the book is kind of unclear on this subject. these motors are timed somewhere around 21 degrees btdc. is that static initial timing? or final timing with any advance input from the mpem? is there any advance or retard added? or is timing always the same at wherever it is initially set? i put a 93ish 587 in my 97 GTI. i hear horror stories about how my 717 mpem is gonna advance the timing so that it will burn pistons up in 30 seconds. can the mpem have any effect on timing? there is no tdc sensor, so i don't see how it can do this. the book says 720's run 20 to 22 degrees. says 580's run 19 to 21 degrees. how can 1 degree of timing be that bad? or is it that these people want to sell me a motor? the 580 ran like a champ for 30 seconds. could hardly tell it was a smaller motor. then it quit. i just got it apart. pistons are fine. the rotary valve quit turning. my fault. something got in there and hung it up. i dunno if i wiped out any gears yet-probly did. but that is another issue.
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can someone explain ignition timing?
- Thread starter derek
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Way of the mark....
No, these engines are not timed are "tweaked" by the ECU like the newer model 951 or 4-TEC model engines.
There timing process is simple, you put your number 1 (MAG) cylinder TDC and arrange the rotary valve to the proper degrees as stated in the manual, to the casing.........that's it!...the manual also states you can be off +/- 5 degrees...........
Timing is important, but not in the way you listed it.........
No, these engines are not timed are "tweaked" by the ECU like the newer model 951 or 4-TEC model engines.
There timing process is simple, you put your number 1 (MAG) cylinder TDC and arrange the rotary valve to the proper degrees as stated in the manual, to the casing.........that's it!...the manual also states you can be off +/- 5 degrees...........
Timing is important, but not in the way you listed it.........
robin savell lloyd
Active Member
Some times we all say something that is not true, not meaning to misslead you but because we thank we know what we are talking about. or missunder stood what the question was. there is a lot of info out there that can get you way off the path that you should be taking to get your task done. keep in mind that it is very hard some times to diagnose something that is not in front of you. Robin :cheers:
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