how do I tell my ignition timing's TOTAL advance?

qunvat

qunvat

Well-Known Forum User
...hi there all my loverlies...

I need to find out the above....at the mo the ignition timing is set to approx 14 degrees @ 1,000 revs (..is this called the STATIC timing?? )....but I need to know the total advance....I'm using a strobe gun at the mo...

Set up:

L28 unmodifed with triple Dellortos

Ta, Si
 
now that would depend on two things.

1. are you talking vacum advance?
2 are you talking mechanical advance?
:eek:
 
grolls said:
now that would depend on two things.

1. are you talking vacum advance?
2 are you talking mechanical advance?
:eek:
Click to expand...

...heres the e mail off Des Hammill who's helping me with car stuff generally, its a bit double dutch to me!

"Dear Simon,

Just had a quick look at your e-mail. First thing is what ignition timing are your running? I would expect the static ignition timing to be 12-14 degrees and the total to be 34-36 degrees. This is what could be causing the misfiring.
Find out what this is and get back to me.

Kindest regards
Des Hammill"

.....I'm not using a vacumm pipe thang on the Dellortos, and I've blocked off the end at the dizzy...the carbs have no inlet for it also.

Ta mate, Si
 
Combined total advance (mech +vac) on an L6 should be in the region of 34-36 degrees at around 3500 (it stops advancing after this).

To measure accurately you must have a good quality digital timing light with a dial back facility

Get someone to hold the accelerator pedal constant (or use the idle screws) and use said timing light to check,

Alternatively if you only have an analogue timing light then take a piece of string the same as the circumferance of the crank damper, divide it by 10 and cut the string. The length of this piece will equal 36 degrees (360/10 =36...close enough:unsure: ) measure (with the string) from the TDC mark on the damper and put a chalk mark....this new mark represents absolute max advance mark and is for referance only. Use timing light in conjunction with friend (on accelerator pedal) to see total advance. please note this method is not as accurate as the digital timing light method for obvious resons but will help you determine if you have a problem ie advance is way under or way over.

Triples (Dellortoes and Webers) have no facility for vacuum advance so you are right to block it off.
Quote from Top End Performance website
DO NOT hookup the distributor vacuum advance to the intake Manifold. That does not work and is a common mistake we see. If you do that you will pull full advance at idle then as soon as you open the throttle it loose vacuum and the timing will retard quickly causing a big stumble or flat spot and very bad throttle response.

When running Sidedrafts you need to either get a centrifugal advance distributor or leave your vacuum advance disconnected and just run more initial timing. You usually need 12-14 degress advance at 1000 RPM and 36 degrees total by 3000 RPM for the carbs to react properly. These timing numbers are baseline estimates only and can vary from car to car. You have to make sure you do not have a detonation problem from too much advance.
Click to expand...

The best way by far though is a fully degree'd crank damper but they are expensive (£300-£700)
 
p.s is the crank damper the circular thang that has the numbers on it you(me) points the timing gun at?

I am NOT blond.

Si
 
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