For testing and experimenting, Remove spark plugs. Rotate engine by hand and observe the rotor. You will see that you must rotate the engine twice to get 1 rotation on the rotor. Using a straw you may also like to probe for the position of the pistons and you should see that each piston must go up and down twice for the rotor to do one revolution. You should also see a relation between when the piston is near the top and the associated magnet and sensor on the rotor (or points and it associated lobe). To rotate engine you may be able to use a socket on the crank shaft or perhaps put the car in highest gear (4th?) and push the car in either direction while observing crank position and rotor position. Or while OUT of gear in Neutral very briefly get someone to turn the engine over using the key, this is my least prefered. I tend to prefer putting in the highest gear and push. Justin On 8 March 2011 05:40, Andre Abelian wrote: > Michael, > > I know one thing for sure that the rotor has 4 magnets and 1 turn of roto= r will > fire 4 cylinder. > I just do not understand what does "Four stroke is 1 spark every two revo= lution" > means? > can you give and example? > > thanks > > AA > > > > ________________________________ > From: Michael Watterson > To: Microcontroller discussion list - Public. > Sent: Mon, March 7, 2011 11:25:56 AM > Subject: Re: [EE]: VW engine RPM question > > On 07/03/2011 18:58, Michael Rigby-Jones wrote: >> This assumes your Beetle engine will hang together for more than one >> spark period at 8000RPM... >> > red line at 5,000 rpm? > my VW van did 55mph > > it was revised flatter flat air cooled twin done after Beetle ceased > production. =A0Eventually the covers over the push rods started to leak := ( > > It had electronic Ignition. When I was very small my Grandfather had a > Beetle with 6V electrics. > > Most 1960s to 1980s cars I worked on =A012V and =A0ignition coil + "point= s" > and distributor cap with 4 sparks in turn per revolution, 4 cam bumps > on shaft opening the "points" to interrupt current to ground through > ignition coil. > > Four stroke is 1 spark every two revolution. So distributor shaft is at > engine RPM x2 since it does 1/4 revolution for distributor each piston > stroke? > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .