Cruise Seems Lean

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Question on this statement, and just a question. If initial timing with vacuum advance disconnected, is set at 18-20 (already well above factory settings) this additional timing is there. Then if connecting to ported vacuum, it is as set. If connected to manifold vacuum, it will be considerably higher but only until the throttle is opened - same as ported vacuum as it is equal to manifold vacuum once the throttle is open. So, with a more aggressive initial timing and the mechanical timing limited due to this, are we talking the same thing to some degree (pun intended)?@mattax your thoughts on this statement?
The problem being is that it is very difficult to make a blanket statement that covers all applications for timed vacuum advance vs full manifold vacuum non timed timing events for performance engines. Some engines are going to react differently depending on their construction configuration.
In your case I con not recommend adding additional advance on top of your initial timing of 20 degrees.
Cap it off and drive it, you may be surprised
 
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This is correct


To some degree yes if you look at it in the way you just did.
In general no, because its fixated on a belief that extremely early timing and lean burns produce power.

@yellowrose
Sorry, My post was referencing
Sorry your post #101 on vac adv is totally incorrect. Set any Chrysler 6 or V8 engine to the factory initial 6-12* timing. With the engine idling, turn the dist slowly to advance the timing. Idle rpm will increase [ more hp ] & vacuum will increase [ increased efficiency ].

@71GSSDemon mentioned he had read Shrinker's posts, in particular the paragraph from post #10. Bewy obviously chose not to, or did but choses to believe the current magazine writers are more knowledgable. The two big points from Shrinker in those two paragraphs is that early timing goes with lean burns and there has to be enough later burn to push the exhaust out. Elsewhere he explains why lean burns are foolish at idle, but the bottom line is they don't make power. Maybe I can dig that out later and post it up. Tests in neutral do not indictate power.

@71GSSDemon following upo on 512stroker's question. Remind us. Was the vacuum advance connected during this last drive? and if so where?

Yes it was connected to the only port on the front carb. It is near the secondaries in the base plate. I assume for now it is manifold vacuum. This is how it has been since putting the tunnel ram on. I am working on another car at the moment while I wait for the radiator.
 
Yes it was connected to the only port on the front carb. It is near the secondaries in the base plate. I assume for now it is manifold vacuum. This is how it has been since putting the tunnel ram on. I am working on another car at the moment while I wait for the radiator.
If you dont have a vacuum gauge (you should) start the engine and at idle stick your finger over the vacuum port on the carb base , if you feel it pull down on your finger that port is drilled to full manifold vacuum.
 
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Eric,
Been thinking about this and there are two paths you could take.
1. Fix the radiator, put in new plugs, connect the distributor as before and retest the situation.
2. Install primary PVs and/or adjust the distributor set up, and start from (nearly) scratch.

Part of that decision should be based on how much time and effort you want to put in at this time.
Whatever the setup has been was pretty close to making it usable for your purposes.

Part of that decision would depend on knowing a little more about the set up as its been.
My suggestion is to gather as much information as you can about the setup. Lets call it 2020 since its was unchanged from last year.

I agree that a vacuum gage would be helpful. I'll add to that a vacuum pump, and assume you have a tach and timing light.
It would be really helpful to know more about the 2020 timing. Part of that is whether the manifold vacuum was actually moving the advance at idle.
Your 660s look like older units. 1970s or early 80s unless someone was swapping parts.
My guess is the base plate vacuum ports are live. If you have the carbs off, look underneath and you can see the connection.

The next question is whether having the vacuum advance connected to that port made a difference. If you know the vac at idle and the vac required to move the distributor's advance plate, we'll have a better picture as to what was going on. Then we'll know if you make a change to ported how radical that change will be.
What distributor?
 
Matt, thank you and this is pretty much what I have been thinking also. I just rebuilt my alternator brackets and mounting yesterday and have that installed. The radiator showed up and it will take a little work but should be really nice. My plan was to reset as it was, get timing and vacuum numbers then go from there. The set up worked very well up until that long, hot drive with only a few things different from all other drives. I have to work a few hours for work today, but hope to have it finished up and running. We will see how long work takes.

Thank you everyone. I am loving all the discussion.
 
Ok, so I had a little bit of time to work on the car. I got it all back together and fired it up. All settings the same. Just the new radiator and a vacuum advance line that wasn't split. It fired right up, stunk of rich idle so I pulled it out of the garage and let it idle in the driveway to get it up to temperature. I wanted to top off the water/coolant. Even running at different idle speeds it never got above 175. It ran for 15 or more minutes. I brought it up to 2500rpm for a bit and it cooled back to 170. Outside temp was in the mid 80's. So, that is a large improvement already. I wasn't able to check timing or vacuum yesterday. Hopefully I can get that done tomorrow.
 
Ok, so I had a little bit of time to work on the car. I got it all back together and fired it up. All settings the same. Just the new radiator and a vacuum advance line that wasn't split. It fired right up, stunk of rich idle so I pulled it out of the garage and let it idle in the driveway to get it up to temperature. I wanted to top off the water/coolant. Even running at different idle speeds it never got above 175. It ran for 15 or more minutes. I brought it up to 2500rpm for a bit and it cooled back to 170. Outside temp was in the mid 80's. So, that is a large improvement already. I wasn't able to check timing or vacuum yesterday. Hopefully I can get that done tomorrow.


That’s progress and that’s all that matters.
 
Ok, so I had a little bit of time to work on the car. I got it all back together and fired it up. All settings the same. Just the new radiator and a vacuum advance line that wasn't split. It fired right up, stunk of rich idle so I pulled it out of the garage and let it idle in the driveway to get it up to temperature. I wanted to top off the water/coolant. Even running at different idle speeds it never got above 175. It ran for 15 or more minutes. I brought it up to 2500rpm for a bit and it cooled back to 170. Outside temp was in the mid 80's. So, that is a large improvement already. I wasn't able to check timing or vacuum yesterday. Hopefully I can get that done tomorrow.
I didn't realize it had heatng issue at idle. Glad you got that fixed. I had a Sunday playing in a parking lot so been busy myself.
 
I didn't really have any issues except after that super hot weekend. How lean can it go and no vacuum advance with a split vacuum line going to manifold vacuum source? Then the failed radiator to boot.

Autocrossing? Nice!
 
I didn't forget about this. I ran low on time but did get about 40 miles on it so I can check the plugs, but also lost a wheel bearing. That gets fixed first. I checked and vacuum advance is hooked to manifold vacuum. It pulls 12hg vacuum at idle and when bringing rpm up to (guessing) 2k, it pulled 18hg. Lots more than I thought. When I get the wheel bearings installed I will put the vacuum gauge in the car so I know rpm better.
 
Hey Mark. I haven't played with it too much. I have driven the car to several shows. Part of the issue was carbs not fully sync'd. Now that they are much closer, I am using lots more fuel. Haven't pulled a plug since the change. I was just in Alaska and now heading to Kentucky for a machine gun shoot. I hope to look at it closer when back and have time. I did pull tunnel ram off and put on a Torker 440 and 850dp. Throttle response was fantastic and ran great, but it was lacking the torque of the tunnel ram at 2500 on up. Night and day difference, so I swapped it back.
 
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