Finned vs smooth brake drum

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TAK65

TAK65

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Having just upgraded my master cylinder to dual circuit, got to thinking if finned drums would be a big improvement over the stock 9" smooth ones?
The car is 1963 Dart, cannot consider discs nor even bigger drums (probably would not fit in my 13" rims) due to strict Spanish regulations concerning cars registered as "historic" as mine is.
Lots of hills and mountain roads here in Andalucia, was thinking the finned drums would be a bit more fade resistant.
 
Improvement? Yes. Noticeable improvement? Maybe. Big improvement? Even at peak efficiency, 9" drum brakes are limited as to their effectiveness versus larger drums and discs. Brakes convert kinetic energy into heat, so any way to better dissipate the heat will improve their function. Fins increase the surface area from which the heat can be released, providing better cooling.
If you can find them, try them. As long as you have the brakes apart, consider changing the shoes to those with an aggressive lining material.
Enjoy your scenic driving! I looked at a satellite view of Andalucia and along with mountains, saw olive groves that seem to go on forever.
 
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The brakes were apart and back together with standard stuff but I just thought I'd get the better stuff on my shelf to be ready when the next brake job is needed.
Spain is producing something like 75% of all the olive oil in the world so yes, the olive groves do go on forever :D
 
It is doubtful that you will ever exercise your brakes enough to test the effectiveness of finned drums versus smooth. If you plan on doing a lot of heavy braking as in road course racing or continuous heavy mountain travel then you need to consider converting to larger disc brakes.
 
roccodart440 said:
Fins dissipate heat, couldn't hurt
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S'cuder said:
Improvement? Yes. Noticeable improvement? Maybe. Big improvement? Even at peak efficiency, 9" drum brakes are limited as to their effectiveness versus larger drums and discs. Brakes convert kinetic energy into heat, so any way to better dissipate the heat will improve their function. Fins increase the surface area from which the heat can be released, providing better cooling.
If you can find them, try them. As long as you have the brakes apart, consider changing the shoes to those with an aggressive lining material.
Enjoy you scenic driving! I looked at a satellite view of Andalucia and along with mountains, saw olive groves that seem to go on forever.
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Exactly! The fins actually add a lot of surface area, which will help heat dissipation quite a bit. Thermodynamics is all about surface area.

Will it make a huge, noticeable difference on the road? Probably not. But it will definitely improve heat dissipation. If you can’t change them, you might as well make them as efficient as possible with the finned drums and better shoe compounds.

Murray said:
It is doubtful that you will ever exercise your brakes enough to test the effectiveness of finned drums versus smooth. If you plan on doing a lot of heavy braking as in road course racing or continuous heavy mountain travel then you need to consider converting to larger disc brakes.
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C’mon man. She already said she can’t change the brakes because of historic car regulations where he’s at and his 13” wheels. And 9” drums can heat up pretty fast. Maybe it’s not gonna be a night and day difference but every little bit helps.
 
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72bluNblu said:
He already said he can’t change the brakes because of historic car regulations where he’s at and his 13” wheels. And 9” drums can heat up pretty fast. Maybe it’s not gonna be a night and day difference but every little bit helps.
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She, actually. But that's allright :)
 
But yeah, I really do need to stick with the 13" wheels and 9" brakes so just trying to figure out my best options with them...
 
I think any extra won't hurt for sure. So to get this straight, are you saying you could not upgrade to safer larger drum or even disc brakes because it's somehow "against the law"?
 
TAK65 said:
She, actually. But that's allright :)
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Sorry! Fixed it.

TAK65 said:
But yeah, I really do need to stick with the 13" wheels and 9" brakes so just trying to figure out my best options with them...
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I think your plan for the finned drums is a good one. If you use a more aggressive brake shoe compound you’ll get better braking, which will create more heat, which hopefully the fins can take care of.
 
RustyRatRod said:
I think any extra won't hurt for sure. So to get this straight, are you saying you could not upgrade to safer larger drum or even disc brakes because it's somehow "against the law"?
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Yeah, basically. When you register a car here as a "historic vehicle" it has to be pretty much as it left the factory, or at least could have done. So as a Dart was available only with 9" drum brakes in 1963, that's what I'm stuck with. They also told me I have to get rid of the back seat belts which I just stuck under the seat and pulled them back again later. And I had to get a special certificate (and pay some extra, of course) to get an approval for 185R13 radial tyres as the only option in 1963 was 6.50-13 tyres.
The reason for "historic" registration is you only need an inspection every 5 years, no emissions regulations and the insurance is very cheap.
 
TAK65 said:
Yeah, basically. When you register a car here as a "historic vehicle" it has to be pretty much as it left the factory, or at least could have done. So as a Dart was available only with 9" drum brakes in 1963, that's what I'm stuck with. They also told me I have to get rid of the back seat belts which I just stuck under the seat and pulled them back again later. And I had to get a special certificate (and pay some extra, of course) to get an approval for 185R13 radial tyres as the only option in 1963 was 6.50-13 tyres.
The reason for "historic" registration is you only need an inspection every 5 years, no emissions regulations and the insurance is very cheap.
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Can the car get a standard registration? Seems there are no advantages to the historical one.
 
RustyRatRod said:
Can the car get a standard registration? Seems there are no advantages to the historical one.
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I think it could but not really sure (I am not actually Spanish but Finnish, just living mostly here). If it could, then it would be subject to annual inspections with the emission tests which I am afraid would fail. Cheap insurance also is kind of appealing.
 
TAK65 said:
I think it could but not really sure (I am not actually Spanish but Finnish, just living mostly here). If it could, then it would be subject to annual inspections with the emission tests which I am afraid would fail. Cheap insurance also is kind of appealing.
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It depends on what standards they test to. If they test to 1963 standards, I see no reason why it wouldn't pass. I don't see how they could hold it to 2022 standards. But then, I don't know anything about Spain. My niece lived and worked there for a short time as part of her higher education, though.
 
I think the fins would help in two ways. Extra metal exposed to the air to dissipate heat. The fins will probably generate some turbulence & help with heat dissipation.
 
TAK65 said:
I think it could but not really sure (I am not actually Spanish but Finnish, just living mostly here). If it could, then it would be subject to annual inspections with the emission tests which I am afraid would fail. Cheap insurance also is kind of appealing.
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Sisu!
 
Don’t know if it would fit within the regulations, but consider some ducting to bring cooling air towards the drums. There are kits for road racing that have powered fans so there is cooling even at low vehicle speed.
Maybe something that you could remove when it is time for a re inspection.

@slant six

one of the early A body guys that does auto cross events found some Porsch IIRC air ducts for brake cooling that were inexpensive and fit well on his early A, I tagged him, perhaps he will respond here
 
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roccodart440 said:
My thought is there would be no one who could tell or notice the difference but i'd bet it would brake belter.
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I think so too, but will a 10" drum fit in a 13" rim? They WILL check if the tire size matches the one on papers so I wouldn't dare putting on 14" wheels.
 
"also told me I have to get rid of the back seat belts".
Another case of stupid laws enacted and enforced by those that don't understand mechanics or physics. I could see not allowing bigger engines in a chassis that wasn't designed for such, but to not allow improvements in safety items like F-kin seat belts or larger brakes. Probably cant add a 3rd brake light, or halogen headlights either.
I would argue that it "pretty much" left the factory with drum brakes. As said, I doubt a swap to 10" would get noticed. I'd give it an attempt anyway.
Did 63 come with dual circuit master cylinders?
 
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