Initial Timing via Vacuum

No, it’s the flat “tang” rather than the hex drive. Since original is important to you (from your signature line), the easy way out is to go thru the oem distributor. That assumes you’ve got the oem carburetor in good condition. Who does that for a 239 I don’t know. The specialty 55-57 bird gigs used to list parts for those. They might know who can do a 239. Or again yblocksforever. If you’re not a member there, here’s a current link to where I described joining.

https://www.fordbarn.com/forum/showthread.php?t=358610
 
I have a distributor that I gutted and removed the cam drive gear from that I used to pre-oil the engine after I built it. Looking at it it appears that the only thing now holding the shaft in is another retainer that could be removed without much trouble. If the '57 and newer shafts are the same length and diameter it appears to be an easy swap. I found a '57 distributor on e-bay but the guy wants $240 for it which I believe is too high. I lowballed him an offer which he has totally ignored. What is a fair price?
 
I looked up Eaton Balancing. His shop is less than 50 miles from me. A little drive is in my future.
 
Anteek29 said:
Your stock mechanical distributor will function just fine on either 6 volts or 12 volts. Personally, I am not a fan of electronic ignitions. I've had good success with points and condensers from NAPA. Oh, were you able to observe ignition timing advance with increase in RPM? Sometimes the vacuum cans develop leaky diaphragms.
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I go with NAPA; For my 54 239 it's: Points ECH CS753; Condenser ECH FA76; Coil ECH IC7; Rotor FF-58. If I remember right, I have to grind butt tip off points to fit in the distributor, but not much.
 
I have a distributor from a '57 Merc 312 with new points, condensor, cap, and rotor ready to go. Do I need to change the carburetor to run it on my '55 272?
 
Lamar Wadsworth said:
I have a distributor from a '57 Merc 312 with new points, condensor, cap, and rotor ready to go. Do I need to change the carburetor to run it on my '55 272?
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That '57 distributor is a great upgrade for your 272. I'd just give it a go and see if that works for you.
 
Lamar Wadsworth said:
I have a distributor from a '57 Merc 312 with new points, condensor, cap, and rotor ready to go. Do I need to change the carburetor to run it on my '55 272?
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The load a matic distributor gets its vacuum from a point above the throttle plates in the carb. The 94 carb only produces venturi vacuum to operate the distributor advance. The '57 distributor is designed to utilize manifold vacuum supplied at he base of the '57 up carb. along with the built in mechanical advance. The 94 carb will not produce adequate vacuum for the '57 distributor. You CAN run the '57 distributor on mechanical advance only, but you will sacrifice performance and economy the vacuum provides.
 
I'm running a '57 dissy with a Holley 2300 carb using venturi vacuum in my '55 Vic with a stock 272. I have approx. 38-40 degree advance open road cruising. Works for me.
 
I know Ted Eaton has an article on modifying a 4 barrel to run the later distributor, but don’t recall a 2 barrel.

Just out of curiosity, what’s the effect at idle with and without the vacuum hooked up?
 
miker98038 said:
I know Ted Eaton has an article on modifying a 4 barrel to run the later distributor, but don’t recall a 2 barrel.

Just out of curiosity, what’s the effect at idle with and without the vacuum hooked up?
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I'm curious too...will check it out and report back.
 
Anteek29 said:
I'm curious too...will check it out and report back.
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OK...virtually no difference at idle. As expected, the vacuum does add more degrees advance in addition to the mechanical advance with increasing RPMs.
They are complementary.
 
Where I’m going with this, and other comments welcomed.

The loadomatic vacuum port on the carb get more vacuum as the throttle opens, as it’s measured thru a Venturi above the throttle plates. So at part throttle cruise it’s not seeing the full manifold vacuum the 57 up can is designed for. Or the full vacuum you’d see off idle on the ported vacuum port on a modern carb.

If I’m right, you’d see better mileage and part throttle response (partial opening not WOT) at cruise.

I’d be interested in other’s thoughts.
 
Manifold vacuum starts out high and then drops off as the throttle plates are opened up. The Venturi vacuum for the LOM picks up more and more vacuum as the throttle plates open so their actions are opposites from each other. The 1957 Y-block and later distributors uses vacuum more as a start off for idle and a higher end load control with the centrifugal advance providing most of the higher rpm advance.
 
Well said. So I was close, the existing loadomatic port on the carb doesn’t provide the correct vacuum signal to the loadomatic can. With the upgrade to a 57, either manifold vacuum, or a modern carb with a port. Or, I guess, a mod like Ted Eaton does on the 4 barrel.

Thanks, rotorwrench .
 
Ford generally had a port on the base of the carb that fed into manifold vacuum from under the carb base. Vacuum specs were published in Ford manuals and Motors manuals for the later distributors. A person can check it with a vacuum gauge or manometer. There are adjustable distributor vacuum cans that can be adjusted using a timing light with the dial back feature to tune the advance unless a person has a distributor machine. An original carburetor used on the 1957 or later Y-blocks should work with no adjustment on the late distributor but I don't know what changes they did on the late y-blocks up into 1964 before they stopped production on it. Most of them were in pickups and trucks.
 
I'm back with another question. Prior to obtaining a '57 distributor I assumed the swap of shafts would be the answer to the slot/hex drive difference. Now that I have one in my hands I find there is other differences as well. It appears my only recourse is to swap in a '57 oil pump and drive shaft. Is the pump a bolt on to the 239 Y-block?
 
GLAmes said:
I'm back with another question.

Prior to obtaining a '57 distributor I assumed the swap of shafts would be the answer to the slot/hex drive difference. Now that I have one in my hands I find there is other differences as well.

It appears my only recourse is to swap in a '57 oil pump and drive shaft. Is the pump a bolt on to the 239 Y-block?
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You definitely want to go with the DUAL ADVANCE STYLE DISTRIBUTOR?

The answer is yes, you will need a later oil pump and hex drive shaft.

How many teeth are on the DIST DRIVEN GEAR LOM TAKEOUT and how many gears on the DUAL ADVANCE GEAR?

 
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The answer is yes.




GLAmes said:
I'm back with another question. Prior to obtaining a '57 distributor I assumed the swap of shafts would be the answer to the slot/hex drive difference. Now that I have one in my hands I find there is other differences as well. It appears my only recourse is to swap in a '57 oil pump and drive shaft. Is the pump a bolt on to the 239 Y-block?
Click to expand...
 
There were two 239CI ENGINES.

First 239CI FYB intro (1954 MODEL RUN) was the EBU (DEARBORN PLANT - DIF) (engine often referred to as BIG CAM). It had a 13T CAM DRIVE and DIST DRIVEN GEAR.

A little later in 1954 production, the EBV (CLEVELAND PLANT - CLVF) 239CI was released (SMALL CAM).

It and all following 256/272 were small cam 13T (CLV PLANT).
 
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