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 > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-30-2004, 12:23 AM   #1
TIMSPEED
 
TIMSPEED's Avatar
 
Join Date: Jan 2003
Location: Modesto, CA
Posts: 1,321
NO WONDER my truck has been so slow lately! Only 28º timing!!

So I went to check my total mechanical advance tonight...come to find out, it was pegging out at 3000rpm, with 28º advance!! No WONDER I've been getting popping through the exhaust when I let off the gas! So, I advanced it to get 36º advance at 3000rpm. Somewhere around 12º advance at idle. I'm about to go put some gas in it, and tune the vacuum advance canister. HOPEFULLY I'll be able to race my friends 78 C10, and THIS time pull away from him!
__________________
I have a few cars...
See Them Here
TIMSPEED is offline   Reply With Quote
Old 07-30-2004, 12:24 AM   #2
79Silv4x4
Workaholic
 
79Silv4x4's Avatar
 
Join Date: Oct 2002
Location: Katy, TX
Posts: 1,589
79Silv4x4 is offline   Reply With Quote
Old 07-30-2004, 02:19 AM   #3
Russell
Professional Grade
 
Russell's Avatar
 
Join Date: May 2003
Location: Fort McMurray, Alberta
Posts: 7,915
hehe, I have no clue where my timing is at... Might have something to do with my bogging, but my harmonic balancer slipped, so I can't check it...
__________________
1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)
Russell is offline   Reply With Quote
Old 07-30-2004, 02:40 AM   #4
plumbcut
california fill
 
Join Date: Apr 2004
Location: Sunny So-Cal
Posts: 694
why dont people get it- advance it until it pings then retard it slightly. end of story, no lights needed

pc
plumbcut is offline   Reply With Quote
Old 07-30-2004, 03:11 AM   #5
Russell
Professional Grade
 
Russell's Avatar
 
Join Date: May 2003
Location: Fort McMurray, Alberta
Posts: 7,915
I did, but I also have some serious carb issues, so its kinda tough to get stuff working right

You can time it that way, like I have been, but you'll never get your optimum gas milage that way... I'd rather take an extra 10 and know for sure where my timing is
__________________
1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)
Russell is offline   Reply With Quote
Old 07-30-2004, 04:34 AM   #6
Tom
driving is in my blood
 
Tom's Avatar
 
Join Date: Dec 1999
Location: Mesa AZ
Posts: 5,748
Quote:
Originally Posted by plumbcut
why dont people get it- advance it until it pings then retard it slightly. end of story, no lights needed

pc

And say goodbye to about 10hp in a setup like mine. No thanks
__________________
-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle.
-98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes.
-02 Suburban 4x4: leveled front
-CBR600F4i, CBR600RR, CBR1000RR, and standup skis
DISCLAIMER: I cant spell for the life of me.
Tom is offline   Reply With Quote
Old 07-30-2004, 11:11 AM   #7
Grim Reaper
Registered User
 
Join Date: Jul 2001
Location: Atlanta GA
Posts: 1,704
Quote:
Originally Posted by plumbcut
why dont people get it- advance it until it pings then retard it slightly. end of story, no lights needed

pc
Good way to burn holes in pistons. Not all detonation is loud enough to hear.
__________________
Grim-Reaper
70 Pontiac LeMans Sport Convertible, worlds longest resto in progress
Looking for 71-72 2wd Blazer or Jimmy Project
Grim Reaper is offline   Reply With Quote
Old 07-30-2004, 02:53 PM   #8
plumbcut
california fill
 
Join Date: Apr 2004
Location: Sunny So-Cal
Posts: 694
boloney. If your truck is running that lean you have other issues.. As a general rule of thumb- if youre working with a streetable driver, (not talking about hot rods or anything exotic) time it until it pings then back it off a bit. This will yield the BEST performance, mileage, driveability, etc... One thing- if your starter has trouble turning over the engine when its hot, and its not pinging, you might want to back it off a tad more... other than that, let 'er rip.

pc
plumbcut is offline   Reply With Quote
Old 07-30-2004, 02:55 PM   #9
plumbcut
california fill
 
Join Date: Apr 2004
Location: Sunny So-Cal
Posts: 694
The only thing is--- it will screw you on the tailpipe smog test.. if they dont catch it in visual, advanced timing creates a lot of HC at idle, and you will have to back it down to 10 or so degrees for the test...

pc
plumbcut is offline   Reply With Quote
Old 07-30-2004, 09:12 PM   #10
swervin ervin
You get what you pay for
 
swervin ervin's Avatar
 
Join Date: Dec 1999
Location: Cherryville, NC
Posts: 4,798
This is or rather was, called power timing it. This was done by a lot of people back in the day. I've done it myself. But, it's not the best way of setting the timing by no means. It has long been known for best power, a small block Chevy likes between 32 and 36 degrees total. But, this isn't the total picture. You need to find the sweet spot where it is all in. A stock HEI usually takes 4500 rpm before you ever see the total centrifugal advance come in. This is bad for power. I have found through a lot of testing, my truck works best with 35 degrees total, starts at around 1000 rpm and is full in at around 3000 rpm. My intial is 13 with 22 in the distributor. Believe you me, I've tried just about every timing chart you can think of. The quicker you can start the mechanical advance, the better. The quicker it is full in, the better. Of course you have to accomplish all this without any pinging. I mean none whatsoever. Pinging is a very bad thing.

The above is what works for me, my truck, and my engine/drivetrain. This may not work for anyone else. You have to find your on combination, through testing. Running around not knowing what you have is foolish since it is so easy to find out by using a light.
__________________
Mike

1985 Chevy C-10
swervin ervin is offline   Reply With Quote
Old 07-31-2004, 10:56 AM   #11
81shavedtrk
Registered User
 
Join Date: Jul 2004
Location: El Dorado, KS
Posts: 94
Here is one for ya. The only time I ran my truck at the track all motor was with a safe 28 degrees (should be 40) and ran a 13.8 @99 spinning with a 2.2 60'. On nitrous I ran it at 20 degrees but will be moving it up from there to get the added bit I need. Shooting for 11's on the 15 of August.
81shavedtrk is offline   Reply With Quote
Old 08-01-2004, 01:27 AM   #12
Grim Reaper
Registered User
 
Join Date: Jul 2001
Location: Atlanta GA
Posts: 1,704
You try this method of tuning I can gaurantee WORSE performance on a fuel injected truck. You attemt this on a ESC truck I can guarantee worse as well. Your dealing with knock sensors and the computer will start dumping the timing.

THis 70's methode of tuning is not any good and does not give any conciderations for fuel being off or changing grade.

Good luck if you want to try it but I stand by my statements and nothing good will come of this tuning method on a computer controled car and you risk at the very least power loss.

On a stock engine with stock profile cam I would stay close to factory recomended timing if you don't have the equipment to see what your total advance is.
__________________
Grim-Reaper
70 Pontiac LeMans Sport Convertible, worlds longest resto in progress
Looking for 71-72 2wd Blazer or Jimmy Project
Grim Reaper 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 08:56 PM.


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