Finding TDC

Discussion in 'Engine, Fuel and Exhaust' started by BOBFLHTC, Aug 9, 2010.


    BOBFLHTC Active Member

    This weekend I was adjusting the pushrods on my 85 EVO and I was trying to find TDC on the compression stroke per the instructions in the self help section “Adjusting Pushrods”. My best friend (also my wife) is sick so I didn’t have anyone who could turn the back wheel for me while I placed my thumb over the spark plug hole to find the compression stroke for each cylinder so this is what I did:

    1. Remove spark plugs

    2. Jack up rear wheel

    3. Seal both spark plug holes with wide masking tape about 6” long and
    secure end of the tape to Rocker cover as a precaution. I pressed it into the plug holes with a socket to get a good seal.

    4. Turn rear wheel in a high gear and when you hear a pop (tape breaking the seal) then that cylinder in starting its compression stroke.

    5. Turn the rear wheel a little more to get the piston to the top of the cylinder

    I hope this isn't bad advice but it seemed to work for me - Bob
  2. Jack Klarich

    Jack Klarich Expert Member

    Pretty good idea I like it:s

    BOBFLHTC Active Member

    It seemed like a good idea but you never know. I wanted to be extra careful not to suck anything into the spark plug hole so I used a longer piece of tape so I could secure it to the Rocker cover. I was thinking of turning it over without the plugs but instead of jacking it up just push it instead. I also want to try to coordinate with the Timing mark for TDC of the front cyclinder. According to the manual it will be a Verticle line. If it makes it easier I am all for it - Bob