The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Engine & Drivetrain

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 09-07-2022, 12:25 AM   #26
evan
Registered User
 
evan's Avatar
 
Join Date: Jul 2005
Location: SK, Canada
Posts: 488
Re: Which adjustment on Edelbrock chart for rich at WOT?

Quote:
Originally Posted by geezer#99 View Post
You can’t count the vac advance until it starts, so you’re only starting with 18 initial.
I had a rowdy 350 once. More cam than yours. 10 to 1 compression, trick flow heads.
I ran 22 initial, 12 from mechanical plus a limited 10 degrees from vac pot.
Used a limiter like this one in the link.
I can tell from the way yours starts that you’re close with timing.
Sounds good.


https://www.summitracing.com/parts/m...yABEgKeI_D_BwE
Thanks. Tomorrow night I'll re-adjust the idle mixture screws and take it for a test drive.

I'll keep that part in mind too. Cheers.
__________________
Evan B.
evan is offline   Reply With Quote
Old 09-07-2022, 09:42 AM   #27
burnin oil
Registered User
 
Join Date: Jan 2013
Location: Eastern TN
Posts: 1,919
Re: Which adjustment on Edelbrock chart for rich at WOT?

Listen real close for pinging under part throttle and WOT. 37 degrees may give you a little headaches if you get a load of crap gas.
burnin oil is offline   Reply With Quote
Old 09-07-2022, 11:39 AM   #28
Dead Parrot
Registered User
 
Join Date: Aug 2012
Location: Oklahoma City, OK
Posts: 2,461
Re: Which adjustment on Edelbrock chart for rich at WOT?

After your test drive, test for ease of hot start. If you have a bit too much initial, it will start easy cold and be hard to start hot. If it starts easy both hot and cold, you can try a couple more degrees initial. Sometimes it is OK to be a couple of degrees short of max initial so you are sure it will start hot on a hot summer day when you are hauling a load or pulling a trailer or both.

Sounds good in the video.

My stock 350 only likes about 13 initial per the factory marks. I have not verified the 0 mark matches true TDC. But a hot day here is 100+F and I am about 1000ft above sea level. With the vacuum pot hooked up, it goes well off the top of the timing mark tab.
Dead Parrot is offline   Reply With Quote
Old 09-07-2022, 04:06 PM   #29
AcampoDave
Registered User
 
AcampoDave's Avatar
 
Join Date: Feb 2013
Location: central California
Posts: 2,723
Re: Which adjustment on Edelbrock chart for rich at WOT?

How much did that timing increase lean it out? I'm curious because after it finally cools off around here, (116 yesterday... tallk about a hot start....yikes) I'm going to get an o2 sensor and do what you're doing. I am appreciative of all the info in this thread. This is a good one.

Last edited by AcampoDave; 09-08-2022 at 05:43 PM. Reason: Typo
AcampoDave is offline   Reply With Quote
Old 09-07-2022, 11:04 PM   #30
evan
Registered User
 
evan's Avatar
 
Join Date: Jul 2005
Location: SK, Canada
Posts: 488
Re: Which adjustment on Edelbrock chart for rich at WOT?

When I got home tonight I warmed it up to operating temp and adjusted the idle. I heard chattering so checked the metering rods. They were chattering up and down. I swapped to lighter springs until they would stay down at idle. That took the lightest springs.

Have some of the spring pairs you’ve seen in Edelbrock calibration kits been different lengths? That was the case for mine. One side would stay down with the second to lightest spring but the side with the longer spring was still bouncing so I went down to the lightest pair.

Took it for a test drive. No pinging as far as I could tell. Fired right up on hot starts.

Here are the new AFR’s.
Idle: mid 12’s
Normal acceleration & cruising: high 14’s to low 15’s
WOT acceleration: low 12’s

Here’s the one I don’t understand - during the WOT shift from 1st to 2nd or 2nd to 3rd and also when I let off the gas from WOT: high 9’s.
Any ideas???
__________________
Evan B.
evan is offline   Reply With Quote
Old 09-08-2022, 08:56 AM   #31
Dead Parrot
Registered User
 
Join Date: Aug 2012
Location: Oklahoma City, OK
Posts: 2,461
Re: Which adjustment on Edelbrock chart for rich at WOT?

Check your vacuum at idle. Your choppy idle vacuum might be in the range the springs normally vary things. If possible, get a long hose and check your vacuum during various aspects of a test drive. Those springs play a major role in adjusting mixture from WOT through cruise and knowing your vacuum through that range would help in selecting the proper springs.
Dead Parrot is offline   Reply With Quote
Old 09-08-2022, 09:13 AM   #32
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Which adjustment on Edelbrock chart for rich at WOT?

Your high 9’s might be the secondary air door reaction time is slow and carb stays rich momentarily.

What transmission you running?
geezer#99 is offline   Reply With Quote
Old 09-08-2022, 09:28 AM   #33
evan
Registered User
 
evan's Avatar
 
Join Date: Jul 2005
Location: SK, Canada
Posts: 488
Re: Which adjustment on Edelbrock chart for rich at WOT?

I’ll get some longer hose to run the vacuum gauge into the cab.

It’s the stock th350.
__________________
Evan B.
evan is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump


All times are GMT -4. The time now is 04:36 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com