timing outta wack
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
My apologies.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
4 speed,
I am glad to read you got your hood open.
I hope your timing issues/concerns and engine performance finally are achieved to your liking. Just tried to offer you helpful advice and possible issues that you may have not thought of....that I have encountered enough to make me comment..
Sorry to make people feel/think that your car has twin magneto's and runs on Nitro methane. Some people can read into "things' instead of comprehending what was written...or are just trying to stir the "pot" and take "things" out of context. I took your initial post seriously...and tried to offer information that would be helpful.
Mike Ward...I apologize. You are clearly entitled to an opinion....and I would defend your RIGHT to express your opinion. And I have to remember that not one person on this planet has walked in my shoes and knows what I know or what I have experienced....and that I can still learn something from EVERYBODY. Because if I close myself to any thoughts or experiences from people...I might lose out on either being reminded of something I forgot...or might actually learn something. I hope you can see I was just trying to be constructive and help out a person who was asking for help. Regardless if it translated differently when you read what I wrote. Was trying to help....that's it.
DUB
I am glad to read you got your hood open.
I hope your timing issues/concerns and engine performance finally are achieved to your liking. Just tried to offer you helpful advice and possible issues that you may have not thought of....that I have encountered enough to make me comment..
Sorry to make people feel/think that your car has twin magneto's and runs on Nitro methane. Some people can read into "things' instead of comprehending what was written...or are just trying to stir the "pot" and take "things" out of context. I took your initial post seriously...and tried to offer information that would be helpful.
Mike Ward...I apologize. You are clearly entitled to an opinion....and I would defend your RIGHT to express your opinion. And I have to remember that not one person on this planet has walked in my shoes and knows what I know or what I have experienced....and that I can still learn something from EVERYBODY. Because if I close myself to any thoughts or experiences from people...I might lose out on either being reminded of something I forgot...or might actually learn something. I hope you can see I was just trying to be constructive and help out a person who was asking for help. Regardless if it translated differently when you read what I wrote. Was trying to help....that's it.
DUB
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Dub-
The point was
1) the source of vacuum advance has nothing to do with what the OP is trying to do. He clearly stated it's already disconnected
2) ported vacuum is not the preferred vacuum source on any street driven car.
3) being that the OP is trying to follow Lar's paper (the acknowledged go-to document on the subject) to calibrate and set his mechanical advance, making a suggestion on what to do with the vacuum confuses the issue tremendously.
The point was
1) the source of vacuum advance has nothing to do with what the OP is trying to do. He clearly stated it's already disconnected
2) ported vacuum is not the preferred vacuum source on any street driven car.
3) being that the OP is trying to follow Lar's paper (the acknowledged go-to document on the subject) to calibrate and set his mechanical advance, making a suggestion on what to do with the vacuum confuses the issue tremendously.
Thread Starter
Pro
Joined: May 2001
Posts: 571
Likes: 5
From: usa
ok. so before getting the hood open, I had taken the car for a test run, it really seemed to run much better then before the springs and timing reset. but once the engine was hot, it was bucking the starter.
then the hood cable clamp came off.
so got the hood open, checking timing with the vac hose off. light set to 0. I couldn't see the mark, I had to retard the timing 2-3 inches of cap rotation. but got it set to 8*BTDC.
I did have to increase the idle has it was below 500 rpm. when I plug in the vac line I lose the mark. sorry I did not use the light to get a reading. also need to get a helper to read the tach for 36*.
went for another ride, still seemed good but not has good has the last ride with high timing.
then the hood cable clamp came off.
so got the hood open, checking timing with the vac hose off. light set to 0. I couldn't see the mark, I had to retard the timing 2-3 inches of cap rotation. but got it set to 8*BTDC.
I did have to increase the idle has it was below 500 rpm. when I plug in the vac line I lose the mark. sorry I did not use the light to get a reading. also need to get a helper to read the tach for 36*.
went for another ride, still seemed good but not has good has the last ride with high timing.
Heel & Toe
Joined: Mar 2012
Posts: 21
Likes: 0
Not sure I understand what you are trying to say, but you may be using your timing light incorrectly.
With your engine at idle, pull the vacuum hose to the distributor and plug it. Turn your dial back timing light to zero "0". (This effectively makes it a standard/normal timing light) Set your initial timing somewhere in the 8-12 degrees BTDC range. Snug the distributor bolt so it won't move.
Once you have that set, turn your dial back timing light to 36 degrees. (The timing tab on the balancer will move out of view)
Have someone slowly rev the engine until the timing mark on the balancer aligns with zero "0" degrees on the timing tab. Note what RPM this happens at....2000, 2500, 3000, 3500?
Once you have that information, you will either replace the distributor springs (heavier or lighter) or adjust your base timing at idle.
If your initial timing is 8 BTDC and you reach 36 BTDC at 2000 RPM, you'll need to use heavier springs.
If your initial timing is 8 BTDC and you reach 36 BTDC at 4000 RPM, you'll need to use lighter springs.
If your initial timing is 8 BTDC and you reach 36 BTDC at 3200 RPM, you'll advance you initial timing to around 10 BTDC.
With your engine at idle, pull the vacuum hose to the distributor and plug it. Turn your dial back timing light to zero "0". (This effectively makes it a standard/normal timing light) Set your initial timing somewhere in the 8-12 degrees BTDC range. Snug the distributor bolt so it won't move.
Once you have that set, turn your dial back timing light to 36 degrees. (The timing tab on the balancer will move out of view)
Have someone slowly rev the engine until the timing mark on the balancer aligns with zero "0" degrees on the timing tab. Note what RPM this happens at....2000, 2500, 3000, 3500?
Once you have that information, you will either replace the distributor springs (heavier or lighter) or adjust your base timing at idle.
If your initial timing is 8 BTDC and you reach 36 BTDC at 2000 RPM, you'll need to use heavier springs.
If your initial timing is 8 BTDC and you reach 36 BTDC at 4000 RPM, you'll need to use lighter springs.
If your initial timing is 8 BTDC and you reach 36 BTDC at 3200 RPM, you'll advance you initial timing to around 10 BTDC.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
I had to retard the timing 2-3 inches of cap rotation. but got it set to 8*BTDC.
I did have to increase the idle has it was below 500 rpm. when I plug in the vac line I lose the mark. sorry I did not use the light to get a reading. also need to get a helper to read the tach for 36*.
went for another ride, still seemed good but not has good has the last ride with high timing.
I did have to increase the idle has it was below 500 rpm. when I plug in the vac line I lose the mark. sorry I did not use the light to get a reading. also need to get a helper to read the tach for 36*.
went for another ride, still seemed good but not has good has the last ride with high timing.
It's normal for the mark to move off the scale when the vacuum line is plugged.
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Le Mans Master
Joined: Aug 2006
Posts: 7,419
Likes: 1,555
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Just saying...
https://www.corvetteforum.com/techti...=109&TopicID=3
from the tips section on this site.
went out to double check idle timing and dag on hood release cable broke........Grrrrrr!
from the tips section on this site.
went out to double check idle timing and dag on hood release cable broke........Grrrrrr!
You might want to email him for the new paper.
v8fastcars@msn.com
Drifting
Joined: Oct 2005
Posts: 1,615
Likes: 150
From: Forth Worth TX
ok. so before getting the hood open, I had taken the car for a test run, it really seemed to run much better then before the springs and timing reset. but once the engine was hot, it was bucking the starter.
then the hood cable clamp came off.
so got the hood open, checking timing with the vac hose off. light set to 0. I couldn't see the mark, I had to retard the timing 2-3 inches of cap rotation. but got it set to 8*BTDC.
I did have to increase the idle has it was below 500 rpm. when I plug in the vac line I lose the mark. sorry I did not use the light to get a reading. also need to get a helper to read the tach for 36*.
went for another ride, still seemed good but not has good has the last ride with high timing.
then the hood cable clamp came off.
so got the hood open, checking timing with the vac hose off. light set to 0. I couldn't see the mark, I had to retard the timing 2-3 inches of cap rotation. but got it set to 8*BTDC.
I did have to increase the idle has it was below 500 rpm. when I plug in the vac line I lose the mark. sorry I did not use the light to get a reading. also need to get a helper to read the tach for 36*.
went for another ride, still seemed good but not has good has the last ride with high timing.
If you had your timing light connected (and set at "0" zero) to get your base timing at 8 BTDC, you then reconnected your vacuum hose and had to use the timing light to see that the timing mark moved off of the timing tab, why didn't you just adjust the timing light to bring the timing mark back to "0" zero and read the dial on the gun? The gun had to be in your hand and on or you wouldn't have been be able to see the timing mark move off of the scale.
I hope you had the vacuum hose plugged (a golf tee works great for this) and your springs were installed?
Do you know what vacuum advance can is installed (360-12, B20, B26)?
If your timing advances after you re-connect the vaccum line to the distributor (engine at idle), you are using manifold vacuum. That's a good thing.
Your idle timing (vacuum hose connected) should be around 24 BTDC if all is operating properly. Don't try to set 24 BTDC, what ever it is, it is. Your readings will tell us what is or isn't working properly.
Let us know the results when you get a second set of hands to help and we'll go from there.
Last edited by Revi; Sep 12, 2013 at 08:56 AM.
Thread Starter
Pro
Joined: May 2001
Posts: 571
Likes: 5
From: usa
any body want to buy a car???? getting fed up. nothing is working and I keep getting confused.
do I want no vacuum at idle?, I had a heavy vac at Ilde, it would stay stuck on the finger, I moved it the port on the front pass side on the base of the carb, no vac at idle.
do I check for the 36* with the vacuum on ???
with the heavy vacuum on I get a reading of 10* after zero.
when I try to rev the engine to bring the mark to zero with the gun set at 36 I can only get 2-4 after ? and that at 4000 rpm.
begining not to like vettes very much.
do I want no vacuum at idle?, I had a heavy vac at Ilde, it would stay stuck on the finger, I moved it the port on the front pass side on the base of the carb, no vac at idle.
do I check for the 36* with the vacuum on ???
with the heavy vacuum on I get a reading of 10* after zero.
when I try to rev the engine to bring the mark to zero with the gun set at 36 I can only get 2-4 after ? and that at 4000 rpm.
begining not to like vettes very much.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Have you thought about trying a different timing light? Maybe this one has gone completely bonkers. I mean, one of your earlier posts would have us believe that the timing was retarding as you increased rpm. That sounds pretty crazy to me.
Scott
Scott
Thread Starter
Pro
Joined: May 2001
Posts: 571
Likes: 5
From: usa
any how been having one of those days.
I have set timing at idle many times, but after reading that our car are limited to 28*, I wanted to it give full advance.
going to go back out and start over
idle timing with out vac.
idle timing with vac
then RPM at 36* without vac
RPM at 36* with vac
Thread Starter
Pro
Joined: May 2001
Posts: 571
Likes: 5
From: usa
thought there was a question about if the vacuum was ported or manifold vacuum.
If you had your timing light connected (and set at "0" zero) to get your base timing at 8 BTDC, you then reconnected your vacuum hose and had to use the timing light to see that the timing mark moved off of the timing tab, why didn't you just adjust the timing light to bring the timing mark back to "0" zero and read the dial on the gun? The gun had to be in your hand and on or you wouldn't have been be able to see the timing mark move off of the scale.
I hope you had the vacuum hose plugged (a golf tee works great for this) and your springs were installed?
Do you know what vacuum advance can is installed (360-12, B20, B26)?
If your timing advances after you re-connect the vaccum line to the distributor (engine at idle), you are using manifold vacuum. That's a good thing.
Your idle timing (vacuum hose connected) should be around 24 BTDC if all is operating properly. Don't try to set 24 BTDC, what ever it is, it is. Your readings will tell us what is or isn't working properly.
Let us know the results when you get a second set of hands to help and we'll go from there.
If you had your timing light connected (and set at "0" zero) to get your base timing at 8 BTDC, you then reconnected your vacuum hose and had to use the timing light to see that the timing mark moved off of the timing tab, why didn't you just adjust the timing light to bring the timing mark back to "0" zero and read the dial on the gun? The gun had to be in your hand and on or you wouldn't have been be able to see the timing mark move off of the scale.
I hope you had the vacuum hose plugged (a golf tee works great for this) and your springs were installed?
Do you know what vacuum advance can is installed (360-12, B20, B26)?
If your timing advances after you re-connect the vaccum line to the distributor (engine at idle), you are using manifold vacuum. That's a good thing.
Your idle timing (vacuum hose connected) should be around 24 BTDC if all is operating properly. Don't try to set 24 BTDC, what ever it is, it is. Your readings will tell us what is or isn't working properly.
Let us know the results when you get a second set of hands to help and we'll go from there.