69 427 Intial and Total timing
Thread Starter
Racer
Joined: Apr 2013
Posts: 302
Likes: 16
69 427 Intial and Total timing
I have a MSD billet distributor.
I'm using the lightest springs
I have 18 deg intial timing and 36 deg total all in about 2300 to 2500 rpm.
I think I have the blue or purple bushing installed.
The vacuum advance when connected is at 36 deg. At idle...
Is that correct?
I'm using the lightest springs
I have 18 deg intial timing and 36 deg total all in about 2300 to 2500 rpm.
I think I have the blue or purple bushing installed.
The vacuum advance when connected is at 36 deg. At idle...
Is that correct?
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,147
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From: US-PNW
How is your idle speed and idle quality?
How does it drive across multiple speeds?
Any predetonation pinging (I wouldn't think so at just 36° total)?
Thread Starter
Racer
Joined: Apr 2013
Posts: 302
Likes: 16
.555 lift intake and exhaust
110 deg lobe separation
106 deg intake C/L
218.6 deg duration intake
226.6 deg duration exhaust
Last edited by Z06CE; May 16, 2021 at 12:32 AM.
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Thread Starter
Racer
Joined: Apr 2013
Posts: 302
Likes: 16
That's not much of a spread (18°) between 18° at idle and full 36°. My weights add 24° of advance between idle (12°) and 2800rpm (36°). You also have a high advance vacuum canister that adds 18° (my stock can is also high and adds 20°).
How is your idle speed and idle quality?
How does it drive across multiple speeds?
Any predetonation pinging (I wouldn't think so at just 36° total)?
How is your idle speed and idle quality?
How does it drive across multiple speeds?
Any predetonation pinging (I wouldn't think so at just 36° total)?
It drives ok but it feels like it should have more power for a 427
No predetonation.
I'm coming to the realization that the timing pointer is not at 0 deg TDC... not accurate. Set the intial timing at 29 deg and the idle is a lot better. Took it for a ride and no detonation.! Has more power.
Race Director
Joined: Jul 2015
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From: SW Florida.
Thread Starter
Racer
Joined: Apr 2013
Posts: 302
Likes: 16
setting timing at 29 degrees. with or without vacuum advance? you suspect your TDC point. https://www.amazon.com/Proform-66792...s%2C264&sr=8-3 you can't be running that beast timed by ear.
I agree I need to verify actual top dead center.
BTW. The harmonic balancer is new.
Is my vette stock?? HAHA
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2020 C3 of the Year Finalist - Modified
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yes ot is correct for your question. 18* is your initial the 36* total is your initial plus your mechanical. When you plug in your vacuum can at idle you are seeing initial plus the vacuum advance which sounds like another 18*. You may have to limit it so your total doesnt exceed 50*
Is my vette stock?? HAHA
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From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
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Now onto having 18* initial is high. If you havent verified tdc at 0 you should, then re asses your settings
Cruising
Joined: Apr 2021
Posts: 13
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From: North Carolina
at slow cruise with vacuum advance connected there could be 50+ timing. This falls back when throttle plates are opened and vacuum falls away. 18 initial and 36 in by 2800 is a great starting point however it’s a mute point since top dead center can’t be verified.
Last edited by C3USA#1; May 16, 2021 at 09:13 AM.
Had a 1976 L-82, 4-sp
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From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Using the lightest springs may be introducing some mechanical advance at idle. Have you checked with your timing light that there is no advance at idle speeds? Mech'l advance shouldn't begin until a few hundred or more rpms above idle.
Safety Car
Joined: Apr 2006
Posts: 4,057
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From: BC
On my 69 427/390 I run a Comp 270 hydraulic roller cam. I run 18 degrees initial advance with 18 degrees mechanical on the original 69 distributor. The trick is to limit the vacuum advance to about 12 degrees or so or you will get pinging/detonation when you step on the throttle. Aftermarket distributors and advance cans usually have way too much vacuum advance so you either have to limit it or run a different advance can. I run the original 69 MS360 advance can on mine as it produces 12 degrees of vacuum advance but vacuum advance limiters are available. I think Lars makes them if you get in touch with him.
Dr. Detroit
Joined: Mar 2012
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From: New Braunfels Texas
You need to verify and mark TDC #1 on the balancer. Your 18/36 setting is a good baseline. Take one silver spring off and run a silver and blue spring. The two light silver spring setup is too aggressive. The vacuum can is adjustable.......18 degrees vacuum adavnce is too much. Shoot for 30 degrees initial with the can plugged in to full manifold vacuum at idle......this means the can pulls 12.
Jebby
Jebby
Race Director
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From: SW Florida.
Idle speed is at 750 but spikes 50 rpm or so
It drives ok but it feels like it should have more power for a 427
No predetonation.
I'm coming to the realization that the timing pointer is not at 0 deg TDC... not accurate. Set the intial timing at 29 deg and the idle is a lot better. Took it for a ride and no detonation.! Has more power.
It drives ok but it feels like it should have more power for a 427
No predetonation.
I'm coming to the realization that the timing pointer is not at 0 deg TDC... not accurate. Set the intial timing at 29 deg and the idle is a lot better. Took it for a ride and no detonation.! Has more power.
Thread Starter
Racer
Joined: Apr 2013
Posts: 302
Likes: 16
I found out why my timing readings are not accurate.
I have a Innova 3568 Digital Timing Light which may not be compatible with the Mallory Hyfire 6A and the MSD 8572 distributor. Is this true?
Which timing light could I use?
I have a Innova 3568 Digital Timing Light which may not be compatible with the Mallory Hyfire 6A and the MSD 8572 distributor. Is this true?
Which timing light could I use?
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
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From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
I have an Innova light also. It works perfect above 3000 rpm where multi spark discharge ends and only a single spark. Idle to 3000 rpm can be challenging on my timing gun at times.