Weber Carb Swap need help!

[hottdog]

I have an 84 nissan 720 king cab with a just rebuilt z 24 engine. Came from the factory carbureted, but hte carb is screwed up.. I'm putting a weber 32/36 on it, and, well, it's a bit confusing. I have a haynes manual, and the installation instructions, but and still lost. I have the old carb off, but am still lost. Here's what I need to know:

 

1. Instructions say "Remove the fuel return hose fromt the old carb and plug it." I never found this hose, so I can't plug it. Any idea where it is?

2. Instructions say "remove the float bowl vent hose and plug it" Can't find it.

3. Instructions say Removethe vaccum control valve and hoses-what and where is this?

4 Instructions say remove both vac switches re vac control valve" what and where is this?

5. Instructions say remove the large anti backfire valve fitting from the intake manifold-what is is and where?

6. Remove vac hoses from EGR valve, BPT valve, and thermal vac valve- I found the EGR, but what/where is the BPT valve and same for thermal vac valve.

7. The stock air cleaner has two short hoses on the front that go to two metal pipes that go around the front of the engine and into the exhaust manifold as part of some air system. How do I plug/remove/deal with these? Can I just run a hose from pipe to pipe?

 

I don't need to worry about passing emissions inspection.

[datsunaholic]

Step 1: Close that book, put it away in the bookshelf. It's doing nothing but confusing you.

 

 

 

You have the carb off. Now, you install the adapter plate, bolt the new carb on, and figure out 3 things:

 

1) Where is the fuel supply line? Just one? Good. Hook it up.

 

2) Where is the vacuum advance line? There's 2? Put a Tee in, then hook them up to the one port on the Weber, UNLESS the Weber has 2. Then it's a bit more complicated to figure which one goes where.

 

3) Any leftover hoses? Plug 'em.

 

4) Hook up throttle linkage.

 

5) The choke is a whole other issue- the Z24 had a plug with a lot more wires, since the carb was a feedback carb. You only need the choke wire and MAYBE the anti-dieseling solenoid wire (if the Weber has one, most don't).

 

 

Don't worry about disconnecting all other emissions stuff until you have the Weber running right. Because if you do it wrong, you'll just end up with vacuum leaks everywhere and possibly raw exhaust escaping.

[hottdog]

Wiull do tonight and I'll report results! Thankx!- Awesome flag on the hood...

[bananahamuck]

Although datsaholic answered your question. if you want real help, post pictures it helps us long distance helpers guess better.

 

And remember the need for pics of your rig rises by every post.

[hottdog]

Ok! Well, the help here has worked like a charm so far! Got the new carb on after 15 year old son perfected his ability to drop nuts into tight spaces on the fabulous Nissan 720 truck's engine compartment. Fuel line went ok, but the pipe is so close to the carb's fuel inlet that I now havea pretty curlique fuel line, but it works! There was only one vac advance line, which went right onto the port. Capped and plugged everything in sight, except the two steel pipes leading from the (old) air cleaner to the exhaust manifold. I did all of this without the manual or the carb instructions, which I inadvertently left at the office. Throttle linkage was a breeze, except I had to widen the notch a litle to get the flat on the linkage housing to go in there. I did not hook up the electric choke. Couple of pumps on the accelterator, and she fired right up! It runs fast, but I have not (a) hooked up the choke; (B) adjusted anything on the carb itself-it's straight out of the box. As I suspected, steel pipes leading to exhaust manifold also lead FROM the exhaust manifold, and created essentially jets of exhaust. I bridged these with a piece of heater hose with hose clamps, and it still ran fine. However, it has not been under load, nor at hi rpm, so I'm not sure if the exhaust pressure will shoot the bridge thru the hood and windshield or not. Per the above, I need to get the weber working right before worrying about this, which will be tonight's project.

 

Per the carb instructions, I need to add the return spring, though it's working as is. I was wondering what that piece was in the bag. I also need to add the float bown vent hose to the float bowl vent fitting, but I dont' see any hose that might be it, so I just capped it. I think it was capped on the old carb, but never found anything about a float bowl vent hose or anything like it. The carb instructions also say to hook up the idle cut off solenoid, which I just figured out, so I'll get that done, too.

 

I'll get some pics of the truck and the new setup tonight!

[hottdog]

Fantastic Success! Carb is on, engine is running fine, lots more power! We'll see re gas mileage, I have the same carb on my 77 Spitfire and it gets 42 miles per gallon, and its about hesmae horsepower 4 cyl. Now if I can only figure out why the ac crapped out; compressonr clutch is not activating for some reason...

 

Any ideas on getting rid of the zillions of now unused vac lines that litter the intake manifold side of the engine-or do I just trace each back to a device and move the exisitng cap from vac line end to device? Is it true that the ADDA valve stands for Annoying Doesen't Do Anything Valve?

[Sealik]

Fantastic Success! Carb is on, engine is running fine, lots more power! We'll see re gas mileage, I have the same carb on my 77 Spitfire and it gets 42 miles per gallon, and its about hesmae horsepower 4 cyl. Now if I can only figure out why the ac crapped out; compressonr clutch is not activating for some reason...

 

Any ideas on getting rid of the zillions of now unused vac lines that litter the intake manifold side of the engine-or do I just trace each back to a device and move the exisitng cap from vac line end to device? Is it true that the ADDA valve stands for Annoying Doesen't Do Anything Valve?

 

You could remove the EGR and cap it.

Remove the BPT

Unplug the hoses going to the TVV...thermal vacuum valve I believe?

Vacuum switches can be removed.

Unplug the white wire coming from dizzy.

Remove the pipe(s) coming from the EM....and plug.

Hmmm...what else...

Basically just need 1 hose from Dizzy to base of Weber

[ggzilla]

I have the same carb on my 77 Spitfire and it gets 42 miles per gallon, and its about hesmae horsepower 4 cyl.

The 720 pickup weighs almost twice ... and has larger footpprint, so expect much worse city and worse highway too.