Exhaust Headers/Pipes

[RonKahn]

Hello everyone. I have a stumbling block to the next step of my build. The kit that I purchased came with a set of headers for a small block that fit the engine and does collect into the “4-way” correctly inside the engine compartment. The side pipes are also not Classic Roadster and are too short for the body, so they will be lengthened anyway. (CR’s are longer of course). My issue is that the pipe collector and the exiting header pipes are nowhere close to being in alignment and I will need to redo some of the header pipes to correct the problem.

My real question is once I get that complete and I am ready to fit the side pipes to the body, how far away should I be mounting the side pipes from the body to avoid damaging the paint/body but at the same time not sticking out too far that the rider has to “jump” over them to exit or enter the car. Maybe even how low should they be hanging as well?

Thoughts?

[Hapnyny]

1/4 inch off is fine, you also need to take into consideration the motor movement.

[eschaider]

A ¼ inch air gap will minimally produce heat damage on the adjacent painted surface and will certainly come into physical contact with anything that close just because of normal engine movement in the motor mounts under normal driving conditions. What we euphemistically call spirited driving will produce mechanical damage.

Open the hood on your car and blip the throttle on your engine. Watch how far the engine moves — that's in neutral! Imagine what happens when the tires are hooked up! You need to provide more clearance than ¼ inch, or you will experience physical contact between the pipes and whatever they are closest to.

Solid mounts will provide the least engine movement (not zero, but the least). They will also produce the least desirable driving experience because they will transmit all the engine vibration to the chassis. That vibration will, in turn, be transmitted to everything attached to the chassis or in the car (you?) and, in time, turn your car into a rattle trap. Did I mention it will make the driving experience less attractive and more numbing the farther you drive the car.

[Hapnyny]

Understood,

I took some pictures and attached a link to a very aggressive build as well.

https://fb.watch/mS98ljkr-Y/?mibextid=HSR2mg

[Hapnyny]

Video

[eschaider]

That looks visually attractive, but the heat shield will get almost as hot as the header, and it will burn your paint and your leg sooner or later. Those heat shields cost upwards of $300 or more and do not protect your leg if you exit the car incorrectly.

Instead of spending money on the heat shields, use a carbon-impregnated welding blanket that you roll out and roll back into the car next to the seats. You can buy it off Amazon for cheap money, and it works better than you would ever imagine. Click here =>Carbonized Welding Blanket, easy, peasy ...

You will really appreciate the fix more after you burn your leg once or twice and need to remove the carbonized pant leg material from your burned flesh. Did I mention you will need to scrape the part of your leg off the header that stuck to the header when you were exiting the car? And, of course, there is always the time and pain to heal.

For some, the experience is a right of passage. Others, not so much. YMMV.

[RonKahn]

That is great advice. I have seen some custom made blankets or towels that drape over the pipes to enter or exit the car. My biggest concern was how close to get the pipes hung to the body, taking into consideration movement and heat that can affect the paint and fiberglass. From the posts, I can get within 1/2 inch and be ok.

[eschaider]

You want the pipes far enough from the body that the radiant heat they give off will not damage the paint. If you don't damage the paint you will also not damage the fiberglass underneath the paint.

Remember, heat can not only damage paint, it can cook the resin that binds the fiberglass together and reduce it to a fine white powder. This type of heat damage is progressive and even more expensive than a repaint. Depending on the skills of the repair shop, the job may or may not look right when finished.

[RonKahn]

I love all the advice everyone!!

I know there is no "required" distance and each one can be different. Not all pipes are bent or welded the same. Was just looking for some pipe-to-body distances that anyone that has a CR or even an Excalibur for their setup. If I give it at least a 9/16"of gap to the body, I should be ok. Burning the leg is not the issue, but preserving the body/paint is. I have alternatives for the legs, but not for the car body. LOL

[RonKahn]

Plus, I will be going with 4" tube all the way back as well, so inherently that will create its own problems.

[eschaider]

If you can, I would attempt to leave a 1-inch minimum clearance. That would allow for a fairly decent airflow between the pipes and the car to both cool and reduce the radiant heat energy that the fiberglass was being exposed to. One inch sounds like a lot, but when you are six feet away looking at it, it becomes vanishingly small.