linkage on 3x2 carbs

[Richie]

I am getting ready to install a set of rebuilt 3x2 carbs on my 67 435 car. Jerry Luck did them so I know they are right. What is the secret to setting the linkage to get these things running right? Also how do you avoid gas leaks from the fuel lines into the carbs? Any other things I should know before a take this project on? I am a rookie with these.

[Jerry Clark]

Re: linkage on 3x2 carbs

Richie:

The AIM and most other manuals I have seen recommended setting the front secondary carb linkage with the rod dead in the center of the carbs throttle lever hole, however they recommend a 1/3 rod diameter "lead" in the rear secondary carbs linkage, i.e. opening the aft secondary throttle blades a bit. I have always followed this procedure without problem but it is the subject of much debate in tri power circles, mine runs like a scalded dog.

The fuel lines require a bit of T:C, start all fittings finger tight, tighten the line to filter carrier nut first, working all three a bit at a time until tight. Move to the Tees next , tightening all three in the same manner. Next the intermittent straight line between the two tees, now the fuel line. Make certain to hold each opposing fitting while tightening the other end of the line, USE TUBING WRENCHES. Two years, no leaks

jer

[Jerry Clark]

Correction

That should read 1/2 rod diameter on rear carb

[Dave Stafford]

Re: Correction/question

Jerry, what size squirter nozzle are you using in the main carb, and at what RPM do you start to get secondaries opening? I am still "tweaking" my set up. Thanks in advance.

[Wayne M.]

Re: linkage on 3x2 carbs

Ritchie, Jer --- As the 3 x 2 secondaries closing rod adjustment procedure was never described in either the '67 or '68 Service Manual, CHEVROLET SERVICE NEWS, Dec '67, went into a 4-step detail on how to properly set-up this linkage.

If you don't have this handy, I can email or post here.

[Dave Stafford]

Re: linkage on 3x2 carbs

Wayne, would you mind to send me the bulletin to my above address. Thank you very mucho!

[Richie]

Re: linkage on 3x2 carbs

Wayne, I would greatly appreciate you emailing me the bulletin at the above address. Thanks greatly. Richie.

[grr]

Re: linkage on 3x2 carbs

Just for kicks did Jerry tell what type of springs he put in your fwd/after carbs. Did he leave the stock diaphragm springs in?

I have very light springs in mine. The lighter the spring the quicker or less vacuum it takes to open the carb up.grr#33570

[Jerry Clark]

Re: linkage on 3x2 carbs

Hi Wayne: Being aware that the 3x2 linkage is a closure device it always seemed unusual that GM used it to open the aft carb, hence the discussion around here.I would like to see the service bulletin also. Hell ya might as well just post it.

jer

[Dave Stafford]

Re: linkage on 3x2 carbs

This is why I was asking Wayne about the squirter nozzle and when his secondaries were opening up. As I understand it, you may have to increase the nozzle size if you you have other than stock, i.e. lighter springs, to avoid the "bog" that can occur as the secondaries open. I'm going to learn how to tune these carb's if it takes all year!

[Jerry Clark]

Didn't Give Up Everything

GRR, ( isn't that GTO language ? )

I run very light springs and my secondaries come in early, maybe a bit too early.

For Dave, because the secondary actuation is a by product of spring tension combined with vacuum the point of actuation will vary from engine to engine depending on springs and camshaft profile.

jer

[grr]

Re: Didn't Give Up Everything

The GTO went to progressive linkage in 65 and 66. But what I was trying to state is what you already know. Try getting some ignition advance and see how you run. I run all I can but my car (67 L-71)is presently getting restored and should get back in a couple weeks. Painted body today.

Thanks for reminding me about the GTO. I restored one back in 80's. Nice cars and it brought back a lot a memories for me and lots of friends.grr#33570.

[David D.]

Re: linkage on 3x2 carbs

Wayne -

Please e-mail carb adjustment info to dgdawdy@hotmail.com. My 400 will hopefully get back on the road this month after many years.

Dave

[Jerry Clark]

GRRRRRR, you know

like the Tiger in your tank ads, like Tom McAnn shoes with tire tread soles, you know : GRRRRRRR as in Varooooom

jer