Exhaust Fab Question?

[drewski]

I'm currently fabricating a set of smooth running boards for my 55 F100 and I intend to exit the exhaust out through the rear portion of the running board.


I want a smooth blended character line around the opening that the tip will pass through, so I have mocked up a ring that will create the opening for the exhaust tip. The lower portion of the running board will be extended down for the tip to pass through and will gradually blend back in.

My question for those that have experience working with exhaust tubing is how much clearance do I need between the exhaust tip and the opening that it will pass through. I really wanted to hold a fairly tight opening, but don't want to create a rattle. The following picture shows the tip inside the mock up ring and it clears the tip by about 1/8" on the top and bottom.



Any information would be appreciated.

Andrew

 

[silver hair deere]

i would mount the tip to the opening and use piece of flex , not the cheap stuff , then you wouldn't have to worry about rattle and you are doing a beautiful job on that truck .

SHD

 

[T1320T]

1/8" gap would be good asthetically but not so good functionally. ^^Rattling would be a big concern of mine too. Also, if your running boards are going to be painted, you run the risk of buring the paint w such a tight gap.

 

[Stinger]

You'll need to use a stainless braided flex section before the tip (at least 6" long flex section), then you'll need to have a solid mount after the flex that bolts the tip directly to the running board. The rest of the exhaust will be soft mounted with typical rubber isolators. With this setup I think 1/8" "may" work, though a slightly larger gap may be required.

 

[warmpancakes]

get some of the tips and pipe used on the winston cup cars cheap and very good quality if you buy used

 

[z28snksknr]

Awesome idea and man, I love your truck. I've been pondering places to put my (eventual) exhaust, and that's an awesome spot. I hope it works out for you.

 

[drewski]

Thanks to all who responded. Guess I'll mock up another ring that will give me more clearance than 1/8". I think the look would be better if it was tight, but way too much trouble to go back and fix later if I have issues like rattles. I've created a lot of scrap metal in this build and I'm trying to cut back.

Andrew

 

[drewski]

Well, I enlarged the ring that the exhaust tip will pass through to give me approximately 1/4" clearance all around and made the cuts in the running board. After a lot of trimming and welding, it is roughed in.



All I've got to do now is a lot of finish welding, blend in all the contours around the opening and oh yeah........do the other side. It would have been a lot easier to just slap on the stock running boards and drop the exhaust under the bed and let that be it. Guess that's why this build has been going on for so long.

Andrew

 

[HOTFR8]

Very neatly done.

 

[T.Hadley]

It would have been a lot easier to just slap on the stock running boards and drop the exhaust under the bed and let that be it. Guess that's why this build has been going on for so long.

But that's not how real hot rod guys do things, just pokin it out under the running boards would have been done by the, that's good enough crowd.

I'm very impressed with the work you are doing, do you have a build thread somewhere?

 

[z28snksknr]

That's really clean looking. No harm done by increasing the clearances I think.

 

[drewski]

But that's not how real hot rod guys do things, just pokin it out under the running boards would have been done by the, that's good enough crowd.

I'm very impressed with the work you are doing, do you have a build thread somewhere?

I certainly appreciate the compliments that you and others have made. I just build to the vision that I have for the truck, some like it, some don't.

I have bits and pieces posted all over the place on various forums, but nothing here on Garage Journal. Might be a good time to start a build thread.

Drewski

 

[T.Hadley]

Please let me know when you put one together where ever it is.

T.

 

[Gearhead559]

mount the tip a solid as you can on that with all your clearances.

use flex section in the main exhaust tubing, and you wont have to worry about it rattling.

 

[Imwalkin]

Iam going to hi jack this tread a little. I'm building the exhaust on my 39 ford and I think i would like to use a flex in the system so I can make part of the system a little ridgid mounted. The flex pieces that I see are stainless can I weld mild steel to stainless with my mig useing the steel wire?

 

[e-tek]

"Ideally to weld mild to stainless you'd want a stainless wire and very low CO2 content gas. Mild steel wire would reduce the corrosion life, and CO2 gas might make the join a bit brittle which could possibly reduce fatigue life. If I were doing the job myself I'd use the stainless wire that I have which is close enough, and argoshield light gas which is close(ish) too.

If closer to perfect is your goal..... it could be worth getting a disposable bottle of pure argon and a little roll of stainless wire."

Recipe for stainless to mild steel: 309L wire with Argon + 2.5% CO2

 

[GTVi]

Looks great and unique, little things like this make your ride stand out from the crowd.
Do you get much exhaust vibration transmitted to the running boards?

 

[drewski]

Looks great and unique, little things like this make your ride stand out from the crowd.
Do you get much exhaust vibration transmitted to the running boards?

I won't know for a while since I'm still under construction. I just wanted to get some opinions from people that had experience with exhaust routing. I'm convinced that the 6" stainless flex section will solve any vibration or rattle problems at the exit point of the running board. Hopefully I'll know for sure sometime in the near future.

Andrew