what exactly is this part?

[Dats Right]

Hello ratsun, could someone please educate me as to the name and purpose of  part mounted on the firewall directly behind the air filter housing, looks like a vacuum, has a hose coming off it., thanks.

[DanielC]

My first Datsun was a single headlight 520, with the J-13.  It did not have that part, as far as I can recall.

[67_1600]

Have you followed the hose and/or wires to see where they go? Or are they not connected to anything?

[Dats Right]

The tube connects to a fitting on the manifold directly below it, is that the pcv valve? It is a 69 521 with a j15 thanks

[ggzilla]

That is a non-Federal part. Not the PCV valve. It might be California emissions. Does the aluminum.plate say J13? Does it have an emissions sticker underside of hood?

[Dats Right]

Thanks i thought it might be somethin like dat, im not sure if it works correctly, is it better to eliminate it and plug off the manifold, or should i make sure the electrical is working and keep it intact, im in massachusetts so no emission inspection is required

[ggzilla]

We don't know. Is it a J13 vehicle? What about the emssions sticker? Does it have month build date on the drivers door post? If you provide that others will know for sure.

[Dats Right]

its a j15, im runnin out to check that door post now

[Dats Right]

Couldnt find the sticker on hood or any thing on the door post, the aluminum plate says engine capacity 1295 cc, car no. 059096, engine no. j-747002, but on the engine it says j15-482781

[Dats Right]

Does that tell ya anything, im trying to eliminate any vacuum leaks, and that connection to the manifold seems like a good source, i cant seem to find another image of this part anywhere

[Dats Right]

[ggzilla]

Yes, that tells us it is not the original engine.

[ggzilla]

And that it was made between May 1968 and Feb 1969. Build plates were not required until Aug 1969. The 1969 model year 521 started Sep 1968, so if the state got the reg correct ...

 

Congrats on it having a rare J15 swap. The original J13 was a bit under powered.

[Dats Right]

Thanks for the info ggzilla, i had a hunch this motor was swapped, but hadnt compared those numbers till today, now if i can just figure out what to do with this mystery emissions device

[wayno]

Just cap the intake manifold outlet and remove the mystery part, that's what I would do.

If you can, follow the wires to where they go, do any of them go to the dist?

What color are the wires?

[Dats Right]

Thanks, one wire is blue and one black and they connect to the carburetor harness

[smoke]

I bet it's some sort of vacuum switch.

[ggzilla]

That's the emissions sticker right there. What does it say?

 

[Dats Right]

It says something like, FUEL CUT OFF this vehicle is equipped with a fuel cut off to maintain emissions, set rpm to 700, timing to TDC, set idle screw, do regular maintenance on fuel system to maintain emissions, 

[ggzilla]

All right, that's what it is, same as a 68.

 

Unplug the hose from the manifold, plug the port.

[ggzilla]

When that part is working correctly, it activates the carb's "Fuel-Cut Valve" when decelerating. There is no downside to it unless the vacuum part is leaking. It will deliver more fuel economy.

[Dats Right]

thanks didnt realize the sticker was refering to that part, seems obvious now

[ggzilla]

This part, the fuel cut switch:

 

Does not go with the the carburetor you have. Your carb has a 3-bolt "Coasting Air" solenoid instead of the original carburetor's screw-in "Fuel Cut" solenoid.

 

Yep, just disconnect the hose from the manifold and plug the manifold port.

[Dats Right]

Ok well that settles it for sure thanks a lot for the follow up