Checking your Armature & Poppet clearances:
The Poppet Valve tends to wear into both it's top and bottom seats. This wear is determined easiest by taking measurements on the Armature, to help figure how much wear has occurred, and where. You need sufficient clearance UNDER the Armature so that the Poppet Valve will rest into it's bottom seat correctly. And you need sufficient clearance ABOVE the Armature so that the Poppet valve will rest into it's upper seat correctly.
All you really need to have to do this are some feeler gauges, a means to hold the injector, some wire and a 12v source.
1) Create a means to hold the injector for inspection.
2) Remove the Solenoid from the injector, as well as one from another injector. You will need the aluminum spacer from the other injector.
3) Mount the 2 aluminum spacers as shown below right. This will give you access to the Armature for accurate measurements. The Armature is the small square plate visible when the Solenoid is removed, shown below left.
4) Check the gap under the Armature. We'll call this measurement 'A'.
5) Next, measure the gap between the top of the Armature and the Solenoid and record this measurement. We'll call it measurement 'B'.
6) Using some Alligator clip wire extensions or the like, connect a 12v power source to your Solenoid pins. One is the power, the other is ground. DO NOT keep the solenoid energized for very long. Have your feeler gauge ready, apply the current and measure the gap between the top of the Armature and the Solenoid again.. Then disconnect the power supply. The solenoid will heat up and you do not want to damage it. We'll call this measurement 'C'.
Now analyze your collected measurements.
Measurement 'A': This distance needs to be between .004" and .002". If it's .002" or less, this indicates that the Poppet Valve has worn into it's lower seat and machining is required to restore proper injector operation. Conversely, If this distance is too great, measurement 'C' could diminish to the point that the Armature will contact the Solenoid. This needs to be avoided.
Measurement 'B': This measurement should be between .014" and .016". There is a point in which if this distance becomes too small, the injector will not function corectly. But generally 'B' can not be too small as long as 'C' is acceptable. If this distance becomes too great, the Solenoid will not be able to 'Grab' the Armature and pull it up for proper operation. A few thousandths of an inch here means it will either work or not work.
Measurement 'C': This should be no less than .002". This distance can not really be too great, as long as 'A' & 'B' are acceptable. But if the distance is too small, less than a measurable amount, then the Armature will contact the Solenoid. This will eventually damage the Solenoid. If you cannot get a .02" feeler gauge between the Solenoid and Armature with the Solenoid energized, then your injector will require specialized machining to correct this.
EXAMPLE Injector #1: You take measurements of 'A' = .003", 'B' = .0014", and 'C' = .000". It would appear that the Poppet has worn into it's upper seat more than it's lower seat. Specially machined Poppet components are then needed to correct this.
EXAMPLE Injector #2: You take measurements of 'A' = .002", 'B' = .016", and 'C' = .004". It would appear that the Poppet has worn into it's lower seat. By following the DIY Armature Machining Instructions, you can add .002" back to 'A', such that 'A' = .004".
This in effect will make 'B' = .014" and 'C' = .002", acceptable tolerances for a properly operating injector.
EXAMPLE Injector #3: You take measurements of 'A' = .002", 'B' = .016", and 'C' = .000". It would appear that the Poppet has worn into both it's upper and lower seats. The first step would be to restore 'A' to proper specs, then take new measurements for 'A', 'B', & 'C'. By following the DIY Armature Machining Instructions, you can add .002" back to 'A', such that 'A' = .004". This in effect will make 'B' = .014" and 'C' will become even smaller. If 'C' was smaller than your feeler gauge, but the Armature was not quite hitting the Solenoid, it would surely hit after machining for 'A'. Specially machined Poppet components are then needed to correct this situation.
