Old School Timing adjustment
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,270
Likes: 4
From: Celeste Texas
Old School Timing adjustment
When I set the timing by the book in my 82 the engine pings real bad. I gave up and set it by retarding a little until it quit pinging on hard acceleration. I would adjust it then go for a drive. Instead of 6 degrees I am down to 2 degrees for timing.
Did anyone else have to do this?
Does the balancer ever slip so the timing marks are in the wrong place?
Bill
Did anyone else have to do this?
Does the balancer ever slip so the timing marks are in the wrong place?
Bill
Race Director
Joined: Jul 2004
Posts: 12,710
Likes: 329
From: Scottsdale Arizona
Originally Posted by texaswilkins
When I set the timing by the book in my 82 the engine pings real bad. I gave up and set it by retarding a little until it quit pinging on hard acceleration. I would adjust it then go for a drive. Instead of 6 degrees I am down to 2 degrees for timing.
Did anyone else have to do this?
Does the balancer ever slip so the timing marks are in the wrong place?
Bill
Did anyone else have to do this?
Does the balancer ever slip so the timing marks are in the wrong place?
Bill
The balancers definately slip on these. It is probably more common than not. Easiest way to check is to look up Lars' paper on finding TDC on corvettefaq. Then you can verify that the mark is correct.
Tech Contributor
Joined: Aug 1999
Posts: 14,382
Likes: 6,402
From: At my Bar drinking and wrenching in Lafayette Colorado
The '82 should not detonate if the timing is set to spec. If you're getting detonation at WOT, you likely have one of two issues going on:
1. Slipped harmonic balancer outer ring is very common on these cars. If the balancer has slipped, you will not be able to set the timing correctly, and you can easily be in an over-advanced condition. Check TDC and verify the timing marks. If the marks are off, replace the balancer.
2. Note that you have to disconnect the ECM connector to the distributor before setting timing - it's the brown & black wire with a black connector just inboard of the power brake booster. If you do not disconnect the ECM, you will get a faulty timing setting.
The knock sensor will signal the ECM to retard timing of knock is detected, but it has limited range for this retard. You can test to see if the sensor is working by running the engine at a cruise-typical rpm (2000 rpm-or-so) and locking the throttle in this position. You can then tap the engine block with a hammer in the area just above the starter. If the sensor is working, you will get an rpm drop as the ECM backs off the timing.
1. Slipped harmonic balancer outer ring is very common on these cars. If the balancer has slipped, you will not be able to set the timing correctly, and you can easily be in an over-advanced condition. Check TDC and verify the timing marks. If the marks are off, replace the balancer.
2. Note that you have to disconnect the ECM connector to the distributor before setting timing - it's the brown & black wire with a black connector just inboard of the power brake booster. If you do not disconnect the ECM, you will get a faulty timing setting.
The knock sensor will signal the ECM to retard timing of knock is detected, but it has limited range for this retard. You can test to see if the sensor is working by running the engine at a cruise-typical rpm (2000 rpm-or-so) and locking the throttle in this position. You can then tap the engine block with a hammer in the area just above the starter. If the sensor is working, you will get an rpm drop as the ECM backs off the timing.
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,270
Likes: 4
From: Celeste Texas
I had the est wire disconnected, on my car it goes in by the wiper motor so I thought for a very long time that I didn't have one. I had never heard of a balancer slipping so I guess I'll add that to the winter project list.
Thanks guys!
Bill
Thanks guys!
Bill
