[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]
On 1 Sep 2003 at 12:23, Chris J Valade wrote: > are the AB and L distributors (311 905 205 AB and 311 905 205 L) > interchangeable? If yes, how would it affect my engine, its > performance, etc.? What is the difference between the two? There's not much difference. You can see all the difference in the advance curves in the Bentley manual. I believe the L gives a bit more advance and it is my favorite. > I > can't adjust the idle and see no change whatsoever even if I take that > idle screw out, although the car will die when I turn it clockwise > enough. Plus, the idle is horrible, even though I got a good condition, > AT AAR with the wire and all, this affected no change. When the car > starts up it has a lower and steady idle, but when it warms up, depending > on where the timing is (I can't time it correctly since I can't get the > idle either anywhere near 850 RPM or it oscillates so much that it would > be pointless), it will either be a low steady idle (around 700 or 800) > under load but oscillating (from what I can recall) between, about, 550 > and 750, and the lower it drops the higher it will go after that (so when > it nearly dies, it will go to 800), or if the idle is great under load it > will oscillate in neutral. Plus, the worse the idle is under load, the > more performance I get--more advanced=worse under load, retarded=worse in > neutral. It sounds like your AAR isn't working right. Check it to make sure that it is open when cold and closes as the engine warms up. > Also, more out of curiosity, could someone explain what the > graphs in Bentleys (chapter 3, pg 54-55) mean? The graphs show the distributor advance in distributor shaft degrees, so you have to multiply the Y-axis by 2 to get crankshaft degrees. The advance is shown as a function of (X-axis) dist shaft RPM for the mechanical advance (mult by 2 to get engine RPM) and as a function of vacuum (in millimeters of Mercury) for the vacuum advance. In general, for good performance you want a nice rapid mech advance as the RPMs go up, to a maximum of 30-34 crankshaft degrees under full load. On all of these distributors, the vacuum advance comes into play under light loads only, to give more than 30-34 deg of crankshaft advance, which the engine can tolerate just fine, and get better gas mileage, as long as the load is light. -- ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org