Timing issues???
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,309
Likes: 24
From: Coastal Georgia
C2 of the Year Finalist - Modified 2020
Timing issues???
Just got the new heads and manifold on, and can't seem to get my timing right. I have confirmed that the engine is at TDC by checking the valves on the #1 cylinder with the valve cover off, and the timing mark on the balancer lines up with the "0" on the tab. Distributor rotor is pointing squarely at the #1 cylinder post on the cap (which I marked). I can't get the engine to fire at all unless I advance the distributor as far as I can until the vacuum advance canister hits the intake...then it will fire and run semi-smoothly, but won't idle under 1,000rpm and the timing mark on the balancer is about an inch and a half completely off the timing tab (WAY advanced). It's also running so rich it burns my eyes.
Am I off a tooth on the distributor? Vacuum leak? Help please.
Am I off a tooth on the distributor? Vacuum leak? Help please.
Racer
Joined: Feb 2009
Posts: 343
Likes: 0
From: San Diego CA
Just got the new heads and manifold on, and can't seem to get my timing right. I have confirmed that the engine is at TDC by checking the valves on the #1 cylinder with the valve cover off, and the timing mark on the balancer lines up with the "0" on the tab. Distributor rotor is pointing squarely at the #1 cylinder post on the cap (which I marked). I can't get the engine to fire at all unless I advance the distributor as far as I can until the vacuum advance canister hits the intake...then it will fire and run semi-smoothly, but won't idle under 1,000rpm and the timing mark on the balancer is about an inch and a half completely off the timing tab (WAY advanced). It's also running so rich it burns my eyes.
Am I off a tooth on the distributor? Vacuum leak? Help please.
Am I off a tooth on the distributor? Vacuum leak? Help please.
Remember when you drop the dist in the hole, it turns a bit as the dist gear meshes w/the cam gear. You need to start with #1 at TDC (you know that's the driver's side, right?) and hold the dist where you want the vacuum can to be. Then aim the rotor a bit ahead of where the #1 plug wire is. If the dist won't drop all the way down, don't pull it back out, just bump the starter. (Or if a 4 speed, put it in 3rd gear & rock the car) to turn the engine just enough for it to drop in to the oil pump shaft.
RE the possibility of vacuum leaks -are you sure you're using the right carb gasket? There are a lot of choices.
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,309
Likes: 24
From: Coastal Georgia
C2 of the Year Finalist - Modified 2020
Thanks, but I know how to install the distributor. Like I said, I've got the distributor installed with the rotor pointing at the #1 spark plug post, and the engine is at top dead center (verified with the valve covers off). The distributor housing itself is centered and pointing straight ahead.
And yes, the carb gasket matches. Thanks for the suggestions, though.
Just realized this post might have come off a bit harsh, and I didn't mean for it to. Just a little frustrated right now....I've had the distributor in and out about 5 times and the valve covers off and readjusted the valves multiple times as well. Everything lines up just as it should, but it's just not running right. Anyways I apologize if I came off as an a$$ in that last post, QuicheLorraine.
And yes, the carb gasket matches. Thanks for the suggestions, though.
Just realized this post might have come off a bit harsh, and I didn't mean for it to. Just a little frustrated right now....I've had the distributor in and out about 5 times and the valve covers off and readjusted the valves multiple times as well. Everything lines up just as it should, but it's just not running right. Anyways I apologize if I came off as an a$$ in that last post, QuicheLorraine.
Last edited by Quil; Mar 21, 2009 at 10:31 PM.
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
Thanks, but I know how to install the distributor. Like I said, I've got the distributor installed with the rotor pointing at the #1 spark plug post, and the engine is at top dead center (verified with the valve covers off). The distributor housing itself is centered and pointing straight ahead.
And yes, the carb gasket matches. Thanks for the suggestions, though.
And yes, the carb gasket matches. Thanks for the suggestions, though.
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,309
Likes: 24
From: Coastal Georgia
C2 of the Year Finalist - Modified 2020
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,309
Likes: 24
From: Coastal Georgia
C2 of the Year Finalist - Modified 2020
I am sure that I am, but I will probably go and check it again for the millionth time to be sure. Just like I'm going to go double check the plug wires again for the tenth time...
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
By what you are saying, it sounds like it runs better with more timing despite already being over advanced.
Make very sure that you dont have the timing light connected to the wrong plug wire. It happens way more than you would believe.
Assuming thats correct, can you be sure that the balancer hasnt slipped?
As long as you can set the timing to spec, then the worst thing that stabbing the distributor one tooth off will cause is a crooked distributor housing.
Make very sure that you dont have the timing light connected to the wrong plug wire. It happens way more than you would believe.
Assuming thats correct, can you be sure that the balancer hasnt slipped?
As long as you can set the timing to spec, then the worst thing that stabbing the distributor one tooth off will cause is a crooked distributor housing.
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
Reading my reply above, it doesnt sound like I think you are off a tooth or two on the distributor.
Actually I do think you are off, but you are having another problem as well preventing you from seeing the correct timing position.
Actually I do think you are off, but you are having another problem as well preventing you from seeing the correct timing position.
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,309
Likes: 24
From: Coastal Georgia
C2 of the Year Finalist - Modified 2020
I think the balancer is still ok...the mark on the balancer lines up with the "0" on both the intake and the exhaust stroke. And I just checked again and I'm definitely at TDC, with the mark on the balancer lined up with the "0" on the tab.
I'll pull the cap off the distributor and check to see if I'm lined up dead nuts on the #1 post, and if not, see if I can move it a tooth or so. I am positive it is not out 180, though.
I'll pull the cap off the distributor and check to see if I'm lined up dead nuts on the #1 post, and if not, see if I can move it a tooth or so. I am positive it is not out 180, though.
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
When it is at zero, can you actually see that the piston is at the top of the stroke?
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,309
Likes: 24
From: Coastal Georgia
C2 of the Year Finalist - Modified 2020
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,309
Likes: 24
From: Coastal Georgia
C2 of the Year Finalist - Modified 2020
Going to try a couple of methods of finding TDC without using the timing marks and then installing the distributor again. Starting to wonder if maybe the balancer has slipped...
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,309
Likes: 24
From: Coastal Georgia
C2 of the Year Finalist - Modified 2020
OK, I've done everything I know to do. I have verified TDC on the #1 cylinder, which does in fact correspond with the "0" on the timing tab. After confirming both of these things, I pull the cap on the distributor and the rotor is pointing at the #1 spark plug post. I can't even get the engine to fire at all now...I've gotten a couple backfires through the exhaust, but that's it. I advanced the distributor as far as I can until the vacuum advance post hits the intake runner, but can't get it to fire there either...just a backfire through the carb.
I checked the plug wire routing on the distributor, and everything is in the correct order. The distributor cap is firmly in place and held down. Checked the carb and I'm definitely getting fuel.
I have no idea what to do now. Is the dizzy toast? My plug wires are old, but I wouldn't think that would be the problem. Spark plugs are brand new.
I checked the plug wire routing on the distributor, and everything is in the correct order. The distributor cap is firmly in place and held down. Checked the carb and I'm definitely getting fuel.
I have no idea what to do now. Is the dizzy toast? My plug wires are old, but I wouldn't think that would be the problem. Spark plugs are brand new.
Instructor
Joined: Jul 2007
Posts: 228
Likes: 0
From: Price Utah
In your post you said you changed heads and intake. Did you change the cam? What procedure did you use to adjust valves? Sounds like you know what you're doing just checking possibilities. Good luck.
BTW I lived for 19yr in Palmer good vette weather in summer; long winters to work on it.
BTW I lived for 19yr in Palmer good vette weather in summer; long winters to work on it.
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
You might be off a tooth or two. Try lifting the dist out enough to turn the rotor counterclockwise 2 teeth and set it back in. It's either that or you are off 180*.
Palmer resident 1975 to 1996
Palmer resident 1975 to 1996
Last edited by '75; Mar 22, 2009 at 10:06 PM.