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By DANIEL TINDER - 16 Years Ago
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Finally obtained an accurate scale for testing point spring tension.
While I WILL likely replace the non-ventilated antique units that were included with the dual-point Loadomatic conversion kit I installed, I did notice that their spring tension is still a couple ounces over the max. specs., even with the spring/condenser nut loosened all the way. Aside from just swapping points until a weaker spring is found (and assuming the pivot is not binding), can anybody with extensive point ignition experience offer an alternative solution for this type of dilemma?
Also, specifically what type of pivot lube is traditional? Oil near the points is usually discouraged, so I'm thinking: greaseless lube or WD40?
P.S. I recently downloaded an article (from a link on this forum?) titled: HOW DOES A LOAD O MATIC DISTRIBUTOR WORK? Can't seem to find it again. I would like to communicate with the author re: additional tech. points concerning the text, if anyone can provide contact info?
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By marvh - 16 Years Ago
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Here is good info regarding the loadomatic and spring tension testing
http://home.earthlink.net/~rchaskell/auto/sun/DT504_505_im.pdf
marv
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By DANIEL TINDER - 16 Years Ago
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Thanks anyway Marv, but I already have that manual. Nothing in it re: my questions.
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By Pete 55Tbird - 16 Years Ago
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Daniel, Try http://m571.com/yblock/loadomatic.htm If that does not work just Google Ford load o matic. Pete
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By pegleg - 16 Years Ago
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Doug T (Y-Blocker) wrote an excellent article on this a couple years ago. I think it was in the Y-Block magazine, maybe he will chip in here and tell us where to find it.
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By DANIEL TINDER - 16 Years Ago
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After reviewing all my ignition literature, I see that 50s brand-X/scrub points were adjusted by simply squeezing the spring with pliers. I will try that technique and see if the tension can be brought within FoMoCo threaded adjustment specs., but worry it might distort enough to effect performance? No big deal I guess, as points are cheap.
My interest in the LOADOMATIC article concerns the apparent fact that the spark control valve feeds full manifold vacuum (20" Hg) to the distributor at low load/revs, even though max. high speed spark advance is set for only 2" Hg (teapot venturi vac.). This results in rough-running when initial timing is excessive, especially if the advance springs are set more aggressive then factory #s. Experimenting now with mechanical advance limiter.
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By Pete 55Tbird - 16 Years Ago
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Daniel, When I re-read the article on load o matic distributors, the take away for me was that they preformed badly as a result of TOO LITTLE distributor advance during acceleration. Why would you want to limit advance. I do not understand how that will increase engine preformance. Can you explain? Pete
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By PF Arcand - 16 Years Ago
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Daniel: Further to Pete's comment, if I'm reading it right, you say the problem occurs when initial timing is to far advanced. So, wouldn't it be prudent to set it back some?!
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By DANIEL TINDER - 16 Years Ago
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Pete/Paul,
Point of article was how Loadomatic advance was SLOW to catch up with revs (restrictive air passage) compared to centrifugal. Weakening the springs should provide less resistance to available low venturi vacuum, allowing quicker advance? If springs too weak, low load manifold vacuum will produce excessive advance (rough running) without a mechanical limiter. Initial advance typically should be as high as possible (limited by hard-starting/pinging) for maximum acceleration? Clear as mud?
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By Pete 55Tbird - 16 Years Ago
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Daniel, It has been a long, long time since I have been inside a load o matic. Are you saying that by finding weaker springs that the points themselves are attached to you believe your distributor will advance the timing at a faster rate? What about point float at a much lower RPM? I remain skeptical of this theory. Pete
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By John Mummert - 16 Years Ago
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Dan, the best article on the load-o-matic I ever saw was written by Barney Navarro. I can't remember where it was printed (circa 1956) but it was very in depth and made it sound like the finest ignition system ever devised. I found this on the net: part of a Navarro article on load-o-matics. "Ford's latest method of controlling spark advance employees an ingenious system utilizing manifold vacuum and venturi vacuum. With this system the flyweight governor is eliminated and in its place is nothing but a diaphragm. This diaphragm not only advances the spark to conform to rpm changes but is also makes load compensation adjustments. All ´49 through ´54 Ford and Mercury carburetors have in addition to the conventional manifold vacuum takeoff, such as is found in the throttle body of most passenger car carburetors, a connecting venturi vacuum passage. The manifold vacuum, as usual, is obtained from a small port in the throttle body located slightly above the butterfly's closed, position, on the side where the butterfly swings upward to open. When the throttle is closed at idling, the vacuum port does not receive vacuum because it is on the opposite side of the butterfly. As the throttle is opened slightly, this port is uncovered and a vacuum is applied to the distributor diaphragm to advance the spark. If the throttle is fully depressed, the manifold vacuum is destroyed and no advance takes place. As speed increases, however, the venturi vacuum increases gradually and advances the spark to conform to the rpm. Letting up on the throttle increases the manifold vacuum (Provided it isn't let up all the way) and the spark receives load compensation. A balance is always maintained so that the correct amount of spark advance is supplied for all speed and load conditions. " check out Red's Headers website for full article. I don't think this is the article I had in mind. PS, should be able to ship Monday
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By DANIEL TINDER - 16 Years Ago
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Pete 55Tbird (11/11/2009)
Daniel,
It has been a long, long time since I have been inside a load o matic. Are you saying that by finding weaker springs that the points themselves are attached to you believe your distributor will advance the timing at a faster rate? What about point float at a much lower RPM? I remain skeptical of this theory. Pete
Pete,
Wrong end of the stick? The two coil springs attached to the breaker plate mostly control the rate/extent of spark advance. Adjusting POINT spring to the high # within it's design range prevents point-float, but any higher wears out the distributor cam & rubbing block. Excessive point-spring tension also applies extra drag to the breaker plate, affecting the advance spring settings. So, point-spring tension should always be adjusted BEFORE adjusting the advance springs.
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By DANIEL TINDER - 16 Years Ago
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[quote][b]John Mummert
check out Red's Headers website for full article.
Interesting point from that article: Plug fouling with daily road use was a big 50s problem for those that ran centrifugal-only distributors. Comments from others on the forum that run successfully with no vacuum diaphragm indicates (possibly) that modern no-lead fuel has changed the situation?
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By aussiebill - 16 Years Ago
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Not sure after reading all this as to what springs you originally wanted to adjust, at one point it sounded like the inbuilt points spring, then the 2 advance coil springs. anyhow if wanting to increase/decrease tension of these 2 coil springs the attaching posts can be rotated to do this. i have original ford tool to set these up and is interesting old tool. regards bill.
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By DANIEL TINDER - 16 Years Ago
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aussiebill (11/12/2009)
Not sure after reading all this as to what springs you originally wanted to adjust, at one point it sounded like the inbuilt points spring, then the 2 advance coil springs. anyhow if wanting to increase/decrease tension of these 2 coil springs the attaching posts can be rotated to do this. i have original ford tool to set these up and is interesting old tool. regards bill.
Bill,
Been looking high & low unsuccessfully for that tool (SnapOn MD5). Twiddling those posts with an ordinary wrench a tricky operation while the distributor is running at 2000 rpm in the Sun machine. Would also be handy for point aligning.
P.S. Total of 4 springs to adjust in a dual-point Loadomatic.
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By PF Arcand - 16 Years Ago
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Daniel: For more info that might be relevant to your question, go back to Home on this site, then to Articles. Scroll to Hot Rod (1956 mag) article. Open, & scroll down to the ignition section. The discussion there may be helpful.
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By DANIEL TINDER - 16 Years Ago
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Thanks Paul,
I had forgotten about that article. Combined with the 55 shop manual rpm/vacuum specs., and other Y-Block performance curve data found, I should be able to come up with a solid baseline for modification.
One MIGHT infer that RPM & corresponding ''inches-of-Hg" specs would indicate a standardized teapot venturi vacuum at that engine speed? Of course, the only way to be certain about a specific carb/engine set-up would likely be to drive around with an accurate manometer spliced into the distributor line, and record the #s.
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By DANIEL TINDER - 16 Years Ago
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Forgot to mention: After setting up a Loadomatic last night with factory springs/advance curve, I then applied a full 20"s of Hg. (low-load cruising manifold vacuum). Assuming the spark control valve orifice actually passes full manifold vacuum to the distributor diaphragm, that would produce over 50 degrees of crank advance, even if the initial timing was set to factory spec.! No wonder there is so little latitude in boosting initial advance before experiencing low-load rough running.
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By Pete 55Tbird - 16 Years Ago
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Daniel, 50 degrees of advance at 20 inchs of manifold vacuum ( this is very low load, low throttle application, cruise condition) IS NOT EXCESSIVE. This is what is desired for HIGH MPG. AS soon as you give it throttle, the manifold vacuum drops, the timing retards, and the rpms pick up. I feel you are trying to fix a problem that does not exist. If your engine pings, there is a problem. If there is no pre-ignition (ping) then there is no problem. Pete
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By DANIEL TINDER - 16 Years Ago
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This brings up an interesting point: The engine damage likely from prolonged pinging under load (pre-ignition/detonation) is well documented. But, what about rough-running from hyper-advance at low load? Aside from disconcerting, what are the long term effects, if any?
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By GREENBIRD56 - 16 Years Ago
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Lots of low rev, low/no load (idle) spark advance isn't necessarily "rough". Mine runs smooth and makes lots of vacuum - that it doesn't make if I take the extra vacuum advance away. Better have a hot, strong spark to fire lean mixtures at idle.
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By DANIEL TINDER - 16 Years Ago
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Better have a hot, strong spark to fire lean mixtures at idle.[/quote]
Extra dwell from the dual points should help. Higher C/R & octane will add unknown factors though. Having two distributors will be an advantage, as I can set one to factory specs. and A-B compare any modifications to the other. Finally finished the mechanical advance limiter rig. It works great on the Sun machine (currently set to add max. 36 crank degrees), but unfortunately can't do a road test as car up on blocks for the winter. Will thus have plenty of time to play with the springs, and calculate new curves for larger displacement motor on the way (it occurred to me that more venturi vacuum will likely be produced at the same RPM).
P.S. Had to go through a half dozen sets of points before finding two that would adjust to proper spring tension (why I started this thread) within the allowed travel range.
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By GREENBIRD56 - 16 Years Ago
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Daniel - Which coil and ballast resistor have you accumulated to run with this outfit? Extended dwell (from the dual points) is part of the equation - how about the in-rush amps? I realize inductance measurements would be impossible to obtain - but the sum of coil primary resistance and ballast resistance is worth knowing. A little paint could help make a "hotter" coil a little less obvious. My '56 outfit had so much small diameter wire (and old connections) in the ignition circuit, that the voltage at the ballast resistor didn't match the battery voltage too well.
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By DANIEL TINDER - 16 Years Ago
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Steve,
No ballast resistor on a 55 6 volt. OEM coil should work OK, as dwell will not be maximized (want to keep point gap on the high side).
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