Author Topic: Air throttles  (Read 1522 times)

Offline Paladin

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Air throttles
« on: January 17, 2008, 10:40:24 AM »
In another thread the other day we were talking a bit about air throttles.

How reliable are they or are they prone to problems? It seems that a mechanical linkage while being a pain in the butt would be maybe more reliable? I'm not saying that I don't want anything else, in fact I'm looking more and more at the air throttles but are they just another thing to cause grief or are they pretty much bullet proof? Ideas on cost to buy? Anyone have any installation diagrams?

If I want to plan for one in the future what sort of things should I put in now? Someone said a 3/8's DOT air line? What else?
I was thinking of laying down an air line enclosed in 1/2" conduit in my tunnel before I close it up.

-Dave 
'75 MC-8   'Event Horizon'
8V71  HT740
Salt Lake City, Utah

"Have bus will travel read the card of the man, a Knight without armor in a savage land...."

Offline Stan

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Re: Air throttles
« Reply #1 on: January 17, 2008, 12:31:06 PM »
If you are planning on a future air throttle, run a 3/8" air line all the way from the front to the back of the bus. You can run it in the tunnel, but the tunnel ends in front of the drive axle.  The connection at the front will be under the floor in the spare tire compartment where the pedal is now.

An air throttle is at least as reliable as the air brake system. The only likely failure point would be the diaphragm in the pot that pushes the governor and you could carry a spare one, although I never had a failure.

Offline JackConrad

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Re: Air throttles
« Reply #2 on: January 17, 2008, 02:00:54 PM »
We installed an air throttle in our MC-8 with Auto transmission and I love it. There is a slight throttle response lag that I had to get used to and you cannot rev up the engine when starting until you have air pressure (unless you start from the engine compartment and manually rev the engine). Our mechanical linkage had enough back pressure that after driving all day, my right leg was tired and sometimes a little sore. With the air throttle, no back pressure, I can push the pedal to full rpm with my little finger. But not when driving, kinda hard to push throttle with little finger and still see the road. LOL  Jack
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Offline PP

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Re: Air throttles
« Reply #3 on: January 17, 2008, 05:30:14 PM »
The lag took a little adjusting to, but other than that, it's all good from a driving standpoint.

Offline Paladin

  • Dave Knight
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Re: Air throttles
« Reply #4 on: January 17, 2008, 09:01:17 PM »
Does anyone have a guess on the cost of a used treadle valve?  Through the floor I guess?

Also, I think I heard someone say that it's easy to connect a cruise up?
What all do you need to run for that and what brand cruise is recommended?


'75 MC-8   'Event Horizon'
8V71  HT740
Salt Lake City, Utah

"Have bus will travel read the card of the man, a Knight without armor in a savage land...."

Offline RJ

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Re: Air throttles
« Reply #5 on: January 18, 2008, 12:58:43 AM »
Dave -

Until the advent of the electronic "drive-by-wire" engines, all you'd ever see in a transit bus was an air throttle.

Think of the abuse they're subjected to on a daily basis.

If they weren't reliable, do you think they would have been as popular?

(Goes w/o saying that it helps keep the worker's comp claims down, too.)

Nick at Nimco in NJ would be a good source for a used Williams unit, and a spare diaphragm for the rare failure point.

The cruise control unit that Pete (RTS/Daytona) sells works great with them, too!

FWIW & HTH. . .

 ;)
1992 Prevost XL Vantaré Conversion M1001907 8V92T/HT-755 (DDEC/ATEC)
Cheney WA (when home)

Offline mikeH8H-649

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Re: Air throttles
« Reply #6 on: January 18, 2008, 06:38:28 AM »
Chuck has a brand new williams air throttle foot valve for sale on the bno board