After THOROUGHLY studying the '55 Loadomatic operation manuals, I have come to the conclusion that the reduction in manifold vaccum produced by a long-duration camshaft would NOT have any discernable effect on the low-load advance, as the spark control valve in the carb which regulates that signal is designed to operate (and pass vaccum) at such a low level.



In fact, if John is correct about running successfully without a vaccum diaphragm (cetrifugal only), then the only obvious way to hop-up a Loadomatic system (aside from an advance-limit stop/increased initial timing) would be to merely plug the carb manifold vaccum signal passage to the throttle bore, and set a more performance-oriented spring curve on the SUN machine using venturi vaccum/engine speed data only, calculated from the factory specs. It should then imitate a cetrifugal advance system.



"Loadomatic" was apparently a very successful system engineered by Ford to extract the best performance/enonomy (for the general public) out of the poor grades of gasoline generally available at the time. It WORKED well within it's design limitations!

6 VOLTS/POS. GRD. NW INDIANA

Update:



Couldn't find article with photos on mechanical stop for Loadomatic (did I imagine it?). Did find recommended performance Y-block ignition curve though. Since PROPER set-up on a specific motor would likely require a lot of trial & error dyno work (who would bother?), and even with a Sun machine, the inscrutable Holley Loadomatic venturi/manifold vaccum signal would be near impossible to calculate/dial in, it would require a lot of REALLY educated guesswork to achieve the same curve.

Looks to me like you could just drill the dist. housing and install a stop bolt that contacted the eccentric spring-post, after determining the desired max. advance/degree point-plate position (from curve specs.) on a strobe machine. You could then loosen the advance springs and crank up the initial timing by ear safely, until trial & error produced the best acceleration result? (1956 all over again)

6 VOLTS/POS. GRD. NW INDIANA

Try running without the vacuum advance.  It may not make much difference in mileage.  In the early '60s I had a '56 Fairlane with a 312, mild cam, centrifugal only distributor, 2-4s, 4.27 gear, OD.  I got 22 mpg on a trip on a toll road, didn't believe it, checked on the way back, got 21+.

John

John - "The Hoosier Hurricane"

I know my dizzy isnt a Loado.  Probably should not have confused the thread with reference to it.  I was just agreeing with one of Daniel's thoughts about the Loadomatics likely being tuned by hot rodders in the 50s with screws limiting advance.  Basically that was what was suggested to me to control the amount of vacuum supplied advance in my 59 model.  It could be run with the vacuum line disconnected, but as I understand it that would have a bad effect on mileage. Sorry about the confusion.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

Mike,



I'll look for that article anyway (even if your distributor is NOT Loadomatic), as I will likely need it myself someday. I'm always trying to track down local rumors of someone with a mint-cond. SUN machine to sell cheap! Race-tuning a Loadomatic distributor seems like a great plan for killing bleak winter days.

6 VOLTS/POS. GRD. NW INDIANA

The '59 would not be a loadamatic unless it is a 6 cylinder.  If the inlet to the vacuum control is hex shaped, about 11/16" hex, the tip of the control will unscrew, and there will be a spring, some spacers, and maybe some washers inside.  The long spacer inside the spring limits the amount of advance, the spring and washers controls the rate.  Lengthening the inner spacer will limit the amount of vacuum advance.

John

John - "The Hoosier Hurricane"

My distributor is from a '59.  Maybe next year I can save enough to buy a new one.  Bill thought that the amount of advance provided by the vacuum was too much and that a limiter should be put on the plate.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

Mike, Whoops, you're right. No springs in a loadamatic. And John, he likes original, even if it didn't work!

Frank/Rebop

Bristol, In ( by Elkhart) 

46yblock:

Why don't you want to upgrade to a later distributor, you can dial in the advance curve you want for performance, and let the vacuum advance help your fuel mileage?

John

John - "The Hoosier Hurricane"

Hmm.  Me not comprehend.  Cam as in the vacuum mechanism?  If so, these are the same vacuum units (post 57) that were used in post Y years arent they?  And if so, seems they should be available.

Mike

P.S.  Daniel sorry about the hijack.  I guess you werent gettin deep at all.  Thanks for starting the thread and I will shut up.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.