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Crank tooth and sync tooth separation


John Appel

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Hi John, 

If you are talking a crank wheel with evenly spaced teeth (i.e no missing teeth) then cam tooth position is quite important.  With a missing tooth crank wheel it is not important.

For multitooth mode our official recommendation is to have the cam tooth centred within the 50% green window (pic below), however that is probably to allow some reasonable margin of safety due to backlash in the cam drive system etc.  It will still work much closer than that as long as the cam tooth always stays on the "same side" of the crank tooth - if it crosses over then the ecu will lose position and your timing will possibly be out by one tooth for the next cycle.

ZlG0OeP.png

 

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Thanks for that Adam. My crank trigger is 24 - 2  so you are saying that it does not really matter where the cam tooth occurs.  I have been told that the Link only needs the cam tooth on the first rotation of the camshaft at startup. Once the cam tooth has gone past the sensor once the engine is synchronised and will stay that way. In other words it does not have to reset itself for every engine cycle and even if you disconnected the sensor wire the engine would keep running.   Is this correct.

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Correct, it is far less important with a missing tooth crank.  All the ECU looks for is whether a cam pulse occured in the last revolution or not.  There is still some basic rules for best practice, shown in the picture below (note the picture in the current help file is wrong).  Basically you dont want the cam tooth to occur too close to the crank tooth after the missing teeth as this is when it does its "sync test".

 

1 hour ago, John Appel said:

I have been told that the Link only needs the cam tooth on the first rotation of the camshaft at startup. Once the cam tooth has gone past the sensor once the engine is synchronised and will stay that way. In other words it does not have to reset itself for every engine cycle and even if you disconnected the sensor wire the engine would keep running.   Is this correct.

Sort of, but not entirely correct.  The ecu will constantly check the cam to confirm sync.  However, it is smart enough that it can keep in sync once running even if you disconnect the cam sensor.  

 

C5dg3Wx.png

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