396 BB Timing issue? - Team Camaro Tech
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post #1 of 2 (permalink) Old Apr 8th, 08, 04:45 PM Thread Starter
 
Join Date: Feb 2008
Posts: 46
396 BB Timing issue?

Ok, i got the timming currently set at 18degrees BTDC / After driving it....
restarting, it cranks slow then starts.... It seems if i advancve it any more u would think it would be too much? Anyone?


BTW / 396 / Edlebrock intake and 750 carb / Mild cam / Hooker headers /
MSD Ignition...
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post #2 of 2 (permalink) Old Apr 8th, 08, 05:53 PM
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Ron
 
Join Date: Nov 2006
Location: North Channel Lake Huron
Posts: 3,934
Re: 396 BB Timing issue?

18 degrees initial advance is about right but a lot has to do with your cam profile and the Installed Intake Lobe Centerline (ILC). For instance; If you have the cam installed straight up at say the cam mfgr's recommended ILC of 110 degrees an 18 degree initial advance may be suitable for starting the engine. Now say you advance the ICL to 106 or in most cases we as Hot Rodder's like a 104 degree ILC (concentrating on when the intake valve closes) in order to lengthen the compression stroke which increases the DCR and Torque (anything for a bigger Bang - LOL) We are advancing the cam 6 degrees or what is considered 2 more degrees then the so called 4 degree built in advance profile that cam mfgr's like to use as an advertising gimmick. From this senero the engine would start better with say 18 - 6 = 12 degrees which obviously seems too low for a BBC but as I mentioned regarding the Mfgr's 4 degree gimmick they claim is 6 -4 = 2 degrees thus 18 - 2 = 16 degrees initial advance for starting is hog wash as it is the ILC that defines the position of the cam.

To tell you the truth I don't worry about the initial advance until it comes time to start the engine. I concentrate on degreeing and installing the cam in a position I figure will optimize my engine. If it likes 16 degrees over 18 degrees to start that's what you have; I don't care as long as I can get the total in with the curve I want on my specifications and that of course depends on tranny, gearing ... etc.

Another thing; a BBC likes a slippery start. Before turning the key Pump twice when cold and once when hot. 3 times when hot will more then likely flood the engine, drowning plugs dumping raw fuel into the pipes and when the the plugs start to light up, ignite the raw fuel in the pipes, and blow your mufflers off - LOL

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Last edited by Z15CAM; Apr 10th, 08 at 03:28 PM.
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