I haven't read through this thread, just the first post, so I don't know what others have said. If I'm repeating, well then, you've just lost 20 seconds you'll never get back.

I must be one of the few original owners left on this forum. I ordered my car and it was delivered to me with fewer than 3 miles on the odometer. I was told not to exceed 4,500 rpm's for the first 500 miles......so I didn't. I thought this restriction was excessively cautious at the time......I didn't see anything in the owner's manual or elsewhere about a break-in period, but I did it anyway.

Did it do any good? Hard to say. I'm skeptical. But at the same time, I still have the original engine in the car and it's running well.

 

How many miles does your engine have now? My original engine had 108k before it blew and it was my own fault.

 

Directly from the Owners manual

 

Sled, I forgot about that owner's manual notation. I stand corrected. But it's also a kind of neither fish nor fowl statement. It says "no special break-in is necessary" but then goes on to say showing restraint during the first 600 miles "MAY add to the performance, economy, and life of your Mazda."

It's like they aren't sure. As I say, it struck me then and now as being overly cautious.
If they really meant it then why not specify these restrictions as part of a break-in procedure instead of saying "no special break-in is necessary?"

I followed the restrictions suggested and it has worked out well. But would running it up to the redline the first day I had it really have made much of a difference? I'm skeptical.

Brakes need to bed in, so the no hard stops when new goes for any car.

 

i hit 10 pounds in the first 100 miles, i have 3k on now, seems fine so far. but then again i probably made 100whp at that 10 psi because it was so rich it wouldnt rev out.

 

A while ago I came across this radically different view on engine breaking in - although it's talking about pistons, its still an interesting read.
http://www.mototuneusa.com/break_in_secrets.htm

Basically they reckon you want to rev it hard, engine brake hard, and repeat. The idea is the acceleration will wear the piston rings, and then the deceleration will create high vacuum levels (?... interesting) which sucks the oil and microshavings out.
You can kind of see why it may work, and can draw certain parallels to a rotary, but I don't think I'd try it myself.

 

JConn2299, how many miles are on that engine now?

 

for the record, I stayed out of boost for 100 miles and went WOT by 500. raised boost to a little over 16psi by 1000 miles, and at 2000miles started taching it up to a little over 8k. Motor currently has ~2300miles on it

 

I went into depth of mototune articles and I realized few things. If engine is badly assembled IE improper clearances on seals, bearings, no amount of soft break-in will change it. Every car, motorcycle is dyno loaded and run WOT to the redline with zero miles.

There is nothing to discuss, that site has real world results of hard vs. soft break-in. More power everywhere, no blow-by, lower oil dilution = longer intervals of change, longer engine life thank to better sealing...

I personally have experience with two-strokes. Two very same bikes, one ridden hard from start, other ridden soft... Second engine never made such power like first. It was so obvious, bike with hard break-in was able to pull on 3rd gear better than soft break-in engine on 2nd gear... After disassembly, first engine had just slight blow-by sings on crown between rings whereas second engine had lots of blow-by all the way to the skirt...

Iīm believer of hard break-in. There isnīt one single drawback of such method....

 

This is a good point.

But I think if you are doing a serious "hard breakin" in the first few miles you need to be sure everything is right with the rest of the engine. The tune has to be safe (no guarantee on a modified turbo engine with a standalone). You need to make sure you have oil pressure, that your ignition system and vacuum routing are all good. I don't think it's an approach for the less experienced.

I feel like I did a "compromise" break in. Some people wait 500-1000 miles before boosting at all, I waited 100 miles just to make sure I didn't have major leaks or other problems. I was a little fretful because this was the first motor of any kind that I had built. But I never had a single engine flood or starting problem, basically no signs of low compression (I've never compression tested the motor since the build) or low oil pressure.

Maybe after I get a few more motors under my belt I will try a straight up hard break in, heat cycling the motor a few times and going WOT within 10 miles.

 

Thanks

I wrote it because many people insist on BS like bearings needs to seat bla bla... Plain bearings - hydrodynamic - no metal contact...
Other bits, like apex seals, side seals... Can seal seat perfectly when merely dragging on sealing surface with low load? I donīt think so...

 

Whats the difference between a "broken in" engine driven hard opposed to a "hard break in" driven moderately ( lower RPM, lower boost)? If its driven hard or pushed further than designed such as cheap boost without proper build/ tune it probably wont last regardless of break in. I built a big block olds engine, gave it 10 miles or so after tuning then hit 6000. Doesnt sound like much but most say dont run a 455ci. past 5-5500. Ive been driving it for six years or so with no problems, but I rarely hit 6000 . Either way if the engines gonna fail less than 1000 mi. its gonna fail.

My rotary building experience (12a) is too new to have any usable info. Again less than 10 miles and its seen 8k+. Well see how long it lasts with modest driving.

Also ive ran the **** out of brand new BMWs (M3s, M5s, M6s and 335s) lots of times with no problems and I seriously doubt it would have ever effected longevity. They wernt built for low RPM. It all comes down to daily driving habbits. Who originally bought all the late '90s hondas, grandma? And now they blow oil at less than 90k? After teenage ricer purchase seeing 6-7000 RPM immediately after every cold start may have something to do with it. Probly not break in. Just my thoughts, sorry no hard rotary evidence yet.