RX7HotPepper

Yes, Iīve searched...!


But I found different theorys about whatīs the BEST for the break IN process.


first 500 or 1000 milles on the highway, better on the street with smooth accelleration (no more than 4000rpm)?


Someone can help me with this?


thanx!

BLKTOPTRVL

Engines are supposed to be boken in using a variety of engine speeds. So, a combination of highway and street would be best.

No high engine speeds (over 4K as you posted).

Each time I needed to break in a new engine, I would take a long trip along secondary roads. Roads where you have longer stretches of 45-55 mph, but also spots where you have to slow to go through little towns at 25 mph.

I would make a weekend trip of it. Take the GF and find a B&B to visit.

books

iTrader: (8)

Here's what the owner's manual states for the first 600 miles:

Don't race the engine.

Don't maintain one constant speed for long.

Avoid unnecessary hard stops.

Avoid full-throttle starts.

adam c

iTrader: (2)

I would contact your engine builder for specific break in instructions. Different engines will require different break in procedures.

chagar

I am inclined to agree with BLKTOPTRVL. That advice is what I have always heard. Had a rebuild two years ago in Kannapolis and took 29 back to home instead of 85. Then I took secondary roads each night to run at various speeds and RPM's. Once I hit 1000 miles I let it go. So far so good.

BobfisH

I broke my car in with a little sidestreet driving, but mostly highway.

Id get in my car, drive my car the 5 miles to a large ring road (120 mile circular highway) and id just drive around it once, and thatd be my run for the night.

I made an effort to change gears, speed up slow down etc, but for the most part it was pretty constant driving.

Cars still running strong, 120psi on both rotors.

FDNewbie

iTrader: (10)

From my discussions w/ Jimlab...(one of the most knowledgeable ppl on the forum...so go by what he says).

"The typical recommended break-in procedure is to vary rpm, always with light to medium throttle, for the first 500-1,000 miles, and change the oil at the same interval to minimize damage by machining or resurfacing debris. You should not just take a long trip and keep the engine in one gear for hundreds of miles, in other words, like Mark says. Normal "street" operation is better, where you'd be accelerating lightly through the first few gears, slowing down, idling, starting out again, etc. but you can vary rpm by changing gears periodically if your only choice is a highway break in.

Varying load is the key to making the engine break in. Heat cycling is ridiculous, because once the engine reaches operating temperature, the heat range of operation is a relatively narrow window. Heat cycling is what you do to condition track tires.

Varying the load = The higher the gear, the more load on the engine.
Heat cycling = Hot. Cold. Hot. Cold. Hot. Cold.

Varying the load has little to do with rpm... more to do with gearing.

Think of trying to pedal a 10-speed bicycle up a hill. If you have it in 1st gear, it would be very easy to pedal, right? Not much effort required, and the pedals move relatively fast, but progress is slow. If you put it in 10th gear, you'd find that pedal effort is vastly increased, pedal movement is slow, but if you had enough power to get up the hill in that speed, you'd do it quickly.

Basically, you're making the engine work harder to move the car in higher gears because the load is higher. So vary the load by changing gears every so often."

So my advice? Make it your daily driver for a few days...some traffic, some slow areas, some highway. That'll break it in perfectly


~Ramy

RX7HotPepper

THANX everybody sooo much!

Can`t tell u how much i apreciate your help!

It`s very difficult to find some good piece of advice in my country, nobody knows anything `bout rotarys...

As an example, my mechanic ( the one that rebuilt my engine) It`s an rx7 owner, and the ONLY one that has imported a 20B engine to Argentina...

So I will drive my car as I am doing, about 50 milles per day, several shifting, low rpms (under 4000), vary the load, until I reach the 1000 milles.

At 500 Milles I will do an oil and Filter change, and at 1000 too.

matty

alot of guys install a new engine and throw it right on the dyno...then off to the strip she goes. from what i ahve heard breaking in a rotary is much different than a piston engine.

BoostCrzy

if you plan on racing the car....break-in wont be very important...as Matty said....but with a long term setup you will benefit from closer tolerances in the long run adding longevity overall.....but for instances in which peak power is a must and rebuilds are eminent and somewhat frequent....a proper break-in will not help....the parts that typically fail on a high power rotary will fail from "other circumstances" rather than improper break-in procedure...in short...if its a daily driver that will see high mileage and long-term driving duty with a majority of its life spent in part throttle driving.....break it in.....but if you plan to put track mileage on it instead, then no break-in is necessary......but dont forget that new clutch!!!...chances are you put one in at the same time....and it definately will need some break-in....

GoodfellaFD3S

iTrader: (213)

Guys that do that are typically drag racers that tear their engine down, then rebuild it reusing all the new internal hard parts (apex/side/corner seals and springs) that aren't broken, to include reusing rotor and stat gear bearings.

For a newly built motor with brand new parts of everything listed above (esp the bearings) the owner most definitely should *not* redline the car, make top speed runs, or throw their rotary on the dyno.

first 500 miles, revs below 4k, minimal boost.
change oil and filter.
next 1000 miles, revs below 6k, boost not to exceed half a bar (around 7 psi).
change oil and filter.
get tuned and go kick ***!

RotaryResurrection

iTrader: (8)

IT largely depends on the parts used in the build. 90% of all rotary rebuilds reuse shafts, rotors, irons, etc. and just replace seals and springs. Many reuse bearings...this is perfectly acceptable, depending on condition, and IMO is often preferrable to changing to new bearings for a couple of reasons I wont go into here. Assuming that these parts are all being reused, breakin is nothing more than letting the seals wear into the used housings a little bit, to fill any imperfections in those surfaces.

When people talked about breaking in a new motor, or one from all new parts, they worry about heat cycling...starting and stopping the engine, which over time makes all the parts stronger and more resistant to wear than new parts right out of the box. So it is preferrable to do short city driving to facilitate this.

When you're reusing parts that are already heat cycled, that concern is pretty much totally wiped away. The only thing you're trying to do in this case is simply let the new seals wear and seat against the used housings. To do this, the more rotations you can make, the better off you are. I dont mean high rpm's...you dont want to force the new seals to dig into the housings via centrifugal force, so you keep the rpm's down to keep the forces on the seals down until they have worn in naturally.

But if you take a highway trip, the rpm's will be up in the midrange and the engine will make millions of rotations by the time you get there and back, and by that time they've worn themselves in. In these cases, a simple compression check every few hundred miles will suffice, and when your numbers start to plateau, you've pretty much done all you're going to do with breakin, and you can let it rip.

Improved FD

good post by Kevin as usual, but if you are running new housings (like me), I would emphasize short trips, lower gears, quick bursts of throttle (just not to redline) and plenty of heat cycling (short trips back and forth to work is perfect) with oil changes (dino juice) at 500 and 1,000 miles, as others have said

Jim was referring to me in the post by Ramy btw, I've done quite a bit of research on this topic over the years and spoken to several engine builders about it

every engine is different, though....my Toyota 2ZZ engine was still breaking in at 10,000 miles (gas mileage started to increase significantly), which shows how "tight"/well-made those engines really are....

and, no, GM hasn't caught up yet

FDNewbie

iTrader: (10)

Not quite... He was in fact correcting you Here's what you had originally posted (https://www.rx7club.com/showpost.php...&postcount=392): And Jim's response (once again): ~Ramy

Improved FD

helpful reading http://www.overboost.com/story.asp?id=1250 (addressing a piston engine, but the basic concept is similar)

Now the question becomes: What specifically in a new engine needs to be broken in? The short answer is "everything." Many engine parts do not require a critical break-in process, but most of the major parts do: Camshaft, lifters, engine block, pistons and rings. The crankshaft and connecting rods don't really wear per se, but they do contain internal stresses as they roll off the assembly line. Heat cycling relieves the stresses over a short period of time, but also changes their shape, in turn affecting how a piston bears against its cylinder wall, how high it reaches at TDC, etc. Anyway, that's practically bordering on a nano approach to engine break-in, so we'll stick to the major points.

Camshaft lobes wear parallel to lifter pads.
Camshaft bearing bores wear to fit camshaft journals.
Piston rings seat to bore shape.
Piston skirts fit to bore shape.
Heat cycling settles bearing caps, head-to-block fit, etc.
Connecting rods stretch at RPM, putting piston higher up into unworn sections of the bore

rfreeman27

iTrader: (5)

On my engines:

If a rebuild only replaces seals, and all bearings are reused, I basically drive the car long enough to ensure that everything is running correctly, change the oil, and then have at it.

If new bearings are used (and have not been broken in on a lathe) I try to get 500 to 750 miles of backroads driving, change the oil, and then have at it.

This process has let to no ill effects so far.

RX7HotPepper

I forgot to tell u that I`d intalled everything new except from the rotors and housings....

I guess that it might make the break in process shorter...
But Anyway, I will follow your especifications!!


Godd bye and Thanx again!


PS: dont fight!

Kento

The heat cycling "stress relief" and "settling" they're referring to basically occurs within the first couple of times you start the engine and run it at proper operating temps. Far more of that occurs due to the stresses of actually running in the engine under varying loads, which is much more important (and will usually take much longer than the first couple of times you start the engine).

Improved FD

from the Amsoil website, about as close to an "expert" as you're going to get on this topic

again, this summary refers to a piston engine, but, contrary to little ramy's snickering comment, the basic concept is similar for a rotary!

Breaking in an engine is a process of properly wearing-in the pistons/cylinders/rings, bearings, valves, camshaft, lifters, rockers, etc... In addition, part of the breaking in process is not only wearing-in and seating the internal engine components but also stress relieving the components as well. Crankshafts, connecting rods, pistons, blocks etc... have many stresses due to the casting or forging process, machining and welding process. We have viewed and measured these stresses, called fringes, using what is called lazer holography. These stresses are properly reduced/eliminated by costly and time consuming heat aging as well as shot peening and or high frequency vibration on a very specialized bedplate for an extended period of time. For production applications this is cost and time prohibitive. Therefore, the next best thing is exposing your engine to multiple heating and cooling cycles under various load and RPM's, which is described in the following paragraph. The heating and cooling break in process continues over a period of time and does not need to be run on petroleum oil.

Breaking in a new engine is the one area that petroleum oil is better for than synthetics. You see, petroleum oil has a very low film strength which is ideal for breaking in a new engine. That is why we recommend you run the factory installed petroleum oil for about the about the first 500 miles. Then drain the oil, remove the factory installed oil filter and then install AMSOIL Synthetic motor oil and an AMSOIL Super Duty oil filter and your ready to go.

Further heat cycling break-in will continue during the multiple heating and cooling cycles from driving your vehicle under varying RPM and engine load conditions and then shutting it down for a long period of time to let it cool completely. The multiple heating and cooling cycles are a extremely important factor in properly breaking in a new engine and are often an overlooked factor in the total break-in process. These heating and cooling cycles achieve what is called stress relieving. Back in the "old days" of engine manufacturing, after casting and before an engine block was machined, it would be set outside for several months to age, during which stress relieving occurred naturally, then the block was machined, which helped to produce a better engine than one that was machined immediately after casting.

By changing the factory installed oil and filter after the first 500 miles you will also be removing the initial wear-in particulates present in the oil and filter. The reason for this is that during initial wear-in there is very high particulate contamination in the oil. These particulates consist mainly of microscopic particles of aluminum, bronze, copper, lead and iron, plus soot particles and other by-products of combustion in your oil. Your filter cannot filter out all these small particulates as many are sub-micron size and too small for the filter to trap, BUT they are also small enough to fit between your bearing and other internal clearances and cause wear. That is why we recommend to that in order to properly break-in a new engine, regardless of what your new car salesman or dealership personnel tell you, is to perform the first oil and filter change at 500 miles. Then you can convert to AMSOIL Synthetic. On a diesel engine we recommend the initial filter and oil change at 500 miles, with another change around 3500 miles, then in the 5000 mile range you can convert to AMSOIL Synthetic.

http://oilspecialist.com/convert.html

F0RSAKEN

I would think that with *new* parts, heat cycling it a couple times would make some sense. Metal (most everything really) expands when it heats up, and contracts when it cools, we all know that. If the parts are new, heat cycling it a couple times would seat them correctly, as has been stated, but after that, it would make no difference. And by "heat cycling", I mean up to operating temp, then shut down and allowed to fully cool, then back to operating temp.

Just my .02, but dont listen to me, Im a n00b.

Kento

With all due respect to Amsoil, I'd have to disagree with the importance of "multiple" heat-cycling to the "proper break-in" of an engine. Especially with regards to performance.

I find it curious they mention the "old days...of manufacturing" with "engine blocks sitting outside for months" to let them stress-relief "naturally" (although, it should be remembered that this is an oil manufacturer's website, whose primary purpose is to sell you something). They fail to mention the fact that production manufacturing techniques and tolerances since "the old days" have progressed far beyond what they were capable of "back then". Look at how many engines in both motorcycles and automobiles now come from the factory with titanium rods (and in motorcycle cases, titanium valves as well). In the "old days" of working with titanium bolts in aircraft, you couldn't even use standard tools when working with them because of various problems resulting from the dissimilar metals. Production metallurgy has come a long way since the "old days"...

Is there some heat-cycle stress relief occuring in various metal components as time goes by? Sure, but how much and how important is it to the actual performance of the part? If it were that critical a factor, then you'd see connecting rods coming apart when people start up their new piston engine and immediately go wide-open throttle (which obviously isn't a good idea for reasons other than heat-cycle stress relief in the metal).

I'm not saying that heat-cycling is BS, my point is that the actual wearing and seating in of various internal components that results in a good-running and reliable engine is more due to subjecting those parts to varying load stresses than the actual act of "multiple" heat-cycling during break-in. Any stress relief that occurs in the internal components' metal structure from the constant heat-cycling that will inevitably occur from usage over time is a bonus.

Improved FD

thanks kento

based on that, I think it makes sense to break the engine in over multiple, short duration events where you are constantly varying the engine load, predominantly in the lower gears during the initial stages of break in, with cool down between events...I still think this makes more sense than simply taking a "road trip" for 500 miles

the primary thing to avoid is droning down the highway in 5th gear, that's the worst thing you can do for break-in, and I'm surprised how many people do it

burnoutking999

well, i made a boo-boo then lol. i had to drive mine @ 500 miles from Raliegh to jax to Tallahassee. it took about a half day and we were at about 80mph average speed. not much boosting though. Well see how long it lasts... experiment in progress. We got ours done about the same time? or was your just turbos?

j9fd3s

iTrader: (3)

um its an fd, break in has nothing to do with why the last engine failed.... and it wont help this one either

burnoutking999

See, the thing is... its stock ports and i want to go streetport so my luck it will last 500k miles and defy everthing known... that or take a siite muslim in the next few thousand before im ready lol