This video shows you in less than four minutes why adjusting the valves in a Porsche engine using the traditional OEM method is so difficult. 


On a 930 Turbo, with the engine out of the car, the technician does a good job demonstrating how hard it is to access the valve gap with the feeler gauge, the small amount of movement that will throw the adjustment off, the judgment call or “feel” the mechanic must employ to decide whether the gap has been set at 0.10 mm and the ultimate final problem of tightening the jam nut down without moving the valve adjustment screw.  Remember, that with the m8 x 1.0 pitch adjustment screw, it only takes a 3.6 degree movement of the adjustment screw to change the gap from 0.10mm to either 0.11mm or 0.09 mm.  Can your eye even discern a 3.6 degree rotational movement of the top of an m8 screw?  Consider that coupled with confined accessibility in the engine compartment, oily hands and the near impossibility to even see some of the valve screws you are working on (such as intake #6).  Whether you do this necessary maintenance yourself or entrust it to a mechanic, you have to wonder whether the valves are ever properly set. 

And, other than putting a dial gauge on the rocker arm to check its axial travel, you really will never know.  Trying to slip the (usually bent) feeler gauge back into the gap tells you very little about whether the gap is correct.  If you can get it in there, it is likely too loose and if you cannot get it in there, it is either too tight or near perfect --- but you will never know, so you will want to start over again and “re-adjust.”  This can result in an endless loop with uncertain final results.

The technician in this video sums it up nicely – “Now you wonder why they charge 4 hours or more to do a Porsche Valve Adjustment?”

There is an alternative that eliminates the guesswork of the feeler gauge and jam nut, is designed to work in the confined spaces of the Porsche engine compartment, takes only minutes to use and results in accurate and replicable valve lash.  If you are interested, watch this 3 minute video.