Total Timing..When?? - Impala Tech
Troubleshooting Diagnosing problems

 
LinkBack Thread Tools
post #1 of 4 (permalink) Old 10-04-2013, 06:48 PM Thread Starter
Senior Member
 
Join Date: Apr 2010
Location: Monroe NC
Posts: 1,094
 
Total Timing..When??

I'm having a senior moment that I hope you guys can help me with.
I'm dialing my distributor on a '68 with a 325 hp 402 bbc and so far what I have is 12* base and 38* total in at 1800. I know this is too soon (going to 2 med. weight springs) but when should this start to happen for best results.
I'm aware each setup is different but looking for a baseline to start with, say initial 12*@ idle; 20*@1500; 30*@ 2000; 38*@ 2500.
This is a fairly stock engine except for the cam in at 224*@515 lift.
68imp is offline  
Sponsored Links
Advertisement
 
post #2 of 4 (permalink) Old 10-04-2013, 07:18 PM
Moderator
 
Join Date: Jan 2006
Posts: 12,367
 
Most start to ramp it up at 2,400 and all in by 3,200. You are in danger of detonation right now with a lot of load at low RPM and with your ignition all in not that far off idle for folks with a cam.

Big Dave
Big Dave is online now  
post #3 of 4 (permalink) Old 10-05-2013, 09:20 AM
Senior Member
 
Join Date: Feb 2012
Location: Florida
Posts: 134
 
MSD suggests that you set your base timing as high as possible without stressing out the starter. Your centrifugal timing curve should start advancing just above idle and be "all in" by 2500-2800. Set total timing for 34-36 deg with vac advance disconnected and plugged. NEVER exceed 36 deg. My big block timing is set at 15 deg base with total at 36 deg and all in by 2600 rpm. I run 93 octane pump gas. Here is a good link to setting timing with links to other useful articles.

http://www.lbfun.com/warehouse/tech_...I%20Tuning.pdf

These MSD graphs show timing maps. Mine is set to "E"

http://s453.photobucket.com/user/bot...ml?sort=3&o=58
wannaSS is offline  
 
post #4 of 4 (permalink) Old 10-08-2013, 12:05 PM Thread Starter
Senior Member
 
Join Date: Apr 2010
Location: Monroe NC
Posts: 1,094
 
Thanks guys, I knew it was too much too soon, but just couldn't remember advance start and ramp rate .
Updated changes with two med. springs result in 16* base; advance starting in
at 900-1000 rpm with a slower ramp rate. Advance ramp stops aprox. 2800 rpm. with
total timing set in at 35*, with added 10* of vacuum adv. on top.
I believe stock early 4 pin HEI's are produced with 20* mechanical, so I'm glad I didn't have to mod. the slots.
I'm also running 93 octane pump
68imp is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Impala Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome