screwed up timing. Missing something?
Thread Starter
Drifting
Joined: Sep 1999
Posts: 1,970
Likes: 91
screwed up timing. Missing something?
Before I start tearing the engine apart, figure I may have overlooked something.
70 350-350HP. MSD 6al with msd tach dist. I set the dist in the block and the rotor tip lined up with the number 1 terminal. The damper marker was right on "0" degrees. Engine fired but idled rough. Checked the timing and it was way off. Dialed in with the timing light to zero on the marker and had 31 degrees advance on the light. Couldn't get close to 8 degrees without stalling. pulled the dist a bunch of times to try to tweek the position. Didn't help, just flooded out. Packed it in for the day.
Am I missing something? Any quick checks before I rip it apart?
70 350-350HP. MSD 6al with msd tach dist. I set the dist in the block and the rotor tip lined up with the number 1 terminal. The damper marker was right on "0" degrees. Engine fired but idled rough. Checked the timing and it was way off. Dialed in with the timing light to zero on the marker and had 31 degrees advance on the light. Couldn't get close to 8 degrees without stalling. pulled the dist a bunch of times to try to tweek the position. Didn't help, just flooded out. Packed it in for the day.
Am I missing something? Any quick checks before I rip it apart?
Melting Slicks
Joined: Oct 2001
Posts: 3,025
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From: Pleasant Grove AL
You don't mention vacuum advance. With vac adv connected, you should be seeing something in the neighborhood of 25* at idle. What you are really looking for is around 35-36* at full mechanical advance, all in by 2800-3000 RPM, with the vac adv disconnected and plugged. The initial advance will be whatever it is. This will usually give you around 52* total advance at cruise with the vacuum connected.
There is lots of info regarding timing in the archives.
There is lots of info regarding timing in the archives.
Thread Starter
Drifting
Joined: Sep 1999
Posts: 1,970
Likes: 91
I just installed the rebuilt engine. started the engine for the first time. No advance.
Don't understand If I have the distributor lined up correctly before I start, why there is such a difference when running. Where are the archives?
Don't understand If I have the distributor lined up correctly before I start, why there is such a difference when running. Where are the archives?
Pro
Joined: Sep 2004
Posts: 517
Likes: 0
Take the vacuum hose off of the vacuum advance can and plug the hose. Take the springs off of the weights in the distributor, put it back together (without the springs) and fire it up. Give it a little gas and set the timing for 36.
That should be your starting point. Then put your springs back in and connect the can and it should work fine. Might need to back off a little at a time if you notice pinging when you drive it under load. For optimum performance, you will want to change the springs to a lighter set that will advance completely by 3000 RPM or so, if they haven't already been changed.
That should be your starting point. Then put your springs back in and connect the can and it should work fine. Might need to back off a little at a time if you notice pinging when you drive it under load. For optimum performance, you will want to change the springs to a lighter set that will advance completely by 3000 RPM or so, if they haven't already been changed.
Pro
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Burning Brakes
Joined: Apr 2004
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From: Des Allemands LA
Check plug wires to make sure firing order is correct: 1-8-4-3-6-5-7-2. I know this sounds simple but there have been more than one person to have goofed up on this-I know from first hand expierience.
Race Director
Joined: Sep 2004
Posts: 11,874
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by dennis
I just installed the rebuilt engine. started the engine for the first time. No advance.
Don't understand If I have the distributor lined up correctly before I start, why there is such a difference when running. Where are the archives?
Don't understand If I have the distributor lined up correctly before I start, why there is such a difference when running. Where are the archives?
your distributor alignment will determine where your number 1 plug is and it will determine where your vacuum cannister is pointed but that is all relative....once the plug wires are hooked up relative to the distributor cap and the car runs. how the distributor is oriented will make a difference on setting your timing , but no matter how many times you take it out and put it in the car will run the same at the same timing degree...
my car runs like crap at 8*....most of us who have performance engines have the inital timing in the 16-20* range with the all the cenrtifugal advance (36*) in by 2500 -3000 RPM with another 16* of vacuum advance....theres lots of posts on setting timing....search Lars name for posts and lots of timing info will come up
Thread Starter
Drifting
Joined: Sep 1999
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Originally Posted by bobs77vet
your distributor alignment will determine where your number 1 plug is and it will determine where your vacuum cannister is pointed but that is all relative....once the plug wires are hooked up relative to the distributor cap and the car runs. how the distributor is oriented will make a difference on setting your timing , but no matter how many times you take it out and put it in the car will run the same at the same timing degree...
Bob
I have the distributor base lined up with the rotor so with the cap on the number 1 terminal is firing, at the same time the damper is at TDC. Moving the distributor base changes the timing.
You made me think though, with a point type distributor, the points need to be open when the distirbutor and rotor are in line in order to fire. I have a MSD distributor, and assume there's no need to set anything since there are no points. Maybe I'm wrong.
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Melting Slicks
Joined: Oct 2001
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From: Pleasant Grove AL
Originally Posted by dennis
Bob
I have the distributor base lined up with the rotor so with the cap on the number 1 terminal is firing, at the same time the damper is at TDC. Moving the distributor base changes the timing.
You made me think though, with a point type distributor, the points need to be open when the distirbutor and rotor are in line in order to fire. I have a MSD distributor, and assume there's no need to set anything since there are no points. Maybe I'm wrong.
I have the distributor base lined up with the rotor so with the cap on the number 1 terminal is firing, at the same time the damper is at TDC. Moving the distributor base changes the timing.
You made me think though, with a point type distributor, the points need to be open when the distirbutor and rotor are in line in order to fire. I have a MSD distributor, and assume there's no need to set anything since there are no points. Maybe I'm wrong.
Thread Starter
Drifting
Joined: Sep 1999
Posts: 1,970
Likes: 91
Thanks.Going to try moving the rotor a little more clockwise. Seems I get the vac can advance nipple in front ,or in the rear of the ignition shield support. Limits how far I can move the distributor.
I moving the distributor so far I had to adjust the plug wires over one tower to re-align. Now I have a no start, but I think thats from flooding. Pulled the plugs to air it out. Hope to figure this out in the morning.
I moving the distributor so far I had to adjust the plug wires over one tower to re-align. Now I have a no start, but I think thats from flooding. Pulled the plugs to air it out. Hope to figure this out in the morning.
Pro
Joined: Sep 2004
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If I recall correctly, you should have the mark on the damper at about the 12 degree notch when the rotor is pointing at #1. From there, set the initial timing with the vacuum can disconnected and the hose plugged. That should give you a good starting point.
Thread Starter
Drifting
Joined: Sep 1999
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Originally Posted by WhichVette?
If I recall correctly, you should have the mark on the damper at about the 12 degree notch when the rotor is pointing at #1. From there, set the initial timing with the vacuum can disconnected and the hose plugged. That should give you a good starting point.
12 *is a fair distance from that. I'll try it.
I was thinking that with the "0" seting I'm getting 31* advance with no vacuum. 12* would just push that further back. But, I think that locating the distributor at 12* or more , will allow me to bring the running timing down before I hit the shield support with the vacuum can nipple. Thanks
Race Director
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by dennis
Bob
I have the distributor base lined up with the rotor so with the cap on the number 1 terminal is firing, at the same time the damper is at TDC. Moving the distributor base changes the timing.
.
I have the distributor base lined up with the rotor so with the cap on the number 1 terminal is firing, at the same time the damper is at TDC. Moving the distributor base changes the timing.
.
i agree and thats not what i am saying, i don't think i'm explaining this very well....what i'm trying to say is that i suspect no matter how you orient the distributor by taking it in and out the results will be the same....and the same timing mark results will show up..i think your issue is some where else and not with how the distributor is oriented.
Last edited by bobs77vet; Jul 10, 2005 at 10:44 AM.
Melting Slicks
Joined: Jan 2004
Posts: 2,672
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From: New Cumberland PA
To a certain degree, it doesn't matter where you drop in the distributor. You adjust accordingly. The idea of dropping in the distributor at the correct location is to get the engine to start. Even then the timing will be off, but the goal is to start the engine and set with a light. As mentioned before, you can only turn a distributor a certain distance before something such as the vacuum advance hits something. Thats the second reason to drop the distributor in at the right spot. If it hits before you can get the timing where it belongs pull the distributor and engage it one tooth clockwise or counterclockwise.
If you dropped it in one tooth off to start with, the engine runs but stalls when approching the correct setting;, changing the position of the distributor won't correct the problem.
If you dropped it in one tooth off to start with, the engine runs but stalls when approching the correct setting;, changing the position of the distributor won't correct the problem.
Race Director
Joined: Sep 2004
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
ok figured out how to say it and i agree with mandm1200. the orientation of your distributor will not effect how the car is running only where the number 1 plug is and when the vac cannister starts hitting things and interferes with getting the timing set right
Thread Starter
Drifting
Joined: Sep 1999
Posts: 1,970
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Sorry to waste so much time on this, but the forum is good for thinking out loud and getting lot's of good feedback. And I've gotten good advice before.
bobs77vet: I think I get what your saying. I can drop it and set it any which way, set it, and still have the problem.
mandm1200:I agree completely.
The thing is, I first set the distributor to 1, with the damper on 0*, started the engine and adjusted it by ear to run decent. Put on my advance timing light, and it read 31* advanced with the vacuum plugged. Checked the piston from the #1 hole and it tops out right on the mark. I just don't understand why, if I set the timing before I started it to 0*, how it could read 31* a moment later when I started it. I didn't change or adjust anything. There, (I think), is the problem.
Now I have a no start. If I can't find a solution, I'm going to pull the MSD and install the original distributor. If that doesn't make a difference I'll drain the tank and try some frech cam 2.(might do that first). Maybe it's somehow a fuel thing. I hope I haven't broken or altered anything mechanically .
bobs77vet: I think I get what your saying. I can drop it and set it any which way, set it, and still have the problem.
mandm1200:I agree completely.
The thing is, I first set the distributor to 1, with the damper on 0*, started the engine and adjusted it by ear to run decent. Put on my advance timing light, and it read 31* advanced with the vacuum plugged. Checked the piston from the #1 hole and it tops out right on the mark. I just don't understand why, if I set the timing before I started it to 0*, how it could read 31* a moment later when I started it. I didn't change or adjust anything. There, (I think), is the problem.
Now I have a no start. If I can't find a solution, I'm going to pull the MSD and install the original distributor. If that doesn't make a difference I'll drain the tank and try some frech cam 2.(might do that first). Maybe it's somehow a fuel thing. I hope I haven't broken or altered anything mechanically .
Drifting
Joined: Nov 2001
Posts: 1,469
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From: 68 427 4.11s Roadster
To your original question. If your idle isn't actually idle your mechanical advance could be getting added in.
If your 8* isn't working can it be your carb idle? Sometimes you have to go back and forth to get it roughly where it should be.
Carb to timing, timing to carb.
Your distributor can spin if you have it loosened for adjustment. This might be why your confused on why it was and now it ain't.
If your 8* isn't working can it be your carb idle? Sometimes you have to go back and forth to get it roughly where it should be.
Carb to timing, timing to carb.
Your distributor can spin if you have it loosened for adjustment. This might be why your confused on why it was and now it ain't.
Thread Starter
Drifting
Joined: Sep 1999
Posts: 1,970
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[QUOTE=Techno]To your original question. If your idle isn't actually idle your mechanical advance could be getting added in.
QUOTE]
Good thought. Would you think that for mech adv to kick in, the idle would be too high ? It seemed to go up and down on initial startup. I'll play with that too. Thanks
QUOTE]
Good thought. Would you think that for mech adv to kick in, the idle would be too high ? It seemed to go up and down on initial startup. I'll play with that too. Thanks
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
This stuff ain't rocket science 
Check to see if your disrtibutor wieghts are free and the balancer isn't slipping. If those two things are OK disconnect the vacuum advance and plug the line, rev it up to 3000RPM and set the timing to 35 deg and your done 
Check to see if your disrtibutor wieghts are free and the balancer isn't slipping. If those two things are OK disconnect the vacuum advance and plug the line, rev it up to 3000RPM and set the timing to 35 deg and your done