Initial timing

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Ok so i checked/confirmed rotor for ccw spring back when rotor is turned cw. I can twist about the width of a reluctor tooth, maybe slightly more.
Set reluctor gap at .008, was tight in places.
Looks like blue and red spring?
Orange pad under rotor.
halifaxhops said:
Yes that is the ported vac. Vacuum should be zero at idle and increase when the rpm's go up. Honestly I dont know if that is the one I sent you what color is the pad under the rotor? I use a different color just for this.
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Checked continuity with with ohmmeter and spun distributor shaft. Good there.
Also hooked Mity Vac to see what it takes to actuate VA(not sure if that matters??) Anyway got movement from7-15" hg.
 
Sadly,
So much ignorance about initial timing. And how it behaves. I have just gone over this on another thread.
Millions of GM cars left showroom floors with well over 20* of initial timing. My GTO had 26*, many Chevs had 24*. If you had put a timing light on my car while in the showroom, it would have shown 26*. Dead stock engine, smooth idle @ 500 rpm.
It was done using Manifold Connected Vac Adv.
6* + 20* added when the VA was connected. The link in post #15 explains how it works.
Chrys missed the boat on this, it is that simple. Chr engines are no different to GM engines: they pistons that go up/down & valves that open/close.
Once the correct amount of idle timing is determined, THEN any combination of initial + MVA can be decided. Examples: 8* init + 22* MVA; 15* init + 15* MVA.
An adj VA unit must be used & most can add up to 30* of timing. A stop may need to be fabricated to limit VA plunger travel. Once static init has been determined [ say, 15* in example two ] the centri curve in the dist can be dialled in for WOT timing. It is all part of the tuning process & always amazes me how folks are quite happy to f*ck around with air bleeds & emulsion jet sizes....but spend no time on the ign timing that will have a great impact on drivability.
 
Rag,
[1] Thanks for the rt click info.
[2] No harm whatsoever Teeing into the choke dashpot. At the carb end, it connects to man vac. You could add ten devices if you wanted, you are only sourcing a signal.
Many engines use a vacuum 'tree' at the rear of the carb. For power brakes, transmission modulator etc that require man vacuum. Chry used to do the same thing except, the vac was taken from a manifold runner, often for the brake booster but with smaller nipples for ancillary equipment that was vac operated.
 
It is Steve, sounds like it is working fine. I will say if it runs good and does not ping run it. Hey did the ballancer outer ring slip by chance?
 
There is other electrical going on too now. I noticed when I tried to start it I left the timing light hooked up and laying on rad cradle that the light wouldnt flash while I was cranking(I noticed this twice now). As soon as the gun fired(spark) the car started. I'm gonna swap a coil(and hobby):BangHead:
The balancer hasnt slipped, I verified tdc with piston stop, BUT I'm gonna put a mark across outer/inner ring to see if it does slip.
Thanks!
halifaxhops said:
It is Steve, sounds like it is working fine. I will say if it runs good and does not ping run it. Hey did the ballancer outer ring slip by chance?
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You have a strange one going on lots of good input here. Prob something seriously simple.
 
Call me when you have chance have a few "dumb" questions.
 
So, still having a hard start. Swapped ECU to an OEM orange box. Have initial now set at around 17/18*.
Took for a 45 minute round trip in to town to get new Champion plugs RN14YC. Currently running Autolite 66's.
Anyway on the trip the car is still backfiring thru exhaust at cruise/part throttle. On acceleration no miss/stumble, it seems "fine".
Gonna change plugs and using the timing light I'll chk for spark on all 8.
Coil swap may be next. And pull distributor again to chk rating on vac adv arm.
Thanks all.

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What's the total timing? 17/18 initial is fine.

Unplugging the VA, cap it and see what it does
 
Ok so heres some readings and I'll post video(s) shortly.
These are with VA unhooked and hose to carb plugged.
Rpm 700, initial 15.
Rpm 1500 timing approx 22/3
RPM 4K, timing approx 25* and no more advancing.
Next is when the symptoms really showed up.
VA hooked back up.
Rpm 700, initial 15
Check out the video, I try to increase rpm and it stumbles/back fires like crazy. If I unplug VA hose it levels back out.
Thanks all
 
So if I understand the math with timing,
15* initial, 11R onVA=22*, 4K Timing maxed at 25* approx. So 25*+22 Vac makes 47 total timing? Total mech is 25?
Thanks
 
Steve,

Usually, Vacuum Advance is not "figured" in on Total Timing. Generally, we look for something around 34⁰ Total without vacuum advance. We set timing with vacuum advance disconnected. Most folks set Total and let Initial fall wherever it lands.

Initial + Mech = Total
Or
Total - Initial = Mech

I use a FBO limiting plate set to 10 and run an initial of 24 to give me a total of 34⁰

Once you got Total where you want it, plug in vacuum advance and cruise timing could reach 56⁰ with your vacuum can.

That's how I understand it.
 
4spdragtop said:
So, still having a hard start. Swapped ECU to an OEM orange box. Have initial now set at around 17/18*.
Took for a 45 minute round trip in to town to get new Champion plugs RN14YC. Currently running Autolite 66's.
Anyway on the trip the car is still backfiring thru exhaust at cruise/part throttle. On acceleration no miss/stumble, it seems "fine".
Gonna change plugs and using the timing light I'll chk for spark on all 8.
Coil swap may be next. And pull distributor again to chk rating on vac adv arm.
Thanks all.

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Check that you dont have exh valves too tight/ hung open.
Find a port that's fed like the pcv , tee off that if need be.
 
I think I'm making things progressively worse lol. Vac at idle is now 4". Gotta check carb. I have a kit for the Eddy 1405 coming, so the plan is to leave Carter on until I get Eddy back together. Also have the 5/16 spacer but waiting to install that with Eddy.
I know when I hooked Mity Vac up to Va. The arm movement started at approx 7-8" of hg which I believe is good.
My VA is adjustable, but I've learned that the "adjustable" part is the "when" of it. NOT the amount of vac adv.
Thanks all, back to work over next few days, so hopefully get Eddy redone when kit arrives....
65TerrorCuda said:
Does it really have 2" of vacuum at idle, or did I misread that?
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66fyssh said:
I just watched your videos. Sure does seem like the can is putting in mega amount of advance.
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MOPAROFFICIAL said:
Check that you dont have exh valves too tight/ hung open.
Find a port that's fed like the pcv , tee off that if need be.
Click to expand...
 
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