Originally Posted by
CARS II
Also out of curiosity I timed my BME 61 twin cylinder engine, it is timed @ 28 degrees exactly to the degree, this engine is about 8-9 years old, has a CH ignition and it is at its best even after been use to race a Spitfire before.
To time the engines I used a buzzer from HK, the timing wheel from CH that you can print from Adrian's web site and also did the spark plug sparking thing, when I was timing the DLE 35 I noticed that the spark came early, the magnet was beginning to go under the sensor when it buzz or sparked ( did it both ways to confirm ) I also noticed that the buzz was long, from the moment the magnet was beginning to go under the sensor to the moment it came out on the other side of the sensor. When I timed the BME it was a short buzz and at 28 degrees.
From what I have learned from adrain at CH, the spark has to come just aftr the magnet is moving from under the sensor, Ialso read somewhere here that the sensors that comes with the DLE sensors are not the best.
Any comments?
When turned in the normal direction, the spark occurs after the magnet passes under the sensor and just passes away from the sensor. The spark occurs when your beeper turns OFF, not on. This will usually be when the magnet has passed under the sensor and is about half visible as it passes away from the sensor. Many people think the spark occurs when the beeper turns on and this is not the case .... though there is one exception .... see below.
There have been some defective or incorrect Hall sensors used on various engines. When connected to an ignition, these may trigger the spark once as the magnet first approaches the sensor then again in the normal location as it passes away. Connected to the beeper device, they act normal. This is the so called "double spark" problem that has been discussed in various forums and can only be resolved by replacing the sensor with one that doesn't exhibit the problem. This problem causes hard starting and poor acceleration though the engine will run. Many people that have this problem will blame the carb for the problem when the issue is really ignition related. Its difficult for the average guy to test for this problem though connecting the sensor to an older A-01 Rcexl, CH or RCXP ignition will show it instantly just by watching the spark. A-02 HV ignitions don't show the problem as readily.
Sensors sold by RC Extreme Power and a few other sources don't exhibit this problem.
I agree with others, as long as you are in the 28 degree range, plus or minus a few degrees, you're good to go. Less advance will yield a smooth running engine with just a bit less power. Power will increase with more advance up until a point where the engine will become rough running and harsh. The much published 28 - 30 degrees just seems to be the best all around compromise between smooth running and power.