Tech Q and A for October, 2024

Q: Rayburn Mitchell writes- Gentlemen,

I often see Model A’s that owners have converted to 16″ tires and wheels. I have spoken to a few of the owners as to the rationale behind the change. I am beginning to suspect that it has more to do with the “look” as compared to the actual advantages as to the change. I would appreciate your honest feedback as to the real advantages of this change. Is more tread on the ground for traction and braking the primary or only reasons for this change? I would also like to know the disadvantages (I know cost and speedometer are two).
The background for this question is that several years ago I purchased an “A” that had 16″ wheel and tires and I nearly have it ready for the road. I have those as well as 19″ ready to go. Which one should I use?

 

A: Lots of people go to 16’s or other wheels for the looks.  Others because they want to run modern tires that are available at almost any tire shop. Some people want to go to larger, wider tires because their car’s front end is worn and instead of fixing the worn part(s), they switch to wider tires so the car handles better.   Lots of reasons. -Paul

Q: Brenden Johnson writes- Hi do you know the number for the wix filter that goes in the [glass] sediment bowl on the Model A?

A: Wix 33039 or Napa 3039. -Paul

Q: Sam Weston writes-

Recently I had the engine rebuilt by Bert’s Model A in Colorado. I just reinstalled it and tried to start the car. I have adjusted the timing using the nu rex tool and the method Paul Shinn outlined in one of his YouTube videos. The car does start, however, it only runs for less than a minute before it stops. Any suggestions on how to keep the engine running or what systems you would look at?
And last question, when the engine is running for a brief minute, I cannot shift the transmission into first gear with lots of grinding. Is it something to do with the clutch pedal adjustment (where the peddle is linked up to the clutch under the car) or something else?

A: Hello Sam–First thing I would check is your fuel line.  Disconnect at the carb, place a can under the line (to catch gas) and turn on the gas.  The line should flow freely and steadily.  As for the clutch, it needs adjustment.  Make sure you have about one inch of “free play” before the pedal starts to engage with the throw out bearing. -Steve Schmauch

Paul adds- Hey Sam, I agree with Steve (as usual!) about the fuel flow being the likely issue.  Just for giggles, try running it with the gas cap removed from the top of the gas tank to be sure it isn’t a venting issue.  -Paul

Sam Responds- Hi Steve and Paul,  Thank you so much for your help. It was a gas flow issue. Once I removed the gas cap and found the gas flow was much better. I have a new gas cap ordered from Berts. Thanks!

Q: Hello Model A Tech Team!  My name is Mike Froeder, from Brazil. I need to know, before I open my engine, how much play in the distributor’s drive shaft (spinwise) is normal?  What causes it and how to fix it? The engine backfires when slowing down, could this be a symptom of it?

A: Hello Mike–There should very little play in the distributor shaft, maybe a few thousands of an inch back and forth to almost none.  If you have more, then it indicates a worn distributor drive gear located below the distributor shafts (2) and visible in the valve chamber.  This unit is driven by the camshaft.  Many vendors carry a replacement gear and it is a fairly simple job to do.  The engine backfires could be a symptom of timing.  I would replace the drive gear first.  -Steve Schmauch