plumbing

[anthony_c]

my 260 came with an n42 block, n47 head, aftermarket headers, 4-screw roundtops, n36 intake and balancing tube, and i think the air cleaner box is from a 260.

the air pump has been removed, the water inlets are not connected, egr solenoid is gone. and near as i can tell, the check valve and opener control valve are gone too. most of the plumbing has been lost/cut/removed and is no longer needed, so there is a collection of open ports on the back of my air cleaner.

but there is a nipple extending from the top of the float bowls. should these be connected to something?

Edited August 25, 2013 by awconroy

[tlorber]

Those are overflows for the bowls. There should be a couple of ports on the back of the air box baseplate to accept tubes from these. That way, if there is an overflow, the fuel goes into the box instead of flowing onto hot exhaust manifolds.

[anthony_c]

well when you put it that way, they do seem kinda relevant.

[EuroDat]

Wondering about something else in the photo. Going from memory, the white plug in the T-piece (Tee off goes to dissy advance) should go to the carbon canistor.

Does it still have one and if not, dont you need it for your roadworthy inspection?

Chas

[anthony_c]

@tlorber: the fsm doesnt show any connections on the back of the cleaner fitting that description , but i do have open ports on the canister. should the lines be connected there instead?

@chas: yes it does still have the canister, but its not required for inspection here.

i've confirmed that the t connector in the photo is running off to the distributor. thanks for the suggestion lead on the other end.

[Captain Obvious]

The nipple on the top of the float bowls is a vent, not an overflow. Yes, in the event of a float valve malfunction, a properly connected tube would direct overflow gas into the air cleaner box instead of spouting straight up making a dangerous flammable mess, but that's not the intent. The intent is that the float valves do not malfunction.

However, there is still a need to vent the upper part of the float bowl even when the float valves are working properly and venting it to the clean side of the air cleaner is the proper location for it.

Problem is (as you have discovered) that the 260 air cleaner backing plate doesn't have nipples specifically for those vent tubes like the 240 base does. There should be a smallish nipple about middle top of the 260 backing plate. Used to go to the throttle opener. Use a "T" there and port to both carbs. If you aren't using the throttle opener deceleration system anymore, that port is surplus.

Question though... The 260 air cleaner doesn't naturally even bolt up to the round top carbs... Are you using adapters?

[anthony_c]

i saw the small nipple on the base you mentioned, seems like the obvious way to go.

and yes, there appears to be an aluminum adapter plate between the air cleaner base and the carbs.

thanks all. now time to sort out the open ports on the balance tube and find a way to make the egr valve just go away.

[anthony_c]

the fsm is a little vague on this topic, but just to confirm,

- the black nozzle threaded into the center of balance tube (below the egr valve) is the pcv valve

- the 1" diameter pipe sticking out of the block (below the #1 exhaust) is the crankcase vent tube.

- the pcv hose is n.l.a. for the 260

is that correct?

[Captain Obvious]

a) Yes.

2) Yes.

III) No idea.

[Stanley]

Motorsport! D.O.T. Approved H-4 Type Headlamp Kit, 70-83 Z&ZX - The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts

Says 71-72 but looks the same as the one on my '73 240 except no filthy cloth braid. The 1" pipe and the pcv valve are in the same places and same sizes (pretty sure) so why wouldn't it fit ?

Might want to check where the emissions stuff was removed from the balance tube to make sure everything that was connected (not just bolted) to it is plugged with the right size and thread (BSPT) plugs so there's no vac leaks.