MSD 6AL missing

[BDR561]

Originally Posted by Eljaro

The gap between rotor and pickup is 0.025.
From what I have read in the MSD Troubleshooting forum the distributor pickup either works or doesn't. So I do not know if replacement will be the solution. Same goes for the 6AL box according to MSD tech support. Or maybe not.
Something somewhere is wrong.The car basically runs fine except for that continuous hesitation which sound like misses. It gets worse as the engine gets hotter.When fully accelerating there are no such misses to be noticed. Only when driving at a steady speed at around 3000-4000 rpm.
What else is there to check?

Double check the gap... I had this issue a few months ago when I replaced my dead pickup. I couldn't get past 3000 - 3500 and the motor would break up, the tack would go berzerk and the car was bouncing off the MSD rev limiter.

Does your tach jump once it reached 3500 - 4000?

Once I passed the 3000 - 3500 rpm limit the tack started registering numbers beyond my rev limiter (even though the motor was still at 3500 rpm) and I would start missing/breaking up from the cyliner deactivation.

It's hard to measure that gap... I thought mine was OK and I was off .010, double check it.

[vector1]

supposed to use non-magnetic feeler when checking also.

[Eljaro]

I finally think I found what was wrong. I modified a distributor cap making a big square hole in front of one of the terminal points for cylinder #1 and checked with the timing light
The spark would jump while the rotor point was past the #1 terminal. I did loosen up the screws holding the magnetic pickup and pushed it as far as I could to the most advanced position.
Now the point and terminal match perfectly at idle and at max engine speed.
Apparently MSD does not do a perfect job in phasing the rotor as they claim.

Now the timing is consistent and does not jump around above 3500 rpm.
I also made myself a larger stop bushing (10mm diameter) in order to be able to set 21º initial advance with a max advance of 36º.
The black stop bushing MSD provides did give me with a 21º initial a 42º maximum advance. Some wear of the interior diameter and a not very tight fixing was giving me 3º more advance than the 18º advertised.
I am using the two heavy silver springs.
Runs very well now.

[FatBoy]

I have almost identical symptoms with my engine. I am also running and MSD 6AL and MSD Pro Billet distributor.
At lower revs, it feels fine, but when cruising at around 3,000rpm, it sounds like it is misfiring and will hesitate and pop if asked to accelerate. Once accelerating, it feels fine again until it settles to an even cruise rpm.

Having read this thread, it sounds like I have to ruin a cap by drilling a large hole in it just to check if the phasing is the problem.

Oh well, needs must I suppose.

One more point, the central terminal in the cap is recessed below the level of the steel ring around it. That doesn't seem right to me, but can someone please confirm. Everything is just over 1 year old and has done less than 3,000 miles.

Paul

[Excaliber]

FatBoy, the center black carbon thingy should not be recessed from the metal ring. Your center cap thing is broken, an all to common occurence. I've replaced my cap twice now for that reason and that's really starting to piss me off. MSD needs to get their act together on that issue.

[FatBoy]

Could that be the cause of my misfire?

Given that my cap is already knackered, it guess it doesn't matter that I have to drill a hole in it to check the phasing....unless the broken terminal won't allow me to get reliable results from the phasing test.

Thank you.
Paul

[Eljaro]

If your center button is worn you need a new cap. Use this one now to make the hole in it. Mark the terminal with white paint ant make a vertical white line on the rotor too where the rotor terminal is.
I did bend the rotor center spring upwards to make real pressure on the central button in the cap. Centrifugal force tend to push it away and down.
I got myself the cap with the holes drilled in it to prevent ionization and rust inside the cap.

[FatBoy]

Wow, that's some hole.

The MSD articles suggests drilling into the top of the cap. Is there any special reason why you went into the side?

Paul

[Eljaro]

If you drill a hole on top with all the spark plug cables you see nothing.

On the side you can mark the rotator with white paint where the tip is and you see exactly when the spark jumps.

[Argess]

As per one of the posts above, I'd be looking at the carbs. Why? Because you say it doesn't misfire under hard acceleration.

Also, I've read that some computer igntion systems do retard the timing at higher rpms. You could be seing that if the hysterisis of the computer retarding is tight and occurs in that 3000 to 3500 range.

[FatBoy]

Originally Posted by Excaliber

FatBoy, the center black carbon thingy should not be recessed from the metal ring. Your center cap thing is broken, an all to common occurence. I've replaced my cap twice now for that reason and that's really starting to piss me off. MSD needs to get their act together on that issue.

I've just discovered that the centre terminal is removable. The external terminal post unscrews and the rest taps out, but I can't find a replacement on the MSD website.
What is the point of having it removable if they don't supply replacements?

Paul