Breakdown- coil/msd?

[rossins]

Hi
GTR let me down yesterday & tow truck got me home @ 1.30am - started misfiring after about 20 mins driving & then cut out & unable to restart- regrettably no tools on board
Need to investigate the cause but initial impression is the MSD Ignition (6AL) or Coil (3 yrs old 4500 miles)- would welcome the answer to a couple of questions.
1 Have people experienced problems with MSD ignitions

2 Where do you locate the MSD control box- mine is in the engine bay I wonder if the heat is causing problems

3 What make of coil are people running & again is heat a problem causing them to breakdown after a certain period of time.

If anyone has any other ideas I would welcome comments.
Cheers
Simon

[steve_d]

I have heard that MSD 6AL can fail.

Most I have seen are mounted, as per build manual, in the engine bay.

I am running the MSD Blaster 2 coil.
This comes in 2 forms the red painted one and a chrome one. It is well known that the chrome one fails at the drop of a hat. It is manufactured in a different factory and country to the red one.

Steve

[rossins]

Thanks steve
where do you buy the coils in the UK
cheers
simon

[ultimacz]

we had a red coil fail after approx. 3000 mile. Engine just did not want to start. Replaced coil and it started immediately.

[adequatespeed]

I have had exactly the same problem with my MSD dizzy and 6AL setup.

Started to misfire while running and suffered intermittent starting problems, usually fixed by a battery charge.

Decided that it might be the battery. Checked the battery and it was fine.

I changed the coil with no improvement.

After much head scratching and worsening problems I thought it might be the MSD start retarder. removing this improved it for a while then it got worse.

I finally diagnosed it using LED indicators on all the wires dizzy, start retarder and MSD to a weak, unreliable trigger form the distributor. I finally resorted to taking the dizzy out of the engine and spinning it manually to see it was not sparking 8 times and was randomly failing to spark.

This was caused by the gap between the pickup in the dizzy was a little too large > 1mm. Over time the permanent magnet in the dizzy has gradually degraded to the point where a reliable trigger is not attainable with a slow passing speed.

This is why it worked OK normally when the engine was running but was unreliable with a start with a normal (not over voltage freshly charged batter). And also I gess removing the start retarder improved things because it was not quite as sensitive as the MSD input.

Solution : dismantle the distributor and move the pickup closer. This has fixed the problem and everything has been returned to normal.

I hope this helps and saves you the grief I have suffered .

[adequatespeed]

Oh yes, I forgot to say this symptom manifested itself after about 2 1/2 years and 4000 miles.

[gtrclive]

A Friend of mine calls MSD's "My Spark Died".....

If you need to check a completely dead MSD 6 box, then Ignition on disconnect the plug on the Dissy, the wires going from the dissy to the MSD6 box, make and break those cables with a link and you should see a spark on the main lead from the Coil (leave the coil lead resting on the engine but be carfull will spark over a 1" away). If no spark MSD Box U/S....

[steve_D]

To add to Clives warning about keeping clear of the HT spark. The low tension side of the coil is not to be messed with either as there is 450volts going through there.

Steve

[rossins]

Thanks for the advice.
New coil fitted & running fine on the drive- getting a tow hook made before venturing out on the road, so i know i can get home if any further problems.
cheers
simon