Camshaft timing - 23 degrees versus 25 ?

Discussion in 'Hot Air (non-intercooled) Tech' started by Hot Air Beast, Oct 11, 2017.

  1. Hot Air Beast

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    Is there any power advantage to setting cam timing at 23 degrees versus 25?
     
  2. Jerryl

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    Are you referring to the Cam sensor timing?
    There is an acceptable operating window for the cam sensor, that is much larger than +-2 Crank degrees.
     
  3. Hot Air Beast

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    Yup - the machine shop has the engine back in the car and i expect your pulley will arrive soon, if it isn't already there. When I rebuilt the engine back in 2008, I had two GM mechanics working with me and they believed that they had tweaked the cam sensor timing to 23 degrees ATDC, back in the day (late 80's) as they continued to learn about the car. Normally I would stick with whatever the GM engineers had recommended. If by chance the machine shop has used 23, I just want to know the upside/downside of doing so. Just being cautious here. Engine is bone stock and I am happy with that, and want to keep it trouble free as long as I can.

    Phil from Canada :cool:
     
  4. Jerryl

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    Hi Phil,
    I am severely disappointed with the USPS and their S-L-O-W shipping to CAN for the price paid! Unbelievable but much appreciation gained for the challenges you guys face in CAN.

    There is no theoretical or any measureable benefits from changing cam sensor timing 2 crankshaft degrees from 25 ATDC, if the car is running correctly, especially on a stock set-up. FWIW; 2 degrees@crank will be 1 degree@camshaft. My suspicion for the "tweak"; Many shops believe cam sensor affects ignition timing and end up "tweaking", which is inaccurate.

    Here some reading material;
    http://www.gnttype.org/techarea/ecmsensors/camsensor_FAQ.html

    Hope that helps.
     
  5. Hot Air Beast

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    Thanks Jerryl - we had a three day week-end here for our thanksgiving so I expect nothing moved on Sat/Sun/Mon. Will let you know. Thanks for the addit info.
     
  6. bison

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    It will inject the fuel 2* sooner. Does this have any effect on anything at 3000+rpm. Absolutely not.


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