mystery manifold part

[frankendat]

Greetings Ratsun,

What is this part? The second pic is the back end, it is solid. How it work?

Thank you for sharing your knowledge.

[datzenmike]

TVV ? Thermal vacuum valve. Closed, but opens at a set temperature. It's fitted in line between a ported vacuum source and probably an EGR valve. It prevents exhaust gas recirculation when the engine is not at operating temperature.

 

Usually mounted onto the thermostat housing on an L series engine. Not used before '74

 

What was it on???? The Z24 has a similar one but 3 pipes. Top one is air inlet from air filter. The valve is open when cold and this destroys the ported vacuum signal to the EGR and the vacuum advance. At a set temperature the valves close and vacuum is restored and passed on to these two. No EGR or vacuum advance when engine cold.

[frankendat]

Thanks for the quick answer,

It was on one of the manifolds that arrived in the mail, I believe a 1989 240sx? It looks like plugged with some kind of resin. I am stripping and cleaning. There is another item near that vacuum valve that stumped me. The bolt, head on the far left, appears to  been solid, maybe? What is/was it for?

 

 

[datzenmike]

That's right under the thermostat on the '80 Z20E intake. One on the right is the temperature gauge sender, (broken?) the one with the plastic plug is the temperature sender for the EFI. Later Z20Es had this sender in the head near the #1 exhaust plug. This location was more accurate and faster than reading the water temperature way over on the intake.

 

 

Early Z20E head top

Later '81 Z20E head fingr pointing to temp sender relocation.

[frankendat]

I think I got it. The manifold  in my picture is from a 200sx, right?  On this manifold was the round fuel rail.