Purchased a one owner 1973 240Z with a L28 transplant (car has not run since 1999). Restored a 1969 SRL 311 (once Datsun always Datsun), the emission removal in 69 was much different then mid to late 70's?, I'm not sure the year of the L28 engine in the car, N42 head. The owner had extensive documentation but the service contract back in 83 neglected to state the year of the L28 engine installed.

My question is where can I find step by step instructions on emission removal, vacuum bypass or plugging diagrams. See engine pics attached (sorry had to throw my Roadster engine pic in as well, car is for sale).

The value in the center of the manifold (with throttle linkage bracket and gasket), remove or not, plate to cove the manifold holes? Vacuum bypass? Wires connected to the censors (2)? Value in the hose connected to the air cleaner, same questions?  

Thanks all, any help will be appreciated. 

Since you have a 73 it's probably a good bet that the carbs and parts are from 73.  Doesn't matter that it's an L28.  There's a chapter in the FSM called Emission Control Device.  Download the FSM and start there.  You won't find removal instructions but you can figure out how things work.  That's the key.

https://www.classiczcars.com/files/

Here's a shot of my '72 with all the stuff plugged on the balance tube.  What air filter housing do you have?  That has a few connections you'll need to figure out as well.

Before...

After...

Here's one from the passenger's side...

 

 

Edited November 30, 20186 yr by siteunseen

All,

Thank you both. Great info and yes it appears the engine was swap but the 1973 240 manifolds and carbs were installed. I have the stock 240 air cleaner. 

Siteunseen - my exhaust manifold N33 has the EGR valve mounted right at the throttle linkage. There is a idle bracket and adjustment screw attached to the base of the mount. This EGR mount uses a gasket and has two studs coming out of the manifold attached with nuts, not bolts. Understand I can purchase a cover and cap off the mount area but how and where do your re-mount the idle bracket and adjustment screw? You can see it in the second photo. 

Thanks again. 

I'm sorry but I can't answer.  Although I've found an older thread you might find useful.  Best of luck...

 

The car may be a 73 with an L28 block, but those are not 73 carbs. From what I can see they are 4 screw early SU round tops. So they're more like 70 - 71 carbs. @siteunseen 's pictures are pretty much like you want it to look when your done de-emmisioning it.

Thanks for the info will review info and pics. Still can't get my head around the EGR valve and the bracket for idle adjustment screw. If I cap off the opening where /how do you remount the bracket? Is it needed? See pics

One other question on the emission removal. The stainless line at the firewall end of the manifold, keep? plug? See pic.

In my prep to start the engine, can you remove and replace the oil pan w ith the engine installed? How difficult? My last project that was sitting for a while, found a ton of sludge in the bottom of the oil pan. Would to clean prior to starting. 

 

 

 

PrOxLaMuSA has a good write up on the process.

That stainless line is most likely the coolant line that runs through the carbs for heat.  I deleted mine, it's never cold here.  There's a lot of discussion on it.  Google is great but you have to always add "classiczcars.com" at the end of your keywords for the best results from here. 

So that EGR mount is on the balance tube between the manifolds on the '73?  Why don't you find a balance tube off an earlier 240Z, say 1970 to 1972, and replace it. Those years do not have the EGR valve mount.  The adjustment screw above the throttle linkage is a idle adjustment that you only when adjusting  carb balance, it's also on the balance tubes from the earlier years.

I  just ordered a set of brass plugs to replace the aluminum ones from zed saver. I would also like to take the balance tube out on my 72 240z for inpection , cleaning and gasket replacement? Should i leave it as it is and just remove the SS plugs, wrap teflón on the new brass ones and replug?

Hi All,

Happy 2024, Hope all is well. Another DA who took apart a stock balance tube with pics and still can't figure out where everything mounts. N33 tube L28 .Even with the FSM manual, I seem to have a couple valves not sure where / how they mount to the tube?

First image What this? Fast Idle for Air con? Where does it mount? 

Second image , have two valves very similar one mounts on the tube where does the other mount? Both have the same two hole mount bracket?

Thank you,

 

Thats all crap. Remove it.

5 minutes ago, jalexquijano said:

Thats all crap. Remove it.

He's in California, probably going to have to get it all back right to pass SMOG