Timing suddenly changed....a bunch! ???
Thread Starter
Melting Slicks
Joined: Nov 2001
Posts: 2,659
Likes: 7
From: Katy (Houston) TX
CI 7-8 Veteran
Timing suddenly changed....a bunch! ???
This is on my new engine (so shouldn't be timing chain or balancer) and everything was running good. I pulled the carb off to check the front bowl cause it was leaking a little gas when it sat overnight. I tightened up the screws on the carb and put it back on. Started the car up and it was running REALLY rough. Sounded like it was missing a cylinder or something. All plug wires are snug and tight. Next, checked timing....HOLY BATMAN!!! it was waaaayyyy off. Like 30 degrees too advanced off. So I retarded it as much as I could (the plug wires started restricting how much I could twist the distributor) and it is running a little better. Something is still off though. The idle is a little rough and if I give it just enough gas to get going I think I hear a knock or ping (don't really know the difference???).
Could there be a vacuum leak or something causing this? I don't have vacuum advance on my distributor and am using a Crane HI-6 ignition box with an MSD Pro Billet distributor.
Could there be a vacuum leak or something causing this? I don't have vacuum advance on my distributor and am using a Crane HI-6 ignition box with an MSD Pro Billet distributor.
Le Mans Master
Joined: Aug 2001
Posts: 7,804
Likes: 4
From: Standing still with all my might Texas
Cruise-In X Veteran
St. Jude Donor '09-'11
Re: Timing suddenly changed....a bunch! ??? (tshort)
Did you pull the cap to see if the mechanical advance was working properly? It sounds like it might be stuck in the advanced position.
Thread Starter
Melting Slicks
Joined: Nov 2001
Posts: 2,659
Likes: 7
From: Katy (Houston) TX
CI 7-8 Veteran
Re: Timing suddenly changed....a bunch! ??? (1979toy)
Nope, not the mechanical advance. Checed it and it's smooth and operating nicely. I've got it back now where at idle it's at about 20 degrees advance and full timing comes in just past 2Krpm at 39 degrees. Any less and it's just too rough.
But something's got to be wrong. It was idling and running very smooth. Now the idle is rough and when looking at the timing mark it seems to bounce down (less-advance) at a fairly regular interval. Could a bad plug cause this? It sounds like it is missing on a cylinder. I tried pulling plug wires one at a time but I couldn't hear any noticeable difference.
But something's got to be wrong. It was idling and running very smooth. Now the idle is rough and when looking at the timing mark it seems to bounce down (less-advance) at a fairly regular interval. Could a bad plug cause this? It sounds like it is missing on a cylinder. I tried pulling plug wires one at a time but I couldn't hear any noticeable difference.
Safety Car
Joined: Jan 2001
Posts: 4,660
Likes: 3
From: South Central Louisiana
St. Jude Contributor
Re: Timing suddenly changed....a bunch! ??? (tshort)
T, I fought an ignition problem in my 71 for 8 months until about a month ago. My timing would "scatter" especially above 2-3k rpm's, jumping 20-40 degrees form where it should have been causing a popping in the exhaust. Lars advised me about my pointless trigger that was in my distributor, and when I finally sent the dist to him and he put points back in, all problems were gone. I now don't have to much faith in these pointless triggers.
