Holley Tuning on a 230 Chevy - 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 05-01-2006, 03:46 PM
sicksixseven's Avatar
Ground Clearance Is Over-Rated
 
Last photo:
Join Date: Dec 2004
Location: Massachusetts
Age: 27
Posts: 99
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Holley Tuning on a 230 Chevy

Hey guys. I need your help once again with my car. This is a problem that I have been having since last summer, but only for about 3 weeks of driving time. I have been at college for the whole winter, and now its time to pull the car out of the garage. Not that I would expect it, but the car didnt fix itself while I was away.

The issue is somewhere in the vaccum system, specifically the carb. I put a holley 390 CFM 4 bbl on my 230 chevy inline in my 67 chevelle. The distributor is a mid 70's Chevy from a 250 CI truck motor, and it was brand new last summer. It also has headers and a full exhaust system on it. I have had problems since that carb left the box. The car itself is an automatic. The idle of the car in park is around 2200 RPM's with the idle screw all the way out. When I put it in gear, the idle with my foot on the brake is like 600 RPM's, that is if it doesnt stall. It bogs a ton from a stop and at low speeds. On the highway, it goes quite well.

I have eliminated the posibility of an intake leak, as I went through the whole system with a can of carb cleaner to look for one. My vaccum is hooked up as best as I could figure it out. There were two small ports on the carb, and I assume that one of those is for the vacc advance. One draws about 12 lbs of pressure in park at idle, and the other draws about 5 lbs of pressure in park as idle. I have not looked at them in gear yet. There were 3 vacc ports on the carb and one on the intake. I hooked the vaccum controller from the transmission, a Powerglide, to the intake port, and that is not leaking. I hooked the PCV vaccum up to the back of the carb, and it is a large vaccum hole that it goes in. There are two on the front, and one of them is for the vaccum advance, and the other is not in use. These are the two mentioned above.

This being said, I can not figure the problem out. I am stumped. My dad is stumped. Every one of my dad's friends is stumped. I told my dad that if I can not figure this out by June, that I am going to start hunting for a big block. Please help with what ever you can, and I will do my best on this end to help you out. Thanks again.


Sam "sicksixseven"

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 05-01-2006, 03:50 PM
Member
 
Last wiki edit: Ford axle ratio codes
Last journal entry: Rear Suspension
Last photo:
Join Date: Aug 2005
Location: Prattsville
Posts: 6,415
Wiki Edits: 31

Thanks: 2
Thanked 61 Times in 57 Posts
maby the powervalves are blown out, possibly.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 05-01-2006, 05:37 PM
T-bucket23's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Engine basic condition - how to check Last photo:
Join Date: Aug 2005
Location: Massachusetts
Age: 57
Posts: 5,362
Wiki Edits: 26

Thanks: 9
Thanked 145 Times in 128 Posts
Well 12 inches of vacuum is not enough, you should be pullin at least 17 or 18 inches of vacuum at the manifold ports at idle. This is being caused, I would guess, buy either a vacuum leak, timing way off or the wrong carb to manifold gasket.
I would disconnect and plug all vacuum hoses except 1 and throw the gauge on it again and see if it improves. If it does you will have to hunt down the culprit. Could be a cracked line or bad modulator or something like that. The fact that you need to turn the mixture screws way out is telling you that you have a lot of extra air entering the engine from somewhere or the carb is no good.
Where in Massachsetts are you, I am also in Mass
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 05-01-2006, 06:31 PM
sicksixseven's Avatar
Ground Clearance Is Over-Rated
 
Last photo:
Join Date: Dec 2004
Location: Massachusetts
Age: 27
Posts: 99
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks so far guys. I live in Amesbury, up in the NE part of the state. I will check on some of the stuff mentioned when I get the chance, which might not be for a week or so. I could imagine the timing being off, mainly because I can't set the timing because the idle is so messed up. I have tried to tear the system apart, but to no avail. I think my next move it to pull the carb and try to re-seal it. Thanks again.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 05-01-2006, 08:36 PM
Registered User
 
Join Date: Mar 2006
Location: N.E.Mass.
Posts: 22
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Experiment-

Do you have another working 4-barrel lying around that you could throw on there to see if it is the carb?Its good to have,say a stock motorcraft 4 barrel off a Lincoln that runs,just so you can narrow down the problems.I had terrible troubles with my 78 Ford P/U with a 300 six/Quadrajet/headers combo.Without enough cam,the power band only went from 1000 to about 1300 rpms-lousy for the time and money invested.It also wouldnt idle lower than about 900 rpms.Or,its possible that a big 2-barrel,say off a 60s-70s Ford,would be another option.Plenty of adapter plates are available.Good luck-by the way,I work at the Housing authority-I own the 66 Impala 4-door out front.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 05-01-2006, 08:46 PM
Old does not mean dumb
 
Last photo:
Join Date: Dec 2003
Location: Central Tennessee
Age: 72
Posts: 98
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
It would not hurt to check that the secondaries are closed properly...
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 05-01-2006, 09:01 PM
sicksixseven's Avatar
Ground Clearance Is Over-Rated
 
Last photo:
Join Date: Dec 2004
Location: Massachusetts
Age: 27
Posts: 99
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by eyesore 1
Do you have another working 4-barrel lying around that you could throw on there to see if it is the carb?Its good to have,say a stock motorcraft 4 barrel off a Lincoln that runs,just so you can narrow down the problems.I had terrible troubles with my 78 Ford P/U with a 300 six/Quadrajet/headers combo.Without enough cam,the power band only went from 1000 to about 1300 rpms-lousy for the time and money invested.It also wouldnt idle lower than about 900 rpms.Or,its possible that a big 2-barrel,say off a 60s-70s Ford,would be another option.Plenty of adapter plates are available.Good luck-by the way,I work at the Housing authority-I own the 66 Impala 4-door out front.
I don't have another 4 bbl laying around unfortunately. The powerband for my motor seems to be somewhere around 3000-3500 RPM's, basically highway. I am not sure where the housing authority is, but you may have seen my car go by before. Its a dark blue 67 chevelle 4 door with chrome wheels on it. What street is the housing authority on?
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 05-02-2006, 05:35 PM
Registered User
 
Join Date: Mar 2006
Location: N.E.Mass.
Posts: 22
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Eyesore 1

The housing authority is on Main Street,on the hill above the post office.
I was also recalling the troubles I had with a Dodge P/U with a slant motor that I tried to hot rod .That truck had a Super Six intake and Clifford headers,but without a cam,it ran considerably WORSE than with the dog 1 barrel and stock exhaust.The Inliners website is an excellent resource for 6-cylinder builders.I wish id known about it when I had those projects going.You could even make a sheetmetal blocking plate and reattatch your original carb,to eliminate that Holley problem possibility.High idle without the ability to lower it is almost certainly a vaccuum leak,unless there is a mechanical throttle plate open issue.Anyone else have any ideas?
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 05-04-2006, 09:58 PM
sicksixseven's Avatar
Ground Clearance Is Over-Rated
 
Last photo:
Join Date: Dec 2004
Location: Massachusetts
Age: 27
Posts: 99
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have finals all this week, and then I will be back up in the area. I will do some more tests with the vaccum gauge when I get the chance. The only thing that I could think of right now is that the adapter plate from the intake to the carb could be leaking. I will test that as soon as I get the chance. Thanks for the help so far.
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:
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
That lousy Holley carb cool rockin daddy Engine 30 02-29-2008 03:01 PM
I Need Help With 31/32? Chevy walt Hotrodders' Lounge 9 03-02-2004 07:42 AM
Tuning a Holley 4150 (Pontiac 400) steppenwolf Engine 4 07-14-2003 09:04 AM
Holley tuning questions. F-1Rodder Engine 16 06-14-2003 02:20 PM
Holley 650 Spread Bore Kaylah Engine 4 03-03-2003 06:50 AM


All times are GMT -6. The time now is 06:30 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.