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Lotus Elan Central
Setting Engine Timing

The base ignition timing is set by altering the position of the magnetic pickup relative to the reflector wheel, by rotating the cam angle sensor (CAS). Please be familiar with the CAS write-up before proceeding.

Please be careful ! If you damage your Elan or endanger your life as a result of something you read here, it is your responsibility. Please use common sense.


Tools needed for adjusting timing:

  • Timing light
  • Paper clip
  • Allen wrench
  • An assistant!

Have the engine in these conditions before staring procedure:

  • Engine coolant at normal operating temperature
  • All electrical accessories turned off
  • Steering wheel in the neutral position
  • Transmission in neutral !!

The adjustment procedure is as follows:

  1. Open the rear convertible top stowage area. Pull back the right side of the carpet to reveal the battery compartment cover. Remove this cover so access to the battery's terminals are available.
  2. Open the hood/bonnet so you can get access to the spark wires. You must remove the 6 hex-head end cap screws to get to the wires.
  3. Jack up the right front wheel and remove it--remember Jack Safety! Set the wheel aside carefully and put a jackstand under the jackpoint.
  4. Locate the "timing degree marks" on a small metal square next to the timing belt pulley--be sure it is clean and visible! (the picture to the above is a general one and not from the Elan) Inspect the condition of the other drive belts. If they are cracked, they should be replaced! Find the little "v"-shaped nick in the timing pulley--> when setting the timing, you will see this nick across from the degree marks with the flashing strobe--> the number across from the nick as the strobe flashes is your current timing. (Hint: to see these marks better, and make them more visible while spinning, you can gently put a bit of white chalk on them; but do not put too big a mark as to obscure the fine nature of them!)
  5. Start car. Be careful as it is on a jackstand!!
  6. Put the car's ECU into "Service Mode"--this mode locks out all engine sensors from inputting to the ECU. This is done by inserting a paper clip into the ALDL. Put in the clip while the car is running at idle with all electrical accessories "off." The clip should be oriented the same way as you would to check your "check engine" light. (You must see ALDL diagnosis for details if you are not familiar with this!!) The "Check Engine" light will flash continually throughout the procedure to confirm the car is in "Service Mode."
  7. Connect the timing light as usual. One clamp goes to the battery's "positive" lead, one goes to the battery's "negative" lead, and the other goes to the "number one" spark plug wire. The "number one" wire is the one traveling to the cylinder on the right side end of the engine--this is the one closest to the timing belt end and farthest from the CAS. You will need to remove the cam cover plate by removing the 6 hex cap screws to attach the timing lead. (get the Allen wrench out of the car's tool kit in the trunk if you do not have another one!)
  8. Important: now you must slowly raise the engine speed over 2,000 rpm, then return to idle slowly to reset the IAC valve (at the 20 count position).
  9. Using the timing marks on the pulley, note the base ignition timing with the strobe light. Specification = 16 degrees BTDC (Before Top Dead Center). You will need to stick your head into the wheel well to get a good view of the timing marks. Block out any excess light so you can see the timing marks (use a flashlight if needed). Take your time and be sure you see them well!
  10. If the timing is not correct (it never is!), one person will need to watch the timing strobe carefully while the other slowly adjusts the timing! Do NOT get your fingers anywhere near the pulleys or the aux. cooling fans!!
  11. If necessary, gently slacken the cam angle sensor housing clamp bolt (it needs a 6mm hex wrench), and then rotate the housing in tiny amounts as required to achieve proper timing. To increase the timing degrees, raise the front of the CAS a tiny increment by gently tapping it upwards; to decrease the timing degrees, lower the front of the CAS a tiny increment by gently tapping it downwards. Tighten the clamp bolt to 24 Nm (17 Ibf.ft) when the timing is perfect.
  12. When done, take the car out of "Service Mode" and cycle the engine RPM. Then return it to "Service Mode" for a final timing check.
  13. Clean up your mess!
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