Any guess about running STATIC timing?
11-02-2007, 07:21 AM
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Car: '82 Camaro 11.7@121
Engine: 377
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Axle/Gears: Dana 44 / 3.31:1
Any guess about running STATIC timing?
Here's the background info...
I'm working on a 383 with a pretty big cam (255/260 @.050 .580/.600 lift).
I currently use a Mallory Unilite. When I advance the initial timing enough to get the BEST idle (> 25*), even on the lowest setting (18*) the mechanical advance gives me too much total (43*).
I have a small cap CC-HEI distributor that I plan on using or a number of reasons:
1 Easier to get parts
2 More reliable
3 Don't need a ballast resistor in the power supply
4 No phasing issues
5 In preparation for Mega-Squirt install
What I plan to do this weekend is install the HEI in "Limp Home Mode" with as much initial advance as possible while still being able to start the engine. I suspect that I can 30*. Then run it with static timing for now.
My questions are:
Is anyone else running static timing (crank trigger, etc.), if so how does it work for you?
does anyone with a similarly large cam have any anecdotal reports about how much static timing you could successfully run?
Thanks,
I'm working on a 383 with a pretty big cam (255/260 @.050 .580/.600 lift).
I currently use a Mallory Unilite. When I advance the initial timing enough to get the BEST idle (> 25*), even on the lowest setting (18*) the mechanical advance gives me too much total (43*).
I have a small cap CC-HEI distributor that I plan on using or a number of reasons:
1 Easier to get parts
2 More reliable
3 Don't need a ballast resistor in the power supply
4 No phasing issues
5 In preparation for Mega-Squirt install
What I plan to do this weekend is install the HEI in "Limp Home Mode" with as much initial advance as possible while still being able to start the engine. I suspect that I can 30*. Then run it with static timing for now.
My questions are:
Is anyone else running static timing (crank trigger, etc.), if so how does it work for you?
does anyone with a similarly large cam have any anecdotal reports about how much static timing you could successfully run?
Thanks,
Last edited by esc; 11-02-2007 at 12:06 PM.
11-02-2007, 08:16 AM
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Re: Any guess about running STATIC timing?
Are you checking the timing properly by disconnecting the ESC wire?
I would check to make sure your timing marks are accurate first. Using a piston stop and a degree wheel, find out where TDC really is.
It sounds like maybe the roll pin broke on the distributor gear and changed your timing.
I run a MSD distributer that's locked out to full advance. My timing is set at 37* all the time but my ignition also has a start retard that will retard the ignition while starting the engine. Once it reaches 500 rpm, it goes back to full advance.
I don't recommend locking out the timing to full advance for a street car.
I would check to make sure your timing marks are accurate first. Using a piston stop and a degree wheel, find out where TDC really is.
It sounds like maybe the roll pin broke on the distributor gear and changed your timing.
I run a MSD distributer that's locked out to full advance. My timing is set at 37* all the time but my ignition also has a start retard that will retard the ignition while starting the engine. Once it reaches 500 rpm, it goes back to full advance.
I don't recommend locking out the timing to full advance for a street car.
11-02-2007, 12:03 PM
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Re: Any guess about running STATIC timing?
The information in my first post is accurate. My timing marks are accurate and there is nothing "wrong" with my current distributor.
I don't have ESC, or any other "electronic" mechanism for controlling my timing.
Most people would not call my car a "street" car, certinly not a "daily driver".
But if you are running 37* at 500 RPM, I don't think I'll have any problems...as long as it will start with out any retard. If it won't start, I'll retard it until it will and that will be my static timing...for now.
Thanks,
I don't have ESC, or any other "electronic" mechanism for controlling my timing.
Most people would not call my car a "street" car, certinly not a "daily driver".
But if you are running 37* at 500 RPM, I don't think I'll have any problems...as long as it will start with out any retard. If it won't start, I'll retard it until it will and that will be my static timing...for now.
Thanks,
11-02-2007, 07:20 PM
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Re: Any guess about running STATIC timing?
I don't run 37* at 500 rpm. My engine idles at around 1000 rpm. Below 800 and it dies. My engine has no cruising ability. It's designed to drive around the pits and back up the return road. When it's working, the throttle is at WOT. With a 6000 stall converter, the rpms are always higher than a typical street driven car.
I still say somethings not right if you can't bring the timing down enough for it to idle. It should still idle at 10*. Once you get a good idle timing, you get the distributor recurved to give full advance (at whatever works best for your engine) to come in before 3000 rpm. Most engines want full advance in the 32-38 range but each engine is different. The best full advance can also be affected by many things such as fuel grade, altitude, heads etc. 43* timing is normally too much.
Years ago after building an engine, I found the engine ran better when I kept bumping the timing up. When I hit 45*, I suspected something was wrong. I was using an adjustable timing pointer. I used a piston stop and degree wheel to check where the balancer was at TDC. I discovered that the timing pointer was off by 8*. What I thought was 45* was actually 37* When I started at 32* and it ran like crap, it was because the timing was really 24*. Readjusting the pointer to point at the mark on the balancer when it was directly at TDC made a big difference.
----------
Best total timing can only be found on a dyno where the engine makes the most power. Any other changes done to the engine such as jetting, plug gap etc won't affect where the engine likes the timing. On the dragstrip, you need to watch the MPH. When adjusting the timing and MPH drops off, the timing needs to be turned back to a previous setting.
The backyard way of advancing the timing until it starts to ping under load then turn it back a couple of degrees is a long way from the best timing. It can usually be 5-10* from the best timing.
I still say somethings not right if you can't bring the timing down enough for it to idle. It should still idle at 10*. Once you get a good idle timing, you get the distributor recurved to give full advance (at whatever works best for your engine) to come in before 3000 rpm. Most engines want full advance in the 32-38 range but each engine is different. The best full advance can also be affected by many things such as fuel grade, altitude, heads etc. 43* timing is normally too much.
Years ago after building an engine, I found the engine ran better when I kept bumping the timing up. When I hit 45*, I suspected something was wrong. I was using an adjustable timing pointer. I used a piston stop and degree wheel to check where the balancer was at TDC. I discovered that the timing pointer was off by 8*. What I thought was 45* was actually 37* When I started at 32* and it ran like crap, it was because the timing was really 24*. Readjusting the pointer to point at the mark on the balancer when it was directly at TDC made a big difference.
----------
Best total timing can only be found on a dyno where the engine makes the most power. Any other changes done to the engine such as jetting, plug gap etc won't affect where the engine likes the timing. On the dragstrip, you need to watch the MPH. When adjusting the timing and MPH drops off, the timing needs to be turned back to a previous setting.
The backyard way of advancing the timing until it starts to ping under load then turn it back a couple of degrees is a long way from the best timing. It can usually be 5-10* from the best timing.
Last edited by AlkyIROC; 11-02-2007 at 07:24 PM. Reason: Automerged Doublepost
11-02-2007, 08:17 PM
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Re: Any guess about running STATIC timing?
I think that you misunderstand.
It's not that it WONT idle with less timing, it just idles better with more.
Every engine I have ever had any experience with, which had a big cam (and there have been several), required more initial advance than stock. The bigger the cam, the more overlap, the more initial timing it will need.
You keep going back to a "typical street driven car." Let me assure you that nothing having to do with a "typical street driven car." is appropriate to this discussion.
My engine has a large cam (as mentioned). Timing that is appropriate for a stock or mild engine will not be appropriate for mine. The idea that 10 degrees initial would be sufficient makes me think that you really don't understand the situation.
Although I am getting tired of repeating myself, i will state it again. There is nothing wrong with my balancer or the timing it indicates.
Earlier today you stated:
"My timing is set at 37* all the time but my ignition also has a start retard that will retard the ignition while starting the engine. Once it reaches 500 rpm, it goes back to full advance."
Now you say that "I don't run 37* at 500 rpm." Which is it?
Thank you again for your advice, but you have said nothing that would convince me that my existing plan is not the best plan. I will continue as planned and let you know how it works out.
It's not that it WONT idle with less timing, it just idles better with more.
Every engine I have ever had any experience with, which had a big cam (and there have been several), required more initial advance than stock. The bigger the cam, the more overlap, the more initial timing it will need.
You keep going back to a "typical street driven car." Let me assure you that nothing having to do with a "typical street driven car." is appropriate to this discussion.
My engine has a large cam (as mentioned). Timing that is appropriate for a stock or mild engine will not be appropriate for mine. The idea that 10 degrees initial would be sufficient makes me think that you really don't understand the situation.
Although I am getting tired of repeating myself, i will state it again. There is nothing wrong with my balancer or the timing it indicates.
Earlier today you stated:
"My timing is set at 37* all the time but my ignition also has a start retard that will retard the ignition while starting the engine. Once it reaches 500 rpm, it goes back to full advance."
Now you say that "I don't run 37* at 500 rpm." Which is it?
Thank you again for your advice, but you have said nothing that would convince me that my existing plan is not the best plan. I will continue as planned and let you know how it works out.
I don't run 37* at 500 rpm. My engine idles at around 1000 rpm. Below 800 and it dies. My engine has no cruising ability. It's designed to drive around the pits and back up the return road. When it's working, the throttle is at WOT. With a 6000 stall converter, the rpms are always higher than a typical street driven car.
I still say somethings not right if you can't bring the timing down enough for it to idle. It should still idle at 10*. Once you get a good idle timing, you get the distributor recurved to give full advance (at whatever works best for your engine) to come in before 3000 rpm. Most engines want full advance in the 32-38 range but each engine is different. The best full advance can also be affected by many things such as fuel grade, altitude, heads etc. 43* timing is normally too much.
Years ago after building an engine, I found the engine ran better when I kept bumping the timing up. When I hit 45*, I suspected something was wrong. I was using an adjustable timing pointer. I used a piston stop and degree wheel to check where the balancer was at TDC. I discovered that the timing pointer was off by 8*. What I thought was 45* was actually 37* When I started at 32* and it ran like crap, it was because the timing was really 24*. Readjusting the pointer to point at the mark on the balancer when it was directly at TDC made a big difference.
----------
Best total timing can only be found on a dyno where the engine makes the most power. Any other changes done to the engine such as jetting, plug gap etc won't affect where the engine likes the timing. On the dragstrip, you need to watch the MPH. When adjusting the timing and MPH drops off, the timing needs to be turned back to a previous setting.
The backyard way of advancing the timing until it starts to ping under load then turn it back a couple of degrees is a long way from the best timing. It can usually be 5-10* from the best timing.
I still say somethings not right if you can't bring the timing down enough for it to idle. It should still idle at 10*. Once you get a good idle timing, you get the distributor recurved to give full advance (at whatever works best for your engine) to come in before 3000 rpm. Most engines want full advance in the 32-38 range but each engine is different. The best full advance can also be affected by many things such as fuel grade, altitude, heads etc. 43* timing is normally too much.
Years ago after building an engine, I found the engine ran better when I kept bumping the timing up. When I hit 45*, I suspected something was wrong. I was using an adjustable timing pointer. I used a piston stop and degree wheel to check where the balancer was at TDC. I discovered that the timing pointer was off by 8*. What I thought was 45* was actually 37* When I started at 32* and it ran like crap, it was because the timing was really 24*. Readjusting the pointer to point at the mark on the balancer when it was directly at TDC made a big difference.
----------
Best total timing can only be found on a dyno where the engine makes the most power. Any other changes done to the engine such as jetting, plug gap etc won't affect where the engine likes the timing. On the dragstrip, you need to watch the MPH. When adjusting the timing and MPH drops off, the timing needs to be turned back to a previous setting.
The backyard way of advancing the timing until it starts to ping under load then turn it back a couple of degrees is a long way from the best timing. It can usually be 5-10* from the best timing.
11-02-2007, 09:41 PM
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Re: Any guess about running STATIC timing?
My timing is locked out at 37* so it has no mechanical or vacuum advance. In a race car I don't need either. My ignition has a built in start retard. While cranking the engine over, it can retard the timing up to 20*. While cranking, the engine only cranks over at 200-300 rpm at the most. As soon as it fires up, the ignition sees it's over 500 rpm and stops retarding the timing. The timing retard is to allow the engine to crank over without trying to kick back with too much advance.
So if your engine starts and likes to idle at 18*, set your base timing to 18* but you don't drive around at an idle. Have your distributor recurved so that the total timing will be 36* before 3000 rpm and go driving. If you don't plan on driving it on the street, lock out your timing to full advance at whatever timing gives you the most power, install a start retard so the engine cranks over easier while starting and run it.
The small cap HEI has a small diameter shaft. Although it will work and I tried using one myself for a couple of years, it's not very strong compared to a large cap HEI or aftermarket distributor. I also took a large cap HEI and welded the weights closed to lock it out.
So if your engine starts and likes to idle at 18*, set your base timing to 18* but you don't drive around at an idle. Have your distributor recurved so that the total timing will be 36* before 3000 rpm and go driving. If you don't plan on driving it on the street, lock out your timing to full advance at whatever timing gives you the most power, install a start retard so the engine cranks over easier while starting and run it.
The small cap HEI has a small diameter shaft. Although it will work and I tried using one myself for a couple of years, it's not very strong compared to a large cap HEI or aftermarket distributor. I also took a large cap HEI and welded the weights closed to lock it out.
Last edited by AlkyIROC; 11-02-2007 at 09:45 PM.
11-03-2007, 12:55 AM
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Re: Any guess about running STATIC timing?
Why not get a vacume advance hooked up to run of manifold vacume?? That way you can have more advance at an idle to tame your cam down and then run whatever kind of mechanical advance curve that you want. Using the vacume advance with full vacume at idle will give you more advance on top of your intial advance, and then once you start to get into the throttle the vacume can will no longer be in effect. That way you can run any kind of total advance that you want and not have to run to much total advance. You may need to play with some weight and spring combo,s but this is what I would do. Lots of guys forget that you can use the vacume advance part of your disti to help with Large cams at idle instead of cruising conditions. Just my thoughts.
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11-03-2007, 01:03 AM
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Re: Any guess about running STATIC timing?
maybe your just to fat at idle, making it seem to run better with more timing. I am sure you know that more timing acts like leaning it out, and less acts like you are richening the mix. That could be something to do with it.
11-03-2007, 07:57 AM
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Re: Any guess about running STATIC timing?
The problem with that is that I get a LOT more vacuum at cruise than at idle.
In a way you are right, an O2 sensor would tell you that I do run rich at idle, but the problem is a result of exhaust returning into the combustion chamber during valve overlap. So it has to be rich in order to get enough fuel to support combustion. At the same time the presence of the exhaust slows down the combustion process. Both resulting the need for more advance.
All of these issues are a direct result of running a big cam.
All of these issues are a direct result of running a big cam.
12-08-2007, 03:28 PM
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Re: Any guess about running STATIC timing?
Well it's a month later and I finally finished up. Scope creep made it take a lot longer than origionally anticipated.
I have yet to put a timing light on it. I just gave it all the advance it could take without problems starting.
I actually runs very well. The idle is smooth (for the size cam) and steady. There are no off idle problems and it pulls strong. I have not taken it over about 5000 RPM so far but there are no problems and no noticeable power loss.
So far, I like static timing. But I'll probably like it even more once the mega squirt is controlling it.
I have yet to put a timing light on it. I just gave it all the advance it could take without problems starting.
I actually runs very well. The idle is smooth (for the size cam) and steady. There are no off idle problems and it pulls strong. I have not taken it over about 5000 RPM so far but there are no problems and no noticeable power loss.
So far, I like static timing. But I'll probably like it even more once the mega squirt is controlling it.
12-08-2007, 04:39 PM
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Re: Any guess about running STATIC timing?
Ha! If you can get the megasquirt to control it. I've heard numerous stories of people never getting megasquirt to run properly.
12-08-2007, 07:06 PM
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Re: Any guess about running STATIC timing?
Thats only because they didnt try hard enough.
The megasquirt is only as good as the effort you take to build it.
With that being said,
my megasquirt system controls the stock HEI with external coil and 8 pin module with no problems. I can make any changes to ignition timing that I want.
The megasquirt is only as good as the effort you take to build it.
With that being said,
my megasquirt system controls the stock HEI with external coil and 8 pin module with no problems. I can make any changes to ignition timing that I want.
12-08-2007, 07:09 PM
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Re: Any guess about running STATIC timing?
I know...but there are plenty of other people with stories of it working (like the post just abvoe this one!). My guess is that it has more to do with the person doing it than anything else. I'm not worried.
12-08-2007, 07:26 PM
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Re: Any guess about running STATIC timing?
I will say one thing!
When using the hall input circuit with the 8 pin module, it is necessary to perform one of two modifications to the circuit (simple mods) to eliminate problems caused by voltage drift of the module on hot days.
If you dont make the mods, you will have a LOT of problems one 90+ degree days. It basically mimics the symptoms of a bad module (bucking, tach fluctuations, stalling, no hot restart) as the module heats up and the signal weakens to the point that you lose an RPM signal to the megasquirt.
The mods make the megasquirt more responsive to the square wave signal generated, and eliminate this problem.
I had a few weeks this summer of very frustrating troubleshooting before I figured out the problem. Since making the mod, ZERO problems on even the hottest days.
PM me if you want more details or a link.
When using the hall input circuit with the 8 pin module, it is necessary to perform one of two modifications to the circuit (simple mods) to eliminate problems caused by voltage drift of the module on hot days.
If you dont make the mods, you will have a LOT of problems one 90+ degree days. It basically mimics the symptoms of a bad module (bucking, tach fluctuations, stalling, no hot restart) as the module heats up and the signal weakens to the point that you lose an RPM signal to the megasquirt.
The mods make the megasquirt more responsive to the square wave signal generated, and eliminate this problem.
I had a few weeks this summer of very frustrating troubleshooting before I figured out the problem. Since making the mod, ZERO problems on even the hottest days.
PM me if you want more details or a link.
Last edited by Toehead; 12-08-2007 at 07:45 PM.
12-08-2007, 09:31 PM
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Re: Any guess about running STATIC timing?
Thank you for the advice.
I am considering using the HEI in limp home mode instead of taking advantage of it's other capabilities. Since I am using a 300+ I don't need to worry about dwell. All I really need is a relatively accurate trigger, which "limp home" mode should provide. I expect it will be relatively easy to make it work. If I'm wrong I'll work a little harder, but I'm confident it will work.
I am considering using the HEI in limp home mode instead of taking advantage of it's other capabilities. Since I am using a 300+ I don't need to worry about dwell. All I really need is a relatively accurate trigger, which "limp home" mode should provide. I expect it will be relatively easy to make it work. If I'm wrong I'll work a little harder, but I'm confident it will work.
12-09-2007, 09:01 AM
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Re: Any guess about running STATIC timing?
That should work, providing you do the mods to make sure you get a clean trigger in the hot weather.
How are you going about controlling the timing? Are you going to run an MSD with the megasquirt.
How are you going about controlling the timing? Are you going to run an MSD with the megasquirt.
12-09-2007, 09:36 AM
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12-09-2007, 05:15 PM
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Re: Any guess about running STATIC timing?
Ah, didnt catch that.
Looks like a good system.
Good luck with your build. If you have any MS specific questions, feel free to PM me.
-Brendan
Looks like a good system.
Good luck with your build. If you have any MS specific questions, feel free to PM me.
-Brendan
01-27-2008, 02:37 PM
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Re: Any guess about running STATIC timing?
OK, I know it has been a while...but I finally had a chance to put a timing light on it and I thought I would relay my results with running static timing with no retard mechanism what so ever.
First, it runs great! It idles better with less of a drop in RPM when shifting from neutral into gear. It pulls about 2"s more vacuum at idle and throttle responce and power both feel better all across the power band. I even think I am getting better mileage!
I played around with the timing for a while, adjusting it, driving it adjusting it again. Even when I have so much timing that it starts to run poorly it will still start..as long as my battery is fully charged. I finally settled on a spot where I had enough timing that it seemed to idle and run very well and would start with a slightly less than fully charged (10.75v) battery. I put the light on it today and it turns out that I am running 32 degrees of advance.
So I am actually running a little more advance that I did with the Mallory mechanical advance distributor. I suspect that a few more degrees of advance would be helpful, but I am much happier with were it is now than I was with the Mallory. So much in fact that I am putting the Mega Squirt on hold while I finish up a few other projects no the car.
In conclusion, to answer my own question, static timing works great, has helped the cars drivability and does not appear to have any negative side effects what so ever.
First, it runs great! It idles better with less of a drop in RPM when shifting from neutral into gear. It pulls about 2"s more vacuum at idle and throttle responce and power both feel better all across the power band. I even think I am getting better mileage!
I played around with the timing for a while, adjusting it, driving it adjusting it again. Even when I have so much timing that it starts to run poorly it will still start..as long as my battery is fully charged. I finally settled on a spot where I had enough timing that it seemed to idle and run very well and would start with a slightly less than fully charged (10.75v) battery. I put the light on it today and it turns out that I am running 32 degrees of advance.
So I am actually running a little more advance that I did with the Mallory mechanical advance distributor. I suspect that a few more degrees of advance would be helpful, but I am much happier with were it is now than I was with the Mallory. So much in fact that I am putting the Mega Squirt on hold while I finish up a few other projects no the car.
In conclusion, to answer my own question, static timing works great, has helped the cars drivability and does not appear to have any negative side effects what so ever.
01-27-2008, 03:34 PM
#20
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Re: Any guess about running STATIC timing?
With the long duration and overlap cam you have you need lots lots lots if timing at idle and low rpm because the exhaust reversion (egr effect) at idle is so strong. This egr effect slows the fuel burn timing, requiring more earlier spark timing at idle to compensate. (spark advance)
On most motors with a cam larger than 240+@.050 or so you can essentually lock out the distributor advance.
Set your timing locked out to what ever timing creates the most high rpm power @WOT.
32 to 36deg BTDC.
To start the motor when hot with this amount of timing install a ignition power cut off switch on the power wire going to the ignition module or amplifier.
The switch most be able to handle the amp draw o the amplifier .
a good 15 amp rated switch is plenty.. Kick the starter over with the spark off, then throw the switch and it will fire easily.
I run my steet car with a comp 284H cam 240-246@.050" with this locked out timing (32 to 36deg BTDC) combined with 12deg of (ported) vacuum advance and it runs, idles, cruises and accelerates like a champ.
The simple dash mounted ignition start up interupt switch takes care of any hot start, starter issues.
Ford actually has had a automatic start retard circuit built into their Duraspark II ignition box for years. Thats why a Ford motors rarely has a hot start/slow starter cranking problem that is very common on GM cars once you dial in the increases spark timing at idle.
Try the cut off switch.
On most motors with a cam larger than 240+@.050 or so you can essentually lock out the distributor advance.
Set your timing locked out to what ever timing creates the most high rpm power @WOT.
32 to 36deg BTDC.
To start the motor when hot with this amount of timing install a ignition power cut off switch on the power wire going to the ignition module or amplifier.
The switch most be able to handle the amp draw o the amplifier .
a good 15 amp rated switch is plenty.. Kick the starter over with the spark off, then throw the switch and it will fire easily.
I run my steet car with a comp 284H cam 240-246@.050" with this locked out timing (32 to 36deg BTDC) combined with 12deg of (ported) vacuum advance and it runs, idles, cruises and accelerates like a champ.
The simple dash mounted ignition start up interupt switch takes care of any hot start, starter issues.
Ford actually has had a automatic start retard circuit built into their Duraspark II ignition box for years. Thats why a Ford motors rarely has a hot start/slow starter cranking problem that is very common on GM cars once you dial in the increases spark timing at idle.
Try the cut off switch.
05-10-2008, 10:55 PM
#21
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Car: '82 Camaro 11.7@121
Engine: 377
Transmission: 400
Axle/Gears: Dana 44 / 3.31:1
Re: Any guess about running STATIC timing?
Well it turns out that the small cap HEI distributor has an advance curve built in to the module which operates without any computer. I have read reports of others with differnt curves, but mine provides an additional 7 degrees abouve 2500 rpm.
So my timing isn't really static after all.
So my timing isn't really static after all.
05-18-2008, 09:41 PM
#22
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Car: 1987 Formula 350
Engine: 6.0 boost and smak
Transmission: 4l80e
Axle/Gears: 9bolt 3.27
Re: Any guess about running STATIC timing?
I never even thought about that... this the advancing taking place in the module? and if so does the aftermarket (MSD) do the same thing? The main thing I am thinking of is getting rid of it. for logging accuracy!!
05-18-2008, 10:03 PM
#23
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Car: '82 Camaro 11.7@121
Engine: 377
Transmission: 400
Axle/Gears: Dana 44 / 3.31:1
Re: Any guess about running STATIC timing?
Yes, the advance is taking place in the module while running in limp home mode, with no computer hooked up. If the module is hooked to an operational computer, I don't think that the built in advance would be triggered.
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