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  1. #1

    Default Timing gear marks

    Greetings all, I am a little perplexed. When I pulled the timing cover off, the two dots were at 12:00. Now that I am putting it back together, it seems that for proper timing it has to go back that way. I thought the two timing dots had to meet for proper timing? When i put it together that way I was not getting any compression out of #1. So then i turned the crank until it had the #1 piston up, turned the cam until the dot was at 12:00 then it had compression. Any input would be appreciated.

    1989 Chevy V1500 Suburban 4X4, long tube headers & xover pipe. w/1985 350 4bbl.
    2002 Silverado 1500 5.3L Ext. Cab
    2005 Wrangler Rubicon 4.0L
    1990 Miata

  2. #2


    I don't remember if you have to time it with the two dots pointing at each other or if they both have to be pointing up. Here's the crux: once you rotate the crank once, the dots will be pointing at each other, or both pointing up. When you turn the crank another full turn, they both point in the opposite position. The cam to crank gear ratio is 2:1, which means both occur in operation. The key difference is if you line it up backwards to what the rebuild manual says, when you install the distributor, you could be 180 degrees out of time with the rest of the engine. Consult your Haynes manual, it'll tell you, and then confuse you with roughly what I just said.

    1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 200K miles
    2005 Saturn ION-2 Stock 277K miles
    1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half

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  3. #3
    stephan's Avatar
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    BigBlue, The timing mark on the crank sprocket needs to be at 12 oclock at the same time as the mark on the cam sprocket is at 6 oclock for correct cam timing.
    #1 piston at TDC, crank mark is at 12 oclock. Then move your cam untill the mark on the cam sprocket is at 6 oclock pointing at the mark on the crank sprocket.

    *If you have moved your ignition distributor during all of this, then you will have to move it back after you have done the cam timing correctly
    Last edited by stephan; 02-07-2011 at 03:55 PM.
    1988 Chevy C-3500 2wd (no pic)
    350 c.i. 5.7 L Stock Block, 4 Bolt Mains
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    Holley 650, Flowtech Headers, Magnaflow exh.
    Jet Trans 700R4, B&M Ratchet, 4:10 gears,
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    No rev limiter, No speed limiter lol

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