Hi Craig

As a Pico fanatic, it might seem strange that I am suggesting that the cam crank relationship waveform is flawed in this case, but I think we have to accept & understand the limits of any test method. For the most part, a cam crank waveform is a great way to expose a problem. But if it doesn't expose a problem, it can be easy to read too much into the result of the waveform & accept that everything is good. But what about the other cam that is not monitored by a cam sensor? this could be two teeth out & no scope in the world will display it (at least not with this approach).

In answer to your question....

>>why do you deem it less accurate to use a cam lobe<<

If you think about how the "average" hall sensor is triggered, i.e. by a precisely engineered "squared off" trigger wheel, passing closely to the tip of the sensor. Compare this to a sensor that is triggered by the approach of an offset ferrous object (the cam lobe).

Okay the cam lobe should share the same profile of each & every other cam shaft, used in the same engine variant, but there are bound to be some manufacturing tolerances that will effect the trigger point. Then you have to consider the same manufacturing tolerances effecting the hall sensor performance & lastly there is the potential for variations in the fitting. If a sensor in this application is "driven home" slightly more than on another car, then this will have an effect on trigger point & this will throw your cam crank capture out.

If you have ever observed a hall sensor response on a scope, as you wave a screw driver across the sensor tip, then my points will become clear.

>>How would you suggest assessing the state of the timing without expensive stripping?<<

Simple answer is.. I wouldn't suggest that there is an easy way. After all the cam crank waveform would at best, only provide a degree of confirmation about the intake cam shaft alignment. The position of the exhaust cam shaft is a complete mystery when using these cam/crank relationship waveforms.

Maybe a pressure transducer waveform would be a more useful test? I don't think it very easy to plumb the tool in though. Perhaps someone who uses one might be able to add to this?

Thankfully it isn't a massive task to pin these up manually & confirm things the old fashioned way.