Timing Marks & Chain Clarification

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Oldmanriver, Nov 14, 2020.

  1. Oldmanriver

    Oldmanriver Junior Member

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    I am in the process of trying to clear P0016 and misfires. Attached a screen shots form the manual and I find it confusing when installing the timing chain. To Remove the chain it states to set cylinder No 1 to TDC on compression to match the illustration. To Install the chain it states this with the marks in the same position as they were in for removal >> INSTALLATION 1. INSTALL CHAIN (a) Set the position of the No. 1 cylinder to 20° ATDC. NOTICE: To prevent the pistons from hitting against valves, the following procedures must be performed in the order below. (1) Set the crankshaft between 40 to 140° ATDC. (2) Set the cams of the intake and exhaust timing sprockets to 20° ATDC. (3) Reset the crankshaft to 20° ATDC. (b) Install the chain vibration damper with the 2 bolts. Torque: 9.0 N*m (92 kgf*cm, 80 in.*lbf)


    Screenshot (62).png Screenshot (61).png
     
  2. ChapmanF

    ChapmanF Senior Member

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    They just want you to have all the pistons safely out of the way while you rotate the camshafts (if necessary) to their proper places. (If I were writing it, I think I would put the instructions to set the crank at 40 to 140° ATDC ahead of tightening down the cam bearing caps.) Then with the cams in the right spot, you can back the crank up to match.

    One thing that is peculiar: cams turn at half the rate of the crank. When the crank is at 20° ATDC, you would expect a protractor on the camshafts to show them 10° past their TDC position. The manual is saying 20° for both. It is possible they are using an automotive convention and talking 'crank degrees' everywhere. But hmm, no, Inkscape is telling me that cam angle in their drawing is pretty exactly 20°. That is puzzling.
     
  3. Oldmanriver

    Oldmanriver Junior Member

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    Well here is where I'm at... I have the valve cover off and made several rotations in order to get the timing marks to align on the cams the orange links are in alignment with the marks as pictured in the manual there is a decent amount of play in the chain and from what I can see the tensioner may be or is close to being maxed out.

    I think I am going to proceed by confirming all reference points are in alignment, pull the chain, note the position of the tensioner, and compare the chain for length discrepancy's against one I have from a lower mileage engine.
     
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  4. ChapmanF

    ChapmanF Senior Member

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    Old chain? New chain? Did you do the measurements in the manual for chain length and chain guide wear?
     
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