fdracer

Just thought I'd ask you guys what you think of the scientific validity of break in periods, since the avg. FD owner is familiar with rebuilds. Every rotary builder recommends breaking in a new motor for 300-500 miles. IMO, the break in period is way overrated. Every type of professional competitive motorsport changes to a new motor between races. Hell, how many of us have seen NHRA dragsters change/rebuild motors in the pits between 1/4 mile runs. IRL, NASCAR, and CART run 300-500 mile races. These guys change to a fresh motor so often they could go through 3 motors on raceweek, one for practice & qualifying, one for the race itself, and a backup when needed. If these newly installed motors all had to be broken in before they were run hard it would take up the whole life of the motor. Keep in mind these motors withstand forces nowhere near what our engines will ever see (6000hp dragsters; 17,000 redline turboed CART engine, etc.). How can engine builders/tuners say we need to break in our motors when professional racecars just drop in motors and go. Hell, they don't even get broken in on an engine dyno cause I see last minute rebuilds on the spot all the time. I think most engine builders just recommend the break in period just to cover they're sorry asses. Sorry to say this but most of them suck, a lot are just high school drop-outs who got a mechanics degree. Of course if you blow your motor within 100 miles of a rebuild you're going to blame the guy who did it. But if you drive it easy for 500 miles to "break it in" then it blows within 100 miles after that, psychologically your looking for other causes, because its been so long after your rebuild. For some guys who don't daily drive their cars, maybe months. By recommending a break in period the builders win either way, if you blow before the period ends they say its cause you didn't break it in long enough. If it dies after, then they'll point out it was perfectly fine for 600 miles so it can't be their fault.
Break in periods are supposed to be intented to get all the internals seated correctly and sealed properly. But, for that to happen the engine has to be subjected to the extreme heat and pressure that only normal to spirited driving will produce. If you want your parts to seat properly at 8,000 rpm then you have to subject it to those kinds of revs. If you want your internals to seal well with your new street port, you have to rev your engine to the point where it is subjected to the increased airflow of the port. The internal environment of your rotary is so different at high revs than at low ones, that you can't just break it in at low revs and think that prepares it for the torturous high rev environment. Damn, I've even seen people break in their upgraded turbo(s) by driving so cautiously that the turbos aren't boosting anything. Yeah that's smart break in your turbos by not using them. IMO if your rebuild is done correctly with tight tolerances, break in periods should consist of about half an hour of free revving, then 50 miles of driving, nothing more.

FoXX

you said yourself, the people at the race track change their engine so often, it doesnt matter about break in. The break in period is to make your engine last in the long run... so on the race track it doesnt matter cause a new engine is goin in next week.

however, i do think that there's some merit to the fact that not driving it hard will make it seem like the engine is lasting longer...

but from personal experience: I have just had my FC engine rebuilt, and it was VERY hard to start at 0km, by 500km it still takes a little bit to kick over, and by 700 it started up first click. This could probably be verified by compression testing a new engine from 0km to 1000km to see the increase as the engine is broken in.

jeremy

iTrader: (1)

hell, why breakin anything? clutches, brakepads.......
take a few mechanical engineering classes then you'll understand a bit more about breakin. besides i really don't think the robots at the plant have their ged's. most of them graduated with at least a masters. ok, slightly exaggerated example. you have a metal rod and a hole. the rod is slightly oversized. do you a) tap it in a slight bit at a time not to damage it very much (mating) or b) use the bfh and pound the s*** out of it until it goes in partially mangled or just snaps off.
point is machining and casting has tolerances and no two are the same. in order for the two to mate properly, thus raising compression and adding hp, a slow, varying rate is the best way to accomplish this. the mileage depends on the materials involved. such as a rotary with ceramic seals will be different then steel seals. it also dpends on how well the tolerance stackup is in favor of the mating parts. point being, breakin has little to do with the builder. if it is built wrong then breakin or not, it will come apart or f up.

DomFD3S

fdracer

Would you like to test your theory regarding break-in periods first w/ your own freshly rebuilt motor? After doing so, report back to us w/ your findings. Heck, have a freshly rebuilt motor installed, put in a brand new clutch, and new rotors and brake pads.

After that, take your car on a performance stomping ground. Push your car to the limits, drive like Enzo, speed like Michael Shumacher. Namely, drive it like how you say you should according to your theory.

After two weeks, let me know how your car is doing then.

rynberg

Funny how not only every rebuilder but EVERY car manufacturer has a specified break-in time. Gee, I guess they're all wrong.

A-Spec

also you have to realize the precision of the parts used and assembly of race engines. And I agree, they only need the engine to last till the end of the race, after that it's getting rebuilt anyway so it doen't really matter.

David

dimaguila1

Nascar - Streetcar
Apples - Oranges
IMO

artguy

foo

MaxRX7

Mister7

bar.

Street King

My god I can tell this guy doesnt get out that much. Break in is for longevity and thats something NHRA could care less about with all the money they got. So if you got a ton of money, feel free to redline cars off the lot and when its rebuilt feel free to redline all you want just becareful that there are no drivers behind you because all that blue smokes gonna blind some drivers. P.S. my brother is a highschool drop out with a degree in auto mechanics and I bet he will let you have a 100 dollar bill after he finishes wipeing his *** with it cuz he makes around 70,000 a year! Get real first then get a life. I know I forgot some periods in there sorry for those long sentences!

DEEPERIMAGE.COM

I read somewhere, wish i could find the magazine about this. It says things like a Clutch, Engine can last up to 40% longer when broken in properly, on a new motor it is recommended you change the oil at 500,1500,3000 and every 3500 miles after wards. And CLutches atleast 500 miles before beating on them.

ek9220ps

iTrader: (4)

its been dyno proven that a well break-in motor make more power.. I juss got my motor running today and im taking no chance. I want my motor to last as long it can..

fdracer

First of all, about the mechanics being high school drop outs thing, I only said that cause that’s who me and my friends are. That’s the reason it popped into my head when I was writing the thing so don’t get offended. Secondly, I never said racecars never break in their motors. What I meant was they get broken in by driving them hard. If you want your 17k rpm CART screamer to operate flawlessly at 17k rpm then you gotta subject it to those revs during break-in. And their motors don’t get torn down after every race because they’re not durable, its for clean-up and preventive maintenance. Hell, these guys go through $3k billet cranks like water. They throw away their perfectly good cranks after every race just for the small possibility that they might have a microfracture unseen by the naked eye. These guys just can’t afford to reuse engines/parts because it might cost them the next race or one down the line. These motors could probably go on for thousands more miles if left untouched, and even if they didn’t they’ve already undergone more stress in one 500 mile race than your 13b ever will even if you drove to all the ends of the earth as hard as you could. Think about it, a rotary at 3,000 rpm at no boost has an internal environment nothing like a motor screaming to redline with a gigantic turbo at full howl. Subjecting your engine to the former will not prepare it for the latter. It’s like comparing a light breeze to a hurricane.

To those who say why break anything in, your just proving my point. I never said not to break in your motor, just that the period is too long and the loads are too light. Would you break in your brakes by riding them for 1500 mi., would you break in your aftermarket lsd by driving in figure 8s for 1500 miles. Hell no. That brings up another point why do we abuse brand new lsds to break them in but think the opposite is true for engines. Moreover, everyone says that stop and go traffic is harder on engines than anything else. If breaking in your rebuild is so important, then shouldn’t you have to avoid all traffic lights during break-in.

Look, I could've been more moderate in opinions in my post, but I took the extreme opposite position of popular opinion so I could spark some ORIGINAL THOUGHT. If anyone said front drive Hondas would be running 8 sec. ¼ miles everyone would’ve said he’s crazy. Everybody would’ve probably called the first guy to put a V8 in his seven an idiot just because the idea is so different. Years back we were campaigning a drag Honda and we’d change the oil and filter after every pass, just because everyone else was doing it. We were using Royal Purple synthetic so you know that got tired fast. I decided that maybe we should keep the oil in there longer. Guess what, we found the car ran exactly the ******* same. For the projects we’re working on now we don’t change oil for the whole race weekend. Don’t just tell me break in periods are good because everyone else says so. You guys say breaking in an engine makes it last longer, but no one has said WHY. I’m not asking for scientific proof just tell me what you think happens inside a motor during break-in that would make it more durable in the long run. BTW, I think the break-in “myth” applies to all motors factory fresh or rebuilt, piston or rotary. I want you guys to prove me wrong tell me where my reasoning is flawed. Call me an idiot, but for gods sake tell me WHY I’m and idiot.

racedriver

i thinkFD racer has a point. I've broken engines in with a few hours of breakin and they have lasted and have had good compression.

maxcooper

Imagine that the surfaces are rough (in the small sense). If you start gradually applying pressure as you rub, you'll knock off the high spots and end up with some good mating surfaces as you increase to full pressure. If you start with full pressure and then rip them against each other, you will probably end up with some rough and gouged surfaces that will never seal well against each other. That is the imagery that comes to my mind when considering the "easy break-in" recommendation.

As for brake pads, I killed a set of new rotors and pads in less than one day after the red mist made me abandon my "nice, easy break-in laps" approach and just start running hard from the get-go. I'll never do that again.

-Max

Fd3BOOST

iTrader: (7)

I partially agree here with fdracer.Alot of these recommendations are on the extremly safe side.Hell I even tell people things like that in my buisness because its safe leway. But I certainly would rather play it safe and break it in for 700 miles or so.Its better than yanking and rebuilding.But when I get nothing but time on my hands and some extra rebuild kits I'll test your theory fdracer.

pp13bnos

iTrader: (1)

Ok...time to let you in on a little secret.

MY sister in laws, family back east builds engines for about 6-10 nascar teams. They even use to build them for Dale Ernheart. Guess what?? Every engine is broken in on a dyno. There is no guess, work when they put a new engine in. It works, it makes good power...and the team does'nt have to worry about keeping it below a certain Rpm for X amount of time.

As far as guys who can't afford dyno time, I know that Rob at pineapple will build a motor allready "loose". If you increase the tolerences in a motor, it will make more power (I'm just talking Rotary here.) than if you whent out and just wound the crap out of a "tight engine". The down side of this, is the motor will not last nearly as long, nor will it make as much peak hp. (only down a little.) But even these motors need a bit of a break in. CJ

dimaguila1

imo, if I just spent 8K-10K on an engine rebuild with my hard *** earned money I'm going to do everything possible to make sure it last as long as it can and to take every precation.

If I have to drive easy for 1500k or so I will. If it pops after 1500k then so be it, at least I drove 1500K in that timeframe as opposed to pop'n after 15 miles of hard driving.

I've been racing motorcycles and bikes professionally since I was 15 and our race bikes constantly gets rebuilt after every 3rd race (avg). My kick around bikes lasts almost the whole year without a rebuild just because I'm a bit more careful with them.

GoodfellaFD3S

iTrader: (213)

Dave at KD Rotary recommends as a minimum easy driving for a few hundred miles, avoiding redline. He did contradict other advice I had been given and told me to give 'some' boost right from the get go, around 5# or so, working up towards 10#. He said the boost is needed to seat the apex seals. He's comfortable dyno tuning FDs with as little as 500 miles on the motor. He was referring to a 7 with a rebuilt (as opposed to brand new) motor, however.

[disclaimer: this is my interpretation of Dave's words of wisdom, and should in no way be seen as direct quotes, or anything resembling the aforementioned. Got it ?]

artguy

Im going a full fifteen hundred. safe is best....such is my lesson after going thru two motors and three sets of turbos in a year and a half.

I am following the words of my engine builder. Nick from rotary reliability and racing has been building race engines for the seven for over twenty years. He held many of the records back in the day. Ill trust him on this one.

j

LUV94RX7

iTrader: (3)

Too many of these FDs blow up pre-maturely. Whether it's bad tuning or abuse by the owner. I for one will break it in the way my tuner and engine builder recommend. I want mine to last and not just for 20k miles.

Ken

jeremy

iTrader: (1)

ok, when i said why breakin anything that was sarcastic. very sarcastic.

maxcooper and i now have both given the reason why. it has to do with mating parts. reread our posts for the short jist of it or take some mechanical engineering classes.

also i didn't know you were supposed to abuse lsd's. maybe its to loosen it up a little (speculation here). you are supposed to use varying engine rpm generally under 4k. the rising boost that was disussed is just a step procedure. as you get more miles and the parts have mated better then upping the boost will cause more pressure causing them to rub more. since the large differences were taken care of earlier, you are now working on the smaller variations. so on and so forth is the procedure. the further through the breakin period the harder you can be. since you can't monitor how well the parts are mating, companies give a safe "window" for it to work. now that was further indepth.

if you have any direct questions about the process or why this does that, then ask. but don't say no one explained why.