[Healeys] An odd OD problem

Healey Bruce healeybruce at roadrunner.com
Thu Jul 2 23:04:39 MDT 2009


Norman Nock suggested I post my experience, as someone might find it useful. 
Here's the story:

My OD was intermittently engaging, sometimes not at all, and recently not at 
all period.  On some occasions, it would cycle in and out rapidly, 
"chattering" in the process.  In fairness, the first time if failed, I had a 
fried relay, and I purchased a used replacement from the Nocks.  The OD 
worked fine for awhile.  In trying to track down the recurring problem, I 
also purchased from the Nocks and replaced the gear selector switch and 
solenoid, since it acted like the solenoid was not strong enough to hold it 
in engaged.  I also disassembled and renewed the points and adjusted the 
throttle position switch, replaced the dash switch and adjusted the solenoid 
engagement lever per Teck Talk.  But I still had no OD engagement.

Finally, I put the car (a BN7) on jacks and proceeded to test and trace the 
entire circuit, including ground connections.  The meter showed that the 
relay and throttle position switch functioned as they should--a relief.  I 
had power to the gear selector switch and leaving the gear selector switch. 
So I started the car and tested it.  First test the OD engaged.  Second test 
it did not, so I hooked up a meter to the gear selector switch, and had no 
power on the downstream side with the lever in 4th.  I flipped the dash 
switch off, depressed the throttle to open the relay, then flipped the dash 
switch on and the OD chattered.  A friend (an electrician--I needed all the 
help I could get) who was helping me saw the lever on the right side of the 
OD jumping up and down.  I immediately reached for the gear lever to pop it 
out of gear and when I grabbed the lever the OD engaged.  I turned off the 
engine and reconnected the meter to the downstream side of the gear switch. 
Wiggling the gear lever caused an intermittent break in the circuit.  If I 
held the lever firmly to the right in 3rd or 4th, I had current and the OD 
engaged. If I jiggled it to the left WHILE STILL IN GEAR, I had an open or 
rapidly intermittent circuit--which explained the chattering.  The problem? 
The fiber washer on the gear selector switch gave just that much too much 
clearance to prevent the switch from being firmly closed by the gear lever 
when in the 3rd/4th slot.

I don't know if anyone else has had a similar problem, but I removed the 
fiber washer and used a generous amount of Teflon tape on the threads of the 
switch and it tested perfectly.  So I hope I've contributed to the 
collective knowledge base.  Thanks for both your (Norman's) input by phone 
and the info in Tech Talk.


Bruce Steele
1960 BN7
Brea, CA 


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