Timing/Dieseling problems on my sbc - LS1TECH

Go Back   LS1TECH > SBC-BBC-LT1-LT4 PERFORMANCE > Small Block & Big Block Chevy Specific
Sign in using an external account
Register Forgot Password?
Search


Small Block & Big Block Chevy Specific Mouse & Rat Motor Discussion & Conversions

Timing/Dieseling problems on my sbc

Reply
 
Thread Tools Search this Thread
Old 08-26-2009, 01:46 PM   #1
On The Tree
 
69Camaro...'s Avatar
 
Trader Rating: 8
Join Date: Oct 2008
Posts: 189
Default Timing/Dieseling problems on my sbc

To start i have a small block chevy 355 with vortec heads-around 440HP and torque. The motor was dynoed and given a set of recommendations. I'm having tons of problems as far as throttle response, idling, and just the feeling of not having the power.
Everything is brand new- Holley 770 Street avenger with stock jets, HEI dizzy with the 65000 volt coil ontop. Brand new spark plugs(champion RS12YC), new mallory 8mm plugs.

The motor calls for 32 degrees of total timing. The idle is set at an average of 12-14 degrees. The timing is completely set, but when i turn off the ignition the motor will diesel and keep turning over after i turn the key off. Which in turn is a sign of in proper timing. The idle mixture screws were adjusted with vacuum gauge. There are lighter springs in the dizzy to make the advance kick in quicker.

So my question is, why is it still dieseling and lacking all this power. I should be able to roast my tires and feel like i have 440hp. I have no low end torque and when i snap the throttle while driving there will be a slight delay. I run 93 octane gas and it passes through 2 fuel filters. Are my jets too large and need to be smaller? And this motor has less than a 1000 miles on it. Its brand new
Here are pictures of my #1 spark plug that i just replaced 2 days ago.
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.

Here is the number 2 plug that has been in the motor for about a month

Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
__________________
Muscle Car T-Shirts and Hats for Sale-!!! CHEAPP
PM for details and pricing.
69Camaro... is offline   Reply With Quote
Old 08-26-2009, 01:57 PM   #2
TECH Addict
 
Trader Rating: 0
Join Date: Jun 2009
Location: Tulsa, OK
Posts: 2,016
Default

"The timing is completely set, but when i turn off the ignition the motor will diesel and keep turning over after i turn the key off. Which in turn is a sign of in proper timing."

Don't know where you got that idea. Dieseling is normally a symptom of too much initial advance. Also, by looking at the plugs you're running rich as hell.
fleetmgr is offline   Reply With Quote
Old 08-26-2009, 02:03 PM   #3
On The Tree
 
69Camaro...'s Avatar
 
Trader Rating: 8
Join Date: Oct 2008
Posts: 189
Default

i read that dieseling is the result of the timing being off. But i have it set dead on 32 degrees. So i need to back the timing off?
__________________
Muscle Car T-Shirts and Hats for Sale-!!! CHEAPP
PM for details and pricing.
69Camaro... is offline   Reply With Quote
Old 08-26-2009, 02:08 PM   #4
Launching!
 
Trader Rating: 0
Join Date: Oct 2006
Posts: 255
Default

You mentioned the motor was dynoed...did it run okay on the dyno? If it did, we can narrow your problem down to what changed between now and then. As for the plugs, the #1 porcelain looks white and the strap isn't discolored. The mixture is probably close in that cylinder. The soot on the #2 threads could just be from the plugs not being tight enough or it could be rich. Its hard to tell from the photos. The better indicator of lean/rich is the part of the porcelain buried down deep in the plug. It is hard to see without a good light...or cutting the threaded portion of the plug away. You want a tan-colored ring down near the base of the porcelain.
pancherj is offline   Reply With Quote
Old 08-26-2009, 02:11 PM   #5
Teching In
 
Hippi's Avatar
 
Trader Rating: 3
Join Date: Nov 2007
Location: IL
Posts: 37
Default

yeah it looks like your running of the main metering circuit at an idle=your throttle blades are open too far and your bypassing the idle circuit.Now this does have a direct relation to timing and your current dizzy setup,I would put one medium spring and one light to get your total advance to come in at 3400-3500,go back and set you initial at 18*,now here is how they are all tied in the more you advance you initial timing the higher the idle speed therefore letting you turn back your idle speed screw(not the mixture screws)and closing throttle blades enough to start using the idle circuit.try this and tell us what happens
Hippi is offline   Reply With Quote
Old 08-26-2009, 02:12 PM   #6
TECH Apprentice
 
k5383's Avatar
 
Trader Rating: 10
Join Date: Apr 2009
Location: Oviedo Fl
Posts: 320
Default

I would start with retarding the timing.

But also making sure that you are not off a tooth, I'm going to assume your aware of the old school bring to TDC on #1 and making sure the rotor and #1 plug wire on cap are aligned procedure.

The hesitation could aslo be a carb issue, mainly the accelerator pump being adjusted wrong.

What size is your cam? Compression ratio? Do you have any clue as to the size of your jets you have now?

I'm running a 67(I believe) jet in my 625 Demon, on my 383, with aluminum heads and a .500 lift cam...

Those plugs do say your running pretty rich, that 770 may be too much.
__________________
84 K5 LQ9/4L80

Gerald and Charlies Auto Machine..
LLC Sanford FL
k5383 is offline   Reply With Quote
Old 08-26-2009, 02:13 PM   #7
On The Tree
 
69Camaro...'s Avatar
 
Trader Rating: 8
Join Date: Oct 2008
Posts: 189
Default

Its a crate motor built by yearone, they send a spec sheet and dyno results. So im hoping it ran good on the dyno lol. The #1 plug was changed 2 days ago and #2 has been in there for a month. At certain times when idling it smells like fuel pretty bad. So i might need to de jet the carb., buy all new plugs and go from there. But still want to see if i can solve the problem before going to that next step. Thanks for all the help guys-If need be, i will try and get a better picture of that #1 plug
__________________
Muscle Car T-Shirts and Hats for Sale-!!! CHEAPP
PM for details and pricing.
69Camaro... is offline   Reply With Quote
Old 08-26-2009, 02:14 PM   #8
Launching!
 
Trader Rating: 0
Join Date: Oct 2006
Posts: 255
Default

Did a quick search. Here was another guy having your same problem with an Avenger carb...

http://www.camaros.net/forums/showthread.php?t=93870
pancherj is offline   Reply With Quote
Old 08-26-2009, 02:17 PM   #9
On The Tree
 
69Camaro...'s Avatar
 
Trader Rating: 8
Join Date: Oct 2008
Posts: 189
Default

Quote:
Originally Posted by k5383 View Post
I would start with retarding the timing.

But also making sure that you are not off a tooth, I'm going to assume your aware of the old school bring to TDC on #1 and making sure the rotor and #1 plug wire on cap are aligned procedure.

The hesitation could aslo be a carb issue, mainly the accelerator pump being adjusted wrong.

What size is your cam? Compression ratio? Do you have any clue as to the size of your jets you have now?

I'm running a 67(I believe) jet in my 625 Demon, on my 383, with aluminum heads and a .500 lift cam...

Those plugs do say your running pretty rich, that 770 may be too much.

Yeah i did it the old fashioned way. Set to TDC and drop dizzy in untill its aligned with #1.
The cam is a 520 lift, 218/228 duration
9:5:1 compression
Jet size i have no idea yet. I will need to pull the bowls and look
__________________
Muscle Car T-Shirts and Hats for Sale-!!! CHEAPP
PM for details and pricing.
69Camaro... is offline   Reply With Quote
Old 08-26-2009, 02:23 PM   #10
On The Tree
 
69Camaro...'s Avatar
 
Trader Rating: 8
Join Date: Oct 2008
Posts: 189
Default

Quote:
Originally Posted by pancherj View Post
Did a quick search. Here was another guy having your same problem with an Avenger carb...

http://www.camaros.net/forums/showthread.php?t=93870
My RPMS do drop quite a bit from park to drive, but i like the idle at around 800when in drive. So it is back to the timing issue thats causing it. But i have many other problems aswell
__________________
Muscle Car T-Shirts and Hats for Sale-!!! CHEAPP
PM for details and pricing.
69Camaro... is offline   Reply With Quote
Old 08-26-2009, 02:49 PM   #11
Launching!
 
Trader Rating: 0
Join Date: Oct 2006
Posts: 255
Default

It seems that too much vacuum advance (springs too light) and the throttle blade issue were the keys (primaries open too far to maintain a decent idle) for that guy.

You could always contact year one for some help...
pancherj is offline   Reply With Quote
Old 08-26-2009, 04:14 PM   #12
In-Zane Moderator
 
ZONES89RS's Avatar
 
Trader Rating: 23
Join Date: Jan 2007
Location: Conroe, Texas
Posts: 10,542
Default

If you had a REAL cam, that carb would work better, you have too much carb for one, meaning as much as you need to lean it out might not completely solve your problem, you need about a 650. That cam is tiny, not much bigger than some stockers.

See what jets you have and if you have a jet kit, go down 2 jettings at a time and see if it helps. From there you should also start out by screwing the idle mixture screws in all the way and then pull out by 1 and a half to start. As mentioned, you need to make sure timing is in effect with the throttle blades being as close to shut as possible, that tame cam should be able to idle about 5-600 RPM no problem. You might need to lower the squirter size as well.

Like i said, it is allot of carb for a 350 with such a mild cam, you need to really detune that thing to get it right.
__________________

BUILT NOT BOUGHT
80 Coupe 6.0 TH400
86 TA 5.3, 4L80
92 S10 ECSB 4.8 T56
Quote:
Originally Posted by -Ross- View Post
Haw mut horzpowa sbc or lsx eenjun mayk b4 eet need tarbo liked da 2jz?
ZONES89RS is offline   Reply With Quote
Old 08-26-2009, 09:12 PM   #13
On The Tree
 
69Camaro...'s Avatar
 
Trader Rating: 8
Join Date: Oct 2008
Posts: 189
Default

One day ill beef this motor up

So i need to possibly make sure the timing is correct. Turn idle screws 1 1/2 turn, de jet the carb and throw some heavier springs on the initial side? What do you guys mean the throttle blades as close as they can be to being shut? So your saying look down the carb while its at full advance and see how far open the butterflies are?
__________________
Muscle Car T-Shirts and Hats for Sale-!!! CHEAPP
PM for details and pricing.
69Camaro... is offline   Reply With Quote
Old 08-26-2009, 09:17 PM   #14
On The Tree
 
69Camaro...'s Avatar
 
Trader Rating: 8
Join Date: Oct 2008
Posts: 189
Default

okay, my jet sizes are primary-72 and secondary-75
__________________
Muscle Car T-Shirts and Hats for Sale-!!! CHEAPP
PM for details and pricing.
69Camaro... is offline   Reply With Quote
Old 08-27-2009, 12:44 AM   #15
Teching In
 
Hippi's Avatar
 
Trader Rating: 3
Join Date: Nov 2007
Location: IL
Posts: 37
Default

ok here ya go the throttle blades at an idle are what we are talking about so here are some pics to help you out
pic#1 throttle blades completely shut idle speed screw backed all the way out the car will not run like this.
pic#2 blades open part throttle notice the long skinny slot on the venturi wall? that is you idle transfer slot the next pics will deal with this
pic#3 are the throttle blades at the preferred setting at an idle notice the the slot is showing about the same length as it is in width(it looks square)now do you have to pull the carb off the set this? no this is just showing you where the carb should have been baselined before it was installed and adjusted from there.Now you can have too much of this slot showing and it will bypass the idle circuit on the carb and run off the primary metering circuit this is not a good thing it will run way rich and have slugish response from the carb even stumbling and falling on it's face when you wack the throttle under load. there is a direct relationship between initial timing and how your idle circuit works on your carb.now the one thing you haven't told us is do you have a vacuum advance on your dizzy if so explain how you go about setting your initial timing.edit i just realized you carb choice and as stated above it is way too big a 650 would of been a much better choice,so year one sold this crate to you carb to pan or was it just a long block?
Attached Thumbnails
Timing/Dieseling problems on my sbc-08-27-09_0034.jpg   Timing/Dieseling problems on my sbc-08-27-09_0035.jpg   Timing/Dieseling problems on my sbc-08-27-09_0036.jpg   Timing/Dieseling problems on my sbc-08-27-09_0037.jpg  

Last edited by Hippi; 08-27-2009 at 01:10 AM..
Hippi is offline   Reply With Quote
Old 08-27-2009, 01:39 AM   #16
On The Tree
 
69Camaro...'s Avatar
 
Trader Rating: 8
Join Date: Oct 2008
Posts: 189
Default

nice pics, that explains a lot. I can easily take my carb off if i need too.

Long block. The only thing i needed to add was carb, fuel pump, front accessories.

HEI dizzy was vacuum adv., i have the old fashioned timing light, so this is being done with a timing tape.
__________________
Muscle Car T-Shirts and Hats for Sale-!!! CHEAPP
PM for details and pricing.
69Camaro... is offline   Reply With Quote
Old 08-27-2009, 01:41 AM   #17
On The Tree
 
69Camaro...'s Avatar
 
Trader Rating: 8
Join Date: Oct 2008
Posts: 189
Default

But they recommend a holley 750 double pumper? I have the same motor with a basic holley 750, not a street avenger, and it runs like a damn beast!! Different carb which means different settings, but i still would know when this motor is running good because it moves a 4000 pound camaro verrrrry easily with 18inch wide wheels.
__________________
Muscle Car T-Shirts and Hats for Sale-!!! CHEAPP
PM for details and pricing.
69Camaro... is offline   Reply With Quote
Old 08-27-2009, 01:49 AM   #18
Teching In
 
Hippi's Avatar
 
Trader Rating: 3
Join Date: Nov 2007
Location: IL
Posts: 37
Default

so your just running the mechanical advance or both?if your running the vac. you are unplugging the vac advance to set your initial?if so what does your timing jump to when you plug it back in?
Hippi is offline   Reply With Quote
Old 08-27-2009, 01:57 AM   #19
On The Tree
 
69Camaro...'s Avatar
 
Trader Rating: 8
Join Date: Oct 2008
Posts: 189
Default

nono, when setting the initial its with it hooked up, then when setting total its plugged.
But i havent set the initial yet completely because to be honest i didn't know where to start and set it at. So the total timing is set
__________________
Muscle Car T-Shirts and Hats for Sale-!!! CHEAPP
PM for details and pricing.
69Camaro... is offline   Reply With Quote
Old 08-27-2009, 02:19 AM   #20
Teching In
 
Hippi's Avatar
 
Trader Rating: 3
Join Date: Nov 2007
Location: IL
Posts: 37
Default

just making sure I know alot of guys that set it backwards.ah so there is part of you issue set your initial first then the advance as far as sbc's go i like 18* at an idle and nothing over 36 total,now is your vac advance adjustable I.E small set screw in the module itself to control the amount it advances?
Hippi is offline   Reply With Quote
Old 08-27-2009, 02:19 AM
LS1Tech
Pontiac Firebird




Paid Advertisement
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
'71 Chevelle LS3 w/ Vararam QUEST4-10S Conversions & Hybrids 9 11-01-2013 09:59 AM
6LE & McNord @ Super Chevy show in PHX McNord Appearance & Detailing 94 05-03-2012 01:00 AM
LED third brake light on a 1999 trans am.LOTS OF PICS!! camaro98man Appearance & Detailing 50 10-14-2011 01:29 AM
Front Breather setup McNord Appearance & Detailing 61 03-05-2011 10:44 PM
identify injectors max1 Fueling & Injection 2 06-22-2009 04:04 AM


Tags
backfire, block, chevrolet, chevy, dieseling, diesels, initial, lt1, rich, sbc, set, setting, shut, small, timing, turning


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are On
Refbacks are Off



Join Ls1Tech

All times are GMT -5. The time now is 12:22 PM.


Powered by vBulletin® Version 3.8.7 AC1
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Advertising - Terms of Service - Privacy Statement - Terms of Service - JOBS
Emails & Contact Details