Big block el camino "dry-popping" - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



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

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 09-15-2019, 03:38 PM
Registered User
 
Join Date: Feb 2017
Location: The Dirty South
Posts: 33
Wiki Edits: 0

Thanks: 12
Thanked 3 Times in 2 Posts
Lightbulb Big block el camino "dry-popping"

I have a mildly built 468, w/long tube headers running a heavier cam & a q-jet carb. When I really stick it on the road, it will kind of bog down on me and pop-pop-pop-pop. (Its also open headers since its too low to run proper exhaust on right now) I reckon it's my fuel pump that's the problem, its only a 50 GPH and I think my trouble is the bowl of the carburetor is being drained out faster than its filled. Was thinking a comp mallory 140 would be a decent replacement, however what would you recommend? Affordability/efficiency.

Car needs to be street-able and practical.



Any opinions on this?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 09-15-2019, 06:58 PM
LATECH's Avatar
Hotrodders.com Moderator
 

Last journal entry: GTO Reproduction Hood
Join Date: Jul 2010
Location: Northeast Pennsylvania
Posts: 7,723
Wiki Edits: 0

Thanks: 550
Thanked 846 Times in 723 Posts
Sounds like it is going lean. Give it a bigger pump. See what happens
__________________
Fact is stranger than Fiction
Reply With Quote Quick reply to this message
The Following User Says Thank You to LATECH For This Useful Post:
LowNLOUD (09-15-2019)
  #3 (permalink)  
Old 09-15-2019, 09:00 PM
Registered User
 
Join Date: Apr 2007
Posts: 12,404
Wiki Edits: 0

Thanks: 182
Thanked 1,143 Times in 913 Posts
Pump, maybe 50 gallons per hour is free flow delivery, add 15 feet of fuel line, put in a few bends and fittings who knows what the pump is actually delivering to the carb.


If I figure you can muster a horse per cubic inch at a half pound of fuel per horsepower per hour the pump needs to deliver about 38 gallons an hour. That strikes me is iffy with a 50 gal per hour pump, so maybe.


If this is an engine driven pump, these loose delivery rate past some RPM, you can see the evidence of this with a pressure gauge as almost for all pumps as they get above 4000 engine rpm you see a pressure drop. This tells you that the pump's max rated flow is at some lower rpm.


Compounding this is the Q-Jets rather limited bowl capacity which is going to be drained fast at a point where the pump is crapping out.


All that said, you can't rule out the carb being jetted or metering rodded too lean up on the top end. This might be a secondary metering problem stemming from jet or metering rod size or from the air valve adjustment or the cam that operates them.


Bogie
Reply With Quote Quick reply to this message

Tags
454, drypop, fuel, pump, quadrajet

Recent Hotrodding Basics 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:
Insurance
Please select your insurance company (Optional)

Log-in



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 02:16 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.