centrifugal switch 100

Had to bypass faulty centrifugal switch to enable O.D. Who has done this and what is the downside? Better yet, who knows of a source for a replacement?

I disabled mine years ago because it started to behave erratically. The only downside is the system will no longer automatically downshift out of OD when your speed drops below about 40 MPH. I found that feature somewhat useful in mountain driving, though I usually ended up downshifting it manually before the switch would demand it.

I really haven't missed it. I'm sure you know that all of the 6 cyl Healeys dispensed with the feature, so life goes on fine without it.

That was my first thought as well, but none of the cars I've had with overdrive (early & late MGBS & the Healey) were ever fitted with the centrifugal switch.

By-passing it is as easy as placing both wires under the same terminal (same method for by-passing the throttle switch, for either testing the rest of the circuit, or permanently).

Interesting someone thought it needed to be there in the first place. I haven't had any issues since I did it but I wanted to throw it out to you guys who always seem to know. Thanks for the comments.

As I recall the centrifugal switch is supposed to keep the overdrive from engaging below a certain speed, the throttle switch keeps it from disengaging until you depress the throttle. Triumphs and MGs with essentially the same Laycock unit seemed to work fine without the add ons. Maybe more concerns with the massive torque of the Healey motor destroying the internals. Anyway you can bypass it and everything will still work fine, the throttle switch is probably more effective in preventing wear and tear on the O/D and drivetrain than the centrifugal switch.

Many years ago I wanted to see what OD in 2nd was like in my 100-6 so I bypassed the shift linkage switch.
The extremely long rev drop from 2nd to 3rd made me wonder what effectively 2nd & 1/2 might be like for acceleration.
I found that if I was in OD 3rd, I could downshift to 2nd and still be in OD.
However, I also found I could not get it to shift into OD in 2nd gear, had to go into 3rd to get it to shift. This was a used, not rebuilt, but very smooth OD unit but I have no idea what pressure it was developing.
I concluded the oil pump just could not make enough pressure in 2nd gear to make it shift but that once in OD there was enough pressure to hold in OD.
Could this be why they used a centrifugal switch? To simply insure there would be enough pressure to shift when asked?

BTW, even though I definitely knew better, I momentarily had a brain fart and put it in reverse and destroyed the sun gear which terminated testing of that particular idea.
Dave

I have heard that a BMC Service Bulletin recommended bypassing the centrifugal switch. It was deleted on the BN2 so perhaps there were warranty problems caused by over-revving the engine due to this switch failing?