Tech Tips

Image by Todd Quackenbush

 Cast Iron Brake Drum Info

by Lynn Sondenaa, Volcano ‘A’s

This information is about reproduction cast iron brake drums. Gray cast iron is what most manufacturers use to produce cast iron parts. It has been in use since the Model ‘T’s & Model ‘A’s came into existence. Even the reproduction cast iron drums made in China are gray cast iron. Some cast iron drums are advertised as nodular iron. Nodular iron is gray cast iron which has small amounts of magnesium added to form a premium cast iron. Nodular iron is also known as spheroidal or ductile iron. It has excellent ductility, higher tensile strength, and better corrosion resistance than gray cast iron.  Ductility refers to the ability of metal to stretch, bend, or twist without breaking or cracking. Tensile strength is the property in metal which resists forces acting to pull the metal apart. Corrosion is the wasting away of metals by slow gradual combination with other elements and chemical compounds.  You may use this information to make an informed decision before purchasing your new re-production cast iron brake drums!


Script ‘A’ News December 2019


Technical Tip on Threadlocks

by Lynn Sondenaa, Sandy, Oregon

To prevent nuts, bolts, and machine screws from loosening due to vibration, the following items can be used. The most common is a lock washer. It is an incomplete circle that has a twist that is flattened when tight. A spring washer is made from spring steel with a slight crown or twist. When tightened the crown is flattened and this pressure holds the fastener tight. Star washers have little fingers that dig into the surface to hold tight. They are made in internal and external styles. Self-locking nuts have a nylon insert to keep them tight. Their disadvantage is that they should only be used once. A liquid thread-lock can be applied to threads. Loctite is a popular brand. Thread-lock liquids are made in different strengths. I use Loctite blue 242 medium strength. The fasteners can be removed with normal tools after it has cured, but it will hold tight. The high strength type takes a lot of work to remove, as it is designed to be permanent. This information should prove valuable when working on the Model ‘A’. 

Volcano View                                                                                                            September 2013




Jim G - June 2013 (Editor’s Note: From the Archives!)


The Zenith carburetor was an excellent choice for the Model ‘A’ Ford. Henry’s highly trusted design engineer, Harold Hicks, selected the French design and adapted it to meet Henry’s demands for the Model ‘A’. This is not a technical tutorial on the Zenith carburetor, just an effort to provide a basic understanding of the fuel flow channels.

Hopefully this will aid someone in the future when issues from contaminants cause reduced performance and require a little TLC to “clean out” the carburetor. Unfortunately, “stuff” does get into the fuel system to mess with the fuel flow in the jets! Fuel arrives in the Zenith carburetor fuel bowl through the “screen” filter in the top casting above the fuel bowl. Near the bottom of the fuel bowl there are three outlets for the fuel.


1.) Near the back side (engine side) of the carb is an opening that allows fuel to flow directly to the main jet! This is a straight shot that feeds this jet only!


2.) In the middle of the three openings, is the Comp Jet. It is the small brass screw with a hole in it. This jet controls/meters fuel flow to the Secondary Well. The Comp Jet is calibrated to provide a measured feed for both the Cap Jet and the Idle Jet. Even though both jets drink from the Secondary Well, they do so at different times as engine demands change. They do not perform/serve at the same time.


3.) Last is the opening on the front side of the fuel bowl and provides fuel to the GAV (gas adjusting valve). The GAV function is to bypass the Comp Jet when “extra fuel is required” for special driving conditions. It increases the fuel available for the Cap Jet to meet high fuel demand conditions (e.g., the heavy engine loading of hill climbing). Well, that does it, not really that complicated when you think it through. So, if you are really having a carburetor/fuel problem, you now have an appreciation for where to start looking for the blockage. I have one further comment about the Idle Jet and the Cap Jet! They not only do not feed at the same time from the Secondary Well, their fuel input requirements are significantly different. The Idle Jet flow requirement is about one quarter (¼) that of the Cap Jet (46 vs. 165 cc/min). Thus, opening or closing the GAV when the engine is at idle rpm, should have no affect! If it does the carburetor is not feeding through the idle circuit. The idle jet, the smallest of them all, is likely the problem.


(All the above assumes no vacuum leaks)


The Steering Column March 2021 

No  More Blind Spots

                                    (from USAA Magazine, May/June  1998, p48)


To reduce  the  blind spots in your  sideview mirrors (and lessen  your chances of  an automobile crash),  make sure your  mirrors  are properly adjusted.  Here’s  how: For  the DriverSide mirror:  Place the left  side  of your face against  the driverside  window  and adjust the  mirror  so that you can  barely  see  the  left side  of  your  car. For the PassengerSide mirror:  Sit  in  the center of  the front  seat  (or lean  as  close to  the center as possible) and  adjust  the mirror so  you  can  barely see the right  side of your car. Approaching vehicles should be  in your  sideview mirrors  before they leave  your rearview mirror and  in  your peripheral vision  before  they  leave  your sideview mirrors.

                                                           BYPASS WIRE: 

                                  A handy item to keep under your Model ‘A’ Seat

                                                                by Bob Toms


This is a simple device that will help you diagnose trouble in your electrical system and, in some cases, offer a temporary solution to get you home: a simple length of wire, about 500mm (20 inches) long, with alligator clips attached to each end. An easy do-it-your-self item!


· Connected across the terminals of the junction box, it can bypass a faulty ammeter.

· Use a longer bolt in the distributor terminal of the condenser. Connect this to the red coil wire using the by-pass wire and you can energize a defective ignition switch or faulty armored cable.

· If the cut-out contacts fail to close, you can by-pass the cut-out to charge the battery. · If the cut-out is stuck closed, the by-pass wire can be used to ground the generator output terminal.

· It can be used to test resistance (or voltage loss) in the horn and lighting circuits by by-passing switches and connectors.

· For that matter, it can be used to test contacts and wires hidden in body work or in con-duits.




Thank you to Andre Millar, in South Australia’s Model A Torque. 


        Technical Notes: Points to Ponder #2 on the Model ‘A’

                                        by Lynn Sondena, Sandy, Oregon

Model A engines like “hot” spark plugs.


• To locate exhaust system leaks, squirt a small amount of kerosene into the air intake of the carburetor while the engine is running. Leaks will be visible from the black smoke appearing at the leak.

• Use zinc chromate primer, it helps to prevent rust.

• Torque spark plugs 34 to 38 pounds.

• Backlash is the play between the teeth of two gears which are engaged.

​• Advanced spark is igniting the fuel mixture before Top Dead Center.

• Retarded spark is igniting the fuel mixture after T.D.C.


• Zenith float level adjustment is done by adding or subtracting washers underneath the float valve.

• Did you know that the float valve fiber gasket is the same size as the distributor shaft sleeve fiber washer? Snyder’s number A-12181 or Mac’s #A-12194.

• A front-end shimmy is usually caused by loose tie rod ends, or drag link ends. It can also be worn ball studs on the steering arms and pitman arm.


Volcano View May 2013 



                                               Tips from  Down Under

                                         Found  in a  newsletter  from New  Zealand, Canterbury  Chapter Brake Rod AntiRattlers


Correct installation: Disconnect rear  rod  clevises,  loosen locking nuts, and remove clevises;  slide  anti-rattlers over  rods  so  that  they  are pushing against donuts toward rear  of  car,  bolt  to  bracket on radius rods;  reinstall  clevises and locking nuts.  


Fronts are different  -  anti-rattlers  slide  on  from  eye end  of brake rods, so disconnect  from  cross-shaft  arm at  center of  car,  slide  anti-rattler on,  bolt  to bracket;  reconnect  rod  at center.  You  may  have to enlarge the  openings  in  the front  anti-rattlers so they  will  slide  over  the  eyes.


Oil Loss:  A quart of  oil is 36,500 drops  of  oil.  A  normal engine  in  the ‘60s used 1/1100 of  a drop  on  every  power  stroke (1  quart  every  1000 miles  was  normal back  then)  and  if an  engine drips  one  drop  every 50  feet,  and  it  doesn’t  matter how  fast  you’re  going,  (think about  it) the engine  will  lose  1 quart in  300 miles. They  used this to illustrate that a  drop was  actually  much higher  consumption than a  burn!


Burning  Points:  Loose  connection somewhere  between  cutout and battery, causing  voltage to  go  berserk and  burn points.  Check connections at: cutout, junction box,  ammeter,  added  fuse holder,  (if any).  Remove both  forward  3/8” nuts  on  junction block  and tighten both of  the  3/8” nuts inside  the  box.  Be  sure ground system  is  good by clipping  test  light to  gearshift,  put  point to middle  of + +battery  post, step  on  starter  with key  off.  No light  =  good grounding.  Light  on = poor  ground connection  somewhere.  Feel each  connection for  being HOT! Loose  connection = HEAT.  In  regard  to  the condenser.  The job of the condenser is  to  take  the brunt  of power from the  coil when  the points break to keep  the points from  sparking/burning.  In modern times  in every  other application  other than  automotive we call  them capacitors.


Painting Fuel Gauge  Figures  :  Has the  black paint  in  the  fuel level markings  disappeared?


1.  Clean  the  curved sector  with  the  markings really  well.


2.  With a  tiny  brush or  toothpick,  fill the  letters with fuel-proof paint. I use a  glossy  black epoxy  spray  paint.  It  will  take 2  or  3  coats.  Do  no worry  about  putting  on  a  bit  too  much.


3.  When  the  paint  is  really  dry,  wet-sand the  sector  with something like  600  grit paper  to  remove all  the  overflow  paint. Gas  Tank Welting:  One piece  goes  from  one side  of the  tank,  all  the way  to  the other side, starting and ending at  the  rear  edge  of  the  hood.  At  the sides,  it runs between the  cowl  and  the tank,  and  in  the  center, between the  tank and that strip that runs right  under  the  windshield. There  are  various tricks for  getting the  welting  to stay  in  place.  You will  need to pre-cut holes or  slots for  the  bolts that  hold the  filler  strip and tank to the  dash  rail.  You will also  need  to make some notches  in the flat  part  of  the  welting  to  help  it  go  around  the corners.  The last inch or so,  where it  passes  under  the  cowl  band,  has  the core removed,  and  it  serves  as  an  antisqueak  under  the  front top corner of the cowl.


Gearbox  Shielded Bearings:  


Main  drive  gear and  main  splined  shaft cannot  be  perfectly shielded  and shielding may  not  be  a  smart  thing. Ford  designed  parts  to  take  advantage  of function.  The front  bearing does  not  matter  much.  It  faces  up  and  there is  the throw-out  bearing sleeve  preventing  oil  from  going anywhere.  The   rear  bearing is  open  to  the  U-joint. The  grease forms a  packing and the  oil that  leaks past will get into  the  U-joint and then back  to  the  speedo gear and  the drive shaft  bearing. So  why  seal  the rear bearing.


Script  ‘A’  News, December 2020    



How long  has  it  been  since you  lubricated  your speedometer cable? Lubrication of the speedometer  cable must rate  among  the  most overlooked,  and definitely the messiest,  maintenance item  on  the Model  ‘A’  Ford.  


While driving,  the speedometer cable rubs  against  the speedometer cable housing, creating hot  spots  where it rubs.  A  good  lubricant  reduces  the friction, increasing speedometer  cable life and reducing  noise.  White  lithium or  black molly  are  good  lubricants.  


Harley  Davison also makes  a  good  speedo-cable lubricant. To lubricate  the  cable, remove  it from  the housing,  and apply  grease  to  the  length of  the  cable  as you put the  cable  back  into the  housing.  You  only  need to  disconnect  one  end of  the speedometer  cable  housing to accomplish this task,  and if  working  over  your head  is not a problem,  disconnecting  the  speedometer  housing from  the  drive assembly  on  the  torque  tube will  allow access to the  speedometer  cable  and leave  your instrument panel untouched.


By Jim McPherson - Aiken A's


Model A Ford Restorer's Club
Niagara Frontier Region