I used a plastic garbage bag tie, from the driver's side lever on the secondary throttle shaft to the rear carb stud, so they could not open. I ran the car out in each gear. The performance was the same as before I tied the secondaries closed, with rpm stagnating around 4000. Obviously the secondaries are not opening. I cleaned the carb thoroughly and blew compressed air through all the passages when I rebuilt it. I believe it has the correct spring in the diaphram, and the throttle plate operates smoothly and freely with no restriction. I would like to get the secondaries to work properly and keep the original carb on the car. What steps can I take to try to allow the secondaries to work properly?
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Re: '66 #3367 SECONDARIES...
Rob,
Do you remember if you had or put a steel check ball in the diaphragm housing ? I would remove it if you did and see if that helps the situation. The different springs determine how soon the secondaries open so I would think you would still get some response even with the wrong spring. With the motor turned off and holding the primary throttle wide open when you manually open the secondaries you should hear a rush of air going into the carb. If you don't then something is blocked or the diaphragm is ruptured.
Wayne -
Re: '66 #3367 SECONDARIES...
Wayne,
Yes, the steel check ball was reinstalled and the diaphram sounds like it's functioning properly.Comment
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Re: '66 #3367 SECONDARIES...
Wayne,
What are the chances the secondary throttle plates are opening, but fuel is not being delivered? I'm going to take it out tonight using Duke's "dab of grease" trick just to make sure they are, in fact not opening.Comment
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Re: '66 #3367 SECONDARIES...
Wayne, I thought I read somewhere that the 66 #3367 did not use the check ball, although it is included in most rebuild kits. I know my 66 L-79 does not have one and I used the grease method and confirmed the secondary function.Comment
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STOP
The 3367 does not use a steel ball in the secondary diaphragm vacuum passage.
This particular diaphragm housing does not have a cast or machined path in the bottom of the vertical chamber to allow vacuum to get past a restricter ball. With a ball in that chamber, there is no way the secondary diaphragm can get vacuum.Comment
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Re: STOP
I'll remove the ball and try it out....hopefully that was my problem....I'll let you know...Thanks...Comment
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Also.
Rob,
After you remove the check ball, check the setting of the secondary throttle stop screw. The secondary throttle plates are supposed to be slightly cracked open a 1/4 turn on the screw from full closed so the diaphragm can sense vacuum in the closest barrel. I think.
Jerry Fuccillo
#42179Jerry Fuccillo
1967 327/300 Convertible since 1968Comment
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Re: STOP
Jerry,
It appears you were right about the check ball. I removed it and it appears the secondaries are opening. I used the "dab of grease" test. Performance is better, rpm higher, and now I can see the secondary throttle plates are wet immediatly after I run it out. Thanks...Comment
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Re: Also.
Jerry,
Thanks....I read that in the Holley book I used when I rebuilt the carb and did adjust them that way.Comment
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Re: '66 #3367 SECONDARIES...
Doug,
That is correct. That is why I suggested Rob should take it out if there was one and Jerry also confirmed that there shouldn't be one.
WayneComment
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Funny thing about the check ball
Wayne,
After reviewing this thread, I thought I'd review the Holley Illustrated Parts and Specs Manual on the check ball.
I found that:
1. On 4150 Holleys with vacuum secondaries, the check ball is a standard part, listed as Index Part No. 90 with a part number of 28R-1 for the standard 4150.
2. On 4160 Holleys with vacuum secondaries, the check ball is still listed as Index Part No. 90 but as a variable part depending upon the list number of the carb. You have to go to variable parts listing to see if that specific list number has a check ball.
3. In going through the listings, I found that none of the Corvette 4160's had check balls listed, yet there were Chevelles, Ford, Willys, Chrysler 4160's with check balls listed. Interesting that the same year Chevelles had the check ball, Corvettes no check ball.
4. So I guess there is no check ball on the following Corvette 4160's: 3367, 3370, 3605, 3606, 3810, 3811, 3814, & 3815. For other 4160's, one needs to check the variable parts listing for the check ball or not. 4150's with a secondary metering block and vacuum secondaries all seem to have the check ball.
Thought this was interesting.
Jerry Fuccillo
#42179Jerry Fuccillo
1967 327/300 Convertible since 1968Comment
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Ball function
It works as a vacuum restricter rather than as a true check valve. It slows the secondary opening rate slightly during hard acceleration, but allows quick closing. This ball does not affect the speed at which the secondaries begin to open.Comment
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the carbs with the check ball
on some engines would open to quickly if you removed the check ball so i would take a small phillips screwdriver and use it as the punch and put 4 shallow grooves next to the vacuum hole and this would speed up the opening but not cause a bog like completely removing the ball check. i think the ball check was only used with heavier cars than corvettes because if the secondary open to quickly it would cause a bog but the lighter corvette would accelerate thru this quicker. JMHO check the parts and specs book to tell if it was in there from the holley factoryComment
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