holley 4150 idle vacuum ????'s - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 08-22-2003, 09:54 AM
juveteach's Avatar
BUILD IT RIGHT, TWIST IT TIGHT !!!
 
Last photo:
Join Date: May 2003
Location: North Carolina
Age: 46
Posts: 79
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
holley 4150 idle vacuum ????'s

I am running a 4150 650 DP with shaved air horns and 67P 75S jets. My question is how do you reduce the amount of vacuum at idle on the Dist.vac.adv. port on the carb. I have enlarged the holes in the primary plates to ,125 seemed to help some but I am still having 3-4hg at idle. This makes my rpm's stay high after an engine pull it won't idle back down to 8-900 rpms stay up due to vac. pulling the weights in the dist causing timing adv. If you pull off the vac adv hose to dist idle comes down.




Anyone with ideas on how to correct this problem I would greatly appreciate it.

Thanks

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-22-2003, 10:45 AM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,655
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
the ported vacuum port is on the passenger side front primary metering block and should not pull vacuum at idle, it should only pull vacuum at off idle. is it connected to this port or to a constant source?
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-22-2003, 07:12 PM
1BAD80's Avatar
The Smell of Nitro in the morn
 
Last wiki edit: How to adjust valves Last photo:
Join Date: Jun 2001
Location: Mich
Posts: 2,423
Wiki Edits: 2

Thanks: 0
Thanked 3 Times in 2 Posts
DITTO: with DV
__________________
Luv the smell of NITRO in the morning.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-23-2003, 01:57 PM
juveteach's Avatar
BUILD IT RIGHT, TWIST IT TIGHT !!!
 
Last photo:
Join Date: May 2003
Location: North Carolina
Age: 46
Posts: 79
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
If ya'll would read the post I have already stated that I know where the ported side is. My question is how do I reduce the amount of vacuum on that port. I am extremly frustrated with this carb in that I sent it off and spent alot of money for a "HOT" carb and it is extremly rich and I can't adjust idle due to vac on the dist port.

I guess I will have to use a adjable vac adv on the dist to block the vac at idle.

I am not trying to be snotty but It seems as though some are not fully reading the posts all the way through.

I have a problem and would like some advice not advice I already know.

Thanks
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-23-2003, 02:10 PM
dmorris1200's Avatar
doesn't play well with others
 
Last photo:
Join Date: Feb 2002
Location: Maine
Age: 49
Posts: 1,834
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Don't mean to be 'snotty' here, but I think it is you that needs to get a grip. You are the one asking how to reduce the amount of vacuum from a port that has no vacuum at idle. I will even quote your original question.

Quote:
Originally posted by juveteach
how do you reduce the amount of vacuum at idle on the Dist.vac.adv. port on the carb.
I would say since we all interpretted your post the same that it is obviously you that needs to make some sense here instead of badmouthing people.

__________________
BUILT FORD TOUGH
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 08-23-2003, 02:59 PM
juveteach's Avatar
BUILD IT RIGHT, TWIST IT TIGHT !!!
 
Last photo:
Join Date: May 2003
Location: North Carolina
Age: 46
Posts: 79
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thats what I'm saying...I have vacuum at that port!!

I have a 550" I and 555" E lift cam with 240I and 244E @.050" and I know I not supposed to have vacumm on the port but I do. The overlap has put vacuum on the port to the dist. I have drilled .125" holes in the pri plates to help with the transition of idle vacuum.

I really am not trying to be "snotty" at all I just asked for some opions on why I have the vac at idle and how to get rid of it.

Thanks
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 08-23-2003, 03:16 PM
dmorris1200's Avatar
doesn't play well with others
 
Last photo:
Join Date: Feb 2002
Location: Maine
Age: 49
Posts: 1,834
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
No problem, asking how to reduce vacuum is different than asking 'why do I have vacuum at this port?'. Usually vacuum at that port happens because the idle screw is adjusted too far to keep an engine with a big cam idleing high. When the throttle plate opens as a result of turning in your idle screw to raise the engines idle vacuum makes it to that port. It doesn't take much of an opennning. If this is the case try backing out your idle screw some and see if it changes anything.

__________________
BUILT FORD TOUGH
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 08-23-2003, 03:46 PM
juveteach's Avatar
BUILD IT RIGHT, TWIST IT TIGHT !!!
 
Last photo:
Join Date: May 2003
Location: North Carolina
Age: 46
Posts: 79
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Ok I have tried that...no help with the idle, would not run with out me popping the throttle to maintain the idle. I even called Holley Tech line they suggested switching to a 4.5"hg power valve and openning up the secondary plates to take some of the primary plate angle out and cover up the transition slots more and use both plates to help with the air instead of just one. They also advised me to step up to a .032" squiter up from the .028".
BTW when I went to the 4.5" PV and openned up the sec plates it develpoed a nasty lean pop just off idle so now I'm back to square one with it.

I believe I'm going to put the sec plates back and keep the 4.5 PV and install the .032" Squiters and see if I was pulling the fuel away from the transition slots in the first part of the throttle movement, maybe I am taking all the idle fuel away and the engine needs more before it begins to draw it on its own from the carb

Still need to know how to stop the vacuum pull on the dist port so I can leave my vac adv hooked up.

What do ya'll think?

Thanks
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 08-23-2003, 04:53 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,655
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
I think, depending on the cam size, and if you have on so big that it needs a 4.5 power valve, it doesn`t even need a vacuum advance. as said before, it does sound as if the primary throttle plates are opened too far and this causes the port to pull vacuum at idle, if you are running a giant cam, where is the timing advance set at idle? In the past, we`ve built many drag engines, we never ran the vacuum advance, even at the times we ran it on the street we didn`t use one. and I did understand your posting the first time, but at idle, it`s not suppose to pull vacuum, the only thing that makes it do so is the throttle plates opened too much as stated, I asking if it were connected elsewhere, just to be sure, since none of us are under the hood of the car, were all just guessing what the problem is, the more we know, the better we can be of help. if your set on running the vacuum advance, then you can do this little trick, use a line T fitting, and run the hose from the port to the advance, connect a short piece of vacuum hose of the 3rd opening of the T, and push in a jet from a Holley carb, a very small jet, or you can make something yourself, what this will do is at idle, there won`t be enough vacuum to pull the advance in, but will be off idle, in a way, it`s just a home brew bleeder valve, but it works.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 08-23-2003, 06:06 PM
datsun350's Avatar
Member
 
Join Date: Aug 2003
Location: minnesota
Posts: 44
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
some of those carbs had an idle screw on the secondaries on the passenger side with the screw head on the gasket side of the baseplate it is very small and you have to take the carb off to adjust it but the reason that it is there is to fix the problem that you have right now

i don't remember for sure if that particular carb has one or not but I think it does. All you have to do is open the secondary side a little bit so that you can close the primary a little. Don't open it too far because you wont be able to idle it down then. It is a PAIN because you have to take the carb off to adjust it but it works

Good luck
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 08-23-2003, 06:15 PM
juveteach's Avatar
BUILD IT RIGHT, TWIST IT TIGHT !!!
 
Last photo:
Join Date: May 2003
Location: North Carolina
Age: 46
Posts: 79
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
BTW when I went to the 4.5" PV and openned up the sec plates it develpoed a nasty lean pop just off idle so now I'm back to square one with it.

Been there already!

Nasty lean pop, any other ways to do it?
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 08-23-2003, 08:42 PM
1BAD80's Avatar
The Smell of Nitro in the morn
 
Last wiki edit: How to adjust valves Last photo:
Join Date: Jun 2001
Location: Mich
Posts: 2,423
Wiki Edits: 2

Thanks: 0
Thanked 3 Times in 2 Posts
But did you change the squirter nozzle after you changed the PV?
The larger nozzle will help with the lean spot giving it a larger squirt of gas to stop it.
If your trying to control the vacuum advance get one that you can adjust.
__________________
Luv the smell of NITRO in the morning.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 11:27 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.