Vacuum Advance on a former Lean Burn '79 'doba

[ybshore]

I have eliminated the Lean Burn System on a 360 as the result of another's sad attempt to do same.

I have wrapped and taped every electrical and vacuum part and port while installing a next generation Holley 2BBL -was 2245 series now 2300 series- at the recommendation of Holley as the 2245/R-8450-A was designed solely for the computer operation and would not work under natural aspiration as vac advance was part of computer ops...

This we found because no amount of blocking ports would make the vacuum advance work and the result was the car idled great and using only mechanical advance the car would operate but it had to be advanced to an un-gawdly spread for if we connected the VA to the carb, you'd think it was running on water with crossed wires.

So we installed a 2300 series/0-7448 with only timed port, replaced the ECU, the distributor, the ignition coil, the ballast resistor, plugs and wires. STILL the if we plug in the advance, the car shudders and virtually refuses to run. Keep the vacuum disconnected and she runs on the mechanical nearly fine.

What am I missing? Taking ALL opines....

 

[Hemi Rebel]

Hmmm. What dizzy are you using?

 

[ybshore]

LB distributor

Cardone 30 3890 Distributor Reman Distributor Electronic | eBay

 

[Jonnyuma]

Is it possible that your dist drive gear got moved? Did you start over from square one? Meaning, find tdc, make sure the rotor is lined up w the #1 terminal, etc. It sounds to me like your timing is off in one direction or the other.

 

[ybshore]

star at square one every time we re-address the situation

 

[ArtH]

If you plug in the vacuum advance and the engine runs poorly, I would check to see if that port on the carburetor has vacuum. I would hook a vacuum gauge to it (if you don't have one, then I would recommend buying one - they really help when tuning an engine) and see if and when it sends a vacuum signal. It may be that your initial timing is too advanced you didn't state that in your post. I converted a LB system using a Pertronix distributor with vacuum advance. This eliminated the ballast resistor which I'm told has it's own set of problems. I also used an Edelbrock carburetor because they are pretty much plug and play and real easy to set up. I started with 10 degrees BTDC with NO vacuum advance. I used manifold not timed vacuum and before everyone gangs up on me, I've found manifold vacuum to work well on two of my older cars, one is a 72 Lincoln, the other a 77 Cordoba. This immediately adds vacuum to the distributor and timing is advanced a bit more as you will see an increase in idle RPM. If you have a hand held vacuum pump, you can also actuate the vacuum advance at the distributor and see what happens there while checking timing. It may be that you are too advanced.