Model A only runs 40 miles
 

Hi guys, another little problem. A friend has now also bought a Tudor, but the engine has too little power. He didn't get more than 40 miles. Acceleration isn't particularly good either. I now have a direct comparison with my 1930 Tudor, and that's worlds apart. We have already checked and adjusted the ignition. But everything was OK. If the GAV is not open at least one turn, there will also be misfires!
Then we removed the Zenith carburetor and installed a Tillotson, which made it run even worse. (The carburetor came out of the grabber box.) But then we installed my Zenith carburetor, with which I drive over 60 miles, which also didn't help. Now we're fishing something in the murky and don't know what to do next. In my opinion, he gets enough gasoline. Nothing is dirty either. We also cleaned his carburetor again, but that didn't help either.
Where else could you look?

Greetings Andy

Re: Model A only runs 40 miles
 

What do you mean by only 40 miles ? It overheats or quits ?

Try a compression test. It may have jumped time.[ gears]

Re: Model A only runs 40 miles
 

Check for a nice blue spark 1/4 inch from a head bolt

Re: Model A only runs 40 miles
 

The engine just doesn't rev up under load. He can't do it anymore.

Re: Model A only runs 40 miles
 

Pretty sure the OP means the engine won't rev up under WOT and is only hitting a 40 mph top speed.

Re: Model A only runs 40 miles
 

You may want to start with some simple diagnostics. By installing your carburetor on his car you have probably eliminated the carburetor as the cause of the problem.

1. Is timing set correctly ? If too retarded, power will be affected.
2. Check compression. Remove all the plugs. Turn off the gas, and check with throttle lever pulled all the way down (Open Throttle)
3. Insure there are no intake manifold leaks.

Re: Model A only runs 40 miles
 

Check and clean the points and points gap, sounds like possibly the point block has worn down closing down the gap.

Re: Model A only runs 40 miles
 

Sounds to me like a timing issue. If you drop the timing all the way down does it ping? It should, lift it just enough to stop the pinging.

Re: Model A only runs 40 miles
 

Check! Exactly, that's what I mean.

We adjusted the timing with the Ignition Timing Tool Kit and the ignition flash gun. Fits exactly to the "gram".

https://www.macsautoparts.com/ford_m...-tool-kit.html

I'll do a compression test. But do I have to get the tester first.
He has no intake manifold leaks. We sprayed it with brake cleaner.


I can still check that. We had not checked the breaker distance and contact.

Changing the timing to a clearer earlier also does not result in an increase in performance. I tried it. I also went up to max, but no improvement.

Re: Model A only runs 40 miles
 

It sounds like you have checked all the normal things that usually cause that kind of problem. So I would do a compression test first, then I would check the cam timing. By removing the #1 spark plug, and finding TDC (actual TDC, not just by the timing pin) Both valves should be moving as you rock the engine back and forth from TDC. If both aren't moving, the timing gear is probably stripped, or never installed properly. Good luck!

Re: Model A only runs 40 miles
 

Check that the car has the proper 6 volt coil, maybe try a different coil.

Re: Model A only runs 40 miles
 

Check for full travel of the throttle. Sometimes linkage gets bent.

Charlie Stephens

Re: Model A only runs 40 miles
 

check your tire pressure

Re: Model A only runs 40 miles
 

Compression test first. All plugs removed.

Points should be set before the timing is checked/adjusted.

Try setting the timing in the normal method.

Again, check the valve/cam timing. it sounds as if the gear jumped a tooth.

Re: Model A only runs 40 miles
 

Charlie makes a good point.
I've seen the main throddle linkage get stuck on the flywheel housing and/or the floor board. The part closest to the carburetor could be bent, as well, not allowing the carburetor to open all the way.

Re: Model A only runs 40 miles
 

One thing that nobody mentioned is check your intake and exhaust valve (lifter) clearances. This is a pretty simple job, depending on what source you read they may vary one way or the other .001 to .002 inch. For example:
1. Les Andrews Exhaust .015" and Intake .013"
2. "The Model A Engine" by McRee Exhaust .012" - .013" and Intake .010 - .012"
3. Per the Ford Service Bulletin page 338 "To ensure a uniform power stroke in each cylinder, it is absolutely necessary that the correct clearance (.010" to .013") be maintained between valves and push rods, ….."


If your valve clearances are not consistent and similar to any of the above the power of the engine will be affected.

Re: Model A only runs 40 miles
 

I would pull the timing cover and ck alignment of the timing gear to the crank gear. JMO
Paul in CT

Re: Model A only runs 40 miles
 

Where was your friends Model A built? If it is a European car some of those had the small 3" Bore engine
.Look at the cylinder castings on the side of the engine if there is a large gap between the cylinder outline on 2 and 3 cylinder about 2" then it is the small engine .
they also had 4.55 rear axle ratio from standard the larger engine had 3.78 gears

Re: Model A only runs 40 miles
 

Check that the vent hole in the gas cap is open and not plugged.

Tom Endy

Re: Model A only runs 40 miles
 

First of all, thanks for the many tips, there are still a few points that can be checked.

Tank is leaking enough. At least there is enough petrol, we have already checked that.
Whether the throttle valve opens fully ... the tip is good, I even had the problem myself. I could have guessed it.

The vehicle itself comes from Sweden, and should actually be an originally Danish model. So 3.3L engine and KMH speedometer ... But now that you have told me the difference, it can be checked.

Valve timing, valve clearance, etc. are very complex to check, I will probably look that up last.
Compression and pressure loss tests, on the other hand, can be done on the side.

First of all, thank you for all the feedback.