TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC V8 Engine Repair and Modifications
  New Posts New Posts RSS Feed - Advance curve set Mr. Gasket 927G
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

Advance curve set Mr. Gasket 927G

 Post Reply Post Reply
Author
Message
ccowx View Drop Down
AMC Addicted
AMC Addicted


Joined: Nov/03/2010
Location: Yukon
Status: Offline
Points: 3510
Post Options Post Options   Thanks (1) Thanks(1)   Quote ccowx Quote  Post ReplyReply Direct Link To This Post Topic: Advance curve set Mr. Gasket 927G
    Posted: Feb/25/2017 at 12:50am
I am lucky to have access to a distributor testing machine, an Allentest model. I took my D-R distributor and decided to run all of the various springs and weights. I will likely not use most of the settings, but I thought it would be nice to have such a chart for future reference. The aftermarket dissy users get nice charts to tell them what theirs do with various parts installed and I thought it would be good to have something similar. I have a 24 degree pole piece and a #159 center piece. I used the bronze bushing from the kit on the advance peg. This is what happened:

With stock advance weights:

Springs         total advance rpms

ST/St             3400
ST/G              3200
G/G                3000
G/S                2700
S/S                2500
S/B                2200
B/B                2100

With Aftermarket advance weights

Springs            Total advance rpms

ST/St                 2900
ST/G                  2600
G/G                   2400
G/S                   2200
S/S                   1900
S/B                    1600
B/B                    1400

PS: ST mans stock springs, G=Gold, S=Silver and B=Black as per the colour coded springs in the kit.


Back to Top
PHAT69AMX View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jul/07/2007
Location: West Virginia
Status: Offline
Points: 5903
Post Options Post Options   Thanks (0) Thanks(0)   Quote PHAT69AMX Quote  Post ReplyReply Direct Link To This Post Posted: Feb/25/2017 at 11:01am
May I ask are posted RPM's Distributor RPM or Crank RPM ?
Is it possible to also post at what RPM the mechanical advance started ?
Thanks for posting.
Back to Top
ccowx View Drop Down
AMC Addicted
AMC Addicted


Joined: Nov/03/2010
Location: Yukon
Status: Offline
Points: 3510
Post Options Post Options   Thanks (0) Thanks(0)   Quote ccowx Quote  Post ReplyReply Direct Link To This Post Posted: Feb/25/2017 at 11:54am
Sorry, I was somewhat time limited on the use of the machine. Thursday before a long weekend, coming on for quitting time! 

These are crank rpms. I did not note down the starting rpms, but generally they seem to start at around 1000 rpms or so. Another thing that I did not have time to map was the actual curve. For example, the heavier weights would tend to exert more rapid advance in the higher rpms, because centrifugal force increase exponentially. Lighter weights would have different values over the mid range of advance. Different pole pieces can affect this too. Lots of different things like this can come into play for those that are really into the finer details. 

With all of the different pole pieces and such there are a million combinations. I just wanted to give people some idea of what the max advance would be and where. That is probably the most critical and what people pay most attention to. 

Thanks!

Chris 
Back to Top
348AMX View Drop Down
AMC Addicted
AMC Addicted


Joined: Jul/03/2007
Location: Massachusetts
Status: Offline
Points: 4165
Post Options Post Options   Thanks (0) Thanks(0)   Quote 348AMX Quote  Post ReplyReply Direct Link To This Post Posted: Feb/25/2017 at 12:07pm
Do you know what the total timing degrees were at the listed RPM's??
Back to Top
6PakBee View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Charter Member

Joined: Jul/01/2007
Location: North Dakota
Status: Offline
Points: 5454
Post Options Post Options   Thanks (0) Thanks(0)   Quote 6PakBee Quote  Post ReplyReply Direct Link To This Post Posted: Feb/25/2017 at 12:38pm
I guess I've always paid more attention to what the shape of the advance curve looks like prior to about 2000 rpm, not just the total advance.  I could be using the wrong approach though.
Roger Gazur
1969 'B' Scheme SC/Rambler
1970 RWB 4-spd Machine
1970 Sonic Silver auto AMX

All project cars.

Forum Cockroach
Back to Top
ccowx View Drop Down
AMC Addicted
AMC Addicted


Joined: Nov/03/2010
Location: Yukon
Status: Offline
Points: 3510
Post Options Post Options   Thanks (0) Thanks(0)   Quote ccowx Quote  Post ReplyReply Direct Link To This Post Posted: Feb/25/2017 at 12:41pm
348: 24 degrees. I have that center piece and that is probably the most popular amount of advance. 

6pack: I also pay attention to those things, as much as possible. I am using a Mallory Group 19 dissy in my car right now, and it has a set up that allows me to have the first 20 degrees come on quickly and then slows down for the last 4. I found that useful for avoiding mid range detonation. 
Back to Top
Lyle View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jul/17/2014
Location: None
Status: Offline
Points: 772
Post Options Post Options   Thanks (0) Thanks(0)   Quote Lyle Quote  Post ReplyReply Direct Link To This Post Posted: Feb/26/2017 at 10:03pm
Correct me if I'm wrong here but that 24° is a good number for mechanical advance but the total advance would be initial + mechanical. So 12° + 24° = 36° total timing which would be good depending on cam/compression ratio ...
Good to know the springs and mechanical advance numbers for given RPM for those using this distributor - thanks.
Back to Top
ccowx View Drop Down
AMC Addicted
AMC Addicted


Joined: Nov/03/2010
Location: Yukon
Status: Offline
Points: 3510
Post Options Post Options   Thanks (0) Thanks(0)   Quote ccowx Quote  Post ReplyReply Direct Link To This Post Posted: Feb/26/2017 at 10:29pm
I use exactly the numbers you suggest. Anything from 34-38 total seems to be common and as much as 38-40 may be good too. 24 is probably the most common but there are a million ways to skin that cat! Pretty much up to the butt dyno and what works without detonation for your particular combination. 

I hope it is useful to some here to know what a common advance kit and a stock type distributor actually is doing. Not everyone is able to access a dissy machine and using your car as a 400 hp distributor machine is both a nuisance and inaccurate.  

Chris 
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.234 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or