![]() With the 3k timing off, you'll either get loss of power or detonation right? I'd think that the 3k timing is more important (unless the car doesn't idle at all) since the majority of the time it's running, it'll be around that mark, whereas the idle timing is only good at idle. If you set the timing at advance, then your idle is not correct. That's why the 009 is not the best for 'street' 912's, if you put the idle 'correct', then it doesn't have enough advance at 3k rpm's (where most of the driving is done). Reducing the advance should reduce preignition.įrom everything i've learn't, unless you rip apart your dizzy (and re-weld etc.), or buy a new one, your advance is your advance. One degree can make a significant difference, so try 31 and 33 degrees also. Bad ones will actually change in value at a fixed rpm.īottom line? 32 deg BTDC at 3K rpm and test by driving. At constant rpm - say at 2K, the notch should show stable in position. You can tell if this problem exists with the timing light. With such a pulley, setting the advance at high RPM would be easy, quick and precise.Īn old worn disty can be hard to set. Another way would be to get a 360 deg plate of the same diameter as the pully attach it in some permanent way. This is available - I've seen one on a 912 engine. A nice after market enhancement would be a pulley with degree marks on it. I find it imprecise to mark the pulley to find the 30-35 degree points. You can buy oxygen sensors and meters that could provide data. The thermocouple was in a washer for the spark plug as I recall. We used to lean light aircraft engines using exhaust temperature. Perhaps exhaust temperature and oxygen sensor data provides a more accurate way to set the advance (and the carbs). Harry Pellow uses one.Īltitude, fuel characteristics, carbs and cams can all be reasons that values different than 32 deg at 3K might be better for your engine. I'm not sure how reliable or accurate these are. The most convenient way is to use one of the Sears strobe lights that has the adjustment knob on the back. The best way to do that is to mark the pulley at 32 deg. The consensus is to set at 32 deg BTDC at 3K and let the idle fall where it will. ![]() I think every one who says 32 deg at 3K RPM is assuming the max has been reached, i.e. The advance reaches its maximum around 3K RPM. ![]() There is an advance curve published in the factory 912 supplement that is intended to be used with a test machine.Īs an experiment, you can change your idle advance from 10 deg BTDC to 5 ATDC and it still idles ok. An 009 disty can actually be fixed to work properly in a street car with the right parts and test equipment. The equipment and expertise was not that uncommon 30 years ago, rare now. It requires a distributor test machine and a supply of springs and weights for the mechanical adjustments fly weights. I guess I might try an new MSD blaster coil and see if that makes a difference.The advance curve can be changed. I checked the coil resistances both primary and secondary and they were right within spec. Everything in the ignition system was rebuilt except I’m using an original used Bosch black CDI coil. It had been about 2 years since I had used the light so I fired up my '73 and connected the light as I always do and it worked like it should.Īnyone have any idea what my problem is? Are there certain types of plug wires that will not fire an inductive light? Could my spark be too weak to fire the light? I am thinking that possibly I might just have too weak a spark to trigger the inductive timing light but enough spark to run the engine. I also put an in line spark detector on the # 1 plug wire and it flashed as it should. I also tried powering the light with my 12V power supply. I double checked for 12 V to the positive and neg leads to the light and also tried another plug wire. Hooked the negative to the coil stud ground, the positive to a terminal on the 3 pin fuse and clamped the inductive lead to the #1 spark wire. This light has always worked well for me on my '73 and previous cars. Did the first oil change and decided to check the timing using my trusty Craftsman inductive light with dial in advance settings. The engine is in the car and has been run in for 20 minutes at 2000 RPM. Getting ready for the first drive on my '70E restoration project. ![]()
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