Mallory Distributor questions

Phred

Phred

Senior Member
I am using a Mallory 2301105 (YH type) single point distributor, H & H G7 cam, and Lion Speed cylinder head (7.0:1 compression), and Stromberg 97 carb on my Model A ford four cylinder flat head engine. Points are set at .020" and Autolite APP64 plugs are at .035". I do not have a "dial back" advance timing light.

The engine runs and pulls great with the exception of low rpms (1200 - 1600 rpm) in 3rd gear. The cam seems to come to life after about 1500 rpm, and depending on the ignition timing, there seems to be a flat spot in the acceleration when shifting from 2nd to 3rd gear. When the ignition timing is advanced to provide good road speed manners, the flat spot in 3rd gear acceleration is nearly minimal, but the car is difficult to start. If I retard the overall timing by twisting the distributor, the engins starts better, but the flat spot rears it's ugly head. I wanted to increase the overall advance range in the distributor to allow for a retarded start and still have enough advance for road speeds, and also "weaken" the springs on the centrifigal advance so the advance curve will rise quicker at lower rpm.

The distributor seems to have two pink springs. According to Mallory's graphs, these are the weakest springs. I removed one spring from the distributor and left one in place. This seemed to be a step in the right direction, so I stretched each of the springs to "weaken" them, however, I stretched them too much as the the springs do not pull the weights all the way closed. Idle speed is now irregular and hard starting has returned. Obviously, I need to get some new springs from Mallory and keep playing, just not as aggressively.

Will using heavier weights in the centrifigal advance also increase the rate of advance, similar to using weaker springs?

Any thoughts, corrections of logic, or advice would be appreciated to help with the hard start/flat spot issue.

Phred Hollister
847-312-0926 cell
 
Did you TDC the engine and put a pointer/notch on the pulley? With out doing that, you don't know were you are! The 2 tabs that hold the springs, you bend them to change the spring pressure, the weights are heavy enough! They don't make different weights. Lets there and move on . Dudley
 
I had a Mallory electronic that had too much advance for my "B" engine that had exactly the same mods as yours, except for larger valves. It had to be timed so that if it had adequate advance at low RPM, it had way too much total advance; or timed for about 30 degrees total which made it too retarded and sluggish to drive under 35-40 in 3rd with any smoothness or response. I was too lazy or hurried to investigate the curving procedure, so have been using "B" distributors with satisfactory, but untested or un-scientific results on my hopped "A" engines. I have an old single-point Mallory that seems to be curved just right for mildly hopped bangers. But I've still never curved one myself. My question is: does anyone have a manual for the adjusting/curving procedure on a vintage Mallory single point?
 
I could only wish to have the manual. Several single point YA's in the parts barn. Going to run one of them so hope I have a variety of parts to choose from. If you find a manual let me know I would be interested in a copy. Rod
 
I don't think there is one. I have been recurving dist for almost 40 yrs. on my 2 SUN dist machines, 1 battery powered the other has its own transformer. I have 2 books, 1 is the Mallory parts book with dist # and Don Zigg's. Dudley
 
Thanks for looking for a Mallory manual, guys. Just a quick note on getting it right. We used to road race SCCA, in fact won the Mid-Div in our class in '75, and, of course there were no timing specs for an engine that had your own mods, so you had to make your own curve and specs. We did this by timing our laps, tweaking, making notes, then the same again until our times were best. Then we kept those specs. Any change in cam, carbs, manifold, headers, etc. required the timing experiment to be done again. The standard fuel at every track was 100 octane av gas. I have noticed over the last 15 years that many banger mods are so similar that you could almost call some of them "standard mods", including my own. The guys building and racing these banger engines have all arrived at their timing specs the hard way and their recommendations are mostly very close to the same for any given set of engine modifications. I'm sure I have been saved from some certain grief by having these recommendations (the experiences and disasters of others) as a reference to start with.
 
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