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440 timing question #1009657
06/08/11 10:05 PM
06/08/11 10:05 PM
Joined: May 2005
Posts: 127
Missoula, Montana
ChadP Offline OP
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Missoula, Montana
New 440 engine build (30 over)...pretty mild (375 hp)...stock intake...Holly dp 750 , Mopar electronic ignition with vacuum advance. Cam is custom grind, but not real radical. What would you suggest to set the timing on this engine. Will be running pump gas (best in Montana is 91 octane). Heads are 906 with hardened seats.
Four speed with 3.09 first gear - 2.74 rear.


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Re: 440 timing question [Re: ChadP] #1009658
06/08/11 10:15 PM
06/08/11 10:15 PM
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Kirkland, Washington
Pacnorthcuda Offline
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Mechanical: 34-36 total. All in by 2500, a little less if the motor/gas will allow.
Vacuum: enough to provide 54 total when added to the above, ported of course.

As far as initial....16-20 is good, the higher numbers may be little hard on starting, but I would be more concerned about the 34-36 mechanical and how fast it comes in than the initial.

Re: 440 timing question [Re: Pacnorthcuda] #1009659
06/08/11 10:45 PM
06/08/11 10:45 PM
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Upper Midwest
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MoparforLife Offline
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Remember your total at 2500 don't count unless you have the distributor recurved so that the mechanical advance is fully advanced by that RPM.

Re: 440 timing question [Re: Pacnorthcuda] #1009660
06/08/11 10:48 PM
06/08/11 10:48 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert Offline
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Lincoln Nebraska
(1) set initial w vac gauge method (max vac minus 1 in hg) then w that figure in hand (2) shorten the slots to get 36 total (vac adv disconnected/plugged)(3) play w springs to get the fastest curve it'll take at WOT up thru the gears staying just under the pinging point on your hottest/driest day no matter where (RPM) that makes it all in by (4) then plug in the vac adv & adj it for the most adv it will take/coming in as fast as it can wo pinging at PART throttle (high vacuum) at a RPM high enough so the slots are maxed out and a 3/32" allen wrench adjusts when (in hg) the curve starts (CCW=later) & can solder strips of feeler gauges on the back of the can to limit the travel of the notch in the arm into the vac can to limit the total a can will offer (2 adjustments on the can). I would suggest using a proportion of race gas so you do not have to compromise the curve which will drastically hurt your power


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Re: 440 timing question [Re: ChadP] #1009661
06/08/11 11:19 PM
06/08/11 11:19 PM
Joined: Jan 2003
Posts: 5,435
So Cal
Sinitro Offline
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If you have the Mopar Electronic Distributor it has 10 degrees mechanical advance, all in by 2K RPM..

10 degrees (distributor) x 2= 20 degrees (@ the crank), one should have about 12-15 degrees initial advance = 32-35 degrees total.
Any more initial advance will likely be hard to start for the street.

Just my $0.02..

Re: 440 timing question [Re: Sinitro] #1009662
06/08/11 11:22 PM
06/08/11 11:22 PM
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Posts: 495
PA--USA
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70VERT Offline
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Quote:

If you have the Mopar Electronic Distributor it has 10 degrees mechanical advance, all in by 2K RPM..

10 degrees (distributor) x 2= 20 degrees (@ the crank), one should have about 12-15 degrees initial advance = 32-35 degrees total.
Any more initial advance will likely be hard to start for the street.

Just my $0.02..




So, if you were to set up initially with a timing light, you would set up at 12-15 deg BTDC with vacuum hose disconnected from dist???

Re: 440 timing question [Re: 70VERT] #1009663
06/08/11 11:30 PM
06/08/11 11:30 PM
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Florida
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mopar346 Offline
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Initial can be deceiving according to the idle speed, 36 total in by 3k mechanical advance. 31-33 if spraying.


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Re: 440 timing question [Re: 70VERT] #1009664
06/09/11 12:29 AM
06/09/11 12:29 AM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert Offline
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Quote:

So, if you were to set up initially with a timing light, you would set up at 12-15 deg BTDC with vacuum hose disconnected from dist???


Correct, disconnected/plugged

Last edited by RapidRobert; 06/09/11 12:30 AM.

live every 24 hour block of time like it's your last day on earth
Re: 440 timing question [Re: RapidRobert] #1009665
06/09/11 11:34 AM
06/09/11 11:34 AM
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dogdays Offline
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IF you are using a stock cylinder head and stock-type pistons you will get best horsepower with 38 degrees total at 3000 rpm. Get a "dial back to zero" timing light and check it at 3K. Years of dyno tests with stock-type big-blocks have shown this to be true. If you somehow built it with 516 or 915 heads which are closed chamber then you might try 36 degrees, but no less.

R.

Re: 440 timing question [Re: mopar346] #1009666
06/09/11 11:39 AM
06/09/11 11:39 AM
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Junky Offline
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Quote:

Initial can be deceiving according to the idle speed, 36 total in by 3k mechanical advance. 31-33 if spraying.



Never thought of this before. What should the idle RPM be when setting timing?


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Re: 440 timing question [Re: Junky] #1009667
06/09/11 12:48 PM
06/09/11 12:48 PM
Joined: Jan 2007
Posts: 780
Woodinville, WA
Viol8r Offline
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As long as your distributor is not advancing at idle, i.e. light springs or vacuum advance, then your timing should not move until your advance starts kicking in. This RPM can vary but idealy it will happen just above your idle RPM, say around 1200-1400 RPM.

Re: 440 timing question [Re: Junky] #1009668
06/09/11 02:33 PM
06/09/11 02:33 PM
Joined: Jan 2003
Posts: 5,435
So Cal
Sinitro Offline
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Quote:

Quote:

Initial can be deceiving according to the idle speed, 36 total in by 3k mechanical advance. 31-33 if spraying.



Never thought of this before. What should the idle RPM be when setting timing?




Force the idle speed down..
As mentioned you want the RPM low enough enough so the mechanical advance has not yet kicked in..
Regarding total advance, running 91 octane and the proper plugs & carb jetting we have found the Mopar BB like 33-35 total degrees advance...

Just my $0.02...

Re: 440 timing question [Re: Sinitro] #1009669
06/09/11 04:04 PM
06/09/11 04:04 PM
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Junky Offline
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Quote:

Quote:

Quote:

Initial can be deceiving according to the idle speed, 36 total in by 3k mechanical advance. 31-33 if spraying.



Never thought of this before. What should the idle RPM be when setting timing?




Force the idle speed down..
As mentioned you want the RPM low enough enough so the mechanical advance has not yet kicked in..
Regarding total advance, running 91 octane and the proper plugs & carb jetting we have found the Mopar BB like 33-35 total degrees advance...

Just my $0.02...





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Custom Shift Knobs www.flameball.com Check It Out






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