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can anyone tell me the best or most recommended way to bread in a street performance 383 stroker SBC? Proper methods to produce the quickest break-in, and to seat the rings properly? How much driving and what kind of driving(city, highway?). 383 with flat top hypereutectic pistons, xtreme energy cam(not new). Thanks for any and all input.
 

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This is just my opinion I like to drive around the city for around 50 miles or so staying close to home making sure everything is working properly then I boldly start venturing a little further then just drive it like any other I like to put about 500 miles on it before I lay the hammer down :D ( wrenchturner )
 

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Monte, WT has some good advice there. I once spun a rod bearing in my old 69 Mustang because another guy wanted to race at a stop light and I just couldn't resist, the motor had all of 50 miles on it.

My advice is RESIST THE TEMPTATION until you have some nice easy miles on it. If the guy in the next lane wants to give you a go, pretend to stall the motor and let him leave-you will get him next time.
 

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I think I'd rather spin a bearing-*$&#*&$&#*$#- oops sorry a little mental instability there- bad brain, bad brain!! :D
 

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monte,hey! idont know guy!25 years back i was the leading voice in my clique for breakin'in engines in a careful way.over the last 25 i've seen alot of things different! my brother in law allways said run them like youll drive them!~ i disagreed!my brother runs the absol;ute dog crap out of his engines!,from start to finish!~at this point i dont see any real difference between theirs and the the ones i've exercised restraint with!aint that a pisser!she...it ,i'm with dee the morriss ,spin the bearinhg!!!
 

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I agree with WRENCHTURNER, the last motor I had rebuilt was a 350 Chevy in a Camaro. I drove it back and forth to work for a couple of weeks (had my trusty long haul AAA card handy) then road trip to Vegas!
 

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You want to vary the engine speed for the first 500 miles or so and no heavy reving. Watch your dipstick and make sure you see nothing unusual. Drain the oil and inspect it after 500 mi. Check spark plugs for excess oil burn. This should do it.

Cam break-in in the first 30 minutes is the big issue. You need to run it at 2000 rpm, no idle. The cam has no direct oiling, it is all splash and hope.
 

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When I ran a Machine Shop Rebuilding engines Stock and Hi Per We would tell the customer to Put in a decent grade of oil and filter,(To break the engine in on) drive it not over 60 MPH for the first 500 miles up and down from 35 to 60 at a gradual increase( Don't beat on it ) it is like honing the cylinders to break in the rings, at 500 miles change the oil & filter( To get all the moly or honings out of the engine) and give the engine a general check over for NO leaks.Run a good grade oil.The next 500 miles not over 70 MPH
doing the same thing, At 1000 Miles change the oil and filter again,Give it a good check over again,At that point put in the oil that you plan on running all the time. From that point on do what you want with it, Have Fun. It sounds like a lot of trouble but in the long run it worked for us.
 

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Hi Monte - First thing you have to do is seat the cam . Run the engine at 1500 rpms for 5 mine, then 2000 rpm for 15 min. That's parked in your driveway, no load. Then, after you make sure everything is still in tune, take it out and do 250 miles on it at varying speeds between 35 and 60. No full load starts or high rpms. Keep your rpms at 80% or less fo redline. When you are done with that - change the oil, check the coolant for any combustion products, and you are good to go. It won't be fully broken in for at least 500 miles - the more variance in the speed the better. Running it at highway speed all the time will not seat the rings properly - you need the variance in load (torque) to help everything settle. Don't forget to check the head and manifold bolts after the first 500 miles also. Good luck with your torquer! - Gene
 

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have you ever gone for a test ride,new car ,no miles?have you ever had a job picking up new cars and delivering them hundreds of miles?do you have or have had daily contact with multiple dealerships through mechanics that you are either related to or know very well?ok!ok!ok!enoough questions.all the above i have done and are doing and guys,new cars get the absolute stink driven out of them daily before you even get a chance to buy them!and at this point there doesn't seem to be a correlation between bad behavior and good!this would be a good topic for a long term comparison done by a mag.now heres a kicker what do you think the breakin is for a f1 engine?,a nascar engine? a top fueler?and dont go gushing about longevity etc.!if those guys sensed any! benefit they would apply it.hey f1 rodder, we drill and tap our big blocks and plumb them [hard line] to provide add'l oil to the cam.see ya! jimm
 

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I've alway's been told after you break the cam in and get everything tuned in,break it in like your going to drive it.That's the way I do it.Pedal to the metal.
 

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Jimm, F1 engines are broken in on a dyno where a computer controls the break-in cycle. The engines are run with reduced boost and are taken up and down the rpm range with 50% operating rpm as a start. As the cycle progresses it slowly goes higher and higher till the engine is running at max rpm. They then start to dial in more boost, I have read that this cycle last anywhere from 6-12 hours depending on whether the engine is a superspeedway engine or short track engine. I seen a video on it once.

I worked a cylindrical grinder for an authorized Ford engine remanufacturer and every engine went we built went onto a 50 HP electric motor driven break-in stand with it's own oil sump and bottom end oiling spray bar system, the engine just sat on top. We hooked up a slip-on driveshaft to the crank snout and broke it in with no spark but blanking plugs in the spark plug holes (these had schrader valves for compression testing), every engine that went out of the shop had a half hour at 3600 rpm. The stand did double duty so you could check for proper oil pressure and compression in each cylinder. Essentially every new car or factory remanufactured engine has some break-in on it because they know what it is going to see before and after delivery.

Another interesting fact, they tested every assembled head for valve seal with a vacuum test jig, if it failed the valves were lapped on that cylinder. Otherwise the valves were never lapped. These were safe guards required by Ford to retain certification and to eliminate returns, good thing too, there was a 10% reject rate on the break-in stand.
 

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4 Jaw Chuck: that is an interesting story about the break-in for the remanufacturing company. I am curious to know what the longer term failure rate of the engines was. Most warranty them for about 10,000 mi and 12 months. Do you know how many came back within those parameters ow whatever the company set as their warranty.
 

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F1,

I don't know much about the long term durability of the engines but a couple interesting facts came up during my time being there,

I had suggested the fabrication of torque plates for the honing of the engines since it is a common hotrodders trick and I knew the Japanese were doing this. So a program was implemented to construct a set to test the actual benefits that the use of torque plates would give to our product. The results were eye opening to me anyway as leak down rates went from 5% to less than 1-2% on initial run-in. Unfortunately the program was never implemented because after the 30 minute break-in the rates equalized and the added expense to install the plates and use them to hone the engine was not considered "cost effective". So much for good old fashioned common sense.

The amount the bores distorted with small block Fords varied depending on the year of manufacture but it typically was around 0.0002" out of round. Since small block Fords have 4 bolts per cylinder for clamping this effectively meant the bores were square after head installation, the rings and cross hatch must wear that amount in the first 30 minutes of unpowered break-in for the leak down rates to have equalized after that time, kind of scary if you ask me. Chevy engines would have pentagon bores with 5 bolts per cylinder.

One more interesting problem related to durability came up when I worked there, it seemed we were having an unusual amount of rod and main bearing failures in some of our remans after very short times after installation. Upon inspection the bearings were found to have the entire surface wiped down to the copper layer, how this was happening was a mystery. What we did was test every engine as it was being run-in and do a chemical analysis on the oil to see if anything would show up, sure enough we found every 5th engine or so would exhibit excessive shedding of tin, lead and copper particles (this indicates bearing failure). Once we had these engines tagged they were disassembled and thoroughly inspected for any abnomalities, none were apparent and the cranks measured good with no taper or other machining mistakes that could cause this problem. It wasn't until we compared the build tags to see who was building what did we find the problem.

Turns out we had a fairly new crankshaft grinder operator who had deviated from the prescribed procedure in finishing his workpieces. The crankshaft is normally ground on a specialized cylindrical grinder with a 4 ft diameter stone and is chucked between offset chucks so that the journal is running true to the stone. The stone runs towards the operator and the crank rotates clockwise with the crank snout on the left and the flywheel end on the right, the finishing micropolish is done with a cork impregnated belt mounted on a purpose built crankshaft polisher. The polishing operation normally would happen right after the grinding operation and the operator would do one journal at a time.

The operator in question deviated from this by grinding all the journals for all the cranks first and then near the end of the shift he would polish all the cranks he did during his shift, it was a good time saving idea but when he did this he reversed the cranks end for end and removed the offset chucks so he could just chuck the cranks between centers saving more time (the tailstocks were spring loaded so removal was quick) What this did in effect was make all the little hills of material on the journal surface lay down in the opposite direction during the polishing operation.

If you can think of the cast steel in the crankshaft as the scales on a snake you would see that what he was doing was making all the little scales lay into the direction of rotation of the rotating journal surface turning it into a miniature rasp that removed the thin surface coating on the bearing shells during each dry startup. This is apparent under high magnification.

So just when you think you know everything about engine rebuilding something comes up that will surprise you. All cranks must be polished this way or you will have problems later, the crank must be rotated clockwise from the snout end and polished this way to prevent this anomaly, remember this is you are polishing your own crank on a lathe.
 

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Well I would have to say it's been years since Ford operated the way Chuck stated. I R&R engines all the time. Sometimes short block, sometimes long block engines. These are not the same as assembly line engines which come complete with pulleys and everything. The engines we get from RMP are not run before we get them. They often come missing parts or loose bolts. I just got a 5.0 for an Explorer last week that the bolts were so loose the pick-up screen was falling off. But one thing is consistant. Even if I order just a block that engine gets assembled, oil put in it, fired up and run long enough to burp the cooling system, and away she goes. Not much of a break in procedure, but then again you've got a shop full of 27 techs getting paid by the job not the hour. Don't get me wrong I treat my own engines a little better but I can't deny seeing hundreds of engines go together with litterally no break-in and no problems. It may not make sense but it is what it is.
 

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Western Engine LTD was the facility and is no longer in business, wonder why? THE ALMIGHTY DOLLAR! It wouldn't surpise me if those jobs went to Mexico.
 

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dear chuck,not convinced![is there some long term study out there that deals with this?]. so, from a physics standpoint,whats happening?is the metal getting harder during break-in ? i was under the impression that the heat -treat on the cam lobes was a done deal,i.e. you cant change it,make it harder /softer etc.ok!,ok! i need to clear up one thing,first ,my knowledge is not all encompassing,second, i know that !, third , i do have knowledge that i must go by and adjust according to fresh input that is substantiated.. iknow that in the world of heat and pressure things act differntly than those under normal atmospheric conditions. i'm not being belligerent or a "know it all "here[actually i'm a " know it barely"] however, i do require convincing.it seems that when you challenge conventional wisdom often you find dogmas and "old wives tales"that need to be swept out.honestly,you guys are great and a wealth of info resides in yo heads!see ya!,jimm p.s. chuck,we are riding on a film of oil here,yes?,and yes ,it is infintessimally fine,nevertheless,the metal does not touch the metal,[lots of friction,mucho heat ,broken stuff if it does!]so, whats happening?

[ May 01, 2002: Message edited by: jimm ]

[ May 01, 2002: Message edited by: jimm ]</p>
 

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hey dee! you are too funny!~ seriously [should you say that wwhen youre talking pfunny] i'm still laughing ,i called my wife in[had to share it with someone] she's laughing ,though not as hard as me.ok dee the morris,.i'll back it off,thanks for the belly laugh,mi casa su casa!see ya! jimm
 

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Jimm,

Although much of what I have learned was in the aircraft industry, most is applicable to the automotive field because these are still 4 stroke internal combustion engines that use basically the same materials. There are thousands of research papers available from SAE that you could peruse if you are willing to pay for them, many are obscure and only deal with specific details (like cylinder wear rates with different oil types). Most of the research done to advance 4 stroke engine technology was for the aircraft industry or the F1 racing fraternity despite what the auto manufacturers would have you believe, many of these were done by junior engineers looking for a paper to receive their PHD in mechanical engineering.

<a href="http://www.sae.org/servlets/techtrack?PROD_TYP=PAPER" target="_blank">http://www.sae.org/servlets/techtrack?PROD_TYP=PAPER</a>

The importance of proper engine break-in is probably the most important to a pilot whose life depends on that engine, burnished cylinder walls and glazed cylinders are some of the dangers that can be avoided by proper break-in procedures. The causes of these can be directly linked to hard break-in procedures and premature wear of piston rings and poor leak down rates. These are all things that may not be apparent unless you scientifically analyze the engines performance during it's life. This has been done down to the last detail in aircraft engine design and fabrication. While it's true that any engine will run even with 10% leakdown rates, a properly assembled and broken-in engine should be under 3%.

I have personally seen engines that leaked down less than 1% and let me tell you there was virtually no blowby from the crankcase-none. I think that should be the goal of any engine rebuild and it is what I strive for. If any of my engines leak down 5% after break-in I tear it down to find out why because I know it will not last long and that cylinder will not be contributing to power production, it's mostly along for the ride.

Leaking cylinders will never get better, only worse after break-in. I know I can't convince anybody to take care during the break-in of their engines and not everybody wants to go to the trouble and expense to leak down their engines especially after spending a small fortune getting it rebuilt and installed. But the notion of a hard break-in is an old wifes tale and leads to looking for trouble. The first thing I do when I go look at a car for the first time is pull the pcv and see how much blowby the engine is producing, if there is a small chimney under the hood I walk the other way.

When you consider that the difference between a 400 HP engine with a 10% leakdown rate and reduce that figure to 1% you now have a free 30-50 horsepower and a much higher torque production down low in the rpm range that can't be seen until you compare dyno curve areas or compare time slips. This is free horsepower to me and I want all of it thank you very much, more please sir!

<a href="http://www.avweb.com/articles/breakin.html" target="_blank">http://www.avweb.com/articles/breakin.html</a>
 
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