cam and quadjet question - 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 06-10-2007, 10:38 PM
Registered User
 
Join Date: Jan 2006
Location: mesquite,tx
Posts: 59
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
cam and quadjet question

i have a 350 40 over 882 heads ported and polished with screw in studs and aftermarket springs vodoo 262 cam edlebrock performer intake 1 1/2 headers. the question i have and am trying to break in cam and have 3 or 4 times had to shut off because first glowing red headers, second plug wire got burnt up, move the wire away so not touching and it still burnt up, got a wire protector so dont burn anymore and it back fires. the carb is a 750 holley that i traded some guy for 600 i had. i have it at 8 degrees advance. so my question is one have i damaged the cam by turning off and on the truck before 20 mins break in and two i think the carb needs to be rebulit and want to put on the 4 bbl quadjet i had on 305 on and breakin cam with that. but is it goin to make my truck run to lean with quadjet on there. if anyone has any suggestions i am all ears. i just want to get the thing running.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-10-2007, 11:46 PM
curtis73's Avatar
Hates: Liver. Loves: Diesel
 
Last wiki edit: How to find cheap parts
Last journal entry: 1999-2001: Getting it on the road
Last photo:
Join Date: Dec 2005
Location: Carlisle, PA
Age: 40
Posts: 5,148
Wiki Edits: 16

Thanks: 0
Thanked 4 Times in 4 Posts
I think the cam should be fine. It is supposed to get fast idle for 20 minutes total. Of course that is best if its getting constant splash from the crank (which is the reason for the fast idle) but I think it should be fine as long as its FIRST twenty minutes is operated at fast idle.

If you read your header's paperwork it says specifically not to use them for break in. Break in temps are very high, especially in the exhuast. Jet Hot specifically voids warranties if you use headers for cam break in. Red-hot headers are to be expected.

I keep a set of manifolds around just for that purpose. Let them take the abuse, not the new headers.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-10-2007, 11:51 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,658
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
So the next best thing, since you already have headers on it is to bring a fan over and let it blow on the engine area to carry the heat away.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 06-11-2007, 12:04 AM
curtis73's Avatar
Hates: Liver. Loves: Diesel
 
Last wiki edit: How to find cheap parts
Last journal entry: 1999-2001: Getting it on the road
Last photo:
Join Date: Dec 2005
Location: Carlisle, PA
Age: 40
Posts: 5,148
Wiki Edits: 16

Thanks: 0
Thanked 4 Times in 4 Posts
Not really. The biggest problem is sustained fast idle with choke. You're shoving massively rich mixtures into the exhaust and it keeps burning making problems.

You might be able to stave it off by kicking the choke off and then holding the throttle open. The main thing is that cam lobes ONLY get lube above about 2000 rpms from crank splash. If you start it, then kick off the choke and keep it somewhere above 2000 rpms (within reason... don't go nuts) it should be fine.

A fan wouldn't hurt, but the main problem is extreme EGT.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 06-11-2007, 09:14 AM
Jmark's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: phoenix
Age: 61
Posts: 4,815
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 3 Posts
Sounds like more timing would help too.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 06-11-2007, 06:57 PM
Registered User
 
Join Date: Jan 2006
Location: mesquite,tx
Posts: 59
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
so quadjet might be ok just to breakin the cam for 20 to 30 mins??
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 06-12-2007, 07:36 AM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,023
Wiki Edits: 0

Thanks: 0
Thanked 23 Times in 23 Posts
The timing is too retarded!!! Advance the timing 15 degrees and the headers will stop glowing.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 06-12-2007, 08:24 AM
curtis73's Avatar
Hates: Liver. Loves: Diesel
 
Last wiki edit: How to find cheap parts
Last journal entry: 1999-2001: Getting it on the road
Last photo:
Join Date: Dec 2005
Location: Carlisle, PA
Age: 40
Posts: 5,148
Wiki Edits: 16

Thanks: 0
Thanked 4 Times in 4 Posts
Depending on the engine (especially one with a little more cam in it) you could advance the timing to hell and back and the headers would still glow cherry red. You're dumping tons of extra fuel (like maybe as much as 5:1 AFR) into it during break in, so no amount of advanced timing will burn all that liquid fuel.

Even if you drop off the choke and hold the throttle open manually, you're still operating at a very low throttle opening cruise.. which puts it on the lean limit which (again with a hefty cam) will raise EGTs. You don't get the fuel burning in the exhaust like when the choke is on, but the exhaust gasses are hotter. Heck, even my cast iron manifolds glow red in the dark after a cruise in my LT1 with 103k on it. Its just a fact of life. Exhaust is hot, and cam break-in is asking a lot from your exhaust.

That is why header manufacturers void warranties if you use them for break in.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 06-12-2007, 04:59 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,658
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
In most cases when is a car sitting at high idle for any period of time? at cam break in, you really won`t do it at any other time. The fuel mix can be dead correct and the timing on the money and they`ll still glow. with the car not in motion there is no airflow to carry the heat away. That`s why the fan was recommended. I`ve seen many a dyno run and they bring a fan in to create air flow to prevent the glowing headers. If in doubt the of the mixture being off, you can use the accelerator pump as a reference since you can work it without moving the throttle. give the acc. pump 4 or 5 good shots of fuel, if the glow starts to go away it`s too lean, if the glow intensifies, it`s too rich.
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
cam choice derek32303 Engine 9 03-04-2007 06:59 PM


All times are GMT -6. The time now is 07:47 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.