hrpchr wrote:Today I did my first ignition timing check on my 2008 Patrol.
First of all, I do realize that there are two different arrows marking the flywheel. I understand that the “plain arrow” ( --> ) is for Top Dead Center for use in setting valve lash. I understand that the “dot arrow” ( . --> ) is for Ignition Timing for use in setting ignition timing. I painted the TDC arrow black to make it easier to see when rotating the engine by kick starter. I painted the Ignition dot arrow silver to make it have a higher contrast with the flywheel for strobe viewing.
When using a timing light, viewing through the M3 port on the right side of the case, with the inductive pickup on the right-side plug wire, I am seeing two different timing arrows illuminated by the strobe. Both arrows are light colored (silver) and are, just estimating, about 1/4" to 3/8” apart when viewed with the strobe. One of the arrows is well aligned with the reference mark on the M3 opening. The other arrow is showing above the first, near the top of the M3 opening, with the strobe held in the same position. The idle speed is somewhere in the 800-900 rpm range (maybe).
With these givens, here are the questions…
1) Is it customary to see two different illuminations of the one timing arrow when timing a Ural?
2) Is the “two arrows showing” cause for alarm that there is an ignition or timing problem?
3) What causes the double arrow illumination? I thought the wasted spark was coincidental with the firing spark.
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