Need MSD help in Texas - The 1947 - Present Chevrolet & GMC Truck Message Board Network

85sqbdy · 10-07-2008, 08:07 PM

I'm currently running a 454 w/a th400 and 3000 conv. need to know about an MSD 6al box. Are they preset to limit rpm without a chip in the hole, or is my box going bad? It seems to start stuttering at around 5700 rpm. I checked the normal stuff. The distributor is locked out at 34 deg. and the fuel delivery is second to none. Don't get me wrong, this thing pulls like crazy up to about 5700 rpm then starts to stutter. I'm just curious if I should put a chip in the hole or just say to hell with it and go with a 7al2. Any help would be greatly appreciated.

1FAST68 · 10-07-2008, 09:43 PM

There is no preset rev limit in a 6al box. The only way to have a rev limit is to plug a chip with the desired rpm in the box.

What type of disy do you have? Make sure you have a full 12v to the coil if it is a msd coil(and it should be).

Might be weak valve springs, they will act like a rev limiter when weak and not pull past a certain rpm.

85sqbdy · 10-07-2008, 10:14 PM

MSD p/n 85551. blaster 2 coil. The valve springs are matched to the cam. The spring rate and installed height are correct to the cam specs. I have zero passes on this set up, just some street time. Could It be a timing issue? Maybe less or maybe more perhaps?

1FAST68 · 10-08-2008, 09:42 PM

Will it free rev past 5700? It could be alot of things really or a combination.
Fouled out plugs sometime only show up under a load.

Marv D · 10-08-2008, 10:11 PM

Blaster 2 coild made in mexico are notorious for having problems like this. First thing I'd do is borrow a good coil like the HVC coils and see if things change. I carried a brand new Blaster 2 in the trailer for a backup and it ws borrowed by a friend at the track. The motor would fall all over it's self at 6000 rpm. That was a brand new Blaster 2 right out of the package. Some of those things are real junk.

May be something else like springs or other ignition,, but a borrowed coil is sure a cheap test.

djracer · 10-09-2008, 11:08 PM

Quote:

Originally Posted by Marv D

Blaster 2 coild made in mexico are notorious for having problems like this. First thing I'd do is borrow a good coil like the HVC coils and see if things change. I carried a brand new Blaster 2 in the trailer for a backup and it ws borrowed by a friend at the track. The motor would fall all over it's self at 6000 rpm. That was a brand new Blaster 2 right out of the package. Some of those things are real junk.

May be something else like springs or other ignition,, but a borrowed coil is sure a cheap test.

A buddy of mine was having problems with one of these this past week.

hotrod 80 · 10-09-2008, 11:48 PM

Also might check around , but one or two of the local race shops have MSD test equipment to check out your box .

Pyrotechnic · 10-14-2008, 06:00 PM

Agreed about the Blaster 2 coils.

The HVC and HVC II are good coils. Made in house at MSD I believe and the price reflects that, but these days, you get what you pay for.

10-07-2008, 08:07 PM	#1
85sqbdy Registered User Join Date: Jul 2008 Location: Orange,Texas Posts: 99	Need MSD help in Texas I'm currently running a 454 w/a th400 and 3000 conv. need to know about an MSD 6al box. Are they preset to limit rpm without a chip in the hole, or is my box going bad? It seems to start stuttering at around 5700 rpm. I checked the normal stuff. The distributor is locked out at 34 deg. and the fuel delivery is second to none. Don't get me wrong, this thing pulls like crazy up to about 5700 rpm then starts to stutter. I'm just curious if I should put a chip in the hole or just say to hell with it and go with a 7al2. Any help would be greatly appreciated.

10-07-2008, 09:43 PM	#2
1FAST68 Registered User Join Date: Apr 2008 Location: east, tx Posts: 149	Re: Need MSD help in Texas There is no preset rev limit in a 6al box. The only way to have a rev limit is to plug a chip with the desired rpm in the box. What type of disy do you have? Make sure you have a full 12v to the coil if it is a msd coil(and it should be). Might be weak valve springs, they will act like a rev limiter when weak and not pull past a certain rpm.

10-07-2008, 10:14 PM	#3
85sqbdy Registered User Join Date: Jul 2008 Location: Orange,Texas Posts: 99	Re: Need MSD help in Texas MSD p/n 85551. blaster 2 coil. The valve springs are matched to the cam. The spring rate and installed height are correct to the cam specs. I have zero passes on this set up, just some street time. Could It be a timing issue? Maybe less or maybe more perhaps?

10-08-2008, 09:42 PM	#4
1FAST68 Registered User Join Date: Apr 2008 Location: east, tx Posts: 149	Re: Need MSD help in Texas Will it free rev past 5700? It could be alot of things really or a combination. Fouled out plugs sometime only show up under a load.

10-08-2008, 10:11 PM	#5
Marv D Registered Truck Offender Join Date: May 2008 Location: hells training ground (aka Ariz) Posts: 3,118	Re: Need MSD help in Texas Blaster 2 coild made in mexico are notorious for having problems like this. First thing I'd do is borrow a good coil like the HVC coils and see if things change. I carried a brand new Blaster 2 in the trailer for a backup and it ws borrowed by a friend at the track. The motor would fall all over it's self at 6000 rpm. That was a brand new Blaster 2 right out of the package. Some of those things are real junk. May be something else like springs or other ignition,, but a borrowed coil is sure a cheap test. __________________ Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral.

10-09-2008, 11:48 PM	#7
hotrod 80 mini truck racer Join Date: Aug 2006 Location: Baytown , texas Posts: 3,010	Re: Need MSD help in Texas Also might check around , but one or two of the local race shops have MSD test equipment to check out your box . __________________ 1949 5-window 1969 Camaro 1976 Chevy Luv yellow 1978 Chevy Luv Blue 1976 Chevy Luv Black 1979 Firebird Flooded in Harvey 1999 F350 Dually 2005 GMC Sierra 4.8 RCSB 2014 Explorer (wifes) My build :http://67-72chevytrucks.com/vboard/s...d.php?t=399148 Build #2: http://67-72chevytrucks.com/vboard/s...d.php?t=653583

10-14-2008, 06:00 PM	#8
Pyrotechnic Registered User Join Date: Feb 2007 Location: Austin, TX Posts: 3,930	Re: Need MSD help in Texas Agreed about the Blaster 2 coils. The HVC and HVC II are good coils. Made in house at MSD I believe and the price reflects that, but these days, you get what you pay for. __________________ 1977 GMC Sierra Grande



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