The secondaries of my Holley won´t open!
06-26-2010, 03:40 PM
#1
Pro
Thread Starter
The secondaries of my Holley won´t open!
I have a Holley carburator with the number 80770 and 3476 on my 427ci Big Block Vette.
The issue is, that the secondaries won´t open and so at 5000 rpm is the deadline.
I have tried the all of the 3 different springs. Low, medium and hard, but the secondaries won´t open.
Once I have tried it without a spring, the secondaries open, but only the half way. So I could go to 5500 rpm.
Here are a few pics of my carb. What the hell is going on here?
BTW: I have already checked if the primaries open and yes, they do!
Best regards, Günther
The issue is, that the secondaries won´t open and so at 5000 rpm is the deadline.
I have tried the all of the 3 different springs. Low, medium and hard, but the secondaries won´t open.
Once I have tried it without a spring, the secondaries open, but only the half way. So I could go to 5500 rpm.
Here are a few pics of my carb. What the hell is going on here?
BTW: I have already checked if the primaries open and yes, they do!
Best regards, Günther
06-26-2010, 03:49 PM
#2
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Are you doing this with the car stationary in the garage? Believe you have to be at speed for vac secondaries to open.
06-26-2010, 03:50 PM
#3
Looking at your pics, I see that you have the quick change vacuum secondary system in place.
1) when you installed the quick change, did you remember the check ball?
2) did you remember to coat the screws with petrolium jelly so they don't twist the rubber diaphram?
3) no matter how much you try, you can't see the secondaries open without load. This means you standing in the drive way revving the engine looking at it wont work.
You have to place a camera in the engine bay and record you driving around placing a heavy load on the engine
4) Vacuum secondaries wont limit your rpms, it just adds more fuel
1) when you installed the quick change, did you remember the check ball?
2) did you remember to coat the screws with petrolium jelly so they don't twist the rubber diaphram?
3) no matter how much you try, you can't see the secondaries open without load. This means you standing in the drive way revving the engine looking at it wont work.
You have to place a camera in the engine bay and record you driving around placing a heavy load on the engine
4) Vacuum secondaries wont limit your rpms, it just adds more fuel
06-26-2010, 03:52 PM
#4
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With the primaries all the way open..can you manually open the secondaries? Sometimes a gasket gets in the way.
Is choke opening all the way? Ck linkage..it can hold them back.
Try without an air cleaner to make sure it's not holding it back.
I'm assuming this is testing on the road and not stationary? If you're just testing in the driveway they won't ever open much.
Maybe you have valvetrain issues holding RPM back?
Fuel delivery?
JIM
Is choke opening all the way? Ck linkage..it can hold them back.
Try without an air cleaner to make sure it's not holding it back.
I'm assuming this is testing on the road and not stationary? If you're just testing in the driveway they won't ever open much.
Maybe you have valvetrain issues holding RPM back?
Fuel delivery?
JIM
06-26-2010, 03:54 PM
#5
Pro
Thread Starter
Yes of corse, I know.
I drove in the 3rd gear with about 2000 rpm, then WOT till redline. So the plan, but 5000 rpm was the redline
I put on a cable clip on the rod of the secundaries to see, if they open or not. And they don´t open
Thanks, Günther
I drove in the 3rd gear with about 2000 rpm, then WOT till redline. So the plan, but 5000 rpm was the redline
I put on a cable clip on the rod of the secundaries to see, if they open or not. And they don´t open
Thanks, Günther
06-26-2010, 04:00 PM
#6
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06-26-2010, 04:19 PM
#7
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Remove the whole can and apply vacuum to the port that seals to carb and see if the can will open. Also depress the can plunger and seal off that hole and make sure it stays retracted...no leaks in housing. Check the seal between the housing and main body and also check for any restrictions in that little port that goes into throttle bore area to provide signal for secondaries.
Sounds like a weak signal or a leak somewhere. They usually flop open awful fast with the light spring in there or with the check ball removed.
JIM
Sounds like a weak signal or a leak somewhere. They usually flop open awful fast with the light spring in there or with the check ball removed.
JIM
06-26-2010, 04:33 PM
#8
Pro
Thread Starter
Remove the whole can and apply vacuum to the port that seals to carb and see if the can will open. Also depress the can plunger and seal off that hole and make sure it stays retracted...no leaks in housing. Check the seal between the housing and main body and also check for any restrictions in that little port that goes into throttle bore area to provide signal for secondaries.
Sounds like a weak signal or a leak somewhere. They usually flop open awful fast with the light spring in there or with the check ball removed.
JIM
Sounds like a weak signal or a leak somewhere. They usually flop open awful fast with the light spring in there or with the check ball removed.
JIM
Thanks, Günther
06-26-2010, 06:04 PM
#12
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There's 3 screws ( I think) that hold it to the side of the carb. Remove them and the little clip that attaches to secondary throttle plate and it slips off as an assy.
There is a little o-ring or cork gasket between it and the main body to seal the vacuum passage that operates the can. Look for it.
There is a little check ball that sits in the passageway that directs vacuum to the top of the diaphragm. When you remove the top lid and diaphragm you'll see it. Like a BB. Now engineers will tell you that it allows enough around it to have no real effect on opening...but it does. If you remove it the can gets very sensitive and will open quickly often requiring a stouter spring to avoid bogging. Usually you can leave it in place with no issues, but it will work with it removed too.
You can always put a screw/nut in the throttle side linkage slot to make it mechanically open the secondaries. It will bog,...but you will get a feel for if they are opening or not.
Understand that it *should* still pull high RPM with just the primaries. Just won't get there as fast. There are many 2BBL racers that run in the 10's with no problem.
Probably shouldn't mention it...but many many years ago...in the "elicit street game scene" (never said *street racing*) I would often play the game of removing the secondary *u-bend* linkage from throttle side and hand it to the other fellow to hold and say I would only run as a 2BBL. They always felt better after that...but with judicious throttle opening and keeping a bog away...that little 2BBL would *become* a 4BBL as RPM climbed. It would open very quickly and everyone was amazed at how fast my 2BBL junk could run!!
He he he......those sure were fun days!
JIM
There is a little o-ring or cork gasket between it and the main body to seal the vacuum passage that operates the can. Look for it.
There is a little check ball that sits in the passageway that directs vacuum to the top of the diaphragm. When you remove the top lid and diaphragm you'll see it. Like a BB. Now engineers will tell you that it allows enough around it to have no real effect on opening...but it does. If you remove it the can gets very sensitive and will open quickly often requiring a stouter spring to avoid bogging. Usually you can leave it in place with no issues, but it will work with it removed too.
You can always put a screw/nut in the throttle side linkage slot to make it mechanically open the secondaries. It will bog,...but you will get a feel for if they are opening or not.
Understand that it *should* still pull high RPM with just the primaries. Just won't get there as fast. There are many 2BBL racers that run in the 10's with no problem.
Probably shouldn't mention it...but many many years ago...in the "elicit street game scene" (never said *street racing*) I would often play the game of removing the secondary *u-bend* linkage from throttle side and hand it to the other fellow to hold and say I would only run as a 2BBL. They always felt better after that...but with judicious throttle opening and keeping a bog away...that little 2BBL would *become* a 4BBL as RPM climbed. It would open very quickly and everyone was amazed at how fast my 2BBL junk could run!!
He he he......those sure were fun days!
JIM
06-27-2010, 06:17 AM
#14
Pro
Thread Starter
Today I removed the vacuum canister and saw, that the kork-gasket is not in a good condition - look at the pic.
Could this be the solution of the parcel? And then I checked, if the vacuum is hold at the canister. Yes, it does.
But I couldn´t find the check ball Hmm, I think I make a pic, maybe you can see it.
Here the link for the video.
Any thoughts?
Günther
Could this be the solution of the parcel? And then I checked, if the vacuum is hold at the canister. Yes, it does.
But I couldn´t find the check ball
Hmm, I think I make a pic, maybe you can see it.Here the link for the video.
Any thoughts?
Günther
06-27-2010, 01:54 PM
#17
The check ball (BB) is located in the cannister and can be located by removing the top off the vacuum can assembly. It lays in the channel where the cork gasket is at.
***as a side note, most people think that when they stomp the throttle and the car bucks hard forward, it's the secondaries coming on....which is wrong. With a properly operating carb, you shouldnt feel the secondaries coming on-it should pull hard with no bucking.
The function of the auto trans kickdown switch/lever is to down shift the trans to provide a higher RPM and of course, the cool bucking that we all love.
Check your kickdown for proper engagement....if you want the feel of secondaries coming on.
***as a side note, most people think that when they stomp the throttle and the car bucks hard forward, it's the secondaries coming on....which is wrong. With a properly operating carb, you shouldnt feel the secondaries coming on-it should pull hard with no bucking.
The function of the auto trans kickdown switch/lever is to down shift the trans to provide a higher RPM and of course, the cool bucking that we all love.
Check your kickdown for proper engagement....if you want the feel of secondaries coming on.
06-27-2010, 08:07 PM
#20
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Check this link and see if it helps.
http://www.oldcarmanualproject.com/m...lB150_0015.htm
Did you check the port in the carb for obstructions? maybe a piece of that cork is wedged up in there. Spray some carb cleaner through the hole in carb body. make sure it comes out in throttle bore.
Apply vacuum to diaphragm canister port and make sure it works.
JIM
http://www.oldcarmanualproject.com/m...lB150_0015.htm
Did you check the port in the carb for obstructions? maybe a piece of that cork is wedged up in there. Spray some carb cleaner through the hole in carb body. make sure it comes out in throttle bore.
Apply vacuum to diaphragm canister port and make sure it works.
JIM