Runs Hot then dies

[Mulliganstein]

Folks, I'm not sure how bad a problem this is but if anyone has seen it before I'd appreciate some advice: I have a 1928 Model A closed cab pickup
I had driven it about 40 miles and then it sat for about an hour before I drove it home.(40 miles). it was a little cooler in the morning and it ran fine the first half of the trip. On the way home, I noticed the temp gauge was getting up very close to the 190 mark (steam) area of the gauge.
I was about to pull over and let it cool down (although I shouldn't have had to because it was only running for about 20 minutes) when it died. Instead of trying to start it right away, I let it cool first and it started right up.
About 20 minutes later, the temp was up again and it died again. I let it cool and it started right back up and I made it home with no further problems. in fact, the temp got up to 190 again but then came back down to normal (about 160-170)
I think it might be some sort of vapor lock but while it was cooling, I felt the gas line and it was NOT too hot to touch. The float bowl however was very hot.
So My questions:
1. What do you think caused the overheating? mybe an intermittent thermostat problem?
2. I think the relationship between running hot and dying out is a result of a vapor lock type problem in the fuel line. What do you think?

Thanks very much for any advice

[Bob C]

When it stops you need to see if you have a spark from the coil.

Bob

[Tom Wesenberg]

I think you are right about fuel boiling. Since using gas without the corn crap I haven't had the problem. I also bought some white split plastic wire wrap that I used to cover the fuel line with. That helped, but only using good gas was the real answer. I just bought 8 more gallons of the good gas today at Fleet Farm, and it was $2.99, so that's much better than a couple years ago when it was always a buck a gallon extra.

[H. L. Chauvin]

Hi Mulligan,

Quick; but thorough Memorial Day Checks that I would quickly try first:

A. Intermittent overheating?

1. First check to see if you have a thermostat; and, if you do,

2. Try running engine without the thermostat.

3. Engine runs cool without thermostat; bad thermostat.

4. Engine runs hot without indicates a dirty radiator that need cleaning. (15 minutes)



B. Engine DEAD?

1. With a DEAD engine, first, have a spark plug wrench handy, and with hood open, pull out choke and choke engine with switch OFF & rotate engine about 8 times;

2. Quickly remove all 4 plugs; dry plugs, fuel problem; plugs wet with gasoline, usually good to go.

3. Quickly lay all 4 plus on sides for ground, turn switch ON, rotate engine. All 4 plugs have no spark electrical problem; have spark, usually ready to go.

4. Either fuel and/or spark problem easily found in above B. 2 & 3. (Another 15 minutes).

5. With a DEAD engine, initially who cares if the horn blows, if the lights work, if the tires have air, or if the windshield wiper works, if one has fire at the points:

6. Bottom line is with either NO fuel and/or NO spark in the "Combustion Chamber" of an "Internal Combustion Engine" you can clearly "see" what and where you need to further investigate.

Hope this helps to enjoy Memorial Day.

[Jacksonlll]

My guess is that you are overheating and the carb. bowl is getting so hot it boils the fuel and you stop. Next time, pour some water on the bowl and see if that fixes it. If it does, then you are running to hot and the heat is getting to the bowl. This usually happens when we fuel up on a hot day and restart. Forget about the temp of the fuel line. It's all liquid in there.

[Mulliganstein]

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H.L.
Not sure what you mean by this.

"Quickly lay all 4 plus on sides for ground"

DO you mean pull the connectors from the distributor and crank the engine to see if there is spark?

Also, It seems to me that the fuel is the place to look. It seems that spark would have to go away and then come back because of a warm (not overheated) engine. That part doesn't seem to add up for me.
Last night I checked the wiring, the timing and tested for spark and everything is in tip top condition and giving a real strong spark.
Of course the car is running fine right now so it's hard to tell anything.
Thanks for your suggestions!

[Mulliganstein]

Quick update, I just pulled the thermostat and put it in a pot of boiling water. It's a 160 thermostat and it opened completely at about 175F. I don't think that's a problem but I'm going to replace it anyway.
Gonna try to figure out a way to get a temp sensor on the float bowl or a flow meter in line with the gas.
driving it another 80-100 miles on friday so we'll see how it goes. If it dies on me again, I'll check the spark and gas right away before it cools down.

[Tom Wesenberg]

I'd keep your thermostat, as 175 is a better running temp than 160.

My neighbor just installed an engine temp gauge in his 1959 Morris Minor, and it's the type that has a copper ring sender that takes the place of the spark plug copper sealing ring. It works great and is very easy to install. I first saw this style back in the 70's for snowmobile engines. Too bad they don't make one with a 7/8" copper ring for the Model A's. You could mount the copper ring in place of the carb mounting lock washer. The only thing I don't like about this is that it's always on, so the digital display always shows. I wonder how long the battery will last?

Someone here posted a picture of his heat shield that bolts to the mounting flange of the carb. It looks like a good idea to me.

[Mitch//pa]

your pulling straws without diagnosing things when the car wont start....

[H. L. Chauvin]

Hi Mulligan,

So simple.

Easy to perform the most common and most often used vintage check for "intermittent" vintage Model A engine problems:

1. With an intermittent engine "running", one can continue messing around and "guessing" for 50 years "why" at times it is "not" running when "hot", cold or lukewarm; or,

2. With engine "not running", one can realize that this is the best time when one can begin to check, (at the very least), the "only" two (2) essential "intermittent" causes for Model A failure to start ........... either no fuel, or no spark; and it has to happen "inside" the combustion chamber.

3. Per reply No. 4:

A. No fuel on plugs: Intermittent fuel problem .... fuel not reaching "combustion chamber". Need to investigate fuel problem.

(With Model A's, most times it is fuel blockage caused by rust/dirt flow restrictions.)

B. No spark from plug gap: Intermittent electrical problem ..... spark not reaching "combustion chamber", again, where it counts.

a. With Model A engines with "heat", many times malfunctioning hot coil or hot condenser; however ..... when coil or condenser is cool, good to go.

b. With Model A's not starting when cool, if not a. above, begin simple continuity voltage check from battery to plugs. Simple and quick.

C. In your reply no. 6, keep plugs connected to distributor body with same connectors and lay plugs on their sides on the engine's head ..... plugs will never fire if not grounded.)

D. When I first bought my first Model A, it was a normal price of $25.00, at a time when Model A's were driven only by the poorest of the poor ..... a medium income person would not want to be caught dead in a Model A Ford.

E. Model A mechanics back then were also the poorest of the poor ...... one never could afford check up at a Ford motor dealer.

F. Back then, set Model A timing, 50 cents ... these shade tree guys did not have time to fart around for weeks with common Model A problems ........ they knew they had to work quickly to find either a fuel or spark problem to solve a problem ...... they knew how to "THINK"

G. But, in my opinions, times have changed ...... today Model A's are owned by medium income people struggling to earn a living who don't take time to think ....... and as far as the poorest of the poor today, they are driving around in new cars with gold plated hub caps and gold plated bumpers.

Hope this helps.

[Mulliganstein]

Thanks for the suggestions!!
I found a SS heat shield that mounts to the head bolts and protects the condenser from the manifold but didn't see anything that mounts to the carb.
Tom can you tell me where the pic is or where to find the one you mentioned?

Yesterday, I removed the anti freeze/water and replaced it with water wetter and distilled water. After about an hour of running around town, it seemed to be running 5-10 degrees cooler and I had no trouble. The real test will be in a few days when I take another 60-80 mile trip.

Just trying a few ideas right now as I like working on the Truck in my garage and not so much on the side of the road.......Although I always seem to make some new friends that way!

[Kurt in NJ]

If you get the A&L condenser you have no more worrys about heat or failure, I have cooke mine hot enough to melt off solder--- still going 25+ years on the same condenser

if you keep water in it you will get rust ---this will cause problems later

[Tinker]

To me... Whatever that means, it does sound like a coil condenser issue. But then again I bring in eth free fuel. A fuel change will not fix your situation though it's just a maintance suggestion.

[Tom Wesenberg]

One of the guys on Fordbarn made his own heat shield that fits the carb to manifold flange. It's just a thin sheet of metal to keep the exhaust heat off the carb. I'm not sure what to search to find it though. You might try the search box and type in "carb heat shield".

[Chuck Sea/Tac]

You can add water wetter, which will drop temps 10* or more. This is a temporary fix, as it sounds like you may have a partially plugged radiator.

[Tom Endy]

I would zero in on the coil. Try a new one and carry a spare. The internal windings in the secondary are very fine and only insulated by a coating of varnish. When the coil gets hot the windings can expand and short out. When it cools down the short goes away. A condenser usually just fails and doesn't heal itself.

Tom Endy

[hangarb7]

Geez, this is fascinating. Really only one person alluded to one of the problems I had when this same scenario happened to me many years ago when i was a newbie.

1) the rad was lightly plugged and after I had it boiled out and some holes soldered, he got it up to 30 gallons per minute flow.
2) even though the book says you can run the fan belt up to 1" slop, I found that 1/2" was what allowed the fan to keep from slipping.
3) here is the biggie... yes, the corn gas would boil in the filter bowl and the bottom of the carb was so hot you couldn't touch it. It would steam if you poured a bottle of water on it. But the reason was timing! I had the timing pretty far out even though the engine ran seemingly OK. Once I had the timing set correctly (I now use the 'rotor position method') she runs cool as anything and have never had boiling gas or a cut out motor since. I still use corn gas (can't find anything else in Western PA ) and no shielding for the condenser although I considered it. Timing properly was the big culprit to overheating.

Good luck and let us know what you find.

JackD

[Mulliganstein]

It's great to know there's such a wealth of knowledge out there and so many folks who are happy to share it.
You're right, I am a newbie. I started helping my dad put this trukk together a couple of years ago and we just got it on the road last fall. So this is my first real season of driving it and I am still learning all its idiosyncrasies.
Here's a couple of quick points I should have made earlier:

1. The radiator is new and the coolant was still like new when I drained it. (Also the "water wetter" says it has rust inhibitors) i hope that's true but I really just wanted to see if it makes a difference.

2. Everything on this car is new or rebuilt and very clean including the coil, distributor and condenser. There's probably 500 miles on it since last year.

3. I checked the timing and it was spot on. I used the Les Andrews light bulb method and it hasn't changed since we set it last fall.

4. We use speedway gas and I'm sure there's ethanol in it and the float bowl does feel pretty hot after a long run.

So, I just ran it another 80 miles or so (with the water wetter) and it stayed right around 175-185 the whole time. My dad and I took it to a car show and it was great fun!
I also put the heat shield between the exhaust and the distributor (the one that Snyders sells) but I don't know if it was necessary or not since the temp gauge stayed within the safe range. I figure it couldn't hurt.

The ambient temperature was right around the same as the other day and it was probably even a little more humid this time.
I'm starting to think it was just an intermittent thermostat not opening.
Either way, I'll sign off now and if it happens again, I will for sure check spark and gas as quickly as I can.
Thanks everyone for the great comments!!

[marc hildebrant]

Just to check the basics...are you adjusting the timing as you drive ?

Retarded spark can cause overheating.

Marc

[H. L. Chauvin]

Mr. Mulligan,

FWIW:

Many may agree, and many may not agree; but, if you live in a warm climate where the coolant and metal engine does not get very cold in constant freezing temperatures ...... here are just a few vintage mechanics' suggestions:

1. First, remove your thermostat, paint it red or green, and hang it on your Christmas tree this December.

2. When you start your Model A, just allow it to idle for a short period where the Babbitt and piston rings can get lubricated with "warm" and "viscous" oil, prior to placing it in gear and taking off like a shop lifter leaving a convenience store with an armed store clerk.

3. Taking off at high RPM's ..... with cold thick oil ..... with a cold engine ...... with or without a thermostat ...... can cause lots of engine wear damage.

4. From experience, a faulty thermostat accompanied with an engine overheating on a road trip can do more damage than not having a thermostat "if" one lives in a warm climate ......... and also ....... after always following the simple vintage mechanics' suggestion to allow the engine warm up, (as mentioned in above paragraph 2), which was preached often by vintage mechanics as far back as Model T days.

No doubt everyone is more grateful than you can ever imagine that you took the time to come back to let us all know the "Rest of Your Model A Story ...... With a Happy Model A Ending".

I can imagine how happy your Dad is to see that you enjoy his company and share good Model A times with him.

Most sincere thanks for everything.