Are there any issues in using an advance (dial back or digital) timing light with an MSD 6A box? I have the factory coil and distributor in my '72 LT-1. I read somewhere that the multiple spark discharge will give an error on total advance by 4 or 5 degrees, when using a dial back timing light. If that's the case, I'll stick with my old Craftsman light and do it the hard way.

 

Keep the Craftsman for this appliction. The MSD Techline can help explain.

 

If you are just interested in checking total timing over 3'300 RPM, then a dial back should work, as the MSD box only provides multiple sparks under 3'000 to 3'300 RPM. For base timing MSD recommends a standard timing light. Hope this helps, -Jeff

 

Thanks. I found these threads on the MSD Tech Line:

http://www.msdignition.com/forum/showthread.php?t=14600

http://www.msdignition.com/forum/showthread.php?t=14309

Their explanation:
We DO NOT recommend using any type of digital or dail back light with the MSD CD Ignition procucts. A 'plain jane' inductive, wire to the battery, point and shoot timing light works best. This is because the CD ignitions produce so much power and creat so much rf noise that many times this rf noise gets induced into the timing and causes the light to flash at an 'odd time' this erratic flashing causes the human eye to percieve timing issues when in fact the timing may be, in fact, correct.


I just don't understand how the human eye can perceive a "timing issue" when using a digital timing light and you're just reading the numbers shown.

 

I understand what they are saying, our dial back timing light does seem to bounce around at times when using it to check total timing. I'm sure it's the RF interferance tricking the light into flashing at the wrong time. -Jeff

 

I believe (though I could be wrong) that I have not had any of those problems with my 6AL and Advance dial-back light. good flashes and it appears to indicate correct advance. Could I be seeing things?

 

I can always read the timing with ours, just sometimes it'll be reading the correct timing, then show 10 or so degrees off for a split second, then right back on correct timing. I always know our engines are in shape as far as cam to crank timing, crossfire, and cam walking, so it doesn't bother me.

 

No problems for me either with my 6AL and advance dial-back light.
But I don't need/use the timing light dial-back function ( it is set to 0° retard ) because my damper has 360° timing mark.

 

I have two timing lights and both read identical on my car with a full MSD ignition. One is an old Sunpro(Actron) dial back style with the ****. The other is a new Sears Craftsman Pro series digital dial back style. Both read dead on. I will get a little flutter in the reading at dead idle, after about 1500rpms or so it is dead smooth. After 3000 rpms the Msd is back to single fire anyway....if checking your total timing you shouldn't have a problem.

 

May I suggest a cheapo timing tape? I have my 30 year old Craftsman and a Snap-On dial back; I just find timing tapes and degreed dampers are sooooo easy to use. And if my dial back was not available, any timing light will do.

 

I put a timing tape on my harmonic balancer and used a regular timing light to set the total timing at 35*. I didn't see any difference from my dial back timing light although I had to "read" through all the flutter.

 

I just got my awesome new Innova 3568 dial back timing light. However, advancing/retarding the timing with the up/down arrows on the timing light does nothing with regard to moving the timing mark. I’ve got an MSD 6A ignition and all the threads I see (and other research I did, too) say that this ignition box is not compatible with dial back timing lights. I will attest to that with my experience here despite several of you stating above that yours works fine.

The question I REALLY have, though, is how the heck can the tachometer display on this timing light be accurate with all the multi-spark features of the MSD [which are also presumably responsible for the lack of digital timing ‘change’ as I advance or retard it with the down/up arrows on the gun]??? I find the two facts - tach very accurate but timing advance/retard inoperable/ineffective — to be baffling.

 

I posted a thread here on the forum a couple months ago regarding this very issue.
I called Innova and their tech services people told me that their light will not function properly on any multi spark ignition systems.
They said it will give false reading and you "would" damage the dial back timing light.
I just purchased a vintage Sears Craftsman timing light on E-Bay which works awesome.
The Sears Craftsman was referred by many on the forum and the tech from Innova.

 

I get by with my Innova 3368. Tach is as accurate as the tach in the car which gets its signal from the MSD box and when hooked up to my laptop for programming. Over 3000 rpm, its just a single spark, so the gun will read accurately above 3000 rpm.

 

resdoggie --- I can't seem to find an "Innova 3368" on the internet. Do you have a picture of yours? The tach in my C3 is fed by a gear-driven cable off of the distributor shaft so it's not using any electronic signal from the MSD box. The tach feature on the digital Innova 3568 (which I just returned to Amazon) was showing the same RPMs as the car's gear-driven tach and that's the mystery that puzzles me --- purely out of curiosity and nothing more. If that Innova 3568 was deriving RPMs based on spark signals, I'd think that the RPM reading would be 3 times higher on the Innova than actual RPM when the engine is idling at around 850RPM since the MSD box is kicking out 3 bursts (sparks) per cycle whereas a normal ignition system would only be kicking out a single burst.

Yes, I understand the gun would flash accurately over 3000 RPMs since the MSD unit is only providing a single spark per cycle at that RPM or higher -- and the dial-back feature might also work at those high RPMs, too. But, that's a pretty limited use of an otherwise high-tech timing light. That's why I guess that I'm going to go back to a normal old analog timing light... although I have to say that until I see it for myself, I won't believe that the analog timing light won't also suffer from the same issue (that is, I expect that at idle RPMs, the light will flash once for each spark signal meaning I'll see 3 timing readings in the same cycle where one is the first spark signal, one is the second spark signal, and one is the third spark signal).

 

You can call MSD (Holley) and talk with their tech services, like I did.
They said any inductive timing light will work with their MSD ignition systems, but the most accurate is their own MSD timing light.
Their light is pricey and even their tech said that unless I’m racing it is over kill.
I figured, if Innova’s own tech services people said their light would be damaged and will give inaccurate readings, that they know the most about their own product.

 

I have a crafstman non digital dial back and it doesnt work with my msd. Marks jump all over the place
Same with an actron

 

Interesting because I have a 5568 and it seems to read AOK on both my brothers 68 C3 with a 6A box and my granddads Ford 8n with a side mount dizzy. Rule of thumb though is you get the inductive clip as close to the plug as possible.

 

I don't disagree at all. The Innova light did not advance or retard the timing mark when using the up/down arrows (and I sure hope I didn't damage it because I'm sending it back). I also read the following post in this thread about putting the inductive clamp as close as possible to the spark plug. It didn't matter for me where the inductive clamp was; I had it up by the distributor as well as right down near the plug and the light behaved the same in both places and simply does not like the MSD 6A ignition.

I'm off to buy a plain old inductive light in the coming days.