Author Topic: Timing issue?  (Read 1223 times)

mikefam

  • Member
  • ***
  • Posts: 224
    • View Profile
Re: Timing issue?
« Reply #15 on: May 14, 2019, 04:04:35 PM »
Points are a simple system and do work.

http://www.camaros.org/articles.shtml

Yes but I can say the same for the electronic pickup once it's installed properly. If you look at the primary and secondary spark on an electronic scope you will see just how good your distributor and points and condensor are. It will show you the spark bouncing if the distributor bearings are worn and it will show you distortions if the points are worn and/or dirty. The electronic sensor is less affected by worn bearings and there are no parts that wear and need to be replaced regularly.

Mike.

EDIT - The electronic magnetic pickup also is not affected by a worn point cam.
« Last Edit: May 14, 2019, 05:37:18 PM by mikefam »
68 Convertible w/327 275hp donor engine from a 67 Impala and TH350

olddragracer

  • Member
  • ***
  • Posts: 49
    • View Profile
Re: Timing issue?
« Reply #16 on: May 14, 2019, 07:58:21 PM »
Something else to check. Chev harmonic balancer outer rings have a habit of slipping making the timing mark position incorrect.  The line on the balancer can be checked for correct position several ways. Bring #1 cylinder piston to top dead center, balancer line should be at 0 on the timing tab. My preferred method is to remove the valve cover on #1 cylinder and rotate the engine watching the rocker arms on #1, when exhaust valve is closing and intake valve is starting to open timing line on balancer should be at 0 on the timing tab.

olddragracer

  • Member
  • ***
  • Posts: 49
    • View Profile
Re: Timing issue?
« Reply #17 on: May 14, 2019, 08:25:31 PM »
The method I am describing is a quick method to check timing mark. It is not used as an exact check. Point gap is .019" with new points and is .016" when rubbing block on the points is worn in. Dwell is the number of degrees the points are closed before spark occurs for each cylinder. Dwell is checked with a Dwell Angle Meter and dwell should be 30 degrees.

Kelley W King

  • Hero Member
  • *****
  • Posts: 1078
    • View Profile
Re: Timing issue?
« Reply #18 on: May 14, 2019, 08:42:34 PM »
You could back off the timing a little and see how it runs for now. I think your balancer has spun or the tab is messed up. When we did not have a light handy we used to time the engine until the started dragged and back off a little and go. Not the correct way to do it but at the time a light was something you borrowed.
69 Z28 RS Scuncio Hi Performance
69 SS L78
67 SS Chevelle
64 Corvette
66 GTO Tiger Gold
77 Trans Am Special Edition

bobs69z

  • Member
  • ***
  • Posts: 24
    • View Profile
Re: Timing issue?
« Reply #19 on: May 14, 2019, 10:25:08 PM »
I haven't checked timing mark yet.  But the results....I borrowed a timing light with a timing advance dial.  Timing was at 58 deg.with vacuum plugged. Hence the hard starting when engine was hot. I cant believe engine ran as good as it did.  I adjusted points to 30.   I backed the timing down to 18 deg.,  about 30 deg with vacuum plugged in.  I couldn't lower timimg anymore because vacuum can is hitting motor bracket. May have to remove bracket or lift dist.  Havent taken a test drive yet because of weather, but car starts much easier when hot now.  I cant get car to idle below 1100/1200 rpms.  At 1000 the car slowly dies. I messed with idle mixture screws and idle screw.  Any ideas?  Thanks for everyones help.  Bob
69 Z28 Hugger Orange, White Vinyl Top

Stingr69

  • Hero Member
  • *****
  • Posts: 689
    • View Profile
Re: Timing issue?
« Reply #20 on: May 15, 2019, 12:36:40 PM »
I would used the dial back timing light to set the maximum ignition advance to 52 degrees at full advance (high RPM) with the vacuum advance disconnected and plugged.  At that point, you can look to the other concerns such as carb settings and overheating etc.  The distributor needs to be re-clocked a bit OR you can just move all the ignition wires by one terminal to give you more room to adjust the timing. If the vacuum advance can is roughly pointing at the passenger front tire you are probably in the zone.  :)

The ignition timing was set that way at the factory when the car was new.  Newer aftermarket kidney bean shaped cylinder heads can run a little bit less timing but original type engines with factory heads will all work set this way.

jvb6648

  • Member
  • ***
  • Posts: 113
    • View Profile
Re: Timing issue?
« Reply #21 on: May 15, 2019, 03:13:19 PM »
Points at .019, dwell at 30 degrees.
Jim
68 Z/28

red69

  • Member
  • ***
  • Posts: 143
    • View Profile
Re: Timing issue?
« Reply #22 on: May 16, 2019, 03:43:34 PM »
I'm a little confused with the 52 degrees total advance (vacuum plugged) referred to in one of the earlier posts. For distributer part #1111480 69 manual calls for 32 degrees total centrifugal@ 4400 RPM. Add 4 degrees initial total would be 36 degrees total with no vacuum. Am I missing something?

Stingr69

  • Hero Member
  • *****
  • Posts: 689
    • View Profile
Re: Timing issue?
« Reply #23 on: May 16, 2019, 04:28:11 PM »
I'm a little confused with the 52 degrees total advance (vacuum plugged) referred to in one of the earlier posts. For distributer part #1111480 69 manual calls for 32 degrees total centrifugal@ 4400 RPM. Add 4 degrees initial total would be 36 degrees total with no vacuum. Am I missing something?

Nope, you are not crazy.  I meant to type 36.  Must be getting old here.