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Author Topic: How much turn of distributor for a couple degrees of timing?  (Read 321 times)

Offline 7Dcuda

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How much turn of distributor for a couple degrees of timing?
« on: April 13, 2017 - 08:45:58 am »
Ive got a 440 with a water pump that has the inlet on the passenger side so it completely covers the timing tab and makes it impossible to use a timing lite.

Ive installed a new distributer and with heavy acceleration have a little valve ping so I need to retard the timing a little.

Its been a loooooong time since Ive had to set timing on an old car like this so my question is:   Approx. how much movement/turning of the distributor does it take to make a degree or two of timing change? 




Offline Beekeeper

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Re: How much turn of distributor for a couple degrees of timing?
« Reply #1 on: April 13, 2017 - 11:34:52 am »
it's not gonna take much to get a couple degrees. If you are doing it by sound and can't see the timing marks, I would loosen the bolt just enough that you move the distributor while it's running. 2-3 flats or so. Then I'd bump up the idle speed on the carb 200 rpm's. Then turn the distributor just a few millimeters until the idle goes down about 200 rpm's back to where it was before you started. Then Tighten distributor clamp and test drive.

Online cudabob496

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Re: How much turn of distributor for a couple degrees of timing?
« Reply #2 on: April 13, 2017 - 07:47:20 pm »
tiny amount.
degree or two of roration.
In fact, dist goes around twice for every firing cycle,
so 2 degree diff in dist equals one degree in timing, I THINK
« Last Edit: April 13, 2017 - 10:39:38 pm by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"


Offline Bullitt-

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Re: How much turn of distributor for a couple degrees of timing?
« Reply #3 on: April 13, 2017 - 07:58:38 pm »
I'd suggest using bother CP's timing method .... you would not even need to see the factory marks as you could make your own.
Key would be to find top dead center on the compression stroke #1 cylinder ..mark a spot on the cover & balancer then measure for the second mark 2-3/8" as in his instruction here  http://www.cuda-challenger.com/cc/index.php?topic=4430.msg33565#msg33565
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Offline 734406pk

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Re: How much turn of distributor for a couple degrees of timing?
« Reply #4 on: April 13, 2017 - 09:17:15 pm »
1 degree of rotation at the distributor = 2 degrees at the crankshaft, so its very sensitive to adjustment. If you can find tdc, you can make your own mark then use an advance indicating timing light to find your base and total timing.
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
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Offline 69bcuda

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Re: How much turn of distributor for a couple degrees of timing?
« Reply #5 on: April 14, 2017 - 07:07:56 pm »
Set TDC at the current timing mark. Scribe an area on the damper where you can see it every 1/16". Fab a pointer. 1/16" on a 7.25 diameter OD is 1° I do believe.

Offline xtopfuel

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Re: How much turn of distributor for a couple degrees of timing?
« Reply #6 on: April 15, 2017 - 09:38:52 am »
can also use a vacuum gauge rotate as stated very slight until highest vacuum point

Offline Rich G

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Re: How much turn of distributor for a couple degrees of timing?
« Reply #7 on: April 15, 2017 - 09:52:42 am »
You might also try getting some timing tape, get TDC , make a mark on the cover where you can see it and start the timing tape from there.

Online cudabob496

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Re: How much turn of distributor for a couple degrees of timing?
« Reply #8 on: April 17, 2017 - 05:10:45 pm »
I'd suggest using bother CP's timing method .... you would not even need to see the factory marks as you could make your own.
Key would be to find top dead center on the compression stroke #1 cylinder ..mark a spot on the cover & balancer then measure for the second mark 2-3/8" as in his instruction here  http://www.cuda-challenger.com/cc/index.php?topic=4430.msg33565#msg33565


could we use TDC for another cylinder, so that side of the damper could be seen?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

Offline xtopfuel

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Re: How much turn of distributor for a couple degrees of timing?
« Reply #9 on: April 17, 2017 - 05:48:28 pm »
Yes number 6