Hi. i recently acquired a grey head 582 dcdi that was supposedly rebuilt about 8 to 10 years ago. Yes, i know, check the seals, which i will do when it comes time to run it. in the mean time i have some questions.

1. i found the tab that is SUPPOSE to contain the serial number data plate, but it appears to be missing.
Is there another place the serial # may be, on or in this engine? if not, can i establish my own number?

If so, what would be an acceptable format to use?

2. I plan (or would like to plan) on using vacuum operated instruments with a gauge.
is this possible and if so, what ports would i use? what can i expect for vacuum?

3. i also plan to use a 12v hobbs meter.

IF i only want to have it operate while running but plan to have full electrical system, can i just use a diode after the rectifier and attach the hobbs + lead before the diode? If so, what value diode should i use? or is there another way?

Thank you very much.
  • Re: 3 questions for now. serial #, vacuum port, hobbs

    by » 11 years ago


    If you are not using the primer port on your carbs, That would be a good point to measure manifold vacuum.

    If you have a key type starter switch (off, acc., on, start), you can wire the hobbs into the ON screw of that switch. The hobbs would not operate with the switch in the ACC. position. Only when the switch is in the ignition ON position. In certified aircraft, the hobbs is usually wired in conjunction with the oil pressure switch so that it won't operate unless the oil pressure is up. Unfortunately, we don't have that option.

    If your aircraft is in an ultralight or experimental category, you don't need a serial number on the engine in the USA. For logbook or selling purposes, it is best to have one but it is not legally required. Someone else on the forum, please correct me if I'm wrong, but I think if that ser.# tag is missing, the number is nowhere else on the engine.


    Thank you said by: roger larocque

  • Re: 3 questions for now. serial #, vacuum port, hobbs

    by » 11 years ago

    On my skyraider I put a micro switch on the throttle so that when the throttle is advanced the hobbs turns on,you might loose a little time like this at idle but if you inadvertently leave the switch on while parked you won't be counting hours unless the throttle is open.

  • Re: 3 questions for now. serial #, vacuum port, hobbs

    by » 11 years ago

    One foolproof method for a Hobbs is to get a DC powered meter. They will only operate when the engine is running. You wire them into the voltage regulator on the DC input side. No switches necessary, it runs only when the engine runs.

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