Tuning my Model A

[Texxracer22]

I just got a 29 model A . I have a 30 hot rod but this new one is all stock . I just got the motor all together and it actually started but runs really rough. What are some good carb start settings? Also what is the screw on the side of the distributor ? It runs rough and backfires. I pulled the head and found a stuck valve, got it moving but it still runs bad and backfires. Any ideas?

[Tudortomnz]

Buy a good Model A maintenance book eg. Les Andrews. You will have to check thru everything, not just tweak a few screws.
Contact your local Model A Ford club guys, they will be glad to help also

[Mike V. Florida]

For timing go here,

http://abarnyard.com/workshop/timing.htm

As for the carb;

http://www.model-a.org/default.html

They say it better then I could!

[Brian SATX]

You are real close to Houston. Contact the Houston Club and join them to get a ton of help. Look on the MAFCA website and see who lives close to you. Come ot the Texas Tour in June in Marble Falls. We hope to have about 200 A's there.

[RonC]

Start with a compression test. As mentioned join a local club.

[1931 flamingo]

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Try running some marvel mystery oil in the gas, along with the above mentioned suggestions.
Paul in CT

[newshirt]

The screw on the side of the distributor is just a set screw to hold it in place.

My Model A ran much like yours when I first got it. So I set out to replace every ignition part on the car regardless of quality. I replaced the coil, coil wire, dist cap, body, rotor, points, and plugs. It ran MUCH better after that.

But then I moved on to replace the carb and distributor with a rebuilts from Bert's. That made it run much, much better. Now it's smooth and responsive like a "new" car.

I know this sounds like a shotgun approach, but it worked well for me. Now I can focus on learning to rebuild the old dist and carb.

[Purdy Swoft]

I'm not sure what you mean by the screw on the side of the distributor. If the distributor is original style, the screw on the passenger side holds and grounds the condenser to the distributor housing and needs to have a clean tight connection. the screw on the drivers side that is in the hole in the lower front of the housing, connects the condenser to the lower distributor plate. You could have a loose or weak condenser. If you removed and replaced the head you will know that the set screw and nut on the center passenger side of the head holds the distributor in place.

Here is how I tune mine . Remove, clean and set the spark plugs at .035 and leave them out for the moment, being carefull not to drop anything in the spark plug holes. file the points and set the gap at .022 . Check the gap on each lobe of the distributor cam and the gap shouldn't vary more than a couple of thousants. There has been a lot of problems with poorly constructed distributor cams and upper distributor shafts. Bill Stipe (stipe Machine) makes the best distributor cam and it gives an additional 10 degrees of dwell for a hotter spark. While your in the distributor check the gap between the rotor tip and the plug wire contacts in the distributor cap. I set mine at .035 for hotter spark and they all need to be the same. I turn the engine over and measure each gap. if the gaps vary it will indicate that the upper distributor shaft is either incorrectly machined or the length of the contacts in the distributor cap are uneven. I have had both problems from many suppliers. The cap contacts can be filed for proper gap BUT be SURE that the problem isn't the distrubtor shaft before you start filing the cap contacts or you run the risk of ruining the cap. Timing, With the spark plugs out, I turn the engine untill the timing pin drops in place. I loosen the screw that holds the points cam to the dist. shaft and turn the cam so that the trailing edge of the rotor tip aligns with the number one spark plug wire contact in the dist cap body, with NO clockwise backlash. There will be backklash but the cam needs to be tightened so that all of the backlash is in the counter clockwise direction or the timing will end up retarded. It may take several tries because when you tighten the cam screw the cam will try to move in the clockwise direction. A cam wrench will make setting the timing much easier. I polish the spark plug wire connectors with a Scotch brite or steel wool for better conduction.

Carburetor. Asuming that the float is properly set and the carb. is not leaking I set the idle air adjust screw at one and one half turns off the seat for a beginning adjustment. Depending on carburetor and the possibility of vacume air leaks,, I run the original style Zenith carb with the Gav turned counterclockwise one quarter turn off the seat. When very cold you may need to open the GAV up to one full turn off the seat untill it warms up. If it will only run with the GAV opened WAY up, this usually indicates a vacume leak where the carb bolts to the intake or a warped carb. housing as in the pot metal Tillotson, Marvel and some others.

Maybe some of this will give some pointers. Many things can cause popping, backfiring. I could be typing all day if I covered all of the possibilities but here is a few more, weak coil, bad ammeter or bad connections,resistance or poor connections in the terminal box, shorts in the armored ignition cable bad ignition switch and bad ethanol adultrated gas. Marvel mystery oil is good for sticking valves. Good luck.

[Texxracer22]

Thanks for the detail. I am going to try all this tomorrow. One thing I know is the screw on the drivers side of the dist is loose. I figured this was a adjustment of some kind. But it should be tight, correct? Also hate to sound dumb but what is the " timing pin" that drops in?
I do plan to join a local club. This is my first "original" model a but I have had other collector cars and find clubs a great way to get info.
Thanks again for the input.

[VWJoe]

Originally Posted by Texxracer22

Thanks for the detail. I am going to try all this tomorrow. One thing I know is the screw on the drivers side of the dist is loose. I figured this was a adjustment of some kind. But it should be tight, correct? Also hate to sound dumb but what is the " timing pin" that drops in?
I do plan to join a local club. This is my first "original" model a but I have had other collector cars and find clubs a great way to get info.
Thanks again for the input.

The timing pin is screwed into the upper right front timing cover. It looks like a smooth shaft with a rounded head & either a square/hex head base. Unscrew the pin, turn it around & insert it in the hole it came out of. With your finger, push in on the pin while you slowly rotate the engine by hand clockwise feeling for the pin to drop into the timing gear hole. When that happens, #1 piston is @ TDC. Set your points & timing at that point. You may have to sharpen the rounded part of the timing pin a little bit as some timing gears have a very small dimple and can be hard to detect.

Joe,,,,