Understanding the "load-a'matic" distributor

BUBBAS IGNITION

BUBBAS IGNITION

Well-known member
UNDERSTANDING THE LOAD-A-MATIC FULL VACUUM DISTRIBUTORS
JIM LINDER “BUBBAS Hot Rod Shop” www.bubbashotrodshop.com

Ford made the “load-a’matic (full vacuum) distributor from 1949 until 1957 on most of their engines . This distributor is very much mis-understood by many owners etc.
The load a matic works by adding spark advance thru a vacuum chamber using vacuum differential at the carburetor.This vacuum signal from the carb is very low with advance typically starting at ½ inch of vacuum and being full advance at 2 inchs of vacuum.
The slightest change in the engine vacuum makes this unit become a problem and not supply the correct signal. A carb change is the most common problem making this unit not work. Twin carbs, a camshaft change also makes the unit become inoperative. I have talked to many owners with the vacuum line disconnected with complaints of engine overheating ( retarded ignition timing) and a poor running engine.

The “fix” for this problem is to use a later distributor that has full centrifugal advance that needs no vacuum signal and is operated by rpm alone . ( may also use vacuum advance as well on some units)

For the 1949-53 Flatheads we offer a remachined Chevrolet unit with a curved mechanical advace suitable for the flathead engine design. We have built and shipped over 700 of these units to very happy customers over the last years..
$180 plus $18 shipping

The 223 six is another story and requires some more thought as the oil pump drive is different at the base of the distributor . Ford offers at least three different drives with a spade, 5/16 hex and a 3/8 hex drive for the distributor oil pump drive.
For these we use a “ butt change” we take the lower drive end of your existing unit and mate it to a later ( full mechanical advance) unit, use another distributor ( like a Chevrolet six) or a older Mallory etc.
$250 plus $18 shipping


Picture on left is early “full vacuum” load a matic design, note exposed springs and adjustable pins. Picture on the right is the later centrifugal advance with weights and springs under the point plate.
 

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wga said:
Your thoughts on the Mallory dual point?
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I am doing some mallory dual points this morning. Mallory must have sold a zillion of these . However its very seldom i see a unit with wornout ( high milage) parts inside etc.
They really need to be set up on a machine ( feller gauge usually wont get them very close) and condensor must be the correct capacity. Especially on the four lobe units .
The large brass condensors are usually good even when cracked and high capacity at .30-.40 mfds.
The advance units are very adjustable.

Overall i give these old ( not new jap units) a A+ rating and have ran a lot of them in my own stuff.
 
Mike51Merc said:
Bubba:
What do you think of the points that Mallory supplies today?
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The contacts are pretty good.
Its not the contacts that cause the problem its the incorrect capacity condensor they supply.
I use a (used) vertex mag i get from a rebuilder friend down the street thats very well made and sealed like they should be with a capicaty of .30-.40 mfds that seems to fix the problem of contact arcing.
On the tester its pretty easy to see the contact arcing when running...:eek:
 
Bubba Your thoughts for a replacement Dissy for 292 Y-Block .... You have my 50, and 39' running better then new.... The only other thing I've done is disconnect the wiper vacuum hose ... I've got to say my old Fords are running great ....Your thought on a Y -Block replacement Dissy ..
 
Another question. In 56 Ford went with a dual diaphram distributor. Vacuum came off the carb from two points - one from about midheight, front, of the carb. The other came from the lower rear of the carb around the throttle plates. 56 was the only year they used this arrangement.

I know that the 57 and later distributors probably should not use the vacuum source from the front, but how about the rear? Is this an acceptable source of vacuum for the 57 and later distributors?

Thanks, it a question I wondered about for a long time.

Paul
 
41ford1 said:
Step-down, Did you see this in the 54 up section? It may be a solution. Bubba, what do you think?
http://www.fordbarn.com/forum/showthread.php?t=85638
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The Y block falls into my initial discussion at the begining of the post. It also was load-a-matic (early years) and needs the later centrifugal advance.
Same problems with the drive gear, and oil pump drive. We have built a few of these as well.
Pretty straight forward conversion , use the later ford with centrifugal advance and the lower drive with correct drive gear etc for the engine. Fit the two together and it makes a really nice running conversion.
 
BUBBAS IGNITION said:
I am doing some mallory dual points this morning. Mallory must have sold a zillion of these . However its very seldom i see a unit with wornout ( high milage) parts inside etc.
They really need to be set up on a machine ( feller gauge usually wont get them very close) and condensor must be the correct capacity. Especially on the four lobe units .
The large brass condensors are usually good even when cracked and high capacity at .30-.40 mfds.
The advance units are very adjustable.

Overall i give these old ( not new jap units) a A+ rating and have ran a lot of them in my own stuff.
Click to expand...

Yay!!! I hope ones headed for New Zealand?
 
i am new to this site so bear with me. i am having problems with my newly rebuilt 200 ford six. the carb which is a YF carter4782S and has been proffesionaly rebuilt. i cant get the timing to set correctly. if i set it to factory specs it wont idle and it gets hot very quickly ,retarded timing maybe? could the fix be a later model dist. with full mechanical advance instead of vaccum. if so which one would you reccomend?
 
The subject of the LOM distributor came up in this thread also. http://www.fordbarn.com/forum/showthread.php?t=86084&page=2

Post #23 is my solution for fitting a later Ford six distributor to a 215 with dual carbs. Performance greatly improved. For the 200" you might only need to adapt the OP hex drive and change the drive gear. The distributor I used has a 5/16" hex for the OP. and it had a 15 tooth gear.
 
"For the 1949-53 Flatheads we offer a remachined Chevrolet unit with a curved mechanical advace suitable for the flathead engine design. We have built and shipped over 700 of these units to very happy customers over the last years..
$180 plus $18 shipping"

Is this electronic ignition?
does this still clamp down on the cylinder head?
 
millersgarage said:
"For the 1949-53 Flatheads we offer a remachined Chevrolet unit with a curved mechanical advace suitable for the flathead engine design. We have built and shipped over 700 of these units to very happy customers over the last years..
$180 plus $18 shipping"

Is this electronic ignition?
does this still clamp down on the cylinder head?
Click to expand...


Yes the units still clamp to the head we add a aluminum plate to the distributor bottom etc.

Electronic version is $ 250 plus $18 shipping....comes with cap and rotor ready to run...:)
 
Bubba:

What are your thoughts of the Load-a-Matic theory when used with the stock carb & components?
I've read that it was a better idea than straight manifold vacuum or centrifugals because it used a better indicator of true engine load (intake velocity).
 
Mike51Merc said:
Bubba:

What are your thoughts of the Load-a-Matic theory when used with the stock carb & components?
I've read that it was a better idea than straight manifold vacuum or centrifugals because it used a better indicator of true engine load (intake velocity).
Click to expand...


The load a magic can never work as good as a centrifugal/mechanical advance....
even in new condition...."
 
BUBBAS IGNITION said:
The load a magic can never work as good as a centrifugal/mechanical advance....
even in new condition...."
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I hear you and respect your opinion, but what about low rpm applications where the centrifugals tend to lag until "spun up"?

Just trying to learn something here.
 
Mike51Merc said:
I hear you and respect your opinion, but what about low rpm applications where the centrifugals tend to lag until "spun up"?

Just trying to learn something here.
Click to expand...


GOOD QUESTION:

Thats what is done when a distributor is curved... the curve of advance is set up ( by adjusting spring tension) to change or move ( adding degrees of timing) as the rpm increases. Then there will be no lag in advance........

Actually i like to see some advance change every 200 rpm or so. I will get a photo bucket link for a movie showing one of our curves...
 
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