Timing

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71scamp78

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Bone stock down to the manifolds and dual point distributor. 68 383 dart just curious what the initial timing should be. Thinking old specs was 0 degrees before tdc..that sound correct.
 
Forget stock. You need to measure the balancer and make some (at least temporary) marks so you know where say, each 5* is up through 40. Now set it "somewhere" so you know where it is, then rev it up with vacuum disconnected and find out how far it advances. While you are at this you might want to take a good hard look at the mechanical advance, is it rusty, sticky, or free? Shaft play? Are the points (dwell) set correctly and are the points in good shape.

Then when you figure out how far it advances, start with about 35 total and see where the initial comes back to.

Does this "have a cam?" Anything with any kind of performance cam, even mild, wants perhaps 10 BTC minimum, depending on the curve
 
71scamp78 said:
Bone stock down to the manifolds and dual point distributor. 68 383 dart just curious what the initial timing should be. Thinking old specs was 0 degrees before tdc..that sound correct.
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If its stock distributor then use stock initial.
Initial is set with a vacuum advance hose plugged and tachometer.
This is even more critical if the distributor was a part of a Clean Air Package (CAP), which it may be for '68.
If you don't have a '68 FSM, download it from Mymopar, or send me a PM with the distributor's tag number and I'll look in my paper copy.
 
stock? PLug VA and rev until advance stops. Set to 38 degrees. See where the base timing falls. If it under 10 degrees, have the dizzy recurved.
 
71scamp78 said:
Bone stock down to the manifolds and dual point distributor. 68 383 dart just curious what the initial timing should be. Thinking old specs was 0 degrees before tdc..that sound correct.
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An old motors manual shows TDC for a standard shift car ; shows 5* BTDC for an automatic car.
It is a 10:1 for 4 BBL motors so premium is required. The points nuts require a 64th's ignition wrench on some brands. Polish the dist. cam with 600 grit. And use dist. cam lube. Carefully set the point gap. A drop of oil under the rotor. Check/oil centrifugal weights. It is a quality distributor.
 
Here is the tag on distributor. If I decide to go electronic I was thinking 4seconds flat go with his conversion but man it's pricey. It's a great unit had one before but is there anything cheaper that's good

20220610_145836_copy_3600x4800.jpg
 
Dual point! Stock, Do keep and save it whatever you do! Worth Good money!

Replace with single point Mopar dizzy and Pertonix III upgrade is my opinion, make sure you use the flamethrower III coil and Run Taylor Resistor wires and bypass Ballast from behind to retain stock appearance!

Limit the advance after 18 initial to 34 total! All in at 2k RPM. Enjoy and smile!
 
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If the stock distributor works now, retain it. There's nothing wrong with points. A dual point distributor with everything in good shape working properly with a good hot coil will rival a good electronic ignition.
 
With that distributor initial should be 5* BTDC at 650 rpm.
You can experiement with adding a degree or two and then take it on a long interstate drive or some long mountanous runs and see how it goes.

PS. if you go to measure timing vs rpm, you'll find that distributor does not stop advancing at mid rpm.
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You need to find out what the total is. THAT IS IMPORTANT. If it's too much you can damage the engine (break piston rings and lands) if it is not advancing or way short, you will be down on power and may run "hot". There is no reason nor should you even make assumptions about advance on old distributors. For all you know, it could have been recurved at some point
 
71scamp78 said:
I set it at 5 degrees yesterday seems to run pretty good. Starts easy but seems to be running rich
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Buy a tachometer if you don't have one. Must know the idle rpm is 650 or less. For example 5 degrees at 850 will retard the entire curve and can make the engine response seem sluggish.
Then if you want you can also check the advance to see if it is within specs, at least up to whatever the tach goes to.
 
Also if nobody has mentioned this, the distributor advance specs are published in "distributor degrees" and also "distributor RPM." That means if it says the dist. has 12* advance, that is 24 at the crank. Ditto the RPM, if they say "at 1500 RPM" then that means the engine (crank) is at 3K
 
67Dart273 said:
You need to find out what the total is. THAT IS IMPORTANT. If it's too much you can damage the engine (break piston rings and lands) if it is not advancing or way short, you will be down on power and may run "hot". There is no reason nor should you even make assumptions about advance on old distributors. For all you know, it could have been recurved at some point
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I agree w this guy. He helped me w something been troubling me for a while. - throw another Thanks.

Stuff you are dealing with is old and no telling how many people had their hands in it.
Set total timing. - to something comfortable. * 32 before?
Check idle timing. If its less than 5* - you need a re-curve with more initial advance.
. And See how fast it starts to advance. Your springs may have been diddled with and timing is floating in the curve at an idle.
 
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