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Crank Trigger Timing Problem
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DRR S/Pro
posted
I have the earlier version of the 7AL-3 (7230) with a MSD crank trigger, all connected to a MSD Grid. I've been running the car using these items for the past four years with no problems, I've checked the timing many time, it has always been spot on. Two days ago I checked the timing which had been statically set at 35 degrees and found that it was actually 22 degrees (total) with a timing light.

(1)There is no start retard (the three terminals on the 7AL-3 do not have a 12 volt connection, all the retard terminals on the 7AL-3 are grounded.

(2) The "Launch retard" total in the Grid is 1.5 degrees and comes in at 4 seconds from the release of the trans brake button, (35 degrees less the retard of 1.5 = 33.5 total).

(3) I checked the ohm readings on the three "Zero chips" on top of the 7AL-3 as well as the burn-out chip, the launch chip, the max RPM chip and the switch chip, the ohm readings were correct for all of them.

(4) I checked the static timing with the damper at 35 degrees, it was spot on.

(5) The rotor is dead center on the #1 terminal in the cap.

(6) The ignition timing spec in the Grid is set at 35 degrees maximum.

Everything indicates that the timing should be at 35 degrees (the pick up is in the same location that it has been for the past four years, dead center in the bracket travel.

When using the timing light it reads 22 degrees (from 1000 rpm to 5000 rpm). I moved the pick up as far as it would go in the bracket (down) and the timing light indicates that it's now at 35 degrees total, the pick up clearance is .050 . The Craftsman timing light is accurate (it does not have the advance/retard feature) .

I have no idea why the total timing retarded from 35 degrees to 22, nothing was changed, nothing was added.

I have followed all the suggestions and checks from the MSD Tech line but have the same results. Today I advanced the crank trigger pick up so it now has 35 degrees. It is at it full limit. I can clearly hear the difference in the engine response.

Any ideas?

Bob
 
Posts: 3125 | Location: Lakeside, Ca | Registered: February 15, 2003Reply With QuoteReport This Post
DRR Sportsman
Picture of 57 Vette
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While checking the timing,get someone to tap on the side of the MSD box to see if the timing jumps around. Possible broken solder joint on one of the circuit boards. Very common problem with the older #7230 Red box. Up grade to the newer #7330 Black box that is much better. I just went through this very same thing with my Vette.

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Posts: 268 | Location: Toronto Ont/Surprise AZ | Registered: August 18, 2003Reply With QuoteReport This Post
DRR S/Pro
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If you had a choice would you buy a 7330 (7AL-3) or a 7720 Grid, (I have the MSD Controller 7730).

I re-set the timing to 35, but it's at the end of travel in the pick-up bracket. As I said, something is wrong this seems like a temporary fix, I'm waiting for the other shoe to drop, that's when it finally dies.

Bob
 
Posts: 3125 | Location: Lakeside, Ca | Registered: February 15, 2003Reply With QuoteReport This Post
DRR Pro
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If it were me, and had an obsolete 7230 that are well known to have ignition timing problems I would replace it with the new 7330 ignition box if wanting to strictly use analog ignition. The newer black 7330 is much improved.

Because you are presently using Grid 7730 digital ignition, consider upgrading your analog to the mating Grid 7720 digital that will plug directly into the 7730. The 7720 has 25% more output power than your present analog ignition.
 
Posts: 2539 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR Pro
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One other consideration if you do decide to upgrade to Grid 7720. It would be wise to use the recommended ignition coil for 7720 that MSD lists if you presently are not using that model with your analog ignition.
 
Posts: 2539 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR S/Pro
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Well, I really can't complain about the 7230 I've running it since 2001 I got my money's worth. Which coil do they recommend with the 7720? I might as well bite the bullet and get both of them.

Looks like I'll be starting that diet sooner than I had planned.

Bob
 
Posts: 3125 | Location: Lakeside, Ca | Registered: February 15, 2003Reply With QuoteReport This Post
DRR S/Pro
Picture of Big Steve
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Bob, IMO get the Grid ignition and a HVC coil. You won't be sorry you did
 
Posts: 2487 | Location: Moving back to the door side | Registered: April 30, 2010Reply With QuoteReport This Post



DRR Trophy
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Bob, I would be curious to know what your static timing is now that you've set your timing at 35. This does not help answer your question but if you had to move your pick-up as far as you could it will be way off statically I would imagine.
David
 
Posts: 135 | Location: Marion, TX | Registered: July 31, 2006Reply With QuoteReport This Post
DRR Pro
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Bob, I prefer the 8261 coil because the plug tower is recessed in the coil out of harms way.
 
Posts: 2539 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR Top Comp
Picture of Curly1
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57 Vette said something about the Solder inside. IF that is the case and the problem then you reset it at 35* when it vibrates and gets a connection you may have around 48*? timing which could be a bigger problem.

I think it is a good idea to try another box.


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Posts: 4133 | Location: United States of Texas | Registered: April 02, 2011Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
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quote:
Originally posted by RPROGAS:
If you had a choice would you buy a 7330 (7AL-3) or a 7720 Grid, (I have the MSD Controller 7730).

I re-set the timing to 35, but it's at the end of travel in the pick-up bracket. As I said, something is wrong this seems like a temporary fix, I'm waiting for the other shoe to drop, that's when it finally dies.

Bob



Bob I ran the same combination, Grid controller and 7AL3 red box, for about 5 years. Was using an MSD distributer to trigger the spark.
I had some issues last sept and never really found what the issue was but I replaced a lot of parts.

I did a lot of testing with the old ignition and with and without the signal from the distributer being fed to the Grid controller and then to the 7AL3

I had the same issue your seeing. I did install a crank trigger and the pickup was over 10 degrees off when you checked it static vs the engine running.

I rechecked it with the distributer pickup triggering the spark and saw the same thing at the distributer pickup...way off static compared to running.

I recall the Grid info said it may show 4-6 degrees off to allow the grid to manipulate timing but not 10 or more like I saw...

I added the Grid ignition black box and a new 8261 coil......and the crank trigger.....and kept the distributer pickup for backup....just plug it in if crank trigger fails...

Timing is right on and works great...

I think the Grid controller connected to the 7AL3 is not a great combination even though I ran it for number of years.....
The 7AL3 worked perfect by itself and I tested it that way.....I sold it and went all Grid...

This message has been edited. Last edited by: SCDIV1,
 
Posts: 2733 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR S/Pro
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After contemplating what would be necessary to convert from the 7AL-3 to the GRID, and believe me it's a massive harness changeover in this car, I opted to buy the 7330. The cost was about the same when you factor in the 8261 coil.

I ordered the 7AL-(7330) through the Summit Pro-Shop this morning.

The second reason to stay with the analog system was the convenience and speed of making changes. Using the GRID requires plugging it into the lap top to make changes while the analog 7AL-3 (7330) requires changing a few chips, and I have lots and lots of chips.

By the way, I did replace the pick-up with a new one, got the same results, it was still retarded by 13 degrees.

Before I fire the engine with the new 7330 box I am going to re-set the pick- up back to it's original position, I don't want to find that I accidentally have 47-48 degrees.

Bob
 
Posts: 3125 | Location: Lakeside, Ca | Registered: February 15, 2003Reply With QuoteReport This Post
DRR Trophy
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Bob[/QUOTE]
I had the same issue your seeing. I did install a crank trigger and the pickup was over 10 degrees off when you checked it static vs the engine running.

I rechecked it with the distributer pickup triggering the spark and saw the same thing at the distributer pickup...way off static compared to running.

I recall the Grid info said it may show 4-6 degrees off to allow the grid to manipulate timing but not 10 or more like I saw...[/QUOTE]

Would this have been related to crank trigger pick up wiring polarity? One way with digital and requires swapping for analog/vice versa?!?!
 
Posts: 192 | Location: Rock><Hard Place | Registered: February 20, 2010Reply With QuoteReport This Post
DRR S/Pro
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The problem that I encountered was without changing anything in the Grid, the 7AL-3 (or even the Mega 450) it simply lost 13 degrees (35 to 22) all on it's own. One week the initial/total timing was 35, the next it was at 22.

Over the past four years I have developed 7 or 8 different programs based on the type of racing:

Wide open (Antique Drags at Barona)
Bracket racing
Super Comp (8.90)
Super Gas (9.90)
Super Street (10.90)
And a few programs to cope with poor track conditions in different areas, starting line, mid track, etc..

I filed (identified) each of them for future use. Over the past 18 months nothing was amended, added or deleted I have been running it at 35 degrees (total). It appears that there was an anomaly within the box, I probably rattled the tires once too often and shook something loose. Rather than spend money to repair an older 7AL-3 (7230) unit I bought the new updated 7AL-3 version (7330), it'll be here in two or three days.

Bob
 
Posts: 3125 | Location: Lakeside, Ca | Registered: February 15, 2003Reply With QuoteReport This Post



DRR S/Pro
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quote:
Originally posted by bry-war:
Bob

I had the same issue your seeing. I did install a crank trigger and the pickup was over 10 degrees off when you checked it static vs the engine running.

I rechecked it with the distributer pickup triggering the spark and saw the same thing at the distributer pickup...way off static compared to running.

I recall the Grid info said it may show 4-6 degrees off to allow the grid to manipulate timing but not 10 or more like I saw...[/QUOTE]

Would this have been related to crank trigger pick up wiring polarity? One way with digital and requires swapping for analog/vice versa?!?![/QUOTE]


No it was not related to pickup polarity wiring.

Using the exact same wiring and color coded connections with the grid ignition triggered by either the crank trigger or the distributer pickup, pickups were directly aligned.

Running the Grid controller to the 7AL3 the pickups were off considerably from actual running timing. Over 10 degrees off.
 
Posts: 2733 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR S/Pro
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When I received the wiring instructions from MSD to connect the 7AL-3 (7230) to the Grid I was told to connect the legacy connector to the RACE port (where the RPM chip was located). I ran it for a few years that way and it worked fine. It was subsequently recommended by someone I know and respect to remove the legacy connector and re-install the chip, which I did and for the past several years it continued to work fine.

I honestly don't recall why I made the change but throughout the entire time that I've been using the Grid I have never had rpm control during the burn-out, that burn-out control chip did nothing so you had to control the rpm with my right foot, really not a problem. This was to my knowledge the only issue using the two ignition components (the 7230 with the Grid), until now. I honestly believe that the box died, it's been in the car a very long time.

I agree with Rich, this is not the best combination to use (7AL-3 and the 7730. At the time I didn't have enough money to also buy the 7720.

Bob
 
Posts: 3125 | Location: Lakeside, Ca | Registered: February 15, 2003Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
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Bob I always ran mine using chips in the 7AL3

I always use the burnout limiter at 6800-7000 and have never found any evidence of issues in the engine from using it. Valve springs, valves, you name it all good.

I bracket raced a few weeks ago and don’t have my inline stop on the car anymore so can’t use it as an SLE. I pulled my plate stop off and used spacers that equal the height of the stop. Just makes it quick and easy and everything fits the same.

I programmed 4400 for a launch rpm limit and checked it at the track before making a run.

I flat footed it with 4 bulbs on since that is what I’m programmed to do and if I do anything else I am more likely to have a brain fade out there.

RPM limiting with the Grid was smooth and worked fine. I only made 3 runs but was happy it worked fine.

I also had the safety run timer enabled and verified that was working.

I had a stuck throttle once and had a Ron’s Terminator so I quickly pulled the fuel shutofff that time. The safety run timer feature is a good one. My good friend totaled his car from a stuck throttle. That feature is one more reason I went to the grid.

I have the usb cable attached to the grid and it can’t come loose. The cable is right inside what used to be where my 7AL3 chips were and my car has an access door. Takes 5 minutes to make any change with my laptop if I have to.

I used to have a launch retard curve programmed in for bracket racing. It did not help on a track when I shook the tires right after the shift.

I remounted my Grid boxes and redid all those wires. It’s pretty easy on a dragster.
 
Posts: 2733 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR Pro
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quote:
Originally posted by RPROGAS:
After contemplating what would be necessary to convert from the 7AL-3 to the GRID, and believe me it's a massive harness changeover in this car,


The 7720 has 4 loose wires to connect. Pos /Neg to the battery and the wires to the ignition coil. The rest plug directly into Grid 7730 that gets mounted on top of 7720. No Brainer.
 
Posts: 2539 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
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Yup!

Wiring is very easy. Just a couple others to connect to K&R panel for tach and shift.

I spent more time mounting it than wiring it.
 
Posts: 2733 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR Trophy
Picture of Mitch H
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quote:
Originally posted by SCDIV1:
Yup!

Wiring is very easy. Just a couple others to connect to K&R panel for tach and shift.

I spent more time mounting it than wiring it.


Good to hear, because I pulled my 7AL-3 and hung the 7720/7730 in my car today. Hope to wire it on Sunday, then start on mounting and wiring up a box full of racepak sensors
 
Posts: 154 | Location: PA | Registered: December 31, 2016Reply With QuoteReport This Post
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