Timing belt/Harmonic Balancer
Thread Starter
6th Gear
Joined: Jan 2016
Posts: 6
Likes: 0
Timing belt/Harmonic Balancer
When I turn the distributor, the timing mark on my harmonic balancer doesn't change. I know that it is not the timing chain, but I don't know what else it could be. Car is a 1986 Corvette.
Is it possible that the timing light is bad?
Is it possible that the timing light is bad?
Safety Car
Joined: Aug 2009
Posts: 3,751
Likes: 276
From: Melbourne, Victoria, Australia
You have disconnected the timing bypass connector?
You have to do that to adjust the timing, or it will be way advanced.
Have you confirmed the harmonic ballancer outer ring has not moved, they can slip and usually move backward toward the timing case. Check this by confirming the no.1 piston is at the top of its stroke, when the ballancer mark aligns with the timing tab on the timing case cover.
Last edited by gerardvg; Apr 25, 2017 at 04:37 AM.
Team Owner
Joined: Sep 2003
Posts: 25,393
Likes: 2,741
This thread was interesting some 13 years ago:
https://www.corvetteforum.com/forums...-88-vette.html
Here's a guide with snapshots:
Corvette L98 Ignition Timing (1).doc
The link was posted by https://www.corvetteforum.com/forums...mihaltian.html many years ago.
https://www.corvetteforum.com/forums...-88-vette.html
Here's a guide with snapshots:
Corvette L98 Ignition Timing (1).doc
The link was posted by https://www.corvetteforum.com/forums...mihaltian.html many years ago.
Last edited by WVZR-1; Apr 25, 2017 at 05:36 AM.
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 764
Hi
You have disconnected the timing bypass connector?
You have to do that to adjust the timing, or it will be way advanced.
Have you confirmed the harmonic balancer outer ring has not moved, they can slip and usually move backward toward the timing case. Check this by confirming the no.1 piston is at the top of its stroke, when the balancer mark aligns with the timing tab on the timing case cover.
You have disconnected the timing bypass connector?
You have to do that to adjust the timing, or it will be way advanced.
Have you confirmed the harmonic balancer outer ring has not moved, they can slip and usually move backward toward the timing case. Check this by confirming the no.1 piston is at the top of its stroke, when the balancer mark aligns with the timing tab on the timing case cover.
- sure sounds like the EST was not disconnected. need more info from the OP - exactly how is he attempting to set the timing?WVZR-1 posted a good "how-to" link.
Last edited by Joe C; Apr 25, 2017 at 06:24 AM.
Thread Starter
6th Gear
Joined: Jan 2016
Posts: 6
Likes: 0
EST is disconnected
I looked at the other forum that was posted in the comments, I did all the steps that they are referring to. The distributor is advanced 18 degrees and won't go up or down whether it's at idle or revving. I can change the distributor and the advance still won't change.
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 764
I looked at the other forum that was posted in the comments, I did all the steps that they are referring to. The distributor is advanced 18 degrees and won't go up or down whether it's at idle or revving. I can change the distributor and the advance still won't change.
Thread Starter
6th Gear
Joined: Jan 2016
Posts: 6
Likes: 0
ETC/EST is disconnected
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 764
if you have disconnected the EST, at this point, i'm not sure what is causing your problem - sorry....
just to see if we're on the same page, this is the connector we're talking about?
Last edited by Joe C; Apr 25, 2017 at 06:32 PM.
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Thread Starter
6th Gear
Joined: Jan 2016
Posts: 6
Likes: 0
I think the computer is holding on to the timing
I think the ECM is holding onto the timing and not letting it come down from advanced. How do I get the ECM to let go of the timing so that the advanced can come down?
Drifting
Joined: Jan 2005
Posts: 1,354
Likes: 325
From: San Antonio Tx
The ECM can not hold the timing when you turn the distributor. It does not know you changed the base timing unless you change the initial timing in the software. I once had an aftermarket distributor that was made with a two piece housing. When I turned the distributor the timing did not change until I turned it so far the spark jumped to the next terminal. Finally figured out I was turning the cap and top of the housing only, the base of the distributor was not turning.