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new engine break in

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Chris1972, Dec 31, 2000.

  1. Chris1972

    Chris1972 Registered Member

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    Just finished my new 400cid engine and i wonder about the "propper" break in procedure. I have read at least 4 different ways to go. Can someone help me. The engine is
    completly rebuilt with everything exept waterpump and
    alternator. Have not started it yet.

    Chris

    www.broadpark.no/~csteinsv/
     
  2. backlash

    backlash 1/2 ton status

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    Congrats ... how can you stand it? Discipline I guess. Would be romping from the get go. Stand by ... someone here will be sure to give you good advice!
     
  3. Cavalry

    Cavalry 1/2 ton status

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    upstate NY(although I cant figure out why)
    Check on <A target="_blank" HREF=http://www.paceparts.com>http://www.paceparts.com</A> there is a section called "engine start up" . Its at the bottom of the crate engine page. Since they are a authorised GM dealer I would go with them.

    <P ID="edit"><FONT SIZE=-1>Edited by Cavalry on 12/31/00 09:34 AM (server time).</FONT></P>
     
  4. FWP

    FWP CRS

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    It's pretty simple, start it, run it around 2000 rpms for about 5 minutes. That's it. Make sure the timing is right before you start it- if not it'll get hot real quick....

    [​IMG]
     
  5. mybeast

    mybeast Registered Member

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    I just got my new 383, and my engine builder(a good honest guy) told me the break in period is about 1000 miles. For the first 1000 miles try not to run the motor above 3000 rpms(if possible), don't let the motor idle for extended periods of time, and don't run at a constant rpm for long periods ie. don't get on the freeway and set the cruise for a 2hr. drive. This is just what I was told i'm sure someone else will tell you different hope this helps.

    When all else fails MASH the skinny pedal!
     
  6. BurbinOR

    BurbinOR 3/4 ton status

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    My builder also recommended at least 500 miles of somewhat mellow driving.............with the same recommendations as above..............no extended idling, etc. I'm at about 450 now, haven't opened up my 406 with TPI yet..........though once to pull into traffic got it to 4000 RPM and it screamed. Make sure you change the oil at about 300 miles, then again at 1000 (at least that is what my builder recommends). Figure can't go wrong with fresh oil.

    <font color=orange>'79 - 406 TPI -<font color=orange> K5#5 - <font color=blue>See it at---&gt;<A target="_blank" HREF=http://www.blazzinor.coloradok5.com>http://www.blazzinor.coloradok5.com</A>
     
  7. 90K5

    90K5 1/2 ton status

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    Definately change the oil at 500 or before. i was with this guy in my neighborhood who just got back to college and put a new engine in about 6 months ago nad has 500 miles on it whe nhe changed it, and it looked very dirty, like it hadn't been changed in 5000 miles, so that is very important.

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  8. Jackson 88K5

    Jackson 88K5 1/2 ton status

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    When I built my first 350 for racing on the street and drag (years ago) we ran it for 20 minutes at about 2000 rpm's at the same time adjusting the timing. Shut it down, change the oil because of the lube used for cam break in. Then, run the engine like you are going to drive it. I can only imagine that you are going to run it hard [​IMG].

    If it breaks, upgade it.
     
  9. northgate

    northgate Registered Member

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    Whenever I start an engine for the first time I always prime the oiling system using an old distributor with the top cut off that is able to attach to a drill motor. This allows the oil to prime both lifter galleries. I also hook up an auxillary oil pressure gauge so I can see the oil pressure without having to look in the rig. Also, make sure you get all of the air out of the cooling system before starting. This can be accomplished by removing the temperature sending unit near the thermostat housing and filling the radiator untill coolant comes out of the sending unit receptacle. Fill the carburetor up with fuel to aid in starting. If you have a timing light, hook it up prior to starting the engine as well. Keep the distributor hold down bolt snug so the distributor doesn't flop back and forth but so that you can move it if you have to make an adjustment. Ignition timing is critical on a new engine--make sure your mechanical and vacuum advances are in good working order. I usually time the engine during break in at 37-41 degrees total advance BTDC, depending on altitude and type of fuel, running at about 2500 rpm. If you had chrome moly rings installed, you should break in for at least a half an hour, cast ring slightly less. Vary your RPM during break in as well (between 1500 to 2500 RPM). Also, after break in change the oil and filter immediately and then again at 500 miles. You would be amazed at how much dirt gets in a new engine-no matter how carefully it was put together. Set your idle speed slighty higher for the first 100 miles or so as well.
     

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