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Re: Help with Ignition Timing- Prestolite Dual Point Distributor [Re: NITROUSN] #2746378
02/25/20 12:05 PM
02/25/20 12:05 PM
Joined: Feb 2009
Posts: 846
NW New Jersey
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RSI700VIPER Offline OP
super stock
RSI700VIPER  Offline OP
super stock
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Joined: Feb 2009
Posts: 846
NW New Jersey
I'm using Sunoco 93 which is the highest octane available where I live. Compression is 10.25 to 1. I'll try backing off initial timing and see what happens. I'll also try to locate a dwell meter and verify settings.


1970 Superbird 440 Six Pack 4-Speed Dana
1971 340 Challenger Conv. PACE CAR
1970 440 Six Pack Challenger 4-speed Dana
1972 Duster 340 4-speed Lemon Twist Survivor
1970 U-Code Challenger R/T, Triple Red, 4-Speed, Dana
1969 Talladega Torino, 428CJ
1969 Gurney Cyclone Spoiler II, 351 4 BBL
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Re: Help with Ignition Timing- Prestolite Dual Point Distributor [Re: RSI700VIPER] #2746398
02/25/20 12:55 PM
02/25/20 12:55 PM
Joined: Jun 2008
Posts: 3,191
usa
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lewtot184 Offline
master
lewtot184  Offline
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Joined: Jun 2008
Posts: 3,191
usa
it's fairly easy to measure how many degrees are in the distributor by measuring the length of the cam slot, minus the pin diameter and dividing by .015.

Re: Help with Ignition Timing- Prestolite Dual Point Distributor [Re: RSI700VIPER] #2746416
02/25/20 01:40 PM
02/25/20 01:40 PM
Joined: Feb 2010
Posts: 1,587
Phila. Pa.
Mattax Offline
pro stock
Mattax  Offline
pro stock

Joined: Feb 2010
Posts: 1,587
Phila. Pa.
Originally Posted by RSI700VIPER
I'm using Sunoco 93 which is the highest octane available where I live. Compression is 10.25 to 1. I'll try backing off initial timing and see what happens. I'll also try to locate a dwell meter and verify settings.

Start with the intial at 5* at whatever rpm the FSM says.
If you plot out the timing specs that DragonSlayer has kindly provided, you'll see how sensitive the timing curve is to the initial setting.
It's a very rise in the advance off of idle.
Also an older distributor its more likely the primary spring has a stretched a little. If you find the advance is starting at a lower rpm than is acceptable, put a little more tension on the primary spring. Test and measure first.

If you don't have the service manual, this will at least get you most of it.
http://www.mymopar.com/index.php?pid=109
Should cover setting for dual points. There also may be a Tech tip on it.

Re: Help with Ignition Timing- Prestolite Dual Point Distributor [Re: Mattax] #2746448
02/25/20 02:49 PM
02/25/20 02:49 PM
Joined: Jun 2014
Posts: 481
VA
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dragon slayer Offline
mopar
dragon slayer  Offline
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Posts: 481
VA
you can probably score a basic dwell meter pretty cheap. It is important because it tells you how long contacts are closed for charging coil. Point gap can be correct, but if the cam is worn or even the point block your dwell will be off.

Re: Help with Ignition Timing- Prestolite Dual Point Distributor [Re: dragon slayer] #2746912
02/26/20 10:54 PM
02/26/20 10:54 PM
Joined: Mar 2003
Posts: 17,808
Fresno, CA
Jim_Lusk Offline
I Live Here
Jim_Lusk  Offline
I Live Here

Joined: Mar 2003
Posts: 17,808
Fresno, CA
Originally Posted by dragon slayer
you can probably score a basic dwell meter pretty cheap. It is important because it tells you how long contacts are closed for charging coil. Point gap can be correct, but if the cam is worn or even the point block your dwell will be off.


I suspect a worn cam (the one in the distributor) like I said above. On my buddy's 340 we swapped a cam from a different distributor and the problem went away. That's why you need a dwell meter or swap the cam with one another distributor.

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