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Author Topic: Pneumatic Transmission Modulator  (Read 306 times)
DEMOMAN
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1978 TMC MC8




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« on: August 09, 2016, 05:44:01 PM »

Hello All,

     I have a 1978 MCI 8 with an 8V71 NA.  I am in the process of changing the mechanical throttle linkage over to an air throttle.  I have purchased the pneumatic transmission modulator which will allows the transmission to kick down into a passing gear when needed. 

     Now, for my question:  If I remove the mechanical throttle rod and leave the stock arm assembly connected to the governor, which has the manual kick down rigid cable connected to it, do I have to use the pneumatic one or will the mechanical one still work?

      I also have to fabricate up a bracket to mount the actuator to the top of the governor and a new arm to go from the actuator end to the governor shaft.  If anyone has any prints from their builds to help me out, I would appreciate it.

Eric
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Eric
Sturtevant, WI
luvrbus
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« Reply #1 on: August 09, 2016, 06:54:11 PM »

The mechanical cable and modulator works but ok, the air modulator works better IMO the actuator has a tough time moving the cable and rod,60 psi is the most you can have on the control cylinder (modulator).

Check with Luke he may have a control cylinder for the 8V71 DD that has the arm and springs and just bolts on to the top of the governor housing it would make life easier for you.
 
 Building your mounting brackets and arm to make a universal control cylinder work the Williams is terrible to adjust for full power and response time and it takes nothing to bind one up because of the low air pressure BTDT Wink 

If the spring in the control cylinder doesn't match the pedal it will drive you nuts  

good luck
« Last Edit: August 09, 2016, 07:03:20 PM by luvrbus » Logged

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DEMOMAN
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1978 TMC MC8




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« Reply #2 on: August 11, 2016, 09:13:45 PM »

Thanks luvrbus!  I ended up putting in the pneumatic modulator and made my own brackets for the actuator.  I am leaving for Florida Friday so I couldn't wait for parts.  I blueprinted the governor top bolt pattern I engineered the mount and arm myself. I build custom machines for a living so that helps Wink

     I have to admit, the bus has way more acceleration now and shifts totally different.  My top speed hasn't changed but when I am topped out at 72 mph, the bus feels like it has way more power for hills.

Thanks for the input!
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Eric
Sturtevant, WI
luvrbus
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« Reply #3 on: August 12, 2016, 06:21:31 AM »

Thanks luvrbus!  I ended up putting in the pneumatic modulator and made my own brackets for the actuator.  I am leaving for Florida Friday so I couldn't wait for parts.  I blueprinted the governor top bolt pattern I engineered the mount and arm myself. I build custom machines for a living so that helps Wink

     I have to admit, the bus has way more acceleration now and shifts totally different.  My top speed hasn't changed but when I am topped out at 72 mph, the bus feels like it has way more power for hills.

Thanks for the input!


LOL that does make a difference with your experience you should see some of the rigging I have to deal with  Grin
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