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Discussion Starter · #1 ·
Hello, working on 83 RC 318, carter 2v carb, “lean burn” system.
I’m trying to improve power on a budget. Current factory distributor has no advance. I’m looking at earlier years (1977-1978) distributors and am only finding vacuum advance (no mechanical advance) my older fords had both. If memory serves I had a 68 dodge truck with both.
Is only vacuum advance the only only option for this vehicle?
Also, where do I run the vacuum to? I see only one port on the tiny 2v carter carb.
Will I need to also swap out electronic ignition module? - they appear the same for many years.

Thanks in advance.
 

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I do not know of any that did not have both. How are you determining that they do not have the mechanical advance? On mopars, it is down below the vacuum advance parts, so they are not as visible as chebys. Hole the bottom shaft tight, and turn the rotor, you will see movement between the two ends, that is the mechanical advance. A dizzy without a mechanical advance will not have any movement between the top, and bottom of the shaft.
 

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Discussion Starter · #3 ·
Just been doing some preliminary research online (eBay, Amazon) and my local O’Reilly’s. This far I can only find vacuum advance. I’ll keep looking though thank you
 

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All Chrysler LA series distributors had both vacuum and mechanical advance systems unless the ignition was computer controlled.  On Chrysler distributors, unlike Ford and Chevy distributors, the mechancial advance weights and springs are hidden underneath the pickup plate insie the distributor.  THe vacuum advance pod is clearly visible from the outside and when the cap is remove, but the mechanical advance is not.  Get any 70s era truck electronic ignition distributor for a 318 or 360 and you will be fine.
 

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agreed , if its got the vac can , it also has the flyweights ( mec advance)
 

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Discussion Starter · #6 ·
Reed said:
All Chrysler LA series distributors had both vacuum and mechanical advance systems unless the ignition was computer controlled. On Chrysler distributors, unlike Ford and Chevy distributors, the mechancial advance weights and springs are hidden underneath the pickup plate insie the distributor. THe vacuum advance pod is clearly visible from the outside and when the cap is remove, but the mechanical advance is not. Get any 70s era truck electronic ignition distributor for a 318 or 360 and you will be fine.
Finally got a 70's era new distributor with vacuum advance. Problem though. My old dist has dual pickups, new one has single. 1)What do I do with the other plug? 2) Which port do I plug vacuum line into, carb or intake tree?
Also, I have pics if need be. It would take some doing to get them uploaded but willing if helpful.
Thanks again
 

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The two connectors for the dizzy, are different. Plug the new dizzy into the one that matches. Then, look on the firewall next to the steering column, for a relay with two wire connectors on it. One has two wires, and the other has three. Unplug the two wire connector, and leave it disconnected.

The vacuum advance needs to be plugged into a ported source on the carb. Post pics of the carb, and we can guide you.

 

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Are you trying to bypass the factory "lean burn" computerized ignition system?  If so, you will be fabriacting a new (but potentially very simple) ignition wiring harness.  I highly recommend you get a factory service manual for your truck so you have the wiring diagrams.
 

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Reed said:
Are you trying to bypass the factory "lean burn" computerized ignition system? If so, you will be fabriacting a new (but potentially very simple) ignition wiring harness. I highly recommend you get a factory service manual for your truck so you have the wiring diagrams.
Oh no... a Dodge Boys plug again. ;D
 

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Setting ignition timing on a small block mopar is pretty straight forward assuming a normal carb setup.  I don't claim any knowledge of lean burn.

From the manufacturer, the basic mopar dizzy should be set by stabbing it in, getting it idling with the hold down loose, reving until it stops advancing, and setting it to 34-36 degrees total advance with the vacuum can hose not hooked up.  When you drop back downt to idle, the distributor will probably be between 5-10 degrees BTDC.  This isn't horrible but not very efficient.  The engine will idle cleaner with way more advance.  You can recurve the distributor to allow more idle timing with less total advance.  You can also plug the vac canister into a manifold port, this will advance somewhere between 10-20 degrees depending on the cam, what vacuum it's set for, etc.  There is no real danger in having 30 degrees of ignition advance at idle as long as it's smooth and happy.

With a heavy truck, a safe all in ignition curve should be full advance at about 3500 rpm.
 

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KurtfromLaQuinta said:
Oh no... a Dodge Boys plug again. ;D
I don't know who this "dodgeboys" person is, I just know a factory service manual is the best tool you can buy for your vehicle.

And a stock mopar distributor uses ported vacuum on the carb, not manifold vacuum.
 

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Reed said:
I don't know who this "dodgeboys" person is, I just know a factory service manual is the best tool you can buy for your vehicle.

And a stock mopar distributor uses ported vacuum on the carb, not manifold vacuum.
DodgeBoys is one of most respected gurus here at RCC... https://ramchargercentral.com/profile/?u=1664
He has a huge supply of Factory Stock Manuals. He's the go to guy for them.
I'll bet you I made his head 3 sizes bigger than before. ;D
 
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