<TABLE cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD class=smalltxt vAlign=top>Hi! I have a 1956 Ford F100 pick-up with the original 272 with all original parts ie stock carb etc. Stock tranny and rear end with ratio changed to 3.23's. I have heard about using a 57 and newer distributor to replace the original load-o-matic one. I have dial-up internet so was hoping to get the info without having to search forever. I already have the cardone unit. Any tips or tricks to do with this would be greatly appreciated.
A few questons
- initial timing should be? and vacuum advance hooked up or not
- vacuum advance hooked to original hook-up on carb - is this ported vacuum????
- or does it hook to manifold vacuum????
A step by step of what I need to do or know would be great.
Thanks a lot for any help
Scott
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May I suggest that you check out what I've written on this to see whether you find it helpful or not?

Why is Ignition Advance Required?

How does a Load O Matic Distributor Work?

Tuning Y Block Distributors at Home

After you go thru these, you will understand that the answer to your question: is "NEITHER" and that you cannot use the vacuum port meant for your Load O Matic for supplying vacuum to a conventional distributor's vacuum advance.

Anyway, please see if these little articles shed any light on your questions.

 

I have read your articles Timmy. So you said in your post "neither" port is right. So where does the vacuum line go? Do you just not use the vacuum advance? I have read to remove the "spark control valve" and block it as to only get "ported vacuum". I remove it and gutted the valve and then filled it with epoxy since I was told can use a holley power valve block off. But get almost no vacuum until past 3000 rpm at this port. And at the manifold source straight into the manifold have 20 inches of vacuum.

As per your articles.
With truck at idle and set timing to 10* when I rev up mechanical advance maxes out at 30*. So that is what you recommend 20* mech advance. Mech advance comes in right off idle. But if I hook up vacuum advance to manifold at idle goes to 36*. This is a new rebuilt Cardone unit bought last week. So I am assuming I need to limit the vacuum advance as per your instructions. But the canister doesn't look like it comes apart.

Any suggestions would be greatly appreciated.
Thanks
Scott

 

Scott, it sounds like you are alright for a start. There is controversy about this, but I prefer to hook up my vacuum advance to straight manifold vacuum. That, like you said, will run in the neighborhood of 20" and should give you an additional 15* to 20* of advance. Disconnect the vacuum advance to set your initial timing at a low speed, such as 600 or 650 rpm. When you've set your initial advance, unplug your vacuum line and reconnect it to the vacuum canister.

If you were to check your advance at that point, it would be about 25* or so and that would be correct, but this isn't the proper way to set the initial advance -- always check it with the vacuum advance disconnected.

If you get no ping with your distributor set up as you have mentioned and adjusted with 10* initial, then you are good to go.

I'd like to mention a word about the ported vacuum issue.

Ported vacuum is tapped just above the throttle plate at idle. The effect of this is to give no vacuum advance at idle, but then apply it as the throttle is tipped open past the port.

Of course, the difference that will be observed when hooking up the vacuum advance to straight manifold vacuum vs. ported vacuum is that the idle speed setting has to be set higher (i.e., the throttle plate is opened a little more) when using ported vacuum.

In the carb, there is a transfer slot just above the hole thru which the idle fuel mixture empties into the carb bore below the throttle plate (when the throttle is at idle). This slot serves two purposes: first, it acts as an air bleed at idle and second, it switches from bleeding air into the idle system to providing fuel from that system into the carb bore as the throttle tips past it, when you step on the gas.

If the throttle blade isn't positioned at the bottom of this slot -- if it is too far above or too far below it, then you will get "tip in" sags as you gently press the accelerator off idle.

If you think about this, you can understand how there would be a difference in where the throttle blade sits at idle if you connect the vacuum advance to straight manifold vacuum or if you connect it to ported vacuum. I would not worry about this unless you are experiencing the problem of tip in sags, and then, if you do, consider that this might be one of the problems causing it.

In the operation of the Load O Matic unit, manifold vacuum is ported, as far as I know from what I've seen.

Under no circumstances would I use the connection for the Load O Matic for anything. You can use a Holley power valve plug or you can fill the cavity with epoxy, and that will cut off ported vacuum from the Load O Matic connection. But that connection will always be connected to the port in the carb venturi, which is why you "get almost no vacuum until past 3000 rpm at this port."

So, if you don't use the Load O Matic distributor, plug that port on the back of the carb. With a conventional distributor, there is only one thing that you can use the Load O Matic port for: If you are using a pair of 4v Teapot carbs, then plug the spark control valves with the power valve block offs and connect the Load O Matic ports of each carb together. This will ensure that the secondaries in both carbs open at the same time.

The venturi port is actually the same port that's used on modern Holley 4v vacuum secondary carbs, and there are special vacuum diaphragm covers with a tap on them that are used to synchronize secondary opening on dual 4v installations with these carbs. Connecting the Load O Matic ports of two Teapot carbs will accomplish the same thing.

 

I am getting 26* advance (when hook up vacuum) from intial of 10* that puts me at 36* total at idle. The runnability and idle quality become garbage and it pops and spits out the exhaust. I haven't tryed drivin it since it is still winter here.

 

Changing to the later model 2V manifold and carb sure would simplify things. The manifolds are cheap and plentiful. If you were local there is one in front of my barn free.