Timing
Thread Starter
Le Mans Master
Joined: Oct 2006
Posts: 8,939
Likes: 35
From: El Cajon California
Timing
Going to time the car this weekend, using the sticky above, I am unable to locate or read the tag that tells me what my initial timing should be.
It is a stock 1978 L-48, auto matic, federal car.
It is a stock 1978 L-48, auto matic, federal car.
Le Mans Master
Joined: Aug 2001
Posts: 7,804
Likes: 4
From: Standing still with all my might Texas
Cruise-In X Veteran
St. Jude Donor '09-'11
Intermediate
Joined: Jul 2010
Posts: 37
Likes: 0
From: Fowlerville Mi.
From Chiltons, 1978 L-82 is 12deg. btdc, L-48 6deg. btdc, and california is 8 deg. btdc.
Chiltons info is correct to the engine tag on my 77,however my initial timing is set to 14deg. so i can get 36 all in by 3000rpm.
Regards,
Sean
Chiltons info is correct to the engine tag on my 77,however my initial timing is set to 14deg. so i can get 36 all in by 3000rpm.
Regards,
Sean
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Initial timing does not mean crap. Find out what the total timing is and work from there. The stocks specs are for the birds. The car will run much better with the distributer curved for performance and the total timing about 34 to 36 degrees depending on the engine. On a stock motor 12 to 14 initial with a total of 36 all in by 2500 to 3000 rpm works the best. You will notice a difference in performance if the timing is setup correctly.
Burning Brakes
Joined: Sep 2008
Posts: 805
Likes: 5
From: Naperville Illinois
Initial timing does not mean crap. Find out what the total timing is and work from there. The stocks specs are for the birds. The car will run much better with the distributer curved for performance and the total timing about 34 to 36 degrees depending on the engine. On a stock motor 12 to 14 initial with a total of 36 all in by 2500 to 3000 rpm works the best. You will notice a difference in performance if the timing is setup correctly.
If you take no other advice from this Forum...
Just curious, if you are going to advance the timing according to the sticky, why do you need the stock spec?
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Thread Starter
Le Mans Master
Joined: Oct 2006
Posts: 8,939
Likes: 35
From: El Cajon California
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
If you need to pass emissions testing, you want to retard the spark as much as possible without causing the engine to stall, lean the idle jets as much as possible and reduce the idle RPM so that the engine just continues to run when in drive range (if an auto tranny). Don't leave those settings on the engine very long....just long enough to pass the smog tests.
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
When undergoing emissions testing (in neutral), my emission readings were lowest when the idle was set to the highest permissable (just under 1100 rpm) with the spark advance dialed back to ~ 4 or 6 degrees, and with stoichiometric A/F ratio.
Drifting
Joined: Feb 2005
Posts: 1,879
Likes: 38
From: Los Gatos CA
The last time I smogged my 68 I had to set the initial at 4* BTDC, or he woulda failed me. I passed the sniffer and visual, but he was gonna fail me! Ha! He lent me a 9/16ths and his timing light when the boss wasn't looking.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
More rpm means more exhaust. And, with hydrocarbons being a percentage of the exhaust, that means more of them, too. I find it hard to believe that a higher idle speed made less hydrocarbons. 
Now, if the equipment actually measures in ppm (a rate of hydrocarbon production), it might be possible that a higher rpm would generate a lower hydrocarbon rate. But, I think many of the states use devices performing 'gross' hydrocarbon detection. Thus, the fewer you produce, the better. If that's true (as I believe), lower idle rpm would be better.
Now, if the equipment actually measures in ppm (a rate of hydrocarbon production), it might be possible that a higher rpm would generate a lower hydrocarbon rate. But, I think many of the states use devices performing 'gross' hydrocarbon detection. Thus, the fewer you produce, the better. If that's true (as I believe), lower idle rpm would be better.
Last edited by 7T1vette; Feb 11, 2011 at 10:17 PM.
Melting Slicks
Joined: Jul 2004
Posts: 3,296
Likes: 8
From: Avon, Indiana
No matter if doing something with timing might improve emmissions, in California they will usually confirm that you are at factory spec before doing the test.The tech will also make sure all hoses are connected properly, including those that go to the air cleaner.
