VVT and cam poistion sensor

[Six_Shooter]

I'm putting an engine together where the cam is currently undecided, simply due to what IS available and what might become available soon(ish).

Anyway, the OEM cam for my engine (GM LZ9 3.9L) has 3 or 4 uneven spaced teeth favoring one side of the cam (I don't have a picture currently and my cam is at the machine shop. D'oh). As far as I know the MS looks for a single tooth, or rather single leading or falling edge on each rotation of the camshaft for cam positioning, is this correct? I can't find anything in the manuals that suggest multi tooth, especially unevenly spaced multi tooth cam position reluctors are supported. Even if I use one of these cams, I can make a single tooth cam trigger, so I'm not worried about the need for a single tooth, just want to verify that I need to make sure that happens.

the ultimate reason for this is retain the VVT of the engine, which is a single cam engine, so I also assume that the setting would be to set to "intake cam", since there is no option for "common" under the cam type selection in the VVT setup.

Any other pointers I might not be thinking about in regards to the cam position trigger and/or VVT?

[Matt Cramer]

The standard VVT decoder can look at a one tooth wheel or a set of equally spaced active trigger edges. Some other irregular wheels can also work as the decoder throws out any pulses if it does not find a pulse within the expected angle - for example, if you had a 6-1 pattern, where there were five teeth 120 degrees apart, you could simply tell it you had six base teeth.

[Six_Shooter]

Ok, so I might be able to just use the stock cam trigger pattern, nice.

I'll try and get a picture in the next day or so, 'I need to stop by the machine shop anyway.

I'll have to look into this a little more then.

Thanks.

[jsmcortina]

The stock "2 wide 2 narrow" wheel (same as VW) works fine.

James