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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: ruthi on February 21, 2011, 06:46:08 AM

Title: bus door
Post by: ruthi on February 21, 2011, 06:46:08 AM
Was looking at the thread by hi yo silver about his door seal and wind noise. We have spent a lot of hours on our bus door and lots of different ideas, and adjustments, but so far have not been able to do away with the noise. It looks good and tight, but go down the highway, and you find out real quick that it isn't. We have been thinking about the possibility of hinging the door on the front side. We know of a good welder locally that might can help with that. That would also do away with the noisy compressor also. Any thoughts on that, and how it would work out?
Title: Re: bus door
Post by: Rick59-4104 on February 21, 2011, 08:35:43 AM
 I wonder how some king of wind "deflector" riveted to the door along side the seam would work? A curved piece of aluminum to pull the wind away from the door seam as the bus is in motion. It also might make a difference if the noise is from air entering the bus or exiting the bus around the seal? If it is air exiting the bus maybe something on the inside?

  It would not have to be big and ugly and not even sure it would have to cover the seam to work, might play around with it to see just how small and effective something like this could be. Something to flow or pull the air away from the seam, or if on the inside something to prevent air flow toward the seam. A wind deflection device or we could call it a "WDD" :)        Just a thought...


Rick
Title: Re: bus door
Post by: ruthi on February 21, 2011, 11:31:23 AM
We kinda thought of something like that also, just havent come up with a way.......
Title: Re: bus door
Post by: Charley Davidson on February 21, 2011, 12:45:13 PM
If it's a "Vacuum" noise then that idea won't work.

try this before you go welding hinges, get a real stout bar 2 or 3 of them that are longer than your horizontal door opening, find someway to attach a ratchet strap to the door near the center or 2 towards the edges and draw your door in tighter to see if you can actually stop the noise.

I hope you get what I'm saying ;)
Title: Re: bus door
Post by: RJ on February 21, 2011, 12:56:42 PM
Ruthi -

Don't have a real answer for you in terms of how to silence your door, but perhaps these comments might lead to some creative thinking and thus a solution.

As you barrel down the highway at speed (anything over 45, actually), the brick aerodynamics of the coach create a large "bow wave" of air flowing off the front end - just like a boat.  Immediately behind this bow wave is a high vacuum area.

Both the door and the driver's window are in this high vacuum area as you roll down the highway.  What this means basically, is that the door (especially the front edge) is constantly being pulled AWAY from the chassis at speed.

If you (and others) still have the small toll window on the driver's side, simply open it while on the freeway and see how much air flow is generated.

If it's raining, sticking your hand out that toll window, palm forward, will soon discover that the BACK of your hand gets wet, but your palm stays dry.  The vacuum formed by the "bow wave" of air coming off the windshield actually pulls the spray off the front wheels forward.

For those of you with coaches that have the driver's exterior rear view mirror close to the side window, you know all too well of this phenomena - as that mirror will be almost useless with the amount of water on it. The curbside mirror, sitting in this bow wave airflow, is, OTOH, virtually dry.

Ruthi - IIRC, your Dina has a plug-style door, with the pivot hinges on the rear.  In my mind's eye, this leaves the front of the door with much less "holding power" when closed, as opposed to the rear.

Is there some type of adjustment that would allow you to "tip" the front of the door into the opening first, thus creating a little more pressure on the seal when the rear snuggles in?  Or does the door come in, then gets moved up more into the opening as the arms seal it shut?  (Which is the way Sean's works, I think.)

Sorry I can't be of more help, but it's certainly an interesting problem.  Keep us posted!

FWIW & HTH. . .

 ;)

Title: Re: bus door
Post by: ruthi on February 21, 2011, 01:31:42 PM
Yeah, it comes in together and then slides up into the claws that hold it in place. We have learned how to change the claw, etc. and it all looks good, but the noise is still bad. We have even tried adding extra rubber to seal, but no luck. I do know what you are talking about, it sucking out. You can see that effect going down the road if it isnt locked in place by the claws good. I hate having so much noise going on. We have a small whistle coming from the drivers side, and we have sealed and sealed and havent found that one yet. We are open to all suggestions at this point, or, it will eventually lead to going a whole nother direction with the door, and hope that works. Thanks
Title: Re: bus door
Post by: babell2 on February 21, 2011, 01:34:32 PM
As stated by RJ there should be a negative pressure outside the door.
If you want to localize the spot of the air leak you could use an old Aircraft trick...
In cruse take some paper or tissue and hold it up to the seam in the door, where the paper sucks it's self to the seam is where the leak is.
Pay attention to that specific area and see what needs to seal, or to adjust the seal to compensate for the leak and repeat.
This should help with the drivers side leak as well but I don't suggest the driver does the paper test.
Warning!!!! sometimes it seems like trying to put out a inferno with a garden hose but usually with enough paper you can see if the entire door needs to come out or just a little tweak here and there.

Brice
Title: Re: bus door
Post by: rampeyboy on February 21, 2011, 02:24:14 PM
Try covering the door gap with 2" wide tape all around the door, and driving it. If it is quiet, then remove a section of tape at a time until the noise picks up considerably. This should help identify the most problematic areas. Good luck with it!

Boyce
Title: Re: bus door
Post by: niles500 on February 21, 2011, 10:52:21 PM
Similar to the last two posters - try lighting some incense - while traveling down the road at speed have your partner move the incense around the perimeter of the doors and windows - the location and volume of any leaks should be very evident - HTH
Title: Re: bus door
Post by: JohnEd on February 21, 2011, 11:30:12 PM
Ruthi,

Ramp and Niles are on the right track as far as I am concerned.  I had this problem with the rear section of the cabin in my Lex and Ranger.  Drove me nuts!  Mine was just intrusive tire/road noise.  I ripped out the entire interior of both vehicles.  I glued rubber stripping on flat surfaces and did spray foam inside cavities and chambers.  I put 5 big cans of foam inside the Lex alone.  Even the rocker panels are filled.  IT STILL HAS WIND ROAR IN THE BACK SEAT.  I finally got smart(fancy that) and bought a sound meter so I could tell in DB what improvements I was achieving.  First time out of the box I discovered the noise was coming from the rear GLASS.  Ford, I have learned, changed the thickness on their hi-ling SUV to reduce noise and that confirmed the problem to me.  The fix is thicker glass and now I know I can's resolve the problem so instead of it being a problem it is "reality".  The noise just seems to come from everywhere at the same time till you can beat that.

Get a 3 foot length of copper tubing with an ID of a quarter inch.  A stethoscope with the "big listening end" removed would be ideal but that is hard to come by.  Get up to speed and go around the inside crack in your door and determine exactly where the noise is coming from.  Listen around the entire front area even though you might think you have found it.  Survey the entire area.  That will get you to working on the exact spot  that is the problem.

I suggest you run the speed up to 75 or whatever your max is and resurvey after doing the enitial testing at 55 or 65 or whatever.  Much of the sealing gaskets are directional.  They will stop air from getting in but don't do a good a job at preventing its escape.  Your leak is going out and if you installed that seal with the big lip then the air is probably rushing past the seal.  Put a strip of paper in the door every 8 inches and scotch tape the paper in place at the end that is inside the coach.  While stopped the paper should be squeezed in place and you should encounter resistance to it being pulled into the cabin.  Now get up to speed and see if it is still fitting tightly all the way around as it was when it was stopped.  Now, in the eventuality of the paper being easily slid while stopped....you know what ya gotta do first.....right?

Good luck and keep us posted.

John at the sound barrier
Title: Re: bus door
Post by: rwc on February 22, 2011, 03:34:43 AM
Harbor Freight has the stethoscope already set up for automotive use. Don't know what the price was but can't be much. Will really help to pin point the problem area. Rod
Title: Re: bus door
Post by: Chopper Scott on February 22, 2011, 05:11:03 AM
If you know someone in the auto body repair business you might ask them if they have a leak detector. You place the unit inside, close the door and run the wand like detedtor along the outside to find any leaks. I like the tape idea also.
Title: Re: bus door
Post by: ruthi on February 22, 2011, 05:46:02 AM
Thanks for all the ideas. When we get home, we will try some of them.
Title: Re: bus door
Post by: buswarrior on February 22, 2011, 08:47:27 AM
Warning! It is very important that whoever is driving is NOT participating in the leak detection.

If both of you are nuts about finding this noise, get a 3rd busnut to do the driving who concentrates only on driving, and pays no heed to the detection efforts.

Either that, or get the video running for you-tube!

happy coaching!
buswarrior
Title: Re: bus door
Post by: Chopper Scott on February 22, 2011, 10:14:51 AM
The leak detector should only be attempted with the bus not in motion!! ;D That or a lot faster runner than I am! (Hate these disclaimers!!! ;))
Title: Re: bus door
Post by: JohnEd on February 22, 2011, 12:29:05 PM
What BW said....of course.

RWC,

The steth sold at HF is for listening to sounds in solids like an engine block.  The noise Ruthi has is air born and that steth won't be much use.  I have one of those $5 wonders and they can easily be pulled apart at the end of the rubber tubes.  They need to be extended after that an d, you are right, they make a great leak detector.

Ruthi,

If you put a small funnel into the hose that runs to your ear it will become a directional pick up and you can listen to areas without being right up close.  You can use that for finding noise sources around the coach generated by ??????

John