definitive answer on brake line insualtion near header?

[NiceGuyEddie]

Brake Line Insulation

Brake line insulation ???

brakeline heat insulation

as usual, i did a search and got more confused. some say do it, others say insulating the lines here will actually retain heat... it gets hottest at the calipers and travels away.

my brake lines are off now, now is the time to do it. they are flat against the footbox front, but only 1-2" from the header.

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[ZoaFan08]

I'm nowhere as knowledgeable as RoadRacer, Jeff and others on the forum but I kept all my fuel lines as far away from my headers as possible. I believe brake fluid doesn't boil till over 400* but I just played it safe.

BTW, working on the car? Need some help, I'm come down and tinker

[Don Payne]

Best solution...move your brake lines away from your headers. Sorry, I know that is not what you wanted to hear. Personally, I moved my brake lines to go all the way to the front of the car along the 4" tubes, then up on the outer driver's side about where the X member is, then back along the 3/4" square tube back to the footbox. That way it was totally clear of the headers. Kind of a long routing, but it was worth it.

[CraigS]

I don't think it will be a problem. I got mine hot enough waiting in line at an autocross to damage the throttle cable but never had a brake problem. But then i built an aluminum shield over the headers and insulated the new cable. I have been using this stuff from Summit lately. A little expensive but it's available in several diameters. You cut to length and then wrap it around your tube and the edges velcro together. Very easy install at any time due to the velcro.
http://www.summitracing.com/parts/THE-14030/
If you got this 1 inch diameter you could move the brake lines close to each other and wrap them both at once. Then you can use the rest for other things. I have short pieces of this on the plug wires that are close to the headers and on the heater hoses too.

[CrawleysCobra]

Eddie, I had a similar issue. My rear brake line ran along the 4” round and then turned up the outside of the footbox and then to my MC. Once I started test fitting my headers I saw that I only had about an inch clearance. So I re-routed the line into the insulated footbox then out of the box to the MC well away from the header.

[canuck1]

Originally Posted by Don Payne

Best solution...move your brake lines away from your headers...

I agree. If it's a POSSIBLE problem, why not eliminate the issue by rerouting the line forward? It' isn't that hard to bend and flare a new line or two.

Sean

[JKleiner]

Eddie,
Here is how I do them.



Follow the line coming out of the front port and you'll see that I run forward on the 3/4" square tube, down along the square tube holding the X member and then rearward along the 4" round main tube.

Is yours too close? I can't definitively say yes or no, but have always been concerned that routing might be too close for comfort. On the other hand you've put on a lot of miles without a problem so who is to say. Take this for what it's worth---I got a partially built Mk3 in here recently to finish. The previous owner had already installed the brakes and lines taking that path down the front corner of the footbox. I removed it and made a new line so that I could route it as shown above.

Good luck,
Jeff

[ZoaFan08]

Another thing I did was buy another master cylinder that had the ports on the left side instead of the right. This way it actually hid the lines all together and you were able to route the lines around the back of the frame and not only away from heat but view.

[GWL]

First, I didn't read your attachments, but just from what you said; that some say it retains the heat, makes a bit of sense not to insulate the brake lines, but let’s think this through.

Let's take two containers of water and insulate the hell out of one with the best insulation you can get. Do nothing to the other one. Put both of them into sub zero weather and both will freeze. The better the insulation the longer it will take the insulated one to freeze. Now bring them inside and put them next to the wood stove. Both will eventually thaw but it will take a while. The better the insulation the longer it will take to thaw. The insulation only slows down the process either way.

Now put the container on the wood stove, (a high end insulation, like Pyrogel, will not burn off) and bring it up close to boiling, say 200º (it will take longer for the insulated container to heat up) and now take both back outside into the sub freezing weather. It takes a lot longer for the insulated container to freeze, but it will. The insulation is now, working in reverse, retaining the heat just as the insulation will retain the heat in the brake fluid, if it gets hot.

What I'm saying is that insulation only slows down the movement/dissipation of heat from a hot area to cooler one.

Another example is an insulated house. On a hot day, the house will eventually get hot if the air conditioning system is not running and will not cool down as fast as the cooler evening air outside. The house is retaining the heat that eventually got in through the insulation during the day.

How does this apply to your brake line?

Remember, there are three ways heat can get transferred to the brake lines. Conduction, Convection and Radiation.

Conduction - moves from one material to another by physical contact. Since there is no physical contact (let’s hope not), there is no transfer of heat to your brake line in this manner.

Convection - actually heats the gas or liquid through conduction but causes the gas or liquid to expand (vibration of atoms) and begin moving up as it becomes lighter/less dense than the surrounding air. I don’t think you can do much about this type of heat as there is so much movement of air in the engine compartment anyway and because of what we talked about above with insulation.

Radiation – Electromagnetic waves move through space and when it hits the object it transfers the heat to it. So we have the hot headers transferring/radiating heat through the air to anything in direct site of the headers. It does not heat the air it moves through. This is the same as the direct heat you feel from the sun or a fire place in the winter. I think this is the most likely way the brake lines are getting most of its heat.

What can you do?

1. Reflect the electromagnetic waves away from the brake lines. If you use insulation, it should have a shinny/reflective covering to it. Some do just for this reason.

2. Polish the brake lines. Stainless Steel lines would be good for this purpose. In addition, stainless steel is the lowest conductor of heat of all the metals so it would then slow the heat transfer to the brake fluid. However, it would also slow the heat movement out of the fluid through the brake lines, just like insulation.

3. Move the brake lines out of sight of the headers. Jeff did this by running the lines forward and down before running them to the rear of the car. Really seems like this is the simplest solution.

4. Mount a deflector of shinny metal, preferably mirrored or polished stainless steel because it will reflect radiant heat and is a low conductor of heat. In addition, if necessary, you could add insulation on the back side of the deflector, the side toward the brake lines. There should be an air space between the insulation and brake lines but the insulation could be directly mounted to the back side of the reflective surface.

Gosh, I got carried away, just my thoughts on the fly here. I’m always thinking about heat transfer in both my construction work and FFR build. This is a subject I’ve been reading and thinking about since I designed and built my house in the early 1990’s. It has many super insulated techniques that are now just becoming popular.

George

[NiceGuyEddie]

thanks guys, i am confident i can make a new front brake line.

but as for the rear, i am not sure i can get to enough convenient places to drill holes for the clamps to hold the rear brake line. even with a right angle drill, it's real tight in there.

and the rear brake line will have to be two pieces for sure.

i'll check it out later on.

[rich grsc]

If its 2" or more from the header, waste of time. The fluid in the caliper is a lot closer to a major heat source, the brake pads. With all the air moving around the engine compartment, the line wont get very hot.

[Big-Foot]

On my FFR Spec Racer I insulated both fuel and brake lines with header wrap and never had a problem..

[Greg_M]

Originally Posted by rich grsc

If its 2" or more from the header, waste of time. The fluid in the caliper is a lot closer to a major heat source, the brake pads. With all the air moving around the engine compartment, the line wont get very hot.

I agree. Go for a drive on the highway, pull off, and feel the lines and the 3/4" frame rail. You can hold your hand on them indefinitely. They probably don't exceed 130*. Your black hood gets hotter than that in the sun.

Greg

[NiceGuyEddie]

okay guys…. I did some bending, and now the brake lines are more flush against the footbox front, and about 2" from the header. i also secured them with two clips and they won't move. re-routing them another direction would make them 4" from the header at the closest point. so that's not much difference.

by all means, if I could do it over, I would Shirley run the lines down the frame like JKleiner did, or get a master with driver-side ports.

I am going to leave it and do what Greg said, if it's exceedingly hot, I'll buy some insulating tape.

[Matstng]

Eddie,
Here's what I did with the intent to hide the lines. The second pic is looking at the side of the drivers footbox. One line is for the rear brakes and the other is the clutch. There's another aluminum block toward the bottom of the footbox where the stainless clutch line links to the hardline.




It does require using the Wilwood pedal assy.

[turbonut48]

My lines come within 2 inches of the headers.
I made up an aluminum cover with a modest amount of space for air flow behind it..

The Nut

[NiceGuyEddie]

HI GUYS

I took the car out last night around the block several times, up and down some side streets. got everything up to running temperature.

my hood is OFF so if anything, it's cooler in the engine bay…

when I got back I felt around the engine bay. as far as heat, EVERYTHING was hot… the lines were hot, the master cylinder itself was hot all around. that surprised me. headers obviously hot, steering shaft hot, front of the footbox hot, and the 3/4" tube going front-to-back like in Jeff's photo was hot.

strange thing is, except for the headers themselves, the black 3/4" tube itself was HOTTER than anything else in the engine bay. running a brake line down that tube is not necessarily helping, even if slightly offset by mounting clips of sorts.

anyway, just an observation. I was very surprised that tube got so hot. maybe partially because it's black.

all in all, good info here….

cheers,

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