pioppiny_81 wrote: ↑Fri Aug 18, 2023 8:24 am
and Rob, what you mean when you say check the advance? to verify the correct oem advance, to verify the movement of mechanism or vary the original advance?
Well, all of the above really.... however, without fairly sophisticated equipment you can't be absolutely accurate with advance angles and timing. What you can do, though, is to view the various events using a strobe timing lamp and the vehicle tacho.
Put simply, the strobe should show the timing marks at the idle setting up to around 1500rpm (800rpm for /5 models) and full advance setting after 3000 rpm. The advance between those two engine speeds should be smooth and continuous. That tells you all you need to know at this point, the engine should run perfectly acceptably unless you are tuning for peak output. An advance that 'hangs' or is sticking might well cause the situation you describe.
If the timing points aren't seen when they should, you need to service the advance mechanism by lubricating it, checking the weight pivot points aren't worn, checking the stops which prevent the weights from moving too far out and, if the rev/advance specs aren't right, replace the advance springs. Exact procedures to do this depend on which year engine you have and how bad the readings seem.
My real point, though, is that checking with a strobe will give you a pretty good idea whether this is the source of your problem and may render a lot of dismantling unnecessary (or rather change the nature of the work you end up doing).
Rob
