> > It seems as though my advance is not working.
>
> One has to ask, how do you know? :-)
>
I have to turn the dist. at higher rpm, to rev, otherwise it backfires.
_________
> > The engine can Idle, and slowly start to rev, if I am manually
> > turning the distributor.
>
> That's because more advance generally gives more power, up to point
> where the timing is too early. This behavior is entirely normal. It
> also means that setting idle speed and idle timing is an iterative
> process. You might consider setting timing statically first, i.e.
> with the engine off.
Yes, I know it is normal, But the advance weights should be doing it, not
me.
__________
> > Now, I need to know how to fix this, I have a TR6 with a Lucas #41219D
> > Distributor. I was wondering if there is a way to check the advance?
>
> The weights work like this. When centrifugal force throws them
> outward, they move the cams and the rotor more forward (i.e. in the
> same direction that the rotor normally spins, which is
> counterclockwise, if I remember). The springs pull the weights back
> in when the spinning slows down or stops.
>
> Systems often have two slightly different springs, and they won't
> necessarily become active at the same time, meaning that one may seem
> to have some free play. This is also normal. The idea is that you
> get two different behaviors, a large advance vs. rpm increase at
> lower rpm's, then less advance increase as rpm's go higher.
>
> If you grab the rotor (with the engine stopped! :-) and try to rotate
> it in its normal spinning direction, you should be able to turn it
> easily enough to see it move, perhaps 5 to 10 degrees depending on
> the spec'ed total advance. You should also be able feel the spring
> pressure working against you. If you then release it, it should
> return back to its starting position. (There may be a small bit of
> play in the at-rest position before the springs become active.)
>
> In most cases this will work perfectly, more or less. There are two
> possible failure modes. The mechanism could have siezed, meaning
> that you can't turn it and you get no centrifugal advance when it is
> running. (This happened to me with a Chevy 305 once.) Or one or
> both spring could have weakened or broken so that whenever the engine
> is running the mechanism advances to its fullest. In either case you
> should be able to observe it with this simple test.
It is not advancing at all.
________
>
> The toughest case is one of weak springs. You usually can't tell by
> feel whether a spring is as stiff as it ought to be. But it also
> isn't a fatal problem. If a spring is too weak, you will get a bit
> too more advance than you are supposed to as rpm's climb. You may
> notice this as pinging or similar sign at higher rpm's even though
> you set the timing to spec at idle. You can correct this by moving
> the timing backwards a bit. In the worst case, you'll have good
> timing at some rpm's but less than ideal timing at others. Given
> that timing is a mushy compromise anyway, especially at higher rpm's,
> this isn't a so bad.
>
> If you really suspect the springs or any part of the centrifugal
> advance mechansim, you can use a timing light and simply observe the
> timing at different rpm's. You'll need some way to rev the engine to
> various higher rpm's. A spouse or friend sitting in the driver's
> seat and watching the tach while reving the accelerator with a steady
> foot is one way. You then observe the timing with your timing light
> while the engine is roaring in your face. Check it at, say, 1000,
> 2000, 3000, and 4000 rpm's. You can compare this to various
> published curves.
I can't rev the engine!!!, Because it does not advance, the second I
start,
It backfires, because the spark is too late!.
__________
>
> Most likely you will have no problem. Setting the timing will then
> be your next task. There are several ways to start. I like to start
> with the static setting. Also with your idle advance (which should
> actually be a retard) disconnected (but plugged to
> prevent extra air from entering the carb) and the idle under 1000,
> the timing should
> be similar to the static timing. So another technique is to pull and
> plug the retard line and then use the static timing (then reconnect
> the retard line and set your idle speed). Or if you trust that the
> vacuum unit works, just set it to the spec'ed idle timing. When
> you're done, rev it a bit and watch the timing climb with rpm.
>
> Hope this helps.
It did, somewhat, I now know more about how it works :-)
Could you please elaborate on the vacuum retard unit?
I'm not sure what it does.
Thanks,
Graham McMicken
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