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 1960 - 1966 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 06-17-2013, 08:23 PM   #1
XtechX
Registered User
 
XtechX's Avatar
 
Join Date: Jan 2011
Location: Edmore, Michigan
Posts: 300
Timing and carb issues??

I have a 230 I6 in my 65. It has a brand new carburetor on it as well as new points, condenser, plugs, plug wires, fuel filter and fuel pump. It spits and sputters,coughs out both ends especially on take off. I know it's not a v8 but still seems under powered. I checked the dwell and it appears to be at about 34 "if I did it right". I put a timing light on it but Im not for sure where it suppose to be. I read that it should be 4* BTDC, I assume that the the zero mark on the front pulley should show up on the right side of the zero with the light on it??? Does each tick mark represent 2*? The timing mark tag is so short, should it ever be st outside the tab marks? Or should it ever be set to the left side of the 0 mark on the tab? A pic would help me figure this out with an approximate setting marked on it. I'm sorry this probably sounds like a dumb inquiry but Im more of a paint and body type of guy.
__________________
Opportunity usually comes disguised....As hard work!!!
XtechX is offline   Reply With Quote
Old 06-17-2013, 10:14 PM   #2
Sharps40
Account Suspended
 
Join Date: Oct 2012
Location: here
Posts: 2,408
Re: Timing and carb issues??

34 degrees is in range for the 230. Motors says set the dwell, vacuum advance off, at 31 to 34 degrees. You usually set it low so that it runs up in dwell as the rubbing block wears down.

Timeing...0 on the tab is TDC for #1 piston when it lines up with the groove on the balancer.

Every hash mark on the tab is 2 degrees per the motors manual. In order then...

1 Set plug gap at 30 thousands or so. Start the engine and fully warm it up. Loosen the distributer clamp enough to turn the dizzy later but not so much it turns by itself, disconnect and plug the vacuum advance so you don't have a vacuum leak to the carb warm the engine fully. Watch out for the fan blades.

2 Turn the dizzy on the fully warmed up motor (30 minutes at idle to warm it up properly) untill the timeing light shows the balancer groove lined up at 2 hash marks (4 degrees) above the 0 mark on the tab. You can probably go to 6 degrees (3 hash marks on the tab above the 0 mark with a good engine and dizzy.)

3 Lock down the dizzy and recheck the advance at idle,,,it should be at 4 to 6 advanced (2 to 3 hash marks above 0). Sometimes it moves a bit when you lock it down and then have to readjust.

4 Reinstall the vacuum advance.

5 Check fuel mix on the carb...set for fastest smoothest idle RPM or highest manifold vacuum, which ever method you prefer.

6 Last, readjust idle speed on the carb...I usually like 500 to 600 RPM on a good engine.

Go drive...should be better.

Last edited by Sharps40; 06-17-2013 at 10:31 PM.
Sharps40 is offline   Reply With Quote
Old 06-17-2013, 10:21 PM   #3
63burban4x4
Registered User
 
63burban4x4's Avatar
 
Join Date: Mar 2012
Location: US
Posts: 446
Re: Timing and carb issues??

You didn't mention changing the distributor cap.....if it's bad it will misfire & crossfire, backfire. The spark can jump around inside, acting like the timing is off. Look for "carbon tracks" inside the cap.
63burban4x4 is offline   Reply With Quote
Old 06-17-2013, 10:56 PM   #4
XtechX
Registered User
 
XtechX's Avatar
 
Join Date: Jan 2011
Location: Edmore, Michigan
Posts: 300
Re: Timing and carb issues??

I just want to be sure on this....

\\\\\\0//x//// The X would represent 6* btdc at idle with vacuum disconnected? When its revved up where should the crank pulley mark move to with the vacuum advanced hooked up?
I did put a new cap and rotor on as well. Thanks for your help
__________________
Opportunity usually comes disguised....As hard work!!!
XtechX is offline   Reply With Quote
Old 06-18-2013, 12:04 AM   #5
dracko
Registered User
 
dracko's Avatar
 
Join Date: Jan 2010
Location: Regina, SK
Posts: 804
Re: Timing and carb issues??

My truck was acting very similar (also a 230) and it turned out the harmonic balancer rubber cracked and the outer ring spun, so the timing marks were way off. Easy to check by getting the #1 piston at TDC on its compression stroke and check where your timing marks are at and may as well also pop the cap off the dizzy and check where your rotor is pointing. Strobe timing is great if your marks are legit, if not, go by sound and vacuum....higher the better.
Posted via Mobile Device
dracko is offline   Reply With Quote
Old 06-18-2013, 06:03 AM   #6
Sharps40
Account Suspended
 
Join Date: Oct 2012
Location: here
Posts: 2,408
Re: Timing and carb issues??

This is what the balancer and tab look like when idleing at or below 600 rpm and you are trying to rotate the dizzy to 4 Degrees Advance static timeing. In this picture the mark on the rotating harmonic blanancer lines up between the 4 and 6 degrees advance marks - i.e. its at 5 degrees advance and you still need to turn the dizzy a touch more to get the harmonic balancer mark lined up with 4 degrees on the tab.



When reved up the crank pully mark will move up...advance, 4, to 6 to 8 to 10 to 12 all the way to about 35 degrees advance at 3000 RPM. This is the mechanical advance kicking in. Vacuum advance only works at specific times..i.e. in the driving range between off idle (750+ish rpm) and when the ported vacuum signal is strong enough to pull in advance.

Last edited by Sharps40; 06-18-2013 at 06:08 AM.
Sharps40 is offline   Reply With Quote
Old 06-18-2013, 01:15 PM   #7
gofastnut
Registered User
 
gofastnut's Avatar
 
Join Date: Feb 2011
Location: Williams, CA
Posts: 760
Re: Timing and carb issues??

I figured you'd have some 2 cents to help this guy out Sharps, You Da Man!

BTW XtechX,
Don't do like I did and try to set timing with engine @ 850rpm, mechanical advance is already starting to kick in!
__________________
Jeff
96 C3500 Crew Cab Long bed (Waiting on Cool Name)
64 C-10 shortie stepside, "Ole Brownie"
C-10 Club
My achingly slow build: http://67-72chevytrucks.com/vboard/s...d.php?t=508345
gofastnut is offline   Reply With Quote
Old 06-18-2013, 03:10 PM   #8
XtechX
Registered User
 
XtechX's Avatar
 
Join Date: Jan 2011
Location: Edmore, Michigan
Posts: 300
Re: Timing and carb issues??

Thanks Sharps!
__________________
Opportunity usually comes disguised....As hard work!!!
XtechX is offline   Reply With Quote
Old 06-18-2013, 04:16 PM   #9
Sharps40
Account Suspended
 
Join Date: Oct 2012
Location: here
Posts: 2,408
Re: Timing and carb issues??

Take it slo...and in order.

Warm

Dwell

Timeing

Mixture

Idle Speed....

Should come out pretty good if there is any compression left in the motor at all. If that don't smooth it up, time to look at spark strength and the quality of the carb and for vacuum leaks.
Sharps40 is offline   Reply With Quote
Old 06-18-2013, 04:20 PM   #10
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,521
Re: Timing and carb issues??

You forgot check dwell again.
Changing timing can affect dwell.
geezer#99 is offline   Reply With Quote
Old 06-18-2013, 04:21 PM   #11
Sharps40
Account Suspended
 
Join Date: Oct 2012
Location: here
Posts: 2,408
Re: Timing and carb issues??

Quote:
Originally Posted by gofastnut View Post
I figured you'd have some 2 cents to help this guy out Sharps, You Da Man!

BTW XtechX,
Don't do like I did and try to set timing with engine @ 850rpm, mechanical advance is already starting to kick in!
Correct. Even if it idles like a damn single cylinder hit or miss engine at 400 rpm, all that you need is that it continues to run. If the rpms are over about 650 you really need to slow it down to set the timeing....Idle rpm is set first by pulling in the right lean best idle mixture and last by adjusting the idle speed screw...but ya gotta do everything else first.
Sharps40 is offline   Reply With Quote
Old 06-18-2013, 04:25 PM   #12
Sharps40
Account Suspended
 
Join Date: Oct 2012
Location: here
Posts: 2,408
Re: Timing and carb issues??

Quote:
Originally Posted by geezer#99 View Post
You forgot check dwell again.
Changing timing can affect dwell.
The relationship is one way. Changeing Dwell changes the timeing and shows as a change in the position of the balancer mark with relationship to the tab.

The reverse is not true...once the dwell (points gap is set) rotating the distributer to advance or retard the timeing will not change the dwell. The proof is in installation of a dwell meter to watch a correctly set dwell remain spot on as you rotate the dizzy to advance or retard the static timing shown by the strobe light at the balancer/tab.

This one way relationship between dwell and static timeing is why you always set dwell (points gap) first and rotate the dizzy to change timing after... The only way to change the dwell is to increase or decrease the points gap with a screwdriver (or from wear out of the rubbing block on the points). Rotating the dizzy does not change the gap, it simply changes when the gap occurs, i.e. Advance or Retard timeing.
Sharps40 is offline   Reply With Quote
Old 06-18-2013, 08:02 PM   #13
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,521
Re: Timing and carb issues??

Dwell isn't points gap. Dwell is the number of degrees when the points are closed. You check the dwell again because of the possibility of slight movement in the top bushing (or bearing) in the distributor.
geezer#99 is offline   Reply With Quote
Old 06-18-2013, 08:07 PM   #14
TJ's Chevy
Post Whore
 
TJ's Chevy's Avatar
 
Join Date: Mar 2013
Location: Southern Oregon
Posts: 10,384
Re: Timing and carb issues??

If it coughs and sputters it sound to me like it is running to lean.
__________________
1966 Chevy C10 "Project Two Tone" http://67-72chevytrucks.com/vboard/s...d.php?t=596643
1964 GMC "Crustine" semi-build:http://67-72chevytrucks.com/vboard/s...d.php?t=665056
My youtube channel. Username "Military Chevy": https://www.youtube.com/channel/UC_h...fzpcUXyK_5-uiw
TJ's Chevy is offline   Reply With Quote
Old 06-18-2013, 08:15 PM   #15
XtechX
Registered User
 
XtechX's Avatar
 
Join Date: Jan 2011
Location: Edmore, Michigan
Posts: 300
Re: Timing and carb issues??

I should mention that even though this is an original engine with 23,000 miles on it, it smokes pretty good at idle sometimes. It seemed to smoke worse after I initially advanced the timing the other day. It sat for years before being started just recently, I wonder if it will clear up or free up the rings or valves or what ever by itself ? This probably has something to do with my issues. Is there a way to help free things up in the engine without causing damage?
__________________
Opportunity usually comes disguised....As hard work!!!
XtechX is offline   Reply With Quote
Old 06-18-2013, 08:19 PM   #16
maxwoof
Registered User
 
Join Date: Mar 2010
Location: Edgewater NJ
Posts: 160
Re: Timing and carb issues??

Hi. Unless I am reading it wrong, I would say the diagram
Posted via Mobile Device
maxwoof is offline   Reply With Quote
Old 06-18-2013, 08:57 PM   #17
Sharps40
Account Suspended
 
Join Date: Oct 2012
Location: here
Posts: 2,408
Re: Timing and carb issues??

Quote:
Originally Posted by geezer#99 View Post
Dwell isn't points gap. Dwell is the number of degrees when the points are closed. You check the dwell again because of the possibility of slight movement in the top bushing (or bearing) in the distributor.
Correct, it is the number of degrees of dizzy rotation for which the ignition contact points stay closed. And dwell degrees are increased or decreased by changing points gap.

And, yes, I see your point. A bit of wear in the top end of the dizzy will change the gap/dwell due to a wobble in the upper portion of the shaft. So rotating a very worn dizzy could change gap/dwell.

Makes perfect sense and I'm tracking with you now. Thanks..

Last edited by Sharps40; 06-18-2013 at 09:05 PM.
Sharps40 is offline   Reply With Quote
Old 06-18-2013, 09:00 PM   #18
Sharps40
Account Suspended
 
Join Date: Oct 2012
Location: here
Posts: 2,408
Re: Timing and carb issues??

Quote:
Originally Posted by XtechX View Post
I should mention that even though this is an original engine with 23,000 miles on it, it smokes pretty good at idle sometimes. It seemed to smoke worse after I initially advanced the timing the other day. It sat for years before being started just recently, I wonder if it will clear up or free up the rings or valves or what ever by itself ? This probably has something to do with my issues. Is there a way to help free things up in the engine without causing damage?
You need to put in good oil with zddp additive and run it some. Three very common issues cause smokeing on engines that sit a lot.

Dryed out valve stem seals...an easy replacment job and probably should be done anyway.

Stickey valve or valves or a valve spring or two that has gone flat due to years under maximum compression. Valves and springs may limber up with some driving.

Sticky rings, especially oil control rings. They may work loose with some driving...worst case you may need to rering.

Get it running good and maybe run some marvel mystery oil thru it and do some driving. If it dosn't settle down a lot in 500 to 1000 miles or so, consider doing both wet and dry compression checks and then unbutton the engine to work either valves or pistons/rings to your satisfaction.

Last edited by Sharps40; 06-18-2013 at 09:07 PM.
Sharps40 is offline   Reply With Quote
Old 06-18-2013, 10:16 PM   #19
Sharps40
Account Suspended
 
Join Date: Oct 2012
Location: here
Posts: 2,408
Re: Timing and carb issues??

Thanks geez, I had to look up dwell definition again to refresh the memory and I think I now know whats up with Kato's wonderin static timeing setting too....Motors slap worn out and prolly the dizzy is the culpret since there ain't no timeing chain to cause such wondering about the timing tab.
Sharps40 is offline   Reply With Quote
Old 06-18-2013, 11:22 PM   #20
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,521
Re: Timing and carb issues??

Precisely why I don't like using a pertronix conversion kit. New electics but in a worn out old dizzy just doesn't cut it.
You don't even need to pull the dizzy to check for play. Just push and pull on the rotor.
Here's some like the shims I used.
http://www.summitracing.com/parts/mor-26140/overview/

OOOPS!! Apologies to the op for jackin' his thread!!
geezer#99 is offline   Reply With Quote
Old 06-19-2013, 06:10 AM   #21
Sharps40
Account Suspended
 
Join Date: Oct 2012
Location: here
Posts: 2,408
Re: Timing and carb issues??

Yep, we got it off track. OP is it timed yet?
Sharps40 is offline   Reply With Quote
Old 06-20-2013, 05:40 PM   #22
XtechX
Registered User
 
XtechX's Avatar
 
Join Date: Jan 2011
Location: Edmore, Michigan
Posts: 300
Re: Timing and carb issues??

I'll be finishing up tonight. Does increasing
The point gap increase the dwell angle or decrease it?
Posted via Mobile Device
__________________
Opportunity usually comes disguised....As hard work!!!
XtechX is offline   Reply With Quote
Old 06-20-2013, 06:43 PM   #23
Sharps40
Account Suspended
 
Join Date: Oct 2012
Location: here
Posts: 2,408
Re: Timing and carb issues??

Dwell should increase with decrease in points gap.
Sharps40 is offline   Reply With Quote
Reply

Bookmarks


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 06:35 PM.


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