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cam swap

Discussion in 'The Garage' started by big dan, Jul 21, 2006.

  1. big dan

    big dan 1/2 ton status Premium Member

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    Im fixing to do a cam swap in my truck and have a question. I am not very good at setting the time and do not have a timing light. so my question is if I pull the old cam straight out and install the new cam in the same position and install everything else such as timing chain and distributor the same way it came out, would my timing be set?
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Cam timing is different than static timing. Cam timing is done by lining up the dots on the cam and crank gear, static timing is done with a timing light. Before you start taking it apart put it on TDC #6 cylinder. This will allow both timing marks on the cam and crank gears to be pointing at each other and makes it easy to hook the chain and gears up properly. Before anyone says i'm wrong about TDC #6 cylinder that is how the gears are aligned to make it easy but once the engine is turned over 1 revolution then it is on #1 cylinder TDC.
     
  3. SchnorrCS

    SchnorrCS 1/2 ton status

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    Not a good idea....
    do this:
    1) Pull number 1 plug (Drivers side front)
    2) Take off distributor cap
    3) Put thumb over plug hole
    4) Have friend "bump ignition until your finger gets blown off hole.
    5) look at distibutor. It should be at 7 oclock. Not 1

    Then just use a big socket on the crank pulley and a breaker bar to move the engine. Theres a timing mark machined into the harmonic balancer, just line it up with the 0 on the timing indicator, and you are now at top dead center!
     
  4. beater_k20

    beater_k20 Banned

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    i hate to be brutally honest, BigDan, but if you have to ask a question like this you have no business tearing into an engine just yet . do a little more research on it, get a good understanding of how everything works, and buy yourself a timing light. then i'm sure you'll be ok.
     
  5. beater_k20

    beater_k20 Banned

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    correct info, the #1 piston will be at TDC, but will it be at TDC between the compression and power strokes, or will it be between the exhaust and intake strokes? the only way to tell is to see what the valves are doing.
     
  6. theperfectgarage

    theperfectgarage 1/2 ton status

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    He did mention the finger in plug hole re. comp. stroke.:D
     
  7. big dan

    big dan 1/2 ton status Premium Member

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    well actually I have tore into it several times. just never done anything with the cam and cam timing. I just figured that if I put everything back in the same way it came out then it would still be set right. from what Im getting I need to line up the marks on the timing chain and then pull it and put it back with the marks lined up. am I correct or still lost? maybe I should ask my old man to help.:confused:
     
  8. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Yes, just line the dots on the cam and crank gears. Once the engine is back together then you need to adjust your timing with a timing light.
     
  9. ryan22re

    ryan22re 1/2 ton status

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    You can rent a timing light from most any parts house that has tool rentals.
     
  10. big dan

    big dan 1/2 ton status Premium Member

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    cool thanks
     
  11. SchnorrCS

    SchnorrCS 1/2 ton status

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    The finger in the hole won't tell if youre on the compression or exhaust stroke, just that the piston is at the top of it's stroke.
    It's looking at the rotor that tells you whicjh it is. If it's in position to fire the #1 piston (approx. 7 o'clock), it's compression stroke. If it's at approx 2 o'clock, it's exhaust...Thought I said that already
     
  12. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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    You wont have compression on the exhaust stroke... The exhaust valve begins to open at BDC of the compression stroke and is open till the piston reachs the top of the exhaust stroke..

    Too many people apparently screw up the finger over the plug method
    (we must get 10 posts a month on dizzy's being 180 out) thus why I recommend to noobs to check by the #1 valves anyway.. far better method... takes 10 seconds to pull a valve cover..

    Also, where the rotor is pointing means nothing... It can be pointed anywhere for TDC and just laced from that point..

    And I don't see what this has to do with changing a cam anyway, other than once its installed.. 4x4HIGH's first post had it all covered.. TDC for #6, install, turn 1 revolution, drop dizzy, lace...

    and Dan, just buy a timing light, a cheapie can be had for $50 or dirt cheap used on EGhey..
     
    Last edited: Jul 22, 2006
  13. diesel4me

    diesel4me 1 ton status Premium Member

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    How I learned..

    I had gutted and rebuilt lots of briggs and stratton motors before I ever got brave enough to tackle a small block chevy--but hey,if you never try,you'll never learn,right??..the basics are the same..

    I just turned over the engine until the dots were lined up and pointing directly at each other,on the two timing gears...which happens to be the TDC position of #6,but thats irrevelant...as long as the dots are perfectly aligned,the motor is timed correctly as far as the valves are concerned..

    I then looked at the distributor rotor,and noted where it was pointed.(should be pointing at the #6 plug wire)...and as long as you put it back where it was,it should be close to being timed perfect,since the oil pump drive slot will only let it go in one way like it was,or 180 degrees out of time...

    I use the thumb over #1 plug hole method to find TDC on #1..I beg to differ that pulling a drivers side valve cover off is "a 10 second job"...sure,on a 67 283,I agree!..but a later 350 with A/C isn't such a picnic!..:doah: ...as long as you dont turn the motor over once the cam and distributor is out,there should be no reason to find TDC on #1 ....:crazy:


    Like losing your viginity,the first time is the hardest...after that it takes several beers to mess the timing up!..ask me how I know!..:rolleyes:
     

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