In my box of 240Z extra parts I came across this speedometer which I know is not from a 240 and I have no recollection of how I came to have it.

Was wondering if anyone might know what Z it belongs too. 

There are no numbers on the speedo, just some barely readable Kanji letters. There is a number on the wiring harness which is: 11660-AJ5000, Japan, G23.

Thanks.....

George

 

  

 

It's a 280Z speedo with the 10mph dropout detector for the BCDD system.

Oh, and it does have numbers on it. It goes from 10 to 160 just like all the others.

Edited March 19, 20187 yr by Captain Obvious
Felt like it?

Oh, My Captain....

The BCDD system.... why of course....

What is the BCDD system????.

BTW, I do know the speedo has numbers on it from  10 to 160.... What I should have said specifically was that there are no serial numbers on the unit....

Many thanks.....

George

 

Of course!  Haha!! 

The BCDD system is part of the emissions system on the 280's. It limits the intake manifold from going sky high under deceleration and making the mixture go all wonky (technical). It limits unburned hydrocarbon under deceleration. The system is only activated once the vehicle speed is above 10mph, and they detect that threshold using the speedometer.

There's a tiny little switch inside the unit and that white electronic nubbin (technical again) on the back is an amplifier that takes the signal from the tiny switch and boosts the power allowing it to control devices that need more power than that tiny switch could provide.

Captain Marvel.....Sorry, Obvious, 

Well, many thanks for that explanation which serves to remind me why I love the simple 240.... and struggle and get frustrated when all the bells and whistles go off, sometimes simultaneously, on my modern cars.  

I think I will just offer up this speedo for free to some 280Z owner as I have no idea if it works or not nor of its value.....

In the meantime I am racking my brain trying to figure out how I got ahold of it.....

Once again, thank you for your help.....

Regards,

George

 

 

Glad to help. My pleasure

11 hours ago, ZIII said:

serves to remind me why I love the simple 240....

I would take the opportunity, however, to point out that even the simple 240 had the exact same feature. It just looked different.

The "Throttle Opener" system on the 240Z's is the exact same thing as the 280's BCDD system. Does the exact same thing... Limits intake manifold during high vacuum deceleration conditions. So your 240 has it too, they just called it something different, and they didn't hook it to the speedometer.

And now that I think about it... I believe they started hooking the throttle opener system to the speedo in 74, so that speedo may be suitable for the 260 as well as the 280s.

TMI? 

PM sent

   I figured that was gonna happen! I was thinking of you when this thread popped up!

Professor, Sorry...Captain Obvious,,,,,

 

TMI?  Never...That's how I learn..... and am grateful for it.

 

Regards,

George

7 minutes ago, ZIII said:

TMI?  Never...That's how I learn..... and am grateful for it.

BoostControlledDecelerationDevice

FYI 

George, do you feel the love yet?