fcdrifter13

I see that alot of people are doing break ins differently now a days. It used to be just drive around for 1000-1500 miles without getting on it at all, and staying away from the redline as far as possible, but is this actually the best way. How about the "let it sit at high idle for hours on end" then drive around method, but through all of these I barely here about a hard break in and the pros and cons of this, and why and why not it may be harmful to your engine, and if it will produce peak power.

After reading a ton of articles this one seems to stand out the most as, what I also believe at this period, to be the best break in procedure. Please read over it and lets have a little discussion of the pros and cons of each, and maybe this would help clean up some of the confusion of the "BREAK IN MYTHS"

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

http://www.ntnoa.org/enginebreakin.htm

GavinJuice

Oh boy i see sticky material! Boy that first link is loaded with info. A definite good read. I spose now the only controversy is what weight oil to use!

OnlyOnThurs

Defientley a good read but would you think that these procedures would work well with our rotary engines? Grant it an engine is still an engine in all sense of the word ...but stll our little wankels are a different animal all together. This thread should get intersting!

81gsl12a

iTrader: (1)

very good read... i read these a long time ago and it makes alot of sence to me and i know alot of ppl that brake pisst on motors in like this... but i dont think it workds the same for the rotarys... are housing dont need to get the apex seals to seat the same way as a ring needs to... besides they are smooth and cant cut the apex seals to be the same. not like a cyl and a piston ring......

braking in a motor sucks... i road around all night in my friends 3rd gen and hes got to shif at 4 k caz its only got 300 miles on it...... if you get a motor built tell the shop to drive it around for the 1st 1000 miles and bill you for the gas lol.... caz i know i want to beat on my car when i get it back

GavinJuice

I still see it as the apex and side seals, sealing to housings and sideplates. Just as a piston ring is to a cylinder wall. They're two dissimilar metals. The tolerances might be close but not ideal initially. Many times have i read on this forum to expect lower compression from an initial build which should increase after the break in period. I definitely see this applying. Rev the **** outa it@!

fcdrifter13

Well I guess Ill try it out. MY t2 motor is almost done(stock rebuild) and ill break it in hard and see what happens.

1badFB

iTrader: (1)

Dont forget, that depending on just how the engine was rebuilt not only the apex seals and side seals are what you are braking in when you first run an engine.

You must also consider parts like your eccentric shaft bearings and stationary gears.

When braking in a new engine it is important to keep the heat down inside of the engine, I believe this is why low rpm break-ins are reccomended. The more heat you put into your engine in the early stages, the more glazed the sealing surfaces are going to be. The opportunity for glazing decreases as the engine has been run for a longer period of time.

Say you build up an engine and immediately go out and romp on it. The way I see things, the sealing surfaces need a bit of roughness (not much) but enough to hold the oil on the surface for lubrication. The hotter the engine gets in the early stages of running the smoother the surfaces get as well as the more tempered the seals get from the extra heat. Once again the glazed surface comes in.
Then we move on to the bearings and gears. I am not an expert on the matter, but I would feel much more comfortable letting the stationary gears and bearings break in slowly. From seeing torn down engines, I would want to keep the heat out of the bearings, and the rpms away from a fresh set of gears for the first little bit forsure.


Im sure I could ramble on all day, but what it comes down to for me is the fact that the "long" break-in is what has been done forever and the engines seem to last and wear well this way. Driving at low RPMs for a few weeks wouldnt bother me if it ensures I wont be rebuilding again soon, so until enough of you go out and test this "fast" break in to prove its the best way to do things... Ill stick to the tried and true method..

84RX_Se7en

I am going to stick to the 1000 mile break in method. Something about beating the hell out of it scares me. We have more and larger seals/gaskets than a piston motor. Seems more room to blow or break something that hasn't acclimated to the temperatures yet. The housings and rotors themselves if fresh and new(hah) have not been exposed to constant temps that high yet and I would think they would need time to acclimate.

84RX_Se7en

Today I'm picking up a used motor with less than 100k on it that has been sitting drained for about a year, maybe a little more, that ran great before being pulled. I'm going to break it in even. Don't want it to blow on me only for the fact that it has been sitting without running.

Gonna fill it with oil and hand turn it before ever starting it up. Gonna let it sit over night after hand turning it a few times to let the oil really penetrate everything well and lubricate it properly.

Nismo Convert86

iTrader: (7)

I did the 1200km variable RPM method, basically after each 500 kms, i would rev it about 1500rpm more from the 3000rpm I started with. Worked good, really good I'm going to try and get it tested with a Mazda compression tester this week!!

Jeff20B

iTrader: (13)

That guy's method works ok for piston engines. I wouldn't use it on a rotary.

JWteknix

iTrader: (2)

i believe i have heard of judge ito breaking his motors in with burn outs!!! lol i guess beating the engine might have some benefits

fcdrifter13

I wonder everyday how they broke in the R26b

JWteknix

iTrader: (2)

burnouts ftw!!!

dj55b

iTrader: (2)

I'm not sure about you guys, but i think that mayby we're overreading some stuff. Now as you can read, the guy says this changes because time changes and we have more precise ways of machining things. So parts are alot more smoother and stuff. Now I'm not sure really if our things do evolve. If we actually buy a 12a rebuild kit. When do you think was it manufactured? 15 years ago? Maybe even 20? Wouldn't this mean that we still have to use the old way? This may be a little different if you have a 13b due to the fact that they were produced later on and might still be produced by mazda but with different technology considering that they still produced RX-7 till 2002 i believe it was in japan. Now if you also use ceramic seals with conjuction of 3rd gen corner seals you would be able to do this too on our 12a's. I haven't done a compression check on mine but i will do so in the summer it would be over a year now since the engine was built. And the way that i brake my engine is by varying the RPMS. Maybe we should try to post as many as we can to come up with a conclusion.

Jeezus

iTrader: (4)

And, if you notice, he was talking about new engines, i dont know of any brand spanking new 12a's..

81gsl12a

iTrader: (1)

the reason this wont work with are cars

"The honed crosshatch pattern in the cylinder bore acts like a file to allow the rings to wear. The rings quickly wear down the "peaks" of this roughness, regardless of how hard the engine is run.

There's a very small window of opportunity to get the rings to seal really well ... the first 20 miles !!

If the rings aren't forced against the walls soon enough, they'll use up the roughness before they fully seat. Once that happens there is no solution but to re hone the cylinders, install new rings and start over again."

are housing are not ruff to start with..they are smooth chrome! they have not been honed or ruff to start with to grind the apex seals. like in a piston motor the rings grind/file there way into a perfect shape... this cant happen with a rotary

neektar

iTrader: (2)

You're right about the grinding but wrong about the perfect shape. Why is it that compression is gained during break-in on a rotary? One reason is because the apex seals, due to the high stress and heat inside of the engine, mold themselves (slightly) to perfectly fit the housings that they are being used on to create good compression. This is one of the two reasons engine builders (good ones) don't re-use apex seals (the other being obvious damage) simply becuase used apex seals will not "form" as fast, or at all, as new ones. Even more compression can be gained by mating a new apex seal with a new (or re-lapped) rotor housing.

The other reason is obvious, the more time the engine internals are used in sync without stress, the greater they will perform when stress is applied.



As for the "Judge Ito beaks in his engines with burnouts" I can guarentee those engines are producing twice the stock oil lubrication, a good cooling system and an experinced driver.

As a side note, in Puerto Rico professional drag racers rebuild their engine days before an event to "refresh" the engine internals, leaving the ports exactly the same (as when they first ported them so they don't have to re-tune as much). I've herd countless stories of people blowing thier engines, going home, rebuilding the engine, and comming back that same night to finish the event.

Back on topic: I would say the old 1k mile give or take 100miles as a break in is good. I would make sure I change the oil at least twice during the time frame and check periodically for signs of metal sheerings, low oil, no oil consumption ect. I would reccomend a heavier weight oil like 10w40 (I run 40 straight) just for lubrication purposes but that's up to you.

I'd love to see compression tests before and after each of these great beak-in myths. It'd be like a Rx-7club Mythbusters episode.

fcdrifter13

Well ill have the compression numbers from my vert in the morning(NA)that we just rebuilt(no break in yet) and compare them to after wards of a hard break in. and hopefully my friends NA will be done shortly, so we can compare his to mine. Both are stock rebuilds using stock parts.