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Engine runs on
Posted By: 71birdJ68
Engine runs on - 04/30/14 03:41 AM
528 Hemi with street compression, and cam. I have noticed that after it gets warm it wants to run on a bit after I turn the switch off. The temp is around 170-180, and the timing is at 10 btdc at idle. Now it has just a mechanical advance with out a vacuum advance, and has been recurved.
Posted By: RSNOMO
Re: Engine runs on - 04/30/14 03:50 AM
Played with the timing any???
Fuel???
Posted By: cjskotni
Re: Engine runs on - 04/30/14 03:54 AM
Few things come to mind that can cause this:
- try more timing, maybe 14-16* initial
- running excessively lean causing hot cylinders - richen up mixture
- idle speed too high
Could be either of these things or some combination thereof.
Good luck!
Posted By: RapidRobert
Re: Engine runs on - 04/30/14 04:17 AM
Quote:
- idle speed too high
Posted By: 71birdJ68
Re: Engine runs on - 04/30/14 04:54 AM
Ok, it has ethanol free 90+ gas in it. It idles around 1100, it seems to like that speed. The mixture seem rich as it is, plugs are a little sooty. I haven't really had time to play with it, I drove it for the first time since 1978 yesterday, and just around the block. A couple more things, it has Edlebrock 650 avs's on it
Posted By: RapidRobert
Re: Engine runs on - 04/30/14 05:28 AM
Quote:
It idles around 1100, it seems to like that speed.
I would suggest adding one of those air conditioning solenoids (an electrical throttle stop) that kick up the throttle position when energized. Use it to get that idle speed when on/idling then when you shut the key off it goes dead/retracts so the throttle position is too low to run & it dies & in the meantime I'd shut it off in gear to kill it
Posted By: RobX4406
Re: Engine runs on - 04/30/14 05:42 AM
10* initial timing... nope no potential issue there.
I run stock 318's with more initial timing!
Fix the initial timing to what the engine wants, re-tune the carbs and go from there. It will take some changes to the distributor internals.
Simple, grab distributor, twist it a bit CW, if it picks up RPM, it wants the timing.
How big of a cam is in this thing?
Posted By: 71birdJ68
Re: Engine runs on - 04/30/14 05:44 AM
Yes I think it needs a solenoid, the harness has the wire for it, but it would cost $500 to buy the real deal, and the brackets. Tell me more about the AC solenoid.
Posted By: RapidRobert
Re: Engine runs on - 04/30/14 05:47 AM
I missed that,
what Rob said it definitely needs more than 10
Posted By: 71birdJ68
Re: Engine runs on - 04/30/14 05:50 AM
I'll try more, at what point would one start to kick back? I'll do this after I get it to the alignment shop. Everything is new.
Posted By: RobX4406
Re: Engine runs on - 04/30/14 05:56 AM
Get it hot, up to operating temp and start feeding it timing, reset idle speed, shut it off and restart it. Find the point it kicks back on the starter when warm. That's your top limit.
If it has any type of camshaft, I'd guess it may want close to 20* or more. Watch out for your total number, that's where the distributor surgery comes into play.
Posted By: RapidRobert
Re: Engine runs on - 04/30/14 05:59 AM
I'd start with the tried & true "vac gauge" method: keep advancing the timing till you reach max vac all the while reducing the idle speed back to the lowest point it will idle in gear at then reduce the timing till the vac drops (1) in hg & that is the ideal initial timing if it does not kick back when starting. If so you can either add an on/off ign switch & get it cranking with the regular ign switch then switch on the auxillary ign sw so it gets power & will fire or reduce the initial 1 degree & retry and another 1 degree if needed
Posted By: 71birdJ68
Re: Engine runs on - 04/30/14 06:04 AM
I told them I wanted a street cam, with without searching for a sweet spot, and a flat torque curve. It was ground by Crower to his specks.
Posted By: Kern Dog
Re: Engine runs on - 04/30/14 06:34 AM
" I drove it for the first time since 1978 yesterday, and just around the block."
Really? This car really has been sitting since 1978? 36 years?
Posted By: 71birdJ68
Re: Engine runs on - 04/30/14 01:04 PM
Yes, that was the last time I drove it. I'm just finishing up the restoration.
Posted By: GTX MATT
Re: Engine runs on - 04/30/14 04:50 PM
Carbs are off the idle circuit, more timing, less idle RPM/curb idle adjustment
Posted By: 383man
Re: Engine runs on - 05/01/14 12:31 AM
If it still gives you problems after the tune is right then I would consider an idle solenoid so it can let the throttle close more at key off. Also if its an auto shut the eng off in gear or if its a stick just let the clutch out when you shut the eng off. Just let the clutch out enough to grab a bit and stall the eng. They are not the real world fixes but many hotrods with large cams idle higher and the popping of the clucth or shut it off in gear helps. Ron
Posted By: 71birdJ68
Re: Engine runs on - 05/01/14 12:40 AM
Where can I find one of those solenoids?
Posted By: Mebsuta
Re: Engine runs on - 05/01/14 01:11 AM
Mine (383 HP) used to run on with lesser grades of gasoline (less than 91 octane). Try the highest grade of gasoline you can get.
Also, the E10 everywhere now helps me. I can actually run 87 or 89 without pinging or running on.
Posted By: RapidRobert
Re: Engine runs on - 05/01/14 03:44 AM
Quote:
Where can I find one of those solenoids?
I ain't sure what year(s) they came on. An ad in the wanted section(s) here would likely produce a good used one. EDIT Or eBay might be faster
Posted By: 71birdJ68
Re: Engine runs on - 05/01/14 04:20 AM
I was thinking other than factory that I could adapt. Just the brackets are over a $100, no telling what a solenoids cost.
Posted By: RobX4406
Re: Engine runs on - 05/01/14 04:39 AM
Quote:
I was thinking other than factory that I could adapt. Just the brackets are over a $100, no telling what a solenoids cost.
I'd fix the issue, not the symptom.
Fixing the likely issue is a lot less than that solenoid and bracket!
Posted By: 383man
Re: Engine runs on - 05/02/14 06:42 AM
I believe all the 69 A12 440 six pack cars had the idle speed solenoid on them. You might be able to make that work. Ron
Posted By: Barry70GTX
Re: Engine runs on - 05/03/14 03:44 PM
The throttle blades are open too far. Increase the initial timing and close the throttle blades. No reason to have 1100 rpm idle speed.
Posted By: lewtot184
Re: Engine runs on - 05/03/14 05:00 PM
edelbrock #8059.
Posted By: RobX4406
Re: Engine runs on - 05/03/14 07:09 PM
Quote:
The throttle blades are open too far. Increase the initial timing and close the throttle blades. No reason to have 1100 rpm idle speed.
And the sellout crowd roars it's approval!
What's it cost to see if more initial timing cures the issue. ZERO.
More initial will also clean up those sooty gas fouled plugs. BONUS! An idle solenoid WILL NOT help here.
I'll bet this car cranks excessively when trying to start and needs to floor the pedal or give it some pedal to fire. That's another symptom of not enough initial timing. The total timing crowd falls victim to this all the time.
People complain all the time about how expensive these cars are... hmmm
If you don't have emissions testing to be concerned about, an idle speed solenoid is a waste of money. Emissions is the reason they were used on these cars in the 60-70's.
Posted By: RSNOMO
Re: Engine runs on - 05/03/14 08:07 PM
Here it is...
Right out of the Service Manual:
'The high performance engines (340, 440, 440 3-2V and 426 Hemi) employ idle speeds between 800 and 1000 rpm to obtain acceptable lower emissions during idle and deceleration. In order to prevent "after running", with such high idle speeds, these engines have an electrical solenoid throttle stop which holds the throttle at the correct idle position when energized but de-energizes when the ignition is turned off, allowing the throttle blades to close more completely.'
My little, old '70 340 Duster had it in place...
900 in neutral;it was needed...
Even back when 10.5 compression burned 97 octane...
Posted By: RobX4406
Re: Engine runs on - 05/03/14 08:24 PM
Quote:
Here it is...
Right out of the Service Manual:
'The high performance engines (340, 440, 440 3-2V and 426 Hemi) employ idle speeds between 800 and 1000 rpm to obtain acceptable lower emissions during idle and deceleration. In order to prevent "after running", with such high idle speeds, these engines have an electrical solenoid throttle stop which holds the throttle at the correct idle position when energized but de-energizes when the ignition is turned off, allowing the throttle blades to close more completely.'
My little, old '70 340 Duster had it in place...
900 in neutral;it was needed...
Even back when 10.5 compression burned 97 octane...
Nice reference from the service manual.
Because the correct initial timing was compromised to obtain those acceptable emission readings, they had to crutch the system using a solenoid. More initial timing usually drives HC levels up.
People used to hunt only with clubs and sticks, but, we've evolved.
I made a real good living tuning cars in the 80's and on because people wanted to use the factory ignition settings or fall victim to total timing thinking. My 340 with a tight lashed 284/528 mechanical idles nicely at 750-800 rpm, not stinking out the neighborhood with raw fuel, clean plugs and 22* initial timing. It runs like junk with 10* initial and smells like a leaking fuel truck at idle when timed there.
The OP's issue is based in the inadequate initial timing setting.
Posted By: RSNOMO
Re: Engine runs on - 05/03/14 08:40 PM
You take issue with EVERYTHING, regardless of its source...
Unless it has your stamp of approval...
Go argue with the engineers who designed it...
Or better yet, go to a Pure Stock event...
And see how poorly OEM performs...
Posted By: RobX4406
Re: Engine runs on - 05/03/14 09:05 PM
Quote:
You take issue with EVERYTHING, regardless of its source...
Unless it has your stamp of approval...
Go argue with the engineers who designed it...
Or better yet, go to a Pure Stock event...
And see how poorly OEM performs...
While you are 
Did you miss this.
Quote:
Nice reference from the service manual.
you need some of this? Little cranky?
Those engineers had to work inside a defined box. I bet if you asked them, they'd tell you they'd have rather increase initial timing, however, the emissions regulations/standards wouldn't allow it. Pretty simple.
How should the OP fix this issue?
Pure stock? Nobody in those pits has taken the time to optimize the timing events on the engines.
Pick your parts, pay your money and tune it up however you like.
Posted By: 383man
Re: Engine runs on - 05/04/14 06:28 AM
Quote:
Quote:
The throttle blades are open too far. Increase the initial timing and close the throttle blades. No reason to have 1100 rpm idle speed.
And the sellout crowd roars it's approval!
What's it cost to see if more initial timing cures the issue. ZERO.
More initial will also clean up those sooty gas fouled plugs. BONUS! An idle solenoid WILL NOT help here.
I'll bet this car cranks excessively when trying to start and needs to floor the pedal or give it some pedal to fire. That's another symptom of not enough initial timing. The total timing crowd falls victim to this all the time.
People complain all the time about how expensive these cars are... hmmm
If you don't have emissions testing to be concerned about, an idle speed solenoid is a waste of money. Emissions is the reason they were used on these cars in the 60-70's.
The idle solenoid can never hurt and if an eng would still run on sometimes when its set to the specs you want then the idle solenoid would be a good idea. I agree with what your saying about setting it so it should not run on but the idle solenoid will never hurt and can only help if the ownwer does not mind spending the money which should not be much as being a tech all my life I had some laying around from jobs so he may be able to fine one from a tech real cheap. Ron
Posted By: Kern Dog
Re: Engine runs on - 05/04/14 10:18 AM
I switched to colder spark plugs and my issue of "Run-on" went away.
Posted By: moparx
Re: Engine runs on - 05/04/14 03:19 PM
I really don't like to jump into pi$$ing contests, but anybody that thinks the "pure stock" class boys don't optimize the ignition events on their engines hasn't been around drag racing very long. why do you think "pure stock" cars are a ton faster than yours is ? all it takes to prove that is to line up yours against a "pure stock" champ car one time.......
