MSD 6AL

nismou20 · Post by **nismou20** » Fri Jul 07, 2006 11:38 pm

Hello,

I thought I would consult the experts out there on how to tell if ones MSD 6AL box maybe failing. After my last run with SoCalRoc I've noticed that my car just doesn't have that extra ooomph that it had before. The MSD box was very very hot to the touch and I wasn't hearing that whirring sound or resonance that one experiences when going thru the R's. The idle is somewhat erratic also. It does not miss though. Is it possible that the box has burned up but still passing the 12 volts to keep the car running? I am running a GB dizzy so I've bypassed the resister and running the box right off the battery. This is a U20 w/SU's and richer RA's and timing @ 16 degrees. The carbs are right on with Jacobs Energy coil supplying constant 28,000 volts. Any thoughts on this would be much appreciated.
Thanks,
Tom

Russell Roach · Post by **Russell Roach** » Sat Jul 08, 2006 9:28 am

Tom,

Msd are really famous for crapping out but usually it is not the 6al but the other 6 model, one of the things I discovered only at the dyno which is what you may have to do to isolate the problem, Gary builds a great dizzy and I have no doubt that in a street roadster it would last a lifetime.

What I experienced after running the dizzy about 3 seasons thats a lot of revs and laps the mechanical advance wasn't working correctly( do you have vac advance or mechanical) I had noticed at the track my car just wasn't pulling as hard as it would not really noticeable but I could tell, when we got the car on the dyno we noticed that the signal from the ignition was really jagged switched the ignition box no change!

We took the dizzy out and just weld the advance all the way out(yes I know thank God for gear reduction starters) so with it held at 36 degrees of total advance it pulled like a tractor almost 110 at the rear wheels.

In all fairness to Gary I haven't talked to him about this but I suspect this may be what is happening to youbut until you can isolate the problem it is a purely uneducated guess.

and Gary If you read this give me a shout I need to send the dizzy back to ya for a little R and R

Russell

Post by **spl310** » Sat Jul 08, 2006 9:39 am

Russell,

I am glad someone else said that besides me. Everyone that I know that runs an MSD has had it fail. Not a good track record in my opinion. When it works, it is good though...

Russell Roach · Post by **Russell Roach** » Sat Jul 08, 2006 9:49 am

Sid,

Not to hijack Tom's post but along those lines, I have not had( and I am far enough away from my car to say this) my msd fail yet I have heard of the 6a units with the external regulater failing but I am on my 5th season with my 6al and it has gone through electrical shorts fire and that one crash you saw without fail......but I do have a spare just in case

Russell

spyder · Post by **spyder** » Sat Jul 08, 2006 11:28 am

I will take this opportunity to once again praise the electromotive diredt ignition system I use. I suppose it you are a casual roadster driver precise timing is not critical but if you thrash or race the car, timing becomes an issue. To add to the equasion high compression and rpm and it is easy to melt internals with sloppy timing. Look at laa the things which affect the timing precision, 2 chains, 4gears, the jackshaft play and slop in the 90 degree gears on the distrubtor which drives the oil pump and lastly the wiggle in the advance springs. This system is crank triggered with a .6 degree accuracy. The timing is at 0 degrees until 400 rpm which means EASY starting with a stock starter and the advance and rev limits are easily set with twisty knobs. Cheap? Hardly but they pop up on ebay from time to time.

Here it the model I use.
http://www.directignition.com/pdf_files/hpv1.pdf

SLOroadster · Post by **SLOroadster** » Sun Jul 09, 2006 12:30 am

My MSD 6AL still seems to be fine. It kicked in at 7k right where it should on the dyno last week.

Will

nismou20 · Post by **nismou20** » Sun Jul 09, 2006 6:38 am

Hello again,

Thanks for all the posts concerning my question, but today after going over all the connections and making sure all my grounds were snug the car started and ran just fine. There was even that audible buzzing again as it always does. I found out the quick way to tell whether you are getting spark with this unit is to turn the key to the on position with out starting and then pull the dist cap side coil wire off to within 1/2 in of ground, then take the white wire apart from the distributor harness and ground it. When pulling the white wire away from ground it should throw a good spark. (trigger)