Piston joint motors

Hello,  the short of it is I can’t seem to get a piston joint motor to work.

Below is some copy & paste code that shows an example  of two objects jointed together with a motor enabled.  Nothing appears to happen, though the joint does exist.  If I change the joint type from piston to pivot the motor seems to work fine.  The docs don’t seem to contain an example of a working piston joint w/ a motor so maybe(probably) I am just missing something.  

Any advice on what’s going on would be mucho appreciated.

[lua]

–init physics

local physics = require(“physics”)

physics.start()

physics.setDrawMode(“hybrid”)

–create a static object which iam kind of using as the anchor

local staticAnchor = display.newCircle( 100, 100, 25 ) 

physics.addBody(staticAnchor)

staticAnchor.bodyType= “static”

staticAnchor.x = 200

staticAnchor.y = 200

staticAnchor:setFillColor(255,0,0, 255)  

–create the dynamic object that will be jointed to the anchor object

local pistonObj = display.newCircle( 100, 100, 40 ) 

physics.addBody(pistonObj)

pistonObj.bodyType= “dynamic”

pistonObj:setFillColor(0,255,0, 255)

pistonObj.y = 300  

–and here is the joint

local jointMotor = physics.newJoint( “piston”,  staticAnchor, pistonObj, staticAnchor.x,staticAnchor.y , 0,10 )

jointMotor.isMotorEnabled  =true

jointMotor.isActive = true

jointMotor.motorSpeed = 6000

jointMotor.maxMotorTorque = 10000

jointMotorisCollideConnected = false

–make ground

local ground = display.newRect(0, 1000, 1000, 100)

ground.y = display.contentHeight -50

physics.addBody(ground)

ground.bodyType = “static”

ground:setFillColor(255,255,255, 255)  

            

[/lua]