Ignition timing with/without vac advance....sticking?

swisherred

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Recurving the distributor will slow down the advance which is what you want.
With today's corn fed gas timing is everything. The 50 year old specs no longer apply.
I do not run vacuum advance. Sure my MPG may drop but rather spend more at the pump than repairing damage from detonation.
12.5 to 14 initial with 34 to 38 degrees all in at 3000 rpm is good for a 383 stock or light mods like mild cam and duals. Vacuum should be between 17. ( slight mods)and 20 inches ( totally stock)
Every engine is different so test and tune. Drive between adjustments to see what makes her happy.
The motor should start first click every time without long crank time with little or no throttle.
Hope this helps.
So I have noticed that it runs pretty nice right now, but you mentioned not having to press the gas to get it to start. If I just get in and crank it...it wont start or after 10 or so revs it fires but runs like its starving. If I give it a couple pumps before I crank it it fores up and runs fine.....What can be causing this?
 

Trace 300 Hurst

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So I have noticed that it runs pretty nice right now, but you mentioned not having to press the gas to get it to start. If I just get in and crank it...it wont start or after 10 or so revs it fires but runs like its starving. If I give it a couple pumps before I crank it it fores up and runs fine.....What can be causing this?
I’m sure it’s because of different carbs. My brand new, modern Street Demon at only 625 cfm gets a lot of “suck” and thus fuel signal from a half rotation from the engine.
That’s my eddycated guess, anyhoo.
 

swisherred

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I think i got it...I had the choke direction wrong in my head...I was leaning it out instead of making it richer. Seems better now...and runs a little better too.
 

Davea Lux

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So I have noticed that it runs pretty nice right now, but you mentioned not having to press the gas to get it to start. If I just get in and crank it...it wont start or after 10 or so revs it fires but runs like its starving. If I give it a couple pumps before I crank it it fores up and runs fine.....What can be causing this?

These older Mopars need to be pretty rich to start. Most of them took a pump or two of the throttle to get a a fast start. You might check to be sure your choke is closing all the way when cold.

Dave
 

Trace 300 Hurst

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These older Mopars need to be pretty rich to start. Most of them took a pump or two of the throttle to get a a fast start. You might check to be sure your choke is closing all the way when cold.

Dave
Yep. When my mill is dead cold, it’s two pumps for an instant start.
 

stubs300

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So I have noticed that it runs pretty nice right now, but you mentioned not having to press the gas to get it to start. If I just get in and crank it...it wont start or after 10 or so revs it fires but runs like its starving. If I give it a couple pumps before I crank it it fores up and runs fine.....What can be causing this?
These older Mopars need to be pretty rich to start. Most of them took a pump or two of the throttle to get a a fast start. You might check to be sure your choke is closing all the way when cold.
Dave

What Dave said! My /6 after it sits a month or so. I have prime the bowl in the carb, then I have to dance a million times on the gas, crank it, dance some more and maybe it will fire. And that's with a manual choke. /6's are just finnicky to start when cold, and with todays crap they call gas just make carbureted motors even harder to start.
 

cbarge

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So I have noticed that it runs pretty nice right now, but you mentioned not having to press the gas to get it to start. If I just get in and crank it...it wont start or after 10 or so revs it fires but runs like its starving. If I give it a couple pumps before I crank it it fores up and runs fine.....What can be causing this?
I should have been more specific sorry...during the tuning process with engine warm should start first click no gas pedal. Take a piss or have a beer wait a few minutes after shut off and twist her tail. If you have to whine her over and give her gas you may have perculation of the fuel in the carb.
Yes when cold or half cold a shot of gas..thats a given
 

Davea Lux

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I should have been more specific sorry...during the tuning process with engine warm should start first click no gas pedal. Take a piss or have a beer wait a few minutes after shut off and twist her tail. If you have to whine her over and give her gas you may have perculation of the fuel in the carb.
Yes when cold or half cold a shot of gas..thats a given

These usually started best at 1/3 throttle warm. They all liked to percolate some fuel when warm and using part throttle helps dry them out quickly.

Dave
 

Trace 300 Hurst

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When it's been sitting in storage for a week or three, it's exactly eight seconds cranking the starter to fill the bowl. Then two pumps. Most times that's it Up and running immediately.
 

Gerald Morris

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I've GOT to get that plate! My 383 pulls 18" vac but I recently retarded the timing to 11 degrees BTDC to eliminate knocking. This did for suppressing detonation, but makes starting in cold, damn weather a little more problematic. After I do my upcoming timing chain replacement, that limiter plate looks to be an excellent investment.
 

saylor

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i too am in this boat, and just a point of note the mopar distributor instruction set (at least for the 440 dist) says take timing to -5*. i took that to mean ditch/forget what the FSM says.

i also dont have vac adv hooked up yet, chasing stuff just like OP.

rotsa ruck!

- saylor
 

Trace 300 Hurst

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After I do my upcoming timing chain replacement, that limiter plate looks to be an excellent investment.

...the mopar distributor instruction set (at least for the 440 dist) says take timing to -5*. i took that to mean ditch/forget what the FSM says. I also dont have vac adv hooked up yet.
The plate is a fantastic, cheap, easy solution to the "having plenty of initial timing but no detonation" problem.

Neg five? Really? 5 degrees AFTER TDC is awful for starting, idling, everything. I would guess that it is known by someone that there's so much advance built into that dizzy that -5 puts the full mechanical advance at 34* or so. If so, that means you absolutely need the plate.

And get that ported vac advance hooked up! Your mileage and piston rings (gas wash) will thank you.
 

Gerald Morris

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The 5 degrees ATC is for a 2 bbl with the Clean (California) Air Package. Note: 1965-75 Chrysler & Imperial Tune-up Specifications

I would like to have a working NOS CAP rig for Mathilda. I believe it consists of some simple vacuum driven widgetry to advance the spark when starting and such, giving a more efficient burn overall. YEARS ahead of the other folk in Detroit for 1966!

The normal timing setting is 12.5 BTDC for the 66 383 2 bbl. I've done well to retard mine to about 10-11 BTDC BUT, it DOES make starting more tedious. Had to replace the starter last week consequently. She RUNS beautifully at this setting. It occurred to me to rig a manual spark advance cable, using some manual choke cable and attaching it to the plate, and perhaps using a set screw to limit how much I can pull such a rig. VERY primitive, yes, but I do well with my manual choke so....

Definitely getting that limiter plate for the mech advance AND later plan to order a dizzy from halifaxhops ASAAffordable....
 

saylor

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forgive my nomenclature i can find no reference online to using " - " and " + " symbols to reference timing. only BTDC and ATDC. again my apologies.

logic would assume that if
TDC = 0
a number smaller than that, or previous to that, would be " -" number
and, conversly, a number greater than 0, or beyond zero, would be marked as " +" number.

so, in the summit racing instructions that come with the 850005 distributor kit orange box for 440, it says set timing to 5 degrees BTDC, is what i meant when i said -5*.

im not sure how yall interpreted it to be a positive (i.e. ATDC), thus the clarification.

your pal -

- saylor
 
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