off 2 sets of tires without thinking twice. Try that 40 years ago and you'd have no compression at ~50k miles.
-Jeff

[RBS14]

On a side note has anyone here done "extensive" cylinder head work??

P&P? solid lifters? Increased quench area? gotta be more specific than that man.