1974 fj40 desmog question (3 Viewers)

[cims1970fj40]

Hello,
I’m sure the question I’m about to ask has already been answered but sometimes I feel it’s easier to start a thread vs trying to do the research.
So I have a 1974 fj40 with a 75 stock carb and plan on running the AC Delco canister. I was told by Red Line Cruisers that I no longer need the VCV if I was planning on doing a desmog. Is this correct and do I need to run some vacuum lines out of it? I recently bought a refurbished VCV from BTB and need to decide if I should return it or not. Any help would be greatly appreciated. Also I’m running a 2f and late 70’s I believe manifold if that makes a difference or not. Thanks

 

[rkymtnflyfisher]

I'm not running the VCV in mine, my setup is a tad different though. I have a non-US spec carb, and the electronic ignition from an 83 60 series.

 

[rkymtnflyfisher]

The charcoal canister is nonexistent on my rig also.

 

[B y r o n]

While looking for information about your issue I ran across this information on manuals and documentation for the Land Cruiser and other models. If you want to know what manuals cover your vehicle you'll want to look at page 13.

 

[Pighead]

Mine started out as a 12/74. Still running the 10/73 carb, but now with an early 2F block, late F head, 60 series bigcap dizzy and '69 intake manifold. And stuff.
I got no VCV or nothing. About as desmogged as you can get.
I got one vacuum line, from base of carb to dizzy.
Seems to get along just fine.

 

[65swb45]

The vcv acts as a circuit interrupt for functions that are better off run as stand-alone. Add a nipple to the underside of your air cleaner to channel the fumes from your charcoal canister, route the vacuum advance port on the dizzy directly to the vacuum advance port on the carb and call it done.

If you are lacking vacuum advance at either end, just cap and be done.

Why a 75 carb?

 

[cims1970fj40]

I'm not running the VCV in mine, my setup is a tad different though. I have a non-US spec carb, and the electronic ignition from an 83 60 series

The vcv acts as a circuit interrupt for functions that are better off run as stand-alone. Add a nipple to the underside of your air cleaner to channel the fumes from your charcoal canister, route the vacuum advance port on the dizzy directly to the vacuum advance port on the carb and call it done.

If you are lacking vacuum advance at either end, just cap and be done.

Why a 75 carb?

I had a trollhole carb and ended up buying the 75 carb from a local member. What year carb would you recommend?

 

[65swb45]

I always prefer a mechanical secondary over a vacuum one. There are several dozen threads on the paper clip test that demonstrate why.

And more so on a motor that originally had one.

 

[jembourbe]

Mine is July '75. I left the computer and vcv in place only to keep the evap emissions system operational.

 

[SoCal74]

The charcoal canister is nonexistent on my rig also.

Where do you vent the fuel tank to if you no longer have the charcoal canister?

 

[charliemeyer007]

My gas cap is vented. I think my vapor recovery unit goes back to the tank. Charcoal can was long gone before I got the rig 7PO's and I only knew number 7.

 

[rkymtnflyfisher]

Where do you vent the fuel tank to if you no longer have the charcoal canister?

Good question.

One I don't have an answer to right now. I'm thinking it's not vented currently, which leads to pressure building up in the tank on hot days.

I'll add that to my list of things to work on. But if it ain't broke don't fix it.

 

[procomsignathid]

The redline cruisers diagram for vacuum hose connections works just fine if you want to keep a charcoal canister. My truck was de-smogged entirely (including the charcoal canister), and I purchased the redline kit so I could stop stinking up the place with gas fumes. I know some people love the smell of gas in the morning but for me its the difference between my wife and kids riding with me or not.

That said, to answer your Q you don't need the PCV valve. Here's the redline hose layout that you should be able to use (its pretty universal):

The main takeaway here is they use they small vacuum port off the base of the carb to activate the VSV (should be included with the kit), which opens the large vacuum port between your intake manifold and the charcoal canister. If you don't have a vacuum-advance dizzy, congrats, use that 6mm hose straight to the included VSV. If you do, use the included 6mm Tee as shown in the pic.