Advance springs.

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George Greer
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Advance springs.

#1

Post by George Greer » Wed Mar 26, 2014 8:25 pm

Fellas,

Can I get some education here concerning spring strength on auto advance circuit breakers?

I was ebay shopping, and came across a ad for three different spring tensions........

What is the advantage or disadvantage of using different spring tensions to get the breaker to advance at various engine RPM's?

Each one listed different RPM's to obtain full advance.

Looked, in the K-base, but to no avail. :oops:

George



ingram
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Re: Advance springs.

#2

Post by ingram » Wed Mar 26, 2014 9:21 pm

The springs control the ignition timing advance curve. The stronger springs will cause the timing to advance slower. The weaker springs will cause it to advance faster. The engine combination and the fuel used will determine what ignition timing curve the engine likes. It is a trial and error process unless you were to put the bike on a dynamometer. If you hear the engine knocking (pinging), the advance is too fast and you would need to install the stronger springs.

Cotten
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Re: Advance springs.

#3

Post by Cotten » Wed Mar 26, 2014 9:37 pm

George!

Different years of auto-advance timers accepted different designs of springs.
Some won't fit the other's weights.

Which do you have?

....Cotten

kitabel
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Re: Advance springs.

#4

Post by kitabel » Thu Mar 27, 2014 5:46 am

Spring tension indicators:
In general more static CR or tall gearing needs a slow curve (strong spring), hot cams need faster.
The advance rate can also be tweaked (with the same spring) by drilling the outer end of the centrifugal weight, which slows up its motion. Fine tuning: thread the hole, and use different length screws to add weight.

58flh
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Re: Advance springs.

#5

Post by 58flh » Thu Mar 27, 2014 12:35 pm

GEORGE!--Exactly as KITABEL put it!--If you don't use a DYNO as IMGRAM implied!--I use a stopwatch & Tach,Simple but VERY EFFECTIVE!--It got to the point on mine when I ran the J-CAM it worked best with medium tension springs!--(if you find you need a inbetweenee/-you can use them mixed also!IE:---a light & a medium).--Be sure your timing is dead-on & a watch & set distance don't lie!---RICHIE

Cotten
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Re: Advance springs.

#6

Post by Cotten » Thu Mar 27, 2014 3:29 pm

Once upon a time Folks,

I worked for a University that had an engine lab, with what would now be perhaps a fifty-year old SUN automotive distributor "machine".

Having an ignition problem with the '65 circuit breaker, I stuck it in and spun it. Bouncing points were displayed by phantom arrows all around the clock!

But back to topic, the '65 timer, which had other problems by design, was nearly 'off-on' for an advance curve.
So the next question is: How appropriate would later weights be for the one-year-only design?

Thanks in advance,

....Cotten

58flh
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Re: Advance springs.

#7

Post by 58flh » Thu Mar 27, 2014 3:44 pm

Cotton --I believe George has the flat-top aftermarket single-auto timer,-I remember talking with him awhile back!---On to the sunnen machine,--I used one as a 19-yearold it had a pulse black & white moniter & was set for 4-6 &-8 cyl. motors--upon putting big-bore kits on VW-bugs,--It would actually show you when a set started to bounce!-& what RPM!---That was as far as I took it & Im sure it could have been rigged-up to hold a timer & spin it on a separate machine--(lathe maybe)spin-up the RPMs & take readings.This is not the IG. machine you speak of however!---Sadly today what cost $3K then is outdated & can be got for $200!---Richie

Cotten
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Re: Advance springs.

#8

Post by Cotten » Thu Mar 27, 2014 8:05 pm

Richie meant "SUN", honest Folks.

We all push the wrong buttons daily.
(If you are married, no explanation necessary.)

Who can do a study of the different weights of weights for us?
I have at least three different springs from TEDD on the wall, for what that is worth..

....Cotten

kitabel
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Re: Advance springs.

#9

Post by kitabel » Thu Mar 27, 2014 10:03 pm

Ah, but it's not the total weight (as in, from a scale), but the inertia where the outermost material has far more effect than material adjacent to the pivot.

Cotten
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Re: Advance springs.

#10

Post by Cotten » Thu Mar 27, 2014 10:09 pm

So Kitabel!

How can we study this concern?

Anyone on the forum have a "machine" similar to the SUN?

....Cotten

kitabel
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Re: Advance springs.

#11

Post by kitabel » Thu Mar 27, 2014 10:33 pm

Just a thought: suspend the weight from a pin through the pivot (like a rod balance), and weigh only the outer end. Won't be exact but closer.

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Re: Advance springs.

#12

Post by RUBONE » Thu Mar 27, 2014 11:52 pm

One thing I did for years to eliminate bouncing points was to use Bendix magneto points as used on H-D lightweights. The dual spring and straight orientation of the follower was good for a crisper ignition and a few hundred RPM.

Cotten
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Re: Advance springs.

#13

Post by Cotten » Fri Mar 28, 2014 12:06 am

Kitabel!

If we had a stack of all the various weights (springs hang on my wall, and even though TEDD's, I doubt they are repops), then a study would only be another R&D exercise.

If only we knew where an old SUN automotive distributor analyzer still existed, it would certainly 'cut to the chase'.

....Cotten

ingram
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Re: Advance springs.

#14

Post by ingram » Fri Mar 28, 2014 12:35 am

Cotten wrote:Kitabel!

If we had a stack of all the various weights (springs hang on my wall, and even though TEDD's, I doubt they are repops), then a study would only be another R&D exercise.

If only we knew where an old SUN automotive distributor analyzer still existed, it would certainly 'cut to the chase'.

....Cotten
Here is a source.
http://paramountd.com/" onclick="window.open(this.href);return false;

Cotten
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Re: Advance springs.

#15

Post by Cotten » Fri Mar 28, 2014 11:24 am

Looks promising, Ingram,..

But the welcome page just stalls out my Opera, and the testers for sale button is dead for me.

It would be great if a forum member had an analyzer.

.....Cotten

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