Timing Curve

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hugger73hatch
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Timing Curve

#1 Post by hugger73hatch » Thu Jul 24, 2008 11:37 pm

Ok, just looking for a suggestion here. Do most people lock out their timing to full advance? Right now I have mine set up to come full advanced at 3000 RPM. Running 8" ATI Treemaster converter with .625/.630 lift solid roller. Just wondering if I should lock mine out or not.
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
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Re: Timing Curve

#2 Post by John_Heard » Fri Jul 25, 2008 5:46 am

Yes lock it out.

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stroker1
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Re: Timing Curve

#3 Post by stroker1 » Fri Jul 25, 2008 7:34 am

Go ahead and lock it out. BUT if you don't have a nice gear reduction starter and a good flex plate you will be in trouble. Especially if you're like me and running over 13:1 compression with a tight LSA cam. Man, my motor has got some cranking compression for a small block. I've got 10 deg. start retard in the ignition box and it's still a little tough to spin over. I'm running a 4:1 gear reduction 3 HP starter and a Scat SFI flexplate.
'87 S10 stock suspension, Caltracs, 9" rearend, 1.82 Glide, 383 SBC,
Brodix Track1 Heads, 14:1 compression, 180 shot plate,
2" tube Hussler Headers, 1.38 60ft., 6.20 ET 1/8th, 109 MPH,
Still Tuning, more to come.

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Re: Timing Curve

#4 Post by ytnova » Fri Jul 25, 2008 8:49 am

Lock it out.
I am not really sure what the question is, but I am pretty sure the answer is Big Block.

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Re: Timing Curve

#5 Post by BILTIT » Fri Jul 25, 2008 9:18 am

Not to hyjack but any cons to locking out for a street car? Have a start retard in my ign. box, good mini starter and factory flexplate.
1974 Pontiac Ventura, 455P (9.5:1 comp.), 850DP, 3100 ''Tight'' 10'', 3.73's/28x13.5
Upgrading in June:
KRE 310cfm@.550 heads, 10.5 comp., hyd roller, 3800 tight 10'', better rear suspension.
Race Weight: 3750#'s
2007 best: 11.97 at 110 1.65 60ft.

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Re: Timing Curve

#6 Post by hugger73hatch » Fri Jul 25, 2008 1:03 pm

stroker1 wrote:Go ahead and lock it out. BUT if you don't have a nice gear reduction starter and a good flex plate you will be in trouble. Especially if you're like me and running over 13:1 compression with a tight LSA cam. Man, my motor has got some cranking compression for a small block. I've got 10 deg. start retard in the ignition box and it's still a little tough to spin over. I'm running a 4:1 gear reduction 3 HP starter and a Scat SFI flexplate.
I have a powermaster stater and a b&m sfi flexplate. I don't think I I'll have any problems with that. It is little bit above 13:1, and I have a lot of cranking compression too. Does everyone here that has the distributor locked out run a start retard in their ignition box?
73 Nova Hatchback, 408 Small Block 13-1, Iron Heads, 6.972 @ 98.362, 1.468 60', 3450 lbs, still tuning
28 x 9 Slick, N/A

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Re: Timing Curve

#7 Post by mytmouz » Fri Jul 25, 2008 1:05 pm

I don't. Starter kickback problems are greatly reduced as long as the rotor is properly phased...
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Re: Timing Curve

#8 Post by stroker1 » Fri Jul 25, 2008 3:02 pm

tporter_02 wrote:I don't. Starter kickback problems are greatly reduced as long as the rotor is properly phased...
Explain that one to me. Phasing the rotor has no effect that I can see except when you initially drop the distributor in. After that when you set the timing with the distributor locked out, the rotor is where it is.
'87 S10 stock suspension, Caltracs, 9" rearend, 1.82 Glide, 383 SBC,
Brodix Track1 Heads, 14:1 compression, 180 shot plate,
2" tube Hussler Headers, 1.38 60ft., 6.20 ET 1/8th, 109 MPH,
Still Tuning, more to come.

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Re: Timing Curve

#9 Post by ytnova » Fri Jul 25, 2008 7:46 pm

Rotor phase can be an issue under certain conditions, especially with timing retards, because you are delaying the normal time between the triggering the pickup and firing the plug, basically all you are doing is making sure the reluctor wheel is triggering the pickup at the same time the rotor is pointed at the terminal under full load. Example, If you have engine with 36 degrees of timing and its locked out and a analog msd(6al, 7al, etc.) you wire the dist. pickup to the retard box, then the white wire from the retard box to the msd(old points wire hookup). Then you have to go back and add 20 degrees of timing to get back to 36 (the retard box delays the trigger point 20 dergrees). This gives you the "window" to retard the timing in, but the phasing is incorrect unless you activate the retard box and are pulling out all 20 degrees. This is one of the many places where a crank trigger and/or a digital box really helps. Alot of cheap distributors or ones that are not locked out have phasing issues with no timing retard, it very easy to check, but not always easy to correct. Take an old cap, cut a hole under number one terminal so you can see the lower portion of the terminal, check the timing with a adjustable light and and then set the timing light to the same amount of timing and shine it at the hole you cut, the tip of the rotor should be directly beneath the terminal. If its off, you can try and move the pickup, clockwise or counterclockwise, or buy a adjustable rotor, which by the way usually move, or step up to a crank trigger. As far as myself, locked out at 40 degrees, with a 13.5 to 1 522 bbc and I have no issues.
I am not really sure what the question is, but I am pretty sure the answer is Big Block.

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Re: Timing Curve

#10 Post by mytmouz » Fri Jul 25, 2008 8:43 pm

The following is a reprint off of another site that explains it better than I can. I am running the same starter for the past 6 years, the only flywheel change has been from going to an internal balance engine from an external...

You must adjust the rotor tip to #1 plug tower index to be perfectly in relationship to one another according to how you are using your box.
All these problems I keep reading about you can not have if the # 1 plug tower is closest to the rotor tip when it is trying to fire # 1 spark plug. Electricical energy will flow through the path of least resistance.

So even if the rotor is closer to #1 it can jump to a different cylinder that has no or low resistance to current flow. 30 deg from the #1 plug tower is too far and if you have much compression I can promise it will be a different cylinder with the piston on the way up that will fire. That is where the kick back comes from, when you are using the start retard and the rotor was already retarded by accident or on purpose You are firing a cylinder that should not get ignition first.

If your distributor is locked out with zero advance and you don't have anything else giving an advance curve and the engine is run as an all motor engine all the time, You bring deg marks on harmonic dampener to the total ignition advance you run. That is where the rotor needs to be in align with # 1 Plug Tower in the distributor cap.

You have an advance curve in either the distributor or in a box so the timing is getting advanced with rpm increases;

Example if you have 20 deg of advance in dist or in box, you adjust Rotor to be 10 deg retarded by backing off till balancer is showing 10 deg retard from where it is supposed to be at full advancve. You are splitting the difference. Never use the MSD Start Retard if total retard will exceed 25 degrees for starting.

If dist is locked in and you are using nitrous, blower, turbo etc, requiring a running retard at launch or down track. Set and adjust rotor to be in index with balancer at 1/2 of the total retard you need maximum. SO for example if your full nitrous or blower hit requires a 15 deg retard, back off on balancer by 7 1/2 deg retard. So if normal timing is 0 deg and you pull out 15 deg total, set your rotor index to be 22 1/2 deg . IN that example this engine can benefit from 15 to 20 deg start retard but no more. 25 deg start retard is too much. That is why we had originally chips of different rates of retard available. You could retard from 2 deg up to 25 deg as you needed it. I am not certain if you can adjust the amount of degrees in the start retard with the new boxes. I do know that if you have rotor indexed perfect at full retard, it will be really tough on starter to start it. You need to split the difference.

Is it Ok to use the retard that is built in to the Digital 7 box.
Of course it is ok to use. Do all of you think MSD would intentionally put something into the ignition systems to cause you problems like broken flywheels, startrs etc?

All of this was thorougly tested with correct ignition systems in two different cars with both having near 17.00 -1 compression before it was ever released to the public. I was the test bed for the first protypes and the original development, being the whole thing was my idea in the first place. After we felt it was ready to be sold, at my request Warren Johnson was included in the testing of the 2nd prototype of this and he liked it. Both his model and mine looked sligtly different than the ones sold to the public but were the same in function.

Of course all of the early versions were analog with manual switching, and all the newer versions have a lot of automatic features and are all high speed oversampling digital resulting from Engineer Steve Masters (Father of all MSD Digital Boxes) taking our old antiquated slow analog technology and incorporting high speed Digital tech.

All of the features of it are ok to use. I do like this regular Digital 7 box that is adjusted with the little rotary adjusters on the end of it (7520) or the programmable (7530 - 7531). What the retard is really, is an adjustable Start-Run Retard function that is contained within. The starting retard is very helpful for engines running locked out distributors with high compression, as they are trying to do the initial start while at full timing advance.

In the past this resulted in either a very slow rotating engine and mucho load on the starting electrical circuits, or by just spinning the engine and flipping the switch, which usually did work ok unless the initial firing cylinder had too much fuel in it and then KABOOM. Intakes were blown off, Carbs were blown off and worse has happened just because of starting the car by spinning engine and flipping switch to on.

In the early prototypes of the original Start-Run Retard we tried several different rates of retard by using the already existing Resistor Plug in Modules, called Chips. I discovered that when we tried to retard beyond 25 degrees to 30 and 35 degree retards, that there was a problem of the wrong cylinder fireing instead of the # 1 cylinder. So by trial and by error on my part we determined that we could retard the ignition to as much as 25 degrees with no failures. The Initial MSD Start-Run Retard came with chips to allow 20 degrees of retard, but the 25 deg chip was available for those requesting for more. This beginning concept was tested by using an engine with 16.85 - 1 compression ratio.

On the opposite side of the little Control Panel we wired a retard to be available for use when engine was running at any desired rpm that was activated by a customer supplied switch, in the car. That retard was designed initially to be used for two different and unique purposes, and also did use a plug in resistor called a Retard Chip.

That retard chip allowed an engine to be run with an intentional too much advance during the initial launch which actually gave it more power in the lower rpm ranges, because race tuners could tune the launch to be on the verge of pre-ignition, which in reality in the lower gears was not harmful and did give more cylinder pressures as the piston was leaving TDC on the power stroke. As the car got into the higher gears where the engine was under hard load, the driver could just by activating a switch (user, supplied and installed) to bring the engine ignition back to where they felt it to be a safe limit and where the engine was comfortable as it was in the higher geared rpm ranges where there was no additional multiplication of forces like in the low gear while launching.
The bottom line was better ET and a harder launch without engine damage.

The High Gear Retard function also could serve as a sort of Traction Control device, maunually operated, when encountering a slick track or bad track conditions. For that let us say that you are sitting in the lanes and almost ready to run. Opps, something happen in the lane you are getting in and you have no time to retune anything. You quickly make a desicion to use the retard chip that is in place or if you have been thoughtful in advance, you had a few retard chips within your reach so quickly swap them for more or less retard (BEFORE Launch) than you had in. You launch with the 3 position toggle switch in the full retard position, which will pull bottom end launch power out of the car. As quick as you get traction, you flip switch to the middle and leave it there until you hit high gear and again move switch to the right to get your high gear retard effect which should bring the engine timing back to where it is comfortable. WE initially had a little small panel with a Resistor Chip on each side, with a 3 position toggle switch in the middle. The switch was a spring loaded momentary switch when pushed to the left for a start retard. When engine started you released it to the center and neutral position. If you wanted to use the High gear retard you moved the switch into a locked position to the right and it stayed there unless you flipped it back to the center to de-activate all retards. Different drivers used different styles of switches in their cars. I had one that I could hit when I shifted high gear. Others used toggle switches.

+========================================

Now that I have told you how to invent the wheel, when all you wanted to know was if you could drive the car (Joke). I will tell you how all I just told is relavent to you now.

Now you have contained in that little Digital Ignition Module all or many of the features I just named that have been made to be simplier and are also now Digital, which makes them act and react much much quicker and better than anything we originally used. Now you can set your Starting Retard to be active or to be non-active, by your selection, and instead of the driver having to release the momentary loaded 3 position, toggle switch, The box senses when engine RPM is sufficient to go back to initial advance settings. You can now activate a two step and a Start-Run Retard in the same box by only flipping a switch or two in your car that you supply. Or in the programmable boxes you can even set a starting launch retard which can be left out or ramped back in as you want.

You can use the starting retard feature to make it easier for a high compression engine to spin for starting. You can use the adjustable for rpm now, second stage of retard for any purpose you wish. Read how we used the original design to aid traction, and at the same time regained full ignition as soon as we had traction. You can too. That wire going to the toggle switch, activates it when it is set correctly in the adjusters on the end of the Digital Box. You can use the retard for retarding the engine for N2o, for blower boost or for turbo boost, or use it for the examples I gave in my writings.

A couple of words of suggestion for all Digital Box users of any brand. Buy a Spike Protector and wire it in line with your Battery fed Positive and Ground. That helps protect your bax from failures that can damage it. All Computers and Digital controls are far more sensitive to Spikes than the former slower acting analog components.

Also in all applications using the Digital 7 box try to install it where it will have fresh air flowing over the heat sinks on the outside case.
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stroker1
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Re: Timing Curve

#11 Post by stroker1 » Sat Jul 26, 2008 9:17 am

Unless I've missed something, it's still pretty much Is What It Is kind of thing. I don't have an adjustable rotor such as the ones found on a crank trigger set up. And my pick up is not adjustable. So if it's off there is pretty much nothing I can do about it except to know that it's off or not off unless I have an adjustable rotor, right?
'87 S10 stock suspension, Caltracs, 9" rearend, 1.82 Glide, 383 SBC,
Brodix Track1 Heads, 14:1 compression, 180 shot plate,
2" tube Hussler Headers, 1.38 60ft., 6.20 ET 1/8th, 109 MPH,
Still Tuning, more to come.

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Re: Timing Curve

#12 Post by ytnova » Sat Jul 26, 2008 10:32 am

You can get a little creative. On my msd rotor, the tip is removeable and just a flat, straight piece of metal, so I took a tip from small block ford rotor, which is t-shaped at the end and cut off one side, making it kinda L shaped. This made the blade or tip wider at the end, the trailing edge is now longer, which allowed the rotor to be out of phase a tad when using the retard box, but the trailing edge of the tip was still under the terminal. This isn't a big deal because I am not pulling out the whole 20 degrees that I had to put back in with retard, only 10 degreesor so, that trailing edge never goes back far enough when the retard is active to cause an issue with the terminal before it. These things are not usually an issue, but if you have high cylinder pressure, boost, or spraying alot of nitrous and are having popping or breakup issues, or are breaking parts when you start the engine, this is a good place to look.
I am not really sure what the question is, but I am pretty sure the answer is Big Block.

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Re: Timing Curve

#13 Post by jmarkaudio » Sat Jul 26, 2008 2:28 pm

Lock it out. Only on a street car with a milder cam do you really need a curve.
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Re: Timing Curve

#14 Post by mytmouz » Sat Jul 26, 2008 7:48 pm

stroker1 wrote:Unless I've missed something, it's still pretty much Is What It Is kind of thing. I don't have an adjustable rotor such as the ones found on a crank trigger set up. And my pick up is not adjustable. So if it's off there is pretty much nothing I can do about it except to know that it's off or not off unless I have an adjustable rotor, right?
As someone referenced in an earlier post, you can get an adjustable rotor for your stock MSD style distributor. The pointer on it is adjustable. You have to keep them checked though as they will slip. I recently swapped over to a crank setup ( it was free ) but until then I ran the 45551 MSD distributor and the adjustable rotor with no problems...
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Re: Timing Curve

#15 Post by dadnova » Mon Jul 28, 2008 5:49 pm

I use the springs and bushings still- MSD
Car starts nice and easy @ 8-10 degrees, cruse around the pits and so on.
By 2500 RPM its at 36-38 degrees.
Works for me.

But that's why the make different cars, different strokes for different folks.
Gotta plan, spend it before she can, and go as fast as you can.

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