Parade Overheating

spinelll

spinelll

Senior Member
[FONT=&quot]My ’30 Roadster overheated yesterday during a slow-moving Memorial Day parade in northern NJ (Outside Temp upper 60’s).[/FONT]
[FONT=&quot]Later, I realized that I was running with my timing fully retarded.[/FONT]
[FONT=&quot]Did that contribute to my issue?[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]Thanks[/FONT]
[FONT=&quot]Leo[/FONT]
 
Yes running with the timing retarded will definitely cause overheating I also feel that that's 1 of the reasons why the exhaust manifolds warp because people sometimes will forget to advance that timing.
 
It also helps to run the GAV a little richer. Some brass cars, pre 1915, will install a second radiator under the car with an electric fan for parades.
 
There's no question that running late ignition timing causes overheating. If you were able to see into your exhaust manifold during this you would see fuel burning inside the exhaust manifold instead of the combustion chamber. In fact, I have seen Model A exhaust manifolds glowing bright cherry red in the daylight because of this. That's around 1000+ degrees F!
 
This is an older picture of retarded spark
 

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spinelll said:
[FONT=&quot]My ’30 Roadster overheated yesterday during a slow-moving Memorial Day parade in northern NJ (Outside Temp upper 60’s).[/FONT]
[FONT=&quot]Later, I realized that I was running with my timing fully retarded.[/FONT]
[FONT=&quot]Did that contribute to my issue? Thanks [/FONT][FONT=&quot]Leo[/FONT]
Click to expand...

hi, do you know how the timing got retarted? since your car is a '30 A roadster... holds interest to me. :) even though all A's time the same as I can best remember...
 
Hello, probably forgot to advance it , If you haven’t driven a Model A for awhile, forget to do that, along with turning on the gas valve!
 
Start the car up in the driveway. Open the GAV about 1/8 turn. Let the car idle after it warms up. The ignition advance should be down lets say 3/4. It should run for one-half-hour without overheating.

If it overheats you have more work to do. If it does not overheat the spark advance setting was the issue.
 
Thank you for all of the quick responses.
I've been driving in parades for 15+ years. Not sure why I set the spark like that this time.

I'm curious; How does a retarded spark lead to overheating?
 
An advanced spark enhances combustion so that more of the heat goes into moving the pistons. So an advanced spark means lower temperature in the combustion chamber. When the spark is retarded the combustion is not efficient and the combustion is hotter. Plus, the combustion is still going on when the exhaust valve opens and the hot combustion is taking place in the exhaust manifold and exhaust system.

Related to this is a higher compression head. Besides more power, the higher compression head increases the efficiency of combustion and at the same road speed the engine temperature is lowered.
 
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