Question reqarding timing to 36 degrees,
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,738
Likes: 53
From: Bogart GA
Question reqarding timing to 36 degrees,
I timed my distributor to 36 degrees with the springs off and vacuum advance disconnected. I used Lars's kit with not problems. I had to mess with the springs some to get all 36 deg in by about 2600 rpm. With the vacuum advance still disconnected I check my initial timing at idle (750 rpm) and found it to be 21 degrees!! That seems high to me. Assuming my weights are seated and not advancing at idle. what else could cause this?
I am going to check with the weights removed. If there is no change it would seem that there may be somthing physically wrong with the distributor.
Thanks!!
I am going to check with the weights removed. If there is no change it would seem that there may be somthing physically wrong with the distributor.
Thanks!!
Safety Car
Joined: Feb 1999
Posts: 3,631
Likes: 14
From: Fountain Hills AZ
Re: Question reqarding timing to 36 degrees, (KJL)
What do you mean by "messed with the springs" and how did you verify that timing was all in by 2600? Lower you idle as low as it will go and take a reading there. With light springs, you might be already getting some centrifugal at 750 rpm. Also, with the light hooked up and the vacuum advance still disconnected, rev the engine to 4500 or so with the springs installed to make sure that you are actually getting full advance at 2600. Unless you plan to run the distributor without springs, take your readings with them installed.
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: Question reqarding timing to 36 degrees, (KJL)
As far as im concerned the springs must be installed when setting the timing. They are what actually pulls the weights back in to retard the timing when the engine slows back down. If you are checking for initial timing with the springs removed, this is why the timing reading is high. The weights will advance the timing at very slow speeds if there are no springs to pull them in. Put the springs back on and test again.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Re: Question reqarding timing to 36 degrees, (Jvette73)
Mine is set at 21 degrees at idle, fifteen degrees is the mechanical advance in a stock ditributor giving me 36 degrees at 2500 RPM. I do not reconnect the vacuum advance as a matter of fact my new MSD Pro Billet distributor lets you completly remove ans lock out the vacuum canister.
Melting Slicks
Joined: Oct 1999
Posts: 2,581
Likes: 14
From: Tolar Texas
Re: Question reqarding timing to 36 degrees, (KJL)
Check out this thread from the C1 & C2 forum.
Centrifugal advance problem - degrees missing
http://forums.corvetteforum.com/zerothread?id=355239
Centrifugal advance problem - degrees missing
http://forums.corvetteforum.com/zerothread?id=355239
Drifting
Joined: Sep 1999
Posts: 1,411
Likes: 1
From: Wylie TX
Re: Question reqarding timing to 36 degrees, (MIKER)
I cannot speak for KCL, but I think he removed the springs in order to be absolutely certain that he had total advance at 36*. Then, he tried different springs until he saw that 36* at 2600 RPM.
If you want to determine if the mech advance is already being "used up" at idle, you can put in the stiffest springs and then check your advance at idle. Now, if you only have 15* of total mechanical advance available, you will need new weights and center plate which should give you more advance.
If you want to determine if the mech advance is already being "used up" at idle, you can put in the stiffest springs and then check your advance at idle. Now, if you only have 15* of total mechanical advance available, you will need new weights and center plate which should give you more advance.
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,738
Likes: 53
From: Bogart GA
Re: Question reqarding timing to 36 degrees, (Chris A)
Yes, that is what I did. Pull the springs and turn the dist until my adjustable timing light showed 36 degrees. Put the correct spring combo to achieve full mechanical advance at about 2500 rpm. With an 8 distributor deg vac advance unit, this will give you a total of 52 deg at 2500 rpm. I had though that by removing the weights, I could check to see if that were advancing the timing at idle with my spring combo. BUT if total mechanical advance is 15 crank degrees...36-15=21 :crazy: So Chris and Motorhead answered my question. I would need to increase the amount of mechanical advance available in order to lower my initial advance at idle.
Thanks to all!!
Thanks to all!!
