Tech Q and A for September, 2024

Q: Chris Ponzi writes- I have picked up a 1929 Tudor sedan from a buddy of mine about a year ago. Have gone through the whole car and runs great with good compression at 80psi each cylinder. When I shift into third up a slight incline the car shakes pretty violently until I get a little faster then is smooths right out. I thought I was shifting too soon and the rpm was too low but I’ve tried everything and still doing it. Is this normal or any ideas what is causing this? Thank you.

A: Hi Chris! Depends on how bad the “shaking” is.  Model A’s vibrate, that’s pretty universal.  But out and out shaking could be several things.

First, check the rear motor mounts.  If you have the “Float-a-motor” type, those will allow a lot of rotational movement under load.  The stock ones are far superior in preventing this.  Make sure the rubber parts are in good shape.

Next, check to see if the timing is correct.  I know, you probably hear that a lot.  It cannot be over-emphasized how important the timing is to how a Model A runs well or not.
Paul

Q: Matthew McDermott writes- I recently added a full flow oil filter to my Model A. Does the filter’s drain-back valve have to be cut or drilled out or will it work fine without any changes to it. I have seen videos stating that it must be drilled and have seen others where the filter is installed without any modifications. I asked this question at our model a tech session this morning but none of the members were using any type of oil filter and could not answer my question. Do you have any specific recommendations for brand of filter?  Thanks for your help.

A: Hey Matt, The Motorocraft FL-1 type filter is what comes with those kits, and it does a great job.  The FL-1 does have a rubber disc check valve.  It takes around 3-5 PSI to push oil through it.  The stock Model A oil pump can overcome that.  However, I like to drill mine out, at least a couple holes, just in case.  Not mandatory, just a preference. They do make oil filters without the check valve, so no modification necessary.  Check the oil filters used for stationary generators.  A lot of those don’t have check valves.

Paul

Q: Del Heibert writes- My 29 Model A has an overheating issue. I’ve tried addressing it by truing the head and installing a new graphite head gasket from Snyder’s all to no avail. I’m suspicious that there may be cracks in the head or block. Are these engines prone to cracking from the combustion chamber into the water jacket? Or is there something I’m missing?  BTW , I joined the club yesterday.

A: Hello Del–Chances are good the problem lies in the condition of your radiator.  Try reverse flushing with a good product available at most auto parts stores to make sure the cooling system is free of grease or rust particles.  If that does not solve this problem, then it is possible that the radiator does not transfer heat as expected.  A new radiator will likely solve the problem.  If there are cracks in the engine block or head, bubbles in the coolant will be visible when observing coolant in the top of the radiator with the radiator cap removed.  Question, when you had the cylinder head trued, was it magnafluxed to check for cracks?

Steve Schmauch

Del Heibert responded- Im taking the head in on Monday for Magnaflux.

I did flush the cooling system, first with hot water rinsing then with a chemical flush. The cooling system yielded very little scuz.

this morning I thoroughly cleaned the mating surfaces of the head and the block and laid multiple strips of plastigauge across all critical areas, bolted the head down , torqued to 20lbs. The results vary across the areas . some had zero clearance , some about .002 “, but a few areas had between .003″-  .004” with a couple of areas with some moderate pitting.  I’m wondering if there is a head gasket that can conform to these conditions should no cracks in the head or the block be found?

Paul Shinn adds- Hi Del, Good job joining the club!  I’m sure you’ll find it was well worth it.

OK, now, let’s talk about the flatness of the block and head. .004″ difference is just barely outside the tolerance of .003″.  If you use the squishy copper type head gaskets, then that might work fine for now.  I’d be interested in seeing if it is the head or the block (deck) that is out of flat.  If it’s the head, that would be a simple fix.  If the block, then that is a bit more involved, but still worth doing.
Paul

Q: Brian Pierce asks- Do you need to take the distributor out in order to replace the ignition cable?

A: You don’t have to remove the distributor.  But you do have to remove the dash panel and the lid of the electrical junction box so you can turn the cable properly to unscrew it from the distributor housing.

Paul

Q: Kenny Roy writes- My 1931, is in decent shape but it seems to have an issue.   For some reason it tends to run on the hot side.  The car was tuned by a very competent mechanic and it starts easily, usually within a crank or two.  It has a new pressurized Brass Works radiator.  It has a five blade “plastic fan” and it has a “B” head.  I am very careful with my spark advance.  I only crank the engine with the spark fully retarded.  I advance it around 4 to 5 clicks after it starts and I usually only advance it about half way in town.  I sometimes retard the spark a bit when I feel it needed to climb hills from a slow start.   I seldom ever advance the spark all the way unless I am running down the highway between 45 and 50 MPH.   It’s a nice car but this is very frustrating.

Kenny Roy
Tri-State Model A’s

A: Hey Kenny, Could be a few things-

First, timing.  You’re being very conservative with the timing, and I’m curious how you set the initial timing (when you do the thing with the timing pin).  You may be running too little advance.
Another thing could be some seepage of combustion gasses into the coolant.  Have you checked the torque of the head lately?
Paul

Q: Rickey Wood writes- Greetings, just received a model a. Yay! I was going to wash it as I wash all my vehicles. Little soap, water sponge brush!!!  But was informed that I should not. What is the recommended way to wash a model A?

I am just getting into it. Purchasing a battery. What should I do before attempting to start it?  Will change the oil. 10w30. Will clean points and spark plugs, check ignition wires, etc. anything most important?  It was sitting for a while, don’t know how long.
Respectfully
Rickey Wood

A: Congratulations on acquiring a Model A! Wash your Model A like you’d wash a modern car.    I always rinse off the car with a shower of water first to dislodge any loose dirt and grime.

Be careful that the sudsy water doesn’t contain any grit or dirt.  I have a raised vented platform in my bucket so that the dirt falls through it and keeps the water above it clean. Keep your sponge or mitt clean (I wash my mitt in the washing machine after each use.)   Use a soap that’s designed for car wash – Maguire’s has several good products that you can use.
Definitely change the oil.  Definitely drain the radiator and refill with distilled water and antifreeze in a 50/50 mix (or buy premixed green antifreeze and water). Set your points to about .020 and the plugs to .035 for starters.   That should get you going.
Make sure you have a good filter on the fuel system.  It wouldn’t hurt to disconnect the fuel line from the carburetor and let some gas flow into a glass jar to see if there’s any serious dirt in your gas tank; if so, drain it and clean it (yes, it’s a big job.)
Have fun!
Rick Black