Msd6al-2 in the 6900-7200+ range experience

Rusty Davenport · 10-17-2016, 09:40 AM

Is it possible for a miss at the finish line in the 7000 rpm plus range to be occurring because the MSD6AL-2 is not "enough" box ??? Everything on this car including the MSD6AL-2 is new except for an MSD distributor which was used very little. I have moved the rpm limiter way out enough that I don't think it is hitting it, but it sure feels like it but to add to the mystery it is worse at times than others. It misses close enough to the finish line to be aggravating. Any comments on the MSD6AL-2 or ideas ???

Mark Lewis · 10-17-2016, 10:01 AM

Could it possibly be going lean on fuel mixture?

Brian Fink · 10-17-2016, 10:07 AM

Although I wouldn't rule out the MSD, I would look elsewhere first ; coil or possibly plugs would be suspect .

1320racer · 10-17-2016, 10:09 AM

Quote:

Originally Posted by Rusty Davenport

Is it possible for a miss at the finish line in the 7000 rpm plus range to be occurring because the MSD6AL-2 is not "enough" box ??? Everything on this car including the MSD6AL-2 is new except for an MSD distributor which was used very little. I have moved the rpm limiter way out enough that I don't think it is hitting it, but it sure feels like it but to add to the mystery it is worse at times than others. It misses close enough to the finish line to be aggravating. Any comments on the MSD6AL-2 or ideas ???

No and put a chip in that is 800 RPM higher than your shift/trap rpm.

terry1 · 10-17-2016, 10:30 AM

Rusty, remember that the MSD stuff draws about 1 Amp for every 1000 RPM's.
If it comes down to the "box", I would check your power supply to it.
Terry K

Woodfin · 10-17-2016, 11:00 AM

Of course, any system can have a problem, yet the MSD 6AL-2 is a good box and very capable of high RPM without issue.

Some things to consider,

*spark plugs
*spark plug wires
*rotor phasing
*condition of cap & rotor
*fuel pressure
*the above suggestion of raising chip RPM is good or run without a high limit chip.
*in addition, valve float is a possibility

all just food for thought.

And consider that just because "everything is new" well, new can have a problem.

cad · 10-20-2016, 01:33 PM

68 Camaro 3300lbs SBC. 7500rpm in the traps.
6AL box, MSD distr.

Mid-season, I had a miss that progressively got worse. Started at the top end, and eventually all the time. Popped like it was on the limiter, so pulled the high side chip. It didnt fix it.
Started watching the fuel pressure, and it was all over from run to run.
Turned out to be a weak fuel pump.
Swapped it out at the track and has run perfect since.

Clark

Everett Vassar · 10-21-2016, 12:38 AM

Too much plug gap can sometimes cause a high gear miss,would normally be a fairly soft miss.

race watcher · 10-21-2016, 09:41 AM

I had the same issue . Same box. Changed the coil wire and fixed it. I might add that was not my first guess.

Tom Moock · 10-21-2016, 12:16 PM

Check for rust in distributor on magnet pickup, I had that problem once. Tom

10-17-2016, 09:40 AM	#1
Rusty Davenport Senior Member Join Date: Jun 2005 Location: Nashville N.C. Posts: 505 Likes: 4 Liked 100 Times in 26 Posts	Msd6al-2 in the 6900-7200+ range experience Is it possible for a miss at the finish line in the 7000 rpm plus range to be occurring because the MSD6AL-2 is not "enough" box ??? Everything on this car including the MSD6AL-2 is new except for an MSD distributor which was used very little. I have moved the rpm limiter way out enough that I don't think it is hitting it, but it sure feels like it but to add to the mystery it is worse at times than others. It misses close enough to the finish line to be aggravating. Any comments on the MSD6AL-2 or ideas ??? __________________ NHRA AND IHRA STOCK ELIMINATOR 2772

10-17-2016, 10:01 AM	#2
Mark Lewis Member Join Date: Apr 2006 Posts: 330 Likes: 55 Liked 184 Times in 37 Posts	Re: Msd6al-2 in the 6900-7200+ range experience Could it possibly be going lean on fuel mixture?

10-17-2016, 10:07 AM	#3
Brian Fink Member Join Date: Jul 2007 Posts: 172 Likes: 35 Liked 28 Times in 9 Posts	Re: Msd6al-2 in the 6900-7200+ range experience Although I wouldn't rule out the MSD, I would look elsewhere first ; coil or possibly plugs would be suspect .

10-17-2016, 10:30 AM	#5
terry1 Member Join Date: Sep 2006 Location: Moncton, N.B. Posts: 276 Likes: 24 Liked 24 Times in 13 Posts	Re: Msd6al-2 in the 6900-7200+ range experience Rusty, remember that the MSD stuff draws about 1 Amp for every 1000 RPM's. If it comes down to the "box", I would check your power supply to it. Terry K

10-17-2016, 11:00 AM	#6
Woodfin Member Join Date: Sep 2006 Location: Kilgore TX Posts: 427 Likes: 5 Liked 70 Times in 38 Posts	Re: Msd6al-2 in the 6900-7200+ range experience Of course, any system can have a problem, yet the MSD 6AL-2 is a good box and very capable of high RPM without issue. Some things to consider, spark plugs spark plug wires rotor phasing condition of cap & rotor fuel pressure the above suggestion of raising chip RPM is good or run without a high limit chip. *in addition, valve float is a possibility all just food for thought. And consider that just because "everything is new" well, new can have a problem.

10-20-2016, 01:33 PM	#7
cad Senior Member Join Date: Apr 2009 Location: Omaha, NE Posts: 673 Likes: 140 Liked 72 Times in 40 Posts	Re: Msd6al-2 in the 6900-7200+ range experience 68 Camaro 3300lbs SBC. 7500rpm in the traps. 6AL box, MSD distr. Mid-season, I had a miss that progressively got worse. Started at the top end, and eventually all the time. Popped like it was on the limiter, so pulled the high side chip. It didnt fix it. Started watching the fuel pressure, and it was all over from run to run. Turned out to be a weak fuel pump. Swapped it out at the track and has run perfect since. Clark

10-21-2016, 12:38 AM	#8
Everett Vassar Member Join Date: Jun 2004 Location: Kennedale,Tx Posts: 227 Likes: 0 Liked 2 Times in 2 Posts	Re: Msd6al-2 in the 6900-7200+ range experience Too much plug gap can sometimes cause a high gear miss,would normally be a fairly soft miss.

10-21-2016, 09:41 AM	#9
race watcher Junior Member Join Date: Nov 2006 Posts: 50 Likes: 5 Liked 1 Time in 1 Post	Re: Msd6al-2 in the 6900-7200+ range experience I had the same issue . Same box. Changed the coil wire and fixed it. I might add that was not my first guess.

10-21-2016, 12:16 PM	#10
Tom Moock Senior Member Join Date: May 2004 Posts: 801 Likes: 1 Liked 10 Times in 6 Posts	Re: Msd6al-2 in the 6900-7200+ range experience Check for rust in distributor on magnet pickup, I had that problem once. Tom __________________ Tom Moock 5704 STK