Remanufactured engine break in
 

Hi guys,

I recently had to get a new engine replacement on my RX-8. It's the 2nd replacement on this car, but the first one since I bought it.

Anyway, I am familiar with the quarks of the car, I love the car. I was just wondering if there were any guidelines I should follow in regards to breaking in the motor. It's a Mazda remanufactured motor. I have been taking it easy thus far (aside from one or two instances of quick acceleration). I have kept it below 5k rpms almost 100% of the time, and just hit 1000 miles since it was installed, varied my speeds, etc.

I was wondering if there was anything I should do from now, or if it was safe to start really driving the car. I'm itching to have some fun.

FWIW, this is Mazda's recommendation, which i tried to adhere to:

The engine should first be run at idle for 30-45 minutes. During this time, be sure to check for leaks and keep an eye on the gauges. Ideally, for the first 100 miles (depending on use of new or used bearings), avoid operating the engine above 5000 rpm or under heavy load.
From 100-200 miles, gradually increase rpm, but never allow the engine to approach red line. Beyond 200 miles we recommend only short bursts of power approaching red line for 100 miles. At this point, change the break-in engine oil. The engine break-in period is now complete.

wish i was familiar with quarks. you're so lucky.

Per racing beat's instructions:

- For the first 1000 miles do not accelerate under full throttle.
- During the first 1000 miles do not exceed 4000 RPM.
- For miles 1000-2000, expand the RPM upwards - but do not accelerate at full throttle.
- Over 2000 miles, full throttle and high RPM is acceptable.

Make sure you change your oil at 2000 miles

LOL, I meant quirks (wiping egg off face now). This is what happens when I can't sleep.

Thanks for the input guys. I will make sure I change the oil soon, and won't push it till I get some more miles on it.

Isn't that for a new engine? For the most part the reman will be used so its really hard to say what needs to be done.

Yes and no. Remans are like refubs. Parts that aren't any good are replaced, but good ones are kept. ALL seals, gaskets, etc are new, which includes the all important apex seals, and the break in process is more-so meant to make sure the seals, and other new parts take correctly.

You're not wrong. However i'd like to pinpoint one thing: good parts means part that are within minimum spec... and some times factory min. specs aren't that good to start with. They also swap damaged parts with other used ones that are still within said specification limit (housings and side plates for sure, can't vouch about the rest).
Breaking in anything freshly assembled is a must, whether it is an expensive freshly built engine or a reman made of junk parts doesn't matter :icon_tup:

Break_in
 

Newly reman engine at 65k miles. Asked about break in and the tech said "Just drive it like you stole it!". I don't buy it. Comments?

post #4

https://www.rx8club.com/tech-garage-...21/#post829318

There are people who do believe in the 'run hard' break in. Especially in reman engines, considering that the housings are usually used in them as well as the rotors, the only parts that are really broken in are the seals and springs. The second post in that thread by Rotarygod is important, and he's somebody who has first hand experience with rotaries. I'm getting a reman engine soon, and I've been having a hard time deciding on how I want to break the engine in. If you research through most of the engine break in threads, you'll see that there are good arguments for both sides. But I think it would probably be best driving the reman engine hard asap, simply to avoid carbon build from happening early on, especially considering that it is a reman with used parts...

Difficult to know
 

I followed the manual to a T on the first engine...now I don't trust it. Granted this is an '04 AT and they may have been amongst the most "flawed" but still...there's so much conflicting info here (ie use different oil weight, synthetic ok, run the hell out of it, etc.) it's hard to know. The warranty on this engine is only good for the balance of 8 year/100k factory warranty so it expires in the next couple of months. I'd like to see this engine last.

From reading a bunch of threads, I notice that most people that get reman engines have something in common. Usually this is not their first reman engine, and second their engine usually ends up dying, and three many have followed the 'babying' and racingbeats extremely long break in procedure. It could be luck, it could be lack of quality control for reman engines, it could be not properly taken care of, or it could be attributed to break in.

There's many factors, but going back to your issue. Considering that your car is a AT, the main reason there were soo many AT failures is because of it being a 4 port, and people driving it like a normal car (lack of redlines/hard driving). So carbon is this car's worst enemy, and even more so for the AT for being even more at a disadvantage mechanically. However you decide to break it in is up to you, I personally lean towards the hard break in, maybe you can incorporate a bit from both. But you especially should drive the car hard to avoid as much carbon build up, and so this car can last you a good while.

these engines are hand build, Cuz there is no choice.

when things are hand build, if the builder is not careful enough (READ: NOT PAYING THEM ENOUGH), then things will most likely go wrong ... one point or another.

Mazda Remans are always a hit or miss, even Engines directly from Japan messes up sometimes, ask one of our mods here :)

your car is AT and the biggest problem for AT is ... it has only 1 oil cooler, at least for the S1. if you want a longer life, you might want to add another oil cooler, just get some lines and the extra cooler at your local junk yard, then buy a few new washer and spend an afternoon and install it yourself. not that hard, just annoying.

and try to use thicker oil than the 5w20 GARBAGE that they ask for ... it's just not good enough for this engine ... tuners all over will tell you to use at least 5w30 ... and thats what they use in Japan and everywhere else EXCEPT NA ... oh and use a QUALITY Synthetic oil ... even Mazda Japan sells 0w30 Fully Synthetic oil (PAO) for RX-8 ... so yeah ... that should tell you something, right ?

still not convince? ahh whatever, it's your car, your call.

Some auto technicians don't know what they're talking about. Just drive it normally if I were you.

Thanks
 

Lots of dissenting opinions out there...I appreciate them all. I guess I'm just going to follow the manual as far as break-in on the reman engine but then switch to 5w-30 after break-in and then drive it hard to prevent carbon build-up. Going to stick with non-synthetic cuz I don't trust it. Live in Tucson area where it gets pretty warm alot and 5w-20 is just too thin for this climate in my humble opinion. Besides, using the thinner oil didn't save me from engine breakdown before. I'm still not sure about the premix issue and would appreciate additional comments in that regard. As usual, nice to have a group to turn to in order to get advice.

I'd recommend synthetic at least 10w30 or 10w40. If you dig deep enough, you'll find that synthetics have the upper hand and don't cause any issues like many people believe. Pre mix helps keep your engine lubricated, and potentially can make it last longer.

The biggest thing is to make sure you don't run the engine at the same speed for long periods of time. During break-in, there will be a larger amount of metal particles in the oil, and if the oil is agitated at the same frequency for long periods of time, certain sizes of metal particles will remain suspended in the oil instead of settling out. Metal particles that remain suspended in the oil will abrade the engine components, producing more similar-sized particles, which then abrade the engine components more and generate more similar-sized particles, etc.

Varying the engine RPM frequently, even while cruising (i.e. shifting to lower gears periodically even though you don't need the extra torque), ensures that the resonant vibrations in the engine don't stay at the same frequency for long, and they won't cause just a single size of metal particles to remain suspended in the oil. That, in turn, ensures that the microscopic scratches that form on engine components during break-in are as varied as possible. This is important, because different-sized scratches are more likely to "erase" each other instead of reinforcing each other.

- - -

Synthetic oil is good for engines that are already broken-in, but you don't want to use synthetic oil during break-in. The freshly-machined surfaces inside the engine need to rub together and shave each other down to produce smooth mating surfaces that will seal properly, and the super-effective lubricating ability of synthetic oil interferes with that. Use dino oil during break-in, then switch to synthetic afterwards.

Just drive it, proper break in does nothing to better the reliability of the Renesis. I followed proper break in on all of my engines and they all failed in different ways.

My advice is to just drive it. Not too hard, not too soft.

Interesting concept. Maybe the should use specailly tuned oil filters during break in to take care of those particles. :)

The reason why varying speed is important for a piston engine is that the varying throttle draws oil up into the rings, helping lube them as they seat.

Perfect Circle recommends breaking in new rings by ten cycles of accelerating in high gear from low speed to moderate speed (I forget the actual speeds) at full throttle, then letting the car slow back to low speed on compression. Not so sure how that works out for bearings, but I don't think PC makes bearings.

I don't know how that applies to a rotary engine, where the seals are lubed by injectors rather than sucking oil up from the sump. But I still followed the conventional wisdom when breaking in my 8.

Ken

On a naturally-aspirated engine, oil will be drawn up past the rings by intake manifold vacuum during the intake stroke, pretty much regardless of throttle position. On a turbocharged engine I suppose it's a different story since intake manifold pressure can be higher than crankcase pressure when accelerating.

Anyway, the oil filter does catch the suspended metal particles, but not until the oil actually makes it back to the sump. The constant motion of engine parts can keep some of the oil from circulating because it keeps getting smeared back-and-forth against metal parts. That is where the runaway accumulation of metal shavings can happen. Varying the engine speed ensures that all the oil actively being used to lubricate metal parts will eventually be able to drip into the oil pan or get flung off the part it's lubricating, taking the metal shavings with it.

I don't think there's much that can be done to improve break-in for the rotor seals, since the only place for the used oil to go is out through the exhaust. The only thing I can think of is to avoid using synthetic oil until the seals have had a chance to seat themselves against the rotor housing walls. Among other things, dino oil burns more easily, which allows it to carbonize faster, and the metal shavings it once held in suspension will be blown out the exhaust as dust.

That's probably why a good oil filter is important.

some people use the cheapest crap they can find and think "it's all the same", no it's not the same.

I find that PureOne Gold is actually quite good and it's not expensive. I bought 10 of them when it was on sale + coupon, end up costing me around 3 bux each. It's quality is on par with Mobil1/K&N(which probably made by Champion labs anyway) if not better, and at 1/2 the price, what else can you ask for?

It can filter 20 micron @ 99%.

Stock Oil filter is not bad, it depends on WHO is the manufacture, it can be good or bad.

so I think the oil filter quality is really important, especially when it comes to break in, there will be more metal particles than you can imagine. if it's smaller than 3 microns, it's actually ok. but anything larger than 10, you better hope ur filter catch them, the more the better.

Premix Ordered
 

Debated on introducing premix into this new reman engine so soon but decided it may be wise to use it now and hereafter to further guarantee adequate lube to the seals and maybe minimize soot/ash from the beginning.

Comments welcome.

Good point!