Classic cars forum & vehicle restoration.

Rick · Site Admin Joined: 27 Apr 2005 Posts: 22442 Location: UK

I mentioned this in the (small) Dodge thread, but it might get lost in there.

It has this device on the dash, but I've not found any concrete info on what it is exactly. I assume some kind of engine-assisted braking device, similar to that found on some commercial vehicles, but really this is just guesswork. Anyone know for sure???

thanks, R

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47p2 · Joined: 24 Nov 2007 Posts: 2009 Location: Glasgow

Does the vehicle have a compressor and air tanks?
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Rick · Site Admin Joined: 27 Apr 2005 Posts: 22442 Location: UK

47Jag · Posted: Sun Jul 29, 2012 7:41 pm Post subject:

Rick,

I posted your picture on the Antique Auto Club of America technical forum. 72 views so far no joy.

http://forums.aaca.org/f120/mystery-switch-333100.html.

Art

victor 101 · Joined: 03 Apr 2009 Posts: 446 Location: East Yorkshire

Can you see the back of it at all to see if there are any pipes or cable runs?

PAUL BEAUMONT · Joined: 27 Nov 2007 Posts: 1281 Location: Barnsley S. Yorks

As a really wild guess it looks like a control for an exhaust brake, but I thought that these were only fitted to diesels.

Rick · Site Admin Joined: 27 Apr 2005 Posts: 22442 Location: UK

Posted as a reply on the AACA forum, the mystery gadget has been identified:

"This an extra air valve - a popular 1920s accessory. The valve introduces extra air into the intake manifold to lean out the mixture and improve economy when running easy. As the effect reduced engine braking, the valve had a "brake" position which closed it. A great idea which probably resulted in thousands of burnt exhaust valves!"

RJ
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dclf1947 · Posted: Wed Aug 15, 2012 12:50 pm Post subject:

"As the effect reduced engine braking, the valve had a "brake" position which closed it."

Interesting, but in that case the "Off" position must be the same function as "Brake". It would be good to see the back of the switch.
Has the inlet manifold got a tapping on it where the "extra air" could enter?

Nice accessory to have though, certainly will be a conversation booster at shows.

Dave
Philippines