Bizarre High RPM Lean... Why? - Page 2 - 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
  #16 (permalink)  
Old 09-15-2006, 08:49 AM
Registered User
 
Join Date: Sep 2006
Location: nowhere
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Frisco
I don't know how you are checking/setting your timing but here is how you should be doing it for a non-computer controlled engine.
I know how to set the timing, ive been doing this for almost 30 years
Read the article I posted and learn something.

ps: the 1/4" stud which holds the air cleaner in place works just as well as a golf Tee and its always avail.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #17 (permalink)  
Old 09-15-2006, 08:56 AM
Frisco's Avatar
Glad To Be Here
 
Last photo:
Join Date: Nov 2002
Location: Canton, North Carolina
Age: 72
Posts: 2,244
Wiki Edits: 0

Thanks: 0
Thanked 8 Times in 8 Posts
Quote:
Originally Posted by BC 73Vette
I know how to set the timing, ive been doing this for almost 30 years
Read the article I posted and learn something.
Well, yes I have learned something from you. You have been setting the timing for almost 30 years and still don't know or understand that the vacuum advance is NOT hooked up when checking/setting the timing.
Reply With Quote Quick reply to this message
  #18 (permalink)  
Old 09-15-2006, 08:58 AM
Registered User
 
Join Date: Sep 2006
Location: nowhere
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Frisco
I am in total agreement with what you "copy & pasted".

However, this does not preclude the fact that you don't seem to understand that there is no vacuum advance occuring when going to WOT and therefore the Total timing is limited to the mechanical timing only at that time.
Did you miss this?
Quote:
Originally Posted by BC 73Vette
The loss of vacuum causes the advance... so, you are shy
The vacuum at idle or low revs keeps the plate from advancing..correct?
Reply With Quote Quick reply to this message
  #19 (permalink)  
Old 09-15-2006, 09:06 AM
Registered User
 
Join Date: Sep 2006
Location: nowhere
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Frisco
Well, yes I have learned something from you. You have been setting the timing for almost 30 years and still don't know or understand that the vacuum advance is NOT hooked up when checking/setting the timing.
Sorry if the arctile I posted is a bit confusing (we had a discussion about the terms used as far as total timing goes)...so call it "Maximum" timing...then it will make sense
My apoligies for not editing the post.
Reply With Quote Quick reply to this message
  #20 (permalink)  
Old 09-15-2006, 09:06 AM
Frisco's Avatar
Glad To Be Here
 
Last photo:
Join Date: Nov 2002
Location: Canton, North Carolina
Age: 72
Posts: 2,244
Wiki Edits: 0

Thanks: 0
Thanked 8 Times in 8 Posts
Quote:
Originally Posted by BC 73Vette


The vacuum at idle or low revs keeps the plate from advancing..correct?
If the vacuum advance is connected to a full vacuum source the vacuum advance will pull in additional degrees of timing at idle.

If the vacuum advance is connected to a ported source the vacuum advance will not pull in additional degrees of timing at idle.

The low revs is to prevent the mechanical advance from pulling in additional timing as well as to keep the carb in the "idle" circuit.
Reply With Quote Quick reply to this message
  #21 (permalink)  
Old 09-15-2006, 09:09 AM
1982 SS's Avatar
Flamethrower
 

Last journal entry: More Cooling fan pictures.
Last photo:
Join Date: Mar 2005
Location: Utah
Age: 26
Posts: 340
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I'm glad I missed that string of posts cuz it's a Drag car that happens to have license plates! It sees WOT where there in no vacuum and no vacuum advance. It has 38 total mechanical.

For those who think it's the carb, it has a K rod hanger CC rods (about .030 at the tip) 69 main jets and not sure right off on metering rod. I have richened the secondaries and it does not improve. I am still thinking it has to do with fuel getting to the carb rather than the metering. Yes I'm going lean but that doesn't mean the metering is wrong, I'm just out of fuel in the fuel bowl. I'm going to go out and take the regulator apart and see if there is somehting stopping it from regulating properly.

FWIW, before this problem, that car was very close to perfection mixture wise at WOT. This is a recent occurence. I richened it up to that combo listed above just to see if it would help, it didn't. Before it had a P hanger and CE rods (about .041).
Reply With Quote Quick reply to this message
  #22 (permalink)  
Old 09-15-2006, 09:10 AM
Registered User
 
Last photo:
Join Date: Nov 2004
Location: Cali
Posts: 994
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by BC 73Vette
The vacuum at idle or low revs keeps the plate from advancing..correct?
Not correct. The vacuum advance mechanism rotates the baseplate counterclockwise with increasing vacuum which increases the advance under high vacuum conditions. When the vacuum goes lower, the mechanism rotates the baseplate clockwise to retard the timing. The vacuum advance and the mechanical advance are two entirely separate mechanisms.
Reply With Quote Quick reply to this message
  #23 (permalink)  
Old 09-15-2006, 09:28 AM
Registered User
 
Join Date: Sep 2006
Location: nowhere
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by onovakind67
Not correct. The vacuum advance mechanism rotates the baseplate counterclockwise with increasing vacuum which increases the advance under high vacuum conditions. When the vacuum goes lower, the mechanism rotates the baseplate clockwise to retard the timing. The vacuum advance and the mechanical advance are two entirely separate mechanisms.
I do not run full vacuum for the advance, I use a ported source... so I am correct

Honestly, this forum looked loke a pretty cool place but now I'm not so sure....I posted an excerpt from paper written by one of the top GM tuners in the country and have been bashed because of a difference of a term "total timing and Max timing" and also criticized for a "copy and paste"
Please excuse me for my ignorance................
Reply With Quote Quick reply to this message
  #24 (permalink)  
Old 09-15-2006, 09:29 AM
Frisco's Avatar
Glad To Be Here
 
Last photo:
Join Date: Nov 2002
Location: Canton, North Carolina
Age: 72
Posts: 2,244
Wiki Edits: 0

Thanks: 0
Thanked 8 Times in 8 Posts
Quote:
Originally Posted by 1982 SS
The fuel is the factory hardline from the tank to the pump and up to the front where I have used 6 AN line to the the Aeromotive return type regulator, 6 AN to the carb and 6 AN all the way back to the tank.

I have no doubt the pump can keep up with it. It can suck my tank dry in about three minutes (17 gallons later...)
Just a thought. Is the factory hard line from the tank to the pump large enough to supply fuel at the rate your engine needs? Is the tank pickup staying in the fuel under hard acceleration?

If the 6 AN return line offers the path of least resistance, is it feasible that the fuel is returning to the tank rather than supplying the carb at the higher RPM?

Just some thoughts. Not sure of any correct answers.
Reply With Quote Quick reply to this message
  #25 (permalink)  
Old 09-15-2006, 09:50 AM
Registered User
 
Last photo:
Join Date: Nov 2004
Location: Cali
Posts: 994
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by BC 73Vette
I do not run full vacuum for the advance, I use a ported source... so I am correct

Honestly, this forum looked loke a pretty cool place but now I'm not so sure....I posted an excerpt from paper written by one of the top GM tuners in the country and have been bashed because of a difference of a term "total timing and Max timing" and also criticized for a "copy and paste"
Please excuse me for my ignorance................
A couple of things. If you are going to quote someone, give them credit with a link to the full text. Lars Grimsrud has a lot of stuff in print about engine tuning and is one of the most respected tuners around and wrote this:

http://www.teufert.net/distrib/vacadvspecs.doc

It makes no difference to the VA mechanism whether you use ported or manifold vacuum, it advances the timing when high vacuum is put to it and releases the advance when the vacuum goes lower. It does not do any of the following:
Quote:
Originally Posted by BC 73Vette
The loss of vacuum causes the advance... so, you are shy
Quote:
Originally Posted by BC 73Vette
Which is it?
The advance comes in as the vacuum drops
Quote:
Originally Posted by BC 73Vette
The vacuum at idle or low revs keeps the plate from advancing..correct?
Here's what you pasted from Lars:

When the load on the engine is light or moderate, the timing can be advanced to improve fuel economy and throttle response. Once the engine load increases, this "over-advance" condition must be eliminated to produce peak power and to eliminate the possibility of detonation ("engine knock"). A control unit that responds to engine vacuum performs this job remarkably well.

Light or moderate loads are synonymous with high vacuum and increased timing. When you increase the load on the engine, the vacuum is reduced and the vacuum advanced timing goes away.
Reply With Quote Quick reply to this message
  #26 (permalink)  
Old 09-15-2006, 10:03 AM
Registered User
 
Join Date: Sep 2006
Location: nowhere
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by onovakind67
A couple of things. If you are going to quote someone, give them credit with a link to the full text. Lars Grimsrud has a lot of stuff in print about engine tuning and is one of the most respected tuners around and wrote this:
Did you ever think that Lars does not want his papers all over the net?

Thats why I only posted an excerpt

Now I have some words for this board
It seemed like a nice place but was wrong as frisco has been breaking my balls for no rason at all

GO ***** FRISCO!
Guess this will get me banned, easier than asking to have my account removed
Too bad too, seemed like a nuce bunch of guys

Last edited by Jon; 09-15-2006 at 10:56 AM. Reason: Profanity. Please see guidelines at: http://www.hotrodders.com/help/board/guidelines.html
Reply With Quote Quick reply to this message
  #27 (permalink)  
Old 09-15-2006, 10:05 AM
1982 SS's Avatar
Flamethrower
 

Last journal entry: More Cooling fan pictures.
Last photo:
Join Date: Mar 2005
Location: Utah
Age: 26
Posts: 340
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The factory hardline has been enough for the first part of this season and all of last season. The new pump and regulator have been more than enough for at least half this season. The only other thought I have is that maybe the canister filter I have before the pump has a bubble in it and it shows up high RPM the most. I am going to bypass the filter and see what happens. While I have the line undone, I will blow some compressed air backwards into the tank in case there is some blockage there.

The regulator is fine I just had it apart and looks good. No junk anywhere in it.

Also, BC that was uncalled for. you know where the door is if you are going to be like that. Too bad it happened in this thread though.
Reply With Quote Quick reply to this message
  #28 (permalink)  
Old 09-15-2006, 11:54 AM
Registered User
 
Last photo:
Join Date: Nov 2004
Location: Cali
Posts: 994
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by BC 73Vette
Did you ever think that Lars does not want his papers all over the net?
Lars Grimsrud's papers are all over the internet whether we like it or not. His generous work is linked through several Corvette sites, like this one:

http://www.corvetteclub.org.uk/kb.php?mode=cat&cat=3

His email address is linked with each article so you can contact him directly.
Reply With Quote Quick reply to this message
  #29 (permalink)  
Old 09-15-2006, 12:27 PM
1982 SS's Avatar
Flamethrower
 

Last journal entry: More Cooling fan pictures.
Last photo:
Join Date: Mar 2005
Location: Utah
Age: 26
Posts: 340
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Latest development. I bypassed the filter I have before the pump. I used a piece of hardline and bent it to shape and connected my line from the tank right to the pump (before it went tank filter pump). It is no better than it was with the filter plumbed in. I even un-screwed the gas cap in the event that my tank was being sucked flat. No change. It starts to surge at 4600 and gets worse the higher it goes.

I am at a loss as to how to fix this.
Reply With Quote Quick reply to this message
  #30 (permalink)  
Old 09-15-2006, 01:42 PM
Registered User
 
Last photo:
Join Date: Nov 2004
Location: Cali
Posts: 994
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
You're investing a lot of energy and time in your fuel system with few results. Are you sure your secondaries are opening? Have you thought of checking the ignition system? Got good valve springs?
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
16 y/r son blew engine/step dad says his RPM way too high.... DHancock General Rodding Tech 31 11-24-2005 06:08 AM
high rpm mis john chaffin Engine 3 11-02-2004 03:08 PM
Emissions HELP cutsupreme Engine 33 12-27-2003 08:22 AM
Raising the Redline Hollywooding Engine 23 07-17-2003 10:19 AM
Single plane and duel plane manifold stonedchihuahua Engine 21 01-06-2003 11:56 PM


All times are GMT -6. The time now is 10:26 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.