burke615 Posted October 15, 2004 Share Posted October 15, 2004 OK, I am taking the plunge and replacing my '99 Legacy Outback with a new '05 Outback XT (5-speed). I have been reading up on how to best break in the engine, and there seem to be two schools of thought: 1. Drive at varying speeds for about 1000 miles or so. -or- 2. Drive it the same way you will do most of your driving. What do you guys think? What is the best way to break in this engine? I'm concerned because I drive 90-100 miles on the highway every day for work. If I need to drive at varying speeds for 1000 miles that may mean that I am doing a *lot* of driving around town this weekend. Any input would be appreciated. Thanks! Charles Quote Link to comment Share on other sites More sharing options...
THAWA Posted October 15, 2004 Share Posted October 15, 2004 redline each gear, and never go below 3k naa, I've actually read about a group that built race engines and drove them like hell right out of the box, at 1k miles they ended up with more power than the ones that had the gentle break in. Personally I wouldn't try it, I'd do as the owner's manual says. I mean they wouldn't give you that information for no reason would they? Quote Link to comment Share on other sites More sharing options...
RallyKeith Posted October 15, 2004 Share Posted October 15, 2004 HA! Owners manual doens't say anything if I remember correctly. Well, I broke in my STi by driving it for 1000miles at varying engine speed no higher than 3000rpm. What's intersting is that Subaru says you don't need to change the oil after 1000miles, so in theory you don't have to do anything special. Just drive it and get the oil changed at 3500. If you do the 1000 mile break in period you need to change the oil, otherwise the whole thing is waisted. The theroy is that things will wear in a small particles of metal could be in the oil. If you go beat on the engine after 1000 miles with the same oil in it's no good. Keith Quote Link to comment Share on other sites More sharing options...
Adnan Posted October 15, 2004 Share Posted October 15, 2004 Hi, Breaking in an engine is not so much about varying the RPM but about varying the load. Every now and then, in top gear, step on the gas a bit. This causes the rings to seat better. A new block comes from the factory with a cross-hone pattern on the cylinder walls. Honing raises the metal surface by displacing it from the pits, or trenches, onto the peaks. This helps with ring clearance but also allows oil to travel all the way up the walls. I forget the exact physics, but applying a load causes the pistons to push either forward or backwards against the walls, a thrust effect. Doing the variable load thing allows them to push and relax, push and relax. Regardless of what the manual says, I would strongly recommend changing the oil and filter after the break-in. What do you have to lose by doing so? Imagine the down-side of having metal particles flowing through your new engine. I don't know whether Subaru uses assembly lube in the engine which is still present when a car is delivered, but that's another reason for changing the oil. Regards, Adnan Quote Link to comment Share on other sites More sharing options...
Snowman Posted October 15, 2004 Share Posted October 15, 2004 When I put my engine together, a pretty good engine builder told me this: Accelerate at WOT as much as you can. When doing anything besides acceleration, just drive normally and avoid really high revs for prolonged periods. Quote Link to comment Share on other sites More sharing options...
DerFahrer Posted October 16, 2004 Share Posted October 16, 2004 My understanding is that you're not supposed to put full boost on new unseated rings... But yes, what THAWA said holds somewhat true. Do you actually think that they put a new engine together and put it right in the car without doing any testing to it whatsoever?? I'm sure every one of our engines saw redline numerous times before they were even put in our cars... But it is true that the #1 rule is to vary the engine speed, as Adnan said... If you do 80mph nonstop for the first 1000 miles, you're going to notice your new engine start to burn oil at maybe 20k miles instead of 200K... Quote Link to comment Share on other sites More sharing options...
ccrinc Posted October 16, 2004 Share Posted October 16, 2004 But yes, what THAWA said holds somewhat true. Do you actually think that they put a new engine together and put it right in the car without doing any testing to it whatsoever?? I'm sure every one of our engines saw redline numerous times before they were even put in our cars... NOT!!!! They don't even lap and seat the new valves! The advice we give is: 1) Drive as you normally would, AND 2) Don't baby the engine, AND 3) Vary the engine speed during the first 3,000 miles. Even at a steady 80mph, your rpms are going to vary due to the varying load on the engine. ANY stopping and starting is varying the rpms, right? Don't stress about it. AND 4) Keep an eye and your oil and coolant. Even brand new cars can use fluids while breaking in. A big reason for an oil change at 1,000 miles is just to give everything a good checkover, make sure everything's alright. Redlining is not recommended. Emily http://www.ccrengines.com Quote Link to comment Share on other sites More sharing options...
DerFahrer Posted October 16, 2004 Share Posted October 16, 2004 I stand corrected, Emily. So if I were to buy an EA82T block off you guys, rig up a 16G turbo and set the boost at 17lbs, you're saying that I can put full boost on the engine almost as soon as I crank it up??? Quote Link to comment Share on other sites More sharing options...
sios Posted October 16, 2004 Share Posted October 16, 2004 Well there's another variety of answers again. Funny. If you think about this, the official Subaru way is simply to drive with varying RPMs versus being too steady for long periods of time, at least for that first 1000 miles. Then there's everyones opinion or definition of a break-in period. Ok, mine is to do as Subaru (or any other car manufacturer) says to do... plus gradually increase highest attained RPM, until finally reaching the limit. Meaning, my OBS with AT chooses to go to the redline on its own when I press the accelerator to the floor before it upshifts. It won't go beyond that point regardless, unless I stupidly were to rev in neutral or park, which is a nice feature of the AT. And I did this redlining stuff at around that one thousand mile mark. Have done so occasionally ever since. Reason: to not allow it to wear in without doing so until someday it might happen to reach the redline and hear it say OUCH! in some mechanical grinding/popping/shearing sort of way. You see, I worry about the internal parts being used to easy driving and then wham! full acceleration for jumping onto a freeway occurs without the engine/tranny being accustomed to it. This way I won't worry about a sudden change zapping the thing after a year or more of 5000 RPM easy-going acceleration (OBS is redlined beyond 6100 RPM or so). None of this is for the faint of heart though, if you ask me, because whatever method you choose will be the way the car will get broken in no matter what anyone thinks. Some ways must be worse and others better, but I still don't know what is truly best overall and its probably because there's always more to it than that simplistic 'vary RPM's for 1000 miles' thing. Got to blame people for making it more complicated than that. Heh-heh. Hmmm, speaking of high revs of accelerations with the automatic transmission... mine makes a momentary shriek sound (for lack of a better description) at the upshift, that brief time as it reaches about 6100 rpm then suddenly jumps back down. I'm guessing it'll tone down later on. Anyone else observe the same? No need to go out and try it if that's not how you drive already! Just curious about that sound I keep hearing. My truck was so broken in when I bought it used I don't think it ever made a shriek at full acceleration+upshift, or at least it would be described as a muted, low tone one if any. Quote Link to comment Share on other sites More sharing options...
Ranger83 Posted October 16, 2004 Share Posted October 16, 2004 Racing engines are built with larger tolerances than passenger engines because they operate under full power and extreme heat. When I raced a Scirocca years ago, even with the heater turned on full, it would start to move the nedle after 3 laps or about 5 miles of racing. So the full-race breakin doesn't really apply. Here's the nub - regardless of what you do, you'll never know if it worked, or not. Most subarus run well over 100K without rebuild. I'm aiming for 200K. More importantly, take 30 seconds after you start for warmup and drive gently the first few miles after each cold start. It's estimated that about 1/3rd or all wear is caused by cold starts. And just warming up the engine doesn't help the rest of the vehicle. Just don't beat on it until fully warmed up, whci can be 10 miles. If you have the block heater, use it. As far as the honing on cyliner walls, I had my head gaskets replaced preemptively at 140,000 miles. You can still see the honing cross-hatch in the cylinder walls. Cyclinder bores don't wear evenly. If you think about the pressures that occur during combustion relative to crank angle, you'll realize that champer pressure is maximum during a certain portion of th downstroke. So that cylinder wall and portion of the piston wears more. You have to check the piston and cylinder bore in a couple different planes and the length of stroke to see if it needs boring. Quote Link to comment Share on other sites More sharing options...
burke615 Posted October 16, 2004 Author Share Posted October 16, 2004 Thanks for all of the advice! I guess I still didn't get a clear-cut answer, but more information and opinions to consider help, too. For the record, the salesman said this when I picked it up: "You don't have to baby it, but try not to go over 4000 RPMs for the first 1000 miles." I asked about cruising at highway speeds, and he replied, "At 4000 RPMs, you'll be doing about 100, so that shouldn't be a problem. Just try to vary your speed." Thanks again, Charles Quote Link to comment Share on other sites More sharing options...
holland_patrick Posted October 17, 2004 Share Posted October 17, 2004 Braking in an engine.. well I seen people baby then i seen people beat on them... I'm a Beater.... My last truck 95 Jeep Cherokee with a standard 4.0l took a ton of beating and she loved it and I got 200k with out a skip no major leaks or drips.and she NEVER burned oil. so with my new Non Turbo baja.. I have been driving a little easier(getting older needing better MPG) but i have had it up there (!!% the other night) I might get the oil filter magnets and will get my oil fiter changed and put in syth oil patrick Quote Link to comment Share on other sites More sharing options...
forester2002s Posted October 17, 2004 Share Posted October 17, 2004 I once worked in a research lab, testing new gears. Two things helped prolong the life of gear teeth: Running-in; and Clean oil. Running-in of new gears in the lab was done by not allowing full-load to be applied until after the gear-teeth had been 'polished' by applying a slowly-increasing amount of load. i.e. go easy on the throttle for about 1000km. I don't think that high RPMs will do too much harm; it is more important to keep the torque low. Clean-oil: I changed my engine oil, gearbox-oil, and rear-diff oil at 1000km on my new 2004 Forester 5MT. The drained rear-diff oil was grey and opaque, and the drain-plug magnet was covered in metal filings. The gearbox-oil was a bit cleaner, and the engine-oil was fine. I repeated the oil-changes at 3000km, and found all 3 drained oils to be 'normal'. I figured that the run-in period was over. As someone has pointed out, I'll never know whether this worked, but it didn't cost me much, and gave me peace of mind. Quote Link to comment Share on other sites More sharing options...
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