Current cam 180 deg out ?

Engine, Transmission & Driveline

  1. ofb383

    ofb383 Member

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    Ok guys, this looks odd to me, looking at these photos, the current set up in the car and when compared to the new equipment going in, crank at TDC No 1, there looks to be 180 difference in the cam gear position / cam position ?

    Did someone put the current one in 180 deg out ? you can see the marker and its up the top and kind of looks like it's pointing down :confused:

    Cam timing 1.jpg

    Cam timing 2.jpg
     
  2. CBODY67

    CBODY67 Senior Member

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    Here's something from the small block Chevy world, which I learned from my machine shop operative/engine builder.

    Normally, with "dot-to-dot" we PERCEIVE that the engine is at #1 TDC AND is firing #1 cylinder. When, in fact, #6 cylinder cylinder (also at TDC, as it's 180 degrees away from #1 in the firing order), is firing. Actually, with the #1 at TDC AND FIRING, it's "dot top" on the cam sprocket and "dot top" on the crank sprocket.

    The engine will not start/run with the cam 180 degree OUT from the distributor.

    CBODY67
     
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  3. ofb383

    ofb383 Member

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    My assumption put me wrong and the current setup correctly installed, everyday is a learning day. So dot top is the correct way

    15758151690191176652452325573790.jpg
     
  4. CBODY67

    CBODY67 Senior Member

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    Given the multi-keyway crank sprocket, make sure it's at "0" and not "+4" or "-4" locations. Which should be in the instructions.

    CBODY67
     
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  5. Badvert65

    Badvert65 Active Member

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    Spin your crank one time and you will see the marks properly align.
    There are two times the piston is at the top of the bore, once for the power stroke (TDC) and the other time for the exhaust stroke. You just have the crank at the top of the exhaust stroke (#1) in the picture.
    Most install directions will state "TDC - Compression stroke", but not always.
    Yes, Mopar big block engines are "dot to dot".
     
    Last edited: Dec 8, 2019
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  6. ofb383

    ofb383 Member

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    Yes 0 at the top gives me the correct position for 0 key and tdc on 1
     
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  7. CBODY67

    CBODY67 Senior Member

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    Also be sure to put the distributor drive "gear" in the correct orientation upon reassembly.
     
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  8. ofb383

    ofb383 Member

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    Just found this in the book, dot to dot

    15758219180431372937789639169248.jpg
     
  9. Badvert65

    Badvert65 Active Member

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  10. stubs300

    stubs300 Senior Member

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    The book is loaded with good info, use it!
     
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  11. CanCritter

    CanCritter Senior Member

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    [QUOTE="Badvert65, post: 814333,
    Yes, Mopar big block engines are "dot to dot".[/QUOTE]

    .........phew......
     
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  12. ofb383

    ofb383 Member

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    :lol: I forget what I downloaded it and printed it off months ago
     
  13. 70bigblockdodge

    70bigblockdodge Old Man with a Hat FCBO Gold Member

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    Dot to dot gives you TDC on exhaust stroke. Dot to Dot on top gives you TDC on compression stroke and where you want to ensure oil pump drive gear is pretty close to parallel with cam then you can drop distributor in with rotor pointing to #1 cylinder terminal on the cap. At this point you should be able to see a almost lined up notch on dist flange and lip on the block if you line them up you will be ready to start up.
     
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  14. ofb383

    ofb383 Member

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    I did notice that the slot for the dizzy was almost parallel with the cam before I removed the oil pump drive:thumbsup:
     
  15. Timothy

    Timothy New Member

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    There can only be one way to time the cam correctly. The BB book I have by HP books say the timing marks must face each other on a centerline between crank and cam.
    I haven't checked my Motor Manual which I usually go by.
     
  16. Badvert65

    Badvert65 Active Member

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    This is exactly correct. I have literally built many dozens of big block Mopars over the years and always done it this way, 'dot to dot', by the book.