MTFCA Forum

Heat shield between exhaust and floorboard?

What is anyone using?
I have plenty of scrap stainless I'm thinking about using.

Have always added thin metal steel sheeting under the #1 and #2 floorboards on the passenger side over the curving up exhaust pipe to the manifold.

Have seen quite a few charred boards in old Ts

A reminder of what did happen! By Bill Saitta on Sunday, March 31, 2013 - 07:02 pm:
We were on the winter tour in Daytona when my wife smelled a fire. Listen to the wife. A floorboard had fallen against the exhaust and flames literally came thru the floor mat. We pulled over and used the trusty extinguisher to put it out. Off we went!!! Bill Saitta


On this install painted with hi temp black to hide the shiny metal sheeting.

I used this on my daily driver's exhaust manifold. After an hour of driving you can touch the fabric without getting burned. The theory too is that hot gases are expelled more quickly. The company also sell's other heat shielding products https://thermotec.com/exhaust-insulatio ... 2430760877 There are many similar brands as well

No heat shield needed. No heat shield used.

Excessive exhaust pipe heat may indicate improper timing and or an overly lean mixture setting.

I have been using an Oatey soldering flame protector. is a heat resistant fabric 9x12. Easily cut and attached to the under side of floor board.

I have had no issues with the floorboard scorching. I use the spark advance and carburetor adjustments as needed for best performance, which minimizes exhaust temperature. Using heat wrap on the exhaust pipe from 3" back of the manifold to aft of the fuel line is a good idea. Prevents fires and reduces the chance of vapor lock. May keep car a little cooler in summer. Will help prevent muffler rust out.

I used a different approach, wrapping the exhaust pipe up to the manifold with a aluminized heat shield material. I wrapped the exhaust all the way back to the muffler and around the muffler as well. It also keeps the floorboards in the rear seat from getting hot.

I have what I think is a flattened out mixed fruit can.

Has been on the car for many years.

I had a problem with hot exhaust pipe. We could smell wood smoke.
I wrapped the first 3-4 feet with exhaust pipe wrap, the kind you wet before you apply. Then I used 3/4" Ka-O-Wool which is a high temperature insulating material. I used HVAC sheet metal as a heat shield and mounted it all with exhaust pipe clamps.

No more Hot board smells.

Is it overkill? YES. Rather have overkill than worry about losing a T to fire if there is something I could do to prevent it.

Now, you all can laugh at, and roast me.

Never needed anything here in Australia.
Allan from down under

Here down under we have a solution, it's called compulsory cabin heating.

With slots for the pedals on the right hand side, the heat naturally enters the car and the added airflow keeps the exhaust pipe cooled, wonderful in winter but a drag in summer.

Well they do prevent heat causing your floor boards to rattle/warp/crack/etc! Wrapping the exhaust pipe will only cause them to rot out at a very fast rate as it makes them sweat with condensation from the outside. 4,000 degree Rockwool in-between is just an added bonus.

Just Sayin"

I live in South Australia. Think southern California heat in summer. So hot an English visitor likened riding in summer in the back seat of my 1915 tourer to being in a fan forced oven! Have I ever needed to shield the exhaust pipe? Never. Perhaps the pedal slots over the exhaust pipe help. Good in winter, but hell in summer. My bride to be and I were returning from an 80 mile drive once with the two front doors tied open and hinged forward to act as fins to draw in some kind of a breeze. Still no floorboard problems though.
Allan from down under.

Simple heat shield, 3 magnet thimbles cut in half at the middle, flashing cut to the size you want to protect. Drill hole in each corner of the thin flashing and two holes in the middle recessed from the edge by a few inches in the middle . Line the thimbles up to the holes spacing the bottom of the floor boards by the height of the thimbles then the flashing placed over the thimbles the flashing & thimbles secured with wood screws. Air flow between the floorboard and flashing will keeps the wood from charring & keep the flashing cool enough that it doesn’t burn the wood.
It works well & is simple to do with stuff most of us have available. Best john

Some of us live in a very humid climate and some live in a very dry climate......, wood is a sponge and when it warms up too quickly after being in that humidity, Oh Crap!

Curly floorboards?

I like the idea of:
1) Giving the shields structure.
2) Spacing them away from touching the wood.
3) Allowing air flow on both sides.
4) Not having extra heat in the passenger compartment.
5) High temp black, yes will want to hide it.

I'll pass on some:
1) Seems like wrapping the exhaust, just kicks the can down the road but at least the heat does not dissipate right under the wood. Our exhaust and muffler are stainless steel. So, no worries of rotting out.
2) Compulsory cabin heating? New Orleans is warm, 76° today and tomorrow. No thanks.
3) Different types of wrap are mentioned, but I already have sheet stainless steel which is FREE.
4) "to aft of the fuel line is a good idea". Except my tank is the cowl.
5) Heat resistant fabric sounds cool. But again, I would have to buy some.

Vernon,
I have owned a 1926 coupe for over 50 years. I have lived and driven it in Texas, Florida, Virginia, California, and Michigan. In all those places over all those years I have never scorched my floorboards, cooked myself, or burst into flames. If you think your exhaust pipe is too hot I will ask you what temperature it is reaching, what temperature do you consider to be normal, and what is your authoritative source for the normal temperature of a model T exhaust pipe.

My experience with fixing things that are not really a problem has generally lead to the fix negatively affecting something else which may result in reduced reliability or reduced performance. Stick with the car the way that Ford built it and it will be a reliable and enjoyable car.

No harm will come from wrapping the exhaust pipe back to the muffler. Some advantages may accrue. It is said that keeping the exhaust or header pipes hotter improves flow. Regardless of that, keeping fuel lines and tanks cooler has clear advantages, especially with the stuff they call gasoline these days. In many parts of the world, seasonal heat can make driving and riding in automobiles less appealing. Reducing engine heat intrusion in the passenger areas of a vehicle can improve riding comfort. Using exhaust wrap and installing the accessory metal shield at the pedal openings in the floor will reduce hot or cold air intrusion and reduce noise level. Dust and engine fumes may be reduced, too. Adding pedal and lever boots will substantially reduce heat, dust, noise, and cold air intrusion. If you have floorboard scorching, you need to do something about it. It isn't normal, and can lead to disaster. Your car; your choice.

Insulating the exhaust pipe will allow the muffler to run hotter, which can be advantageous. It is unlikely to overheat since the gases expand rapidly upon entering the muffler, which reduces the heat concentration very rapidly. A hotter muffler may flow better, and it will stay drier and probably cleaner.

Exhaust pipes etc do not run hot on low grade fuel, up the octane, compression ratio, overhead valve....., you are creating heat or power (typical KW conversion). The coolant temp does not raise. Look how your modern car creates power.

Maybe it's our economy radiator.
I'm advancing the timing as much as it will run on and have been.
I only use 87 octane non-ethanol fuel.
We do have a temperature reader. I just need to pull it out to spot check the exhaust manifold and pipes. It's 80° today, if someone wants to tell me what the readings should be?

The spark advance linkage needs to work as it should for the lever position to have any meaning. Too much spark advance for the engine's speed and load can cause problems. Late timing will definitely raise exhaust temperature. Over advanced timing is also detrimental. Leaks or cracks around the exhaust manifold combined with a rich mixture can cause the exhaust to get very hot. The Model T engine is capable of causing the exhaust manifold and forward part of the exhaust pipe to get red hot when timing and mixture are not within proper operating ranges. This causes a lot of radiant heat to be emitted, which will heat up anything nearby, especially at low car speeds. Low speeds, high engine load, and incorrect timing and/or mixture are very hard on the engine and could lead to hot floorboards, cracked or warped manifolds, warped or burned exhaust valves, engine overheating, and perhaps cracked exhaust valve seats.

Stock or near stock Model T engines don't need high octane fuel. Using it will cause no harm and give no benefit. Ethanol-free gasoline may cause slightly higher exhaust temperatures due to its slightly higher BTU content, but I doubt there would be any practical effect other than slightly more power and fuel efficiency. It's difficult to impossible to provoke "spark knock" in a stock Model T engine using any modern gasoline, since it all has far higher octane equivalency than the T engine requires under any normal operating condition, including running uphill on full throttle. That assumes the engine is in good condition and a good state of tune, with a properly functioning cooling system. Engines that have clogged water jackets or that burn a lot of oil or that have leaky exhaust valves could have detonation problems at high loads. That's not a fuel problem.