Achieving 34 degrees total timing?
Thread Starter
Melting Slicks
Joined: Mar 2001
Posts: 2,362
Likes: 46
From: New Milford CT
Achieving 34 degrees total timing?
Does this sound like a correct method to achieve 34 degrees total timing without any vacuum advance? 1957/283/220hp
Calculated that 34 degrees eguals 2" on the damper from TDC
Marked a line there and advanced timing at idle, no vacuum
Set intitial advance to 14 degrees to get 34 degrees total at 3000rpm
Car runs great, no pinging or knocking on 93 octane
Would it be better to lock the throttle at 3000 rpms and advance the timing to get maximum rpm?
Honest, using my butt dyno, I can tell no difference if I time it at 6 degrees or 14 degrees initial advance
Calculated that 34 degrees eguals 2" on the damper from TDC
Marked a line there and advanced timing at idle, no vacuum
Set intitial advance to 14 degrees to get 34 degrees total at 3000rpm
Car runs great, no pinging or knocking on 93 octane
Would it be better to lock the throttle at 3000 rpms and advance the timing to get maximum rpm?
Honest, using my butt dyno, I can tell no difference if I time it at 6 degrees or 14 degrees initial advance
Le Mans Master
Joined: Jan 2002
Posts: 8,913
Likes: 283
You are on the right track, but the IDLE timing is calculated with the vacuum hooked up.
Un-hook the vacuum module, which you have done, then set at 14, which you did.
Then plug the vacuum can in, and check the timing. I take it you do not have a "roll back" timing light? Hence the marking on the balancer.
The fly-weight advance sound like it is working and depending on your application, 2300-3000 is in the ballpark. The key here to note is at what RPM the fly-weights add no more advance. To check this, un-hook the vacuum module and plug the vacuum line. Next rev the motor in incremental amounts and note the movement of the balancer line. When it stops moving, note RPM. You can also rev it to about 4000 RPM and back it down slowly and note at what RPM the balancer line begins to retard.
You can install lighter fly-weight springs, to get the centrifugal in faster, and get some more snap out of the motor. The key here is to get the centrifugal in as fast as possible, without any detonation.
For my 327-365 motor, 2350 RPM and the centrifugal is maxed out.
Note: if you make these reading with the vacuum can hooked up, your timing will be in the 52-60 degree range.
14 initial
+
20 Vacuum Advance
+
20 from Centrifugal
=
54 total degrees of advance at 2350 RPM for my motor, free revving.
PS - if you are going to power tune the dist. I recommend a dial back timing light, one with an RPM read out. Not essential, but very nice to have, as the timing mark at this point will be on the other side of the balancer
Mark
Un-hook the vacuum module, which you have done, then set at 14, which you did.
Then plug the vacuum can in, and check the timing. I take it you do not have a "roll back" timing light? Hence the marking on the balancer.
The fly-weight advance sound like it is working and depending on your application, 2300-3000 is in the ballpark. The key here to note is at what RPM the fly-weights add no more advance. To check this, un-hook the vacuum module and plug the vacuum line. Next rev the motor in incremental amounts and note the movement of the balancer line. When it stops moving, note RPM. You can also rev it to about 4000 RPM and back it down slowly and note at what RPM the balancer line begins to retard.
You can install lighter fly-weight springs, to get the centrifugal in faster, and get some more snap out of the motor. The key here is to get the centrifugal in as fast as possible, without any detonation.
For my 327-365 motor, 2350 RPM and the centrifugal is maxed out.
Note: if you make these reading with the vacuum can hooked up, your timing will be in the 52-60 degree range.
14 initial
+
20 Vacuum Advance
+
20 from Centrifugal
=
54 total degrees of advance at 2350 RPM for my motor, free revving.
PS - if you are going to power tune the dist. I recommend a dial back timing light, one with an RPM read out. Not essential, but very nice to have, as the timing mark at this point will be on the other side of the balancer
Mark
Safety Car
Joined: Feb 1999
Posts: 3,631
Likes: 14
From: Fountain Hills AZ
Unless you are certain that your distributor reaches max centrufugal at 3,000 or lower, rev it higher to make sure that there's not more after 3,000. Many stock curves don't see max advance until around 5,000 rpm and setting total sooner results in a bogus setting. Considering the age of the car, odds are good that distributor specs are not the same as original. Also, if your mark is at 34º (and you're not having any problem with 34º total) you might try a little more. Aligning your 34º mark with 2º on the tab would be 36º, etc..
