What is your initial timing?
Thread Starter
Safety Car
Joined: Mar 2001
Posts: 3,725
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From: Rochester NY
What is your initial timing?
Hi All,
I have been playing around with my timing as of late. Just seeing how the car runs at different settings. But anyway when I set my 80 HEI at 36 degrees at 3000 rpm the idle setting is about 24 degrees! What are you guys seeing with this deal? I have talked to Lars and he says that is a by-product of the 80 HEI, slow and short curve. Also I am surprised that the sound of the exhaust changes dramatically when the timing is moved around.
Joe
I have been playing around with my timing as of late. Just seeing how the car runs at different settings. But anyway when I set my 80 HEI at 36 degrees at 3000 rpm the idle setting is about 24 degrees! What are you guys seeing with this deal? I have talked to Lars and he says that is a by-product of the 80 HEI, slow and short curve. Also I am surprised that the sound of the exhaust changes dramatically when the timing is moved around.
Joe
Melting Slicks
Joined: Oct 2000
Posts: 3,023
Likes: 2
From: TEXASTEXASTEXASTEXAS TEXASTEXASTEXASTEXAS
St. Jude Contributor
Re: What is your initial timing? (MikeC)
Two. That's right, two puny I-got-too-much-compression-and-damned-93octane-gas degrees. Still goes like a scalded cat, though I do get some pinging still at WOT.
JB
[Modified by JB, 10:57 AM 9/30/2002]
JB
[Modified by JB, 10:57 AM 9/30/2002]
Thread Starter
Safety Car
Joined: Mar 2001
Posts: 3,725
Likes: 0
From: Rochester NY
Re: What is your initial timing? (73 LS-4)
Mines at 13 initial. Sounds like it's time for some lighter springs in your distributor.
:cheers:
Pat Kunz
:cheers:
Pat Kunz
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Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Re: What is your initial timing? (Xracer)
I use an MSD timing computer and have my curve fixed in the distributor. I only set the total timing and that is around 3000rpm. I bring it up to about 35oo to be sure, set the timing at about 38degrees then check the idle but let it fall where it wants. Since the msd pulls about 20 degrees out of it I get about 18 at idle. The MSD also pulls 20 out for starting. I also have an MSD adjustable timing pot in the car so I can add or pull timing out while driving down the road.
Safety Car
Joined: Feb 1999
Posts: 3,631
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From: Fountain Hills AZ
Re: What is your initial timing? (Xracer)
Xracer, did you confirm that your distributor is through advancing at 3,000rpm? Many distributors, especially those on emission controlled engines, don't reach full advance until much higher rpm. If that's the case, a reading taken at 3,000 rpm may be way lower than what the actual total advance is and it would also result in a higher initial setting. Keep in mind that the springs control the rate of advance, not the amount of advance.
Drifting
Joined: Nov 2000
Posts: 1,361
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From: Honolulu Hawaii
Re: What is your initial timing? (Vetterodder)
Vetterodder is right-on-the-money, again!quote: "According to Lars, your timing @ idle is irrelivant.
You dont drive your car @ idle so therefore it doesnt apply."
Maybe true for stock or near stock builds. Less true for performance builds. ;)
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Re: What is your initial timing? (nunus79)
Take your distrubutor apart and clean and lube everthing, you only have 11 degrees mechanical and you should have 15 degrees bet you find some rust in the advance assembly.
When I had the stock HEI on mine I was at 21 degrees at idle and 36 degrees at 3000RPM. I do not use a vacuum advance it is for emissions and better gas mileage two things that my car doesn't like :D
When I had the stock HEI on mine I was at 21 degrees at idle and 36 degrees at 3000RPM. I do not use a vacuum advance it is for emissions and better gas mileage two things that my car doesn't like :D
Melting Slicks
Joined: Apr 1999
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From: Moon Twp. PA USA
Re: What is your initial timing? (nunus79)
quote: "According to Lars, your timing @ idle is irrelivant.
You dont drive your car @ idle so therefore it doesnt apply."
Maybe true for stock or near stock builds. Less true for performance builds. ;)
[/QUOTE]
Could you explain your last sentence? Why is Lars' statement less true for performance builds?
Drifting
Joined: Nov 2000
Posts: 1,361
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From: Honolulu Hawaii
Re: What is your initial timing? (glen242)
When you install a high performance cam, the stock distributor settings no longer apply. Smart tuners will try to run as much advance and as quick an advance curve without pre-detonation, to optimize the new high performance build. A stock distributors timing setup will not be ideally setup for best performance, almost guaranteed. That's why a high performance distributor should be tops on the list when you run a hi-po motor. You can then optimize both total and initial timing settings and the rate of advance. Doing just one adjustment without the others is leaving too much power/drivability on the table.
Does that make sense?
Does that make sense?
Melting Slicks
Joined: Apr 1999
Posts: 2,010
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From: Moon Twp. PA USA
Re: What is your initial timing? (nunus79)
OK, I am running 36* advance all in by 2600 rpm. I am using the stock distributor with lighter springs. Stock distributor weights will give about 20* - 22* maximum advance, rest is from initial.
Are you saying I can do better with some other ignition set up?
Check my signature for my mods.
Are you saying I can do better with some other ignition set up?
Check my signature for my mods.
Burning Brakes
Joined: Sep 2002
Posts: 1,179
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From: SF East Bay CA
Re: What is your initial timing? (Xracer)
Started 18, now 20 runs great, but I also have a magnum cam.... before engine mods I was running 10 with stock cam... also replaced dist as well for optimal performance
Drifting
Joined: Nov 2000
Posts: 1,361
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From: Honolulu Hawaii
Re: What is your initial timing? (glen242)
Are you saying I can do better with some other ignition set up?
Also, be aware that some fast-burn type heads actually need less advance (34) for optimum performance. So, 36 deg total for all engine builds may not always be optimum. If I remember correctly, when I was running smog heads, my optimum total timing was 38 based on 1/4 mi track times.
The guys with the big cam many times need the extra initial timing to help maintain an idle. Therefore, to just let the stock mechanical advance dictate the inital advance settings is not a good "general" performance tuning recommendation. Some guys, like you, maybe lucky to fall upon a near ideal setup. While others might try it and end up frustrated.
[Modified by nunus79, 9:19 PM 9/30/2002]