4-BBl ain't opening the Secondaires?

I,m also Posting this in the Regals With Extra Cylinders section

Well

I thought I had it cured, got the lower secondary throttle blades to quit catching by loosening up the screws and adjusted, also with the top secondary blades.

Still no.......TTTHHHWAAP ..... sound when I nail it to pass someone.

Now I'm gauging the cars performance based on the /or lack thereof of that sound, since Ive owned many Q-jets before and they did that.

Now mind you I can get this Regal to move just seems to take longer, it's not instant like I've been used to in the past.

Now I can only come with 2 conclusions, my throttle cable isn't pulling back far enough, or when I switched over to a different throttle plate rod(to run the T.V. cable) it's activation point ( to push back a rod to activate the secondaires )was shorter.
(Forgive me kinda lame on terms of carb parts)

Have you guys ever experinced this in a G-body conversion to a BBB?

thanks

 

I never put a 400-430-455 in a G body


However, I have had the secondaries bind.

In my case, it was one of two things:

on my stock manifold and my aluminum Edelbrock, for some bizarra reason, the seconadaries would open about 1/4 way with the carb on the manifold. No idea why. When I took it off, the secondaries worked fine. I played with it awhile, and eventually, for some bizarre reason, it worked

the other reason was: a bit of the gasket was binding the secondaries. i trimmed the inside to match the pattern of the barrels, problem solved.


If you disconnect your throttle cable, bodily climb on top of the engine, and look down while pushing open the throttle, you can look into the carb to see if the secondaries will open all the way. If it will do this with the throttle cable off but not with it on, you've just pinpointed the trouble.

Some throttle cables are actually adjustable. Also look at the trottle cable bracket- are you 100% sure that the cable isn't getting bound? You need a nice 'straight shot' (well ideally you would want the linkage just a teeny bit low to sort of split the difference in angles, but let's not get into that, it will make it all needlessly complex) from the center of that bracket opening to your carb linkage. if there's enough up or down movement, consoder what the cable must do to pull back: is it actually binding?

In the top figure, consider that the carb linkage MUST travel on an arc. It is not a linear motion; the point at which the carb linkage mates to the throttle is not the pivot point. Otherwise, how would the cable open the carb? You want a nice, straight path, to minimise any up and down travel of the cable. On a stock set-up, this isn't an issue, because the path the linkage will travel is nearly straight.

In the bottom figure, the same holds true, but now your linkage is not in the path of the cable. As the cable moves backward (as you open the throttle), the linkage travels in an arc, just like the top figure, but now the cable must travel so far up, the cable may actually bind. Compare the two bright green lines that go from the cable bracket to the top of the arc of travel, and then take a look at the difference in the angles that those lines make with the path of the cable.

What I mean to get at is: consider what the cable has to do to pull back the carb linkage, and what happens to it as it goes back. Also note that if the cable bracket can twist, yoiu're robbing yourself of usable travel.

 

I have a 455 with the same problem. I have never had a Buick before but have had problably 40 Quadrajets and never had one that didnt scream. Everything is working as it should as far as linkage and such. I have even loosened the top butterfly setting and it didnt help.Maybe these Buicks just dont behave like all the other GM products. Any opinions ED

 

Well, for reference, my original 800 cfm Q-jet that was on the 455 when I bough the car it was in had a definite sound that announced the secondaries were open. The Q-jet makes that sound because the secondaries are a fuel dump rather than classic venturis.

 

I installed a factory stage one cam in a 1974 engine that had the right year heads but they had the big valves for some reason. Im thinking it has to low of compression to go with this cam because the original 400 was much more responsive than this engine. I changed engines just so i wouldnt blow up the matching numbers one. Anybody agree or disagree with compression ratio to low.

 

Under the choke setup on the side the is a little secondary lock that keeps them from opening untill it's warm, loosen the chake setup up and through it away.

 

A spacer

I had at one time a problem with the lower part of the carb arm on the passangerside hitting a part of the spacer I was using.Had to grind some clearance into it for the carb.Couldn't feel it in the gas pedal.
Also check the vaccum secondary pull-off.

 

:TU:

Thanks for the input guys.....

looks like some seroius adjustments have to be made

Come to think of it I never head those secondaires open up when the carb was on the cast iron intake, and the eng was still in the Lesabre

Thanks I will try those suggestions tho

Later