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DCOE Airhorn/Airbox issue
http://prodracing.com/viewtopic.php?f=7&t=19054
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Author:  disquek [ Tue Apr 30, 2019 12:03 pm ]
Post subject:  DCOE Airhorn/Airbox issue

Not a production racing car, but I know there are some smart folks here, so I thought I'd ask.


This car uses 45DCOE152s and a fiberglass two piece airbox.

The airhorns slip through the airbox back half and into the carbs.

The air horn tabs hold the airbox back half on and should retain the air horns. But .....

However (on mine) the tabs would work perfectly if there were no air box. With the airbox there, the tabs do not engage the rings on the air horns because the ring is just slightly proud of the carburetor mating face and thus the airbox thickness separates the tab and the air horn ring allowing the air horns to rattle around.

Does anyone have a solution for this? I've got some ideas, but all of them seem like a lot of work for what has to be a simple problem that I'm sure isn't new.

Thanks!!
-Kyle

Author:  racer_tim [ Tue Apr 30, 2019 1:08 pm ]
Post subject:  Re: DCOE Airhorn/Airbox issue

Kyle, the backing plate I have is flat, and the tabs fit OK. Here are 2 photo's. Don't ask me why I have safety wired the bolts.

Attachments:
airhorn tab.JPG
airhorn tab.JPG [ 183.67 KiB | Viewed 1036 times ]
airbox backing plate.JPG
airbox backing plate.JPG [ 215.32 KiB | Viewed 1036 times ]

Author:  disquek [ Tue Apr 30, 2019 5:36 pm ]
Post subject:  Re: DCOE Airhorn/Airbox issue

Tim,

The rings on your airhorns are being held up by your airbox back plate. The rings should stick into your carb inlets. If your carbs are older or 40s, the airhorns are used to locate the booster/aux venturis.

You might want to look into that.

-Kyle

Author:  racer_tim [ Tue Apr 30, 2019 5:53 pm ]
Post subject:  Re: DCOE Airhorn/Airbox issue

These are 45's, and there are o-rings on the other side of the backing plate, to go where the "rings" are now. Dave Rebello helped with developing this, since the last set of air horns I had, were soft aluminum and 2 piece, glued together, and see the photo's from Fontana 2017

https://www.facebook.com/tim.linerud/me ... 941&type=3

Author:  disquek [ Wed May 01, 2019 5:11 am ]
Post subject:  Re: DCOE Airhorn/Airbox issue

I remember your issue.

Why not just go to a flanged airhorn?

I think that's what I'm going to do here (and what I did in the GTL car).

-Kyle

Author:  Protech Racing [ Wed May 01, 2019 6:06 am ]
Post subject:  Re: DCOE Airhorn/Airbox issue

Some retainer rings may be thic enough to turn a little( and fit the filter back plate) and get the correct stack height to compress the venturi tubes a little.

I would avoid anything like an Oring that could get sucked in,IMHO

Author:  racer_tim [ Wed May 01, 2019 9:42 am ]
Post subject:  Re: DCOE Airhorn/Airbox issue

The o-ring is on the outside of the airhorn and takes up the space of the ring. There is no physical way it could get sucked in.

Author:  disquek [ Wed May 01, 2019 11:35 am ]
Post subject:  Re: DCOE Airhorn/Airbox issue

I found a set of Jenvey flange style 60mm air horns on fleaBay. I'm all set. It's only money .... lol

Less parts is more betterer.

Thanks All!

-Kyle

PS: Tim the second cylinder from the right in your pic has the lower bolt wired backwards.

Author:  VWRalf [ Wed May 01, 2019 5:27 pm ]
Post subject:  Re: DCOE Airhorn/Airbox issue

disquek wrote:
PS: Tim the second cylinder from the right in your pic has the lower bolt wired backwards.


QA fail Tim! :lol:
As a matter of fact, looking at the pigtails, I think all the bottom ones are being pulled loose.

Author:  Bob Hess [ Wed May 01, 2019 6:14 pm ]
Post subject:  Re: DCOE Airhorn/Airbox issue

If my air boxes are wired that way it's the Loctite that keeps the bolts in and the wire that keeps them out of the engine....

Bob

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