msd retard 8972 questions

I hooked up the box and my timming is dropping like 20 degrees. from unhooking the crank trigger to the 7al to connecting to the retard box. I have zero in all 3 retards. I have the same box on my other car and I don't remember it changing at all. until you ground the wires for it to retard. I called msd and he told me to make sure the 3 wires for the retard are grounded. which I rechecked and they are. which shouldn't matter if I have zero in all 3 retard slots. anyone else have this box have to move the timming this much hooking up the box.I don't have the start retard hooked up either. thks Danny

Is it the 8975 digital or the 8970 3-stage? MSD site does not list 8972??? Why unhook the crank trigger?

It's 8970 my son's was the 8972. I disconnect the retard box and hook the crank trigger wires back to the 7al and the timming changes 20 plus degrees

Make sure the trigger wires are not hooked up backwards. I did it on a distributor and it changed timj ng like 25°.

The basics of it are that you interrupting the signal from the crank trigger to the 7al-2. You now plug the crank signal into the retard then to the 7al-2 with the white points wire. You no longer use the poles for the trigger on the ignition box. If it changes the timing some, you need to reset the crank trigger to the timing you want and re phase the rotor on the dist.

I understand this. I have had crank triggers for over 30 years. but I haven't seen the timing change that much hooking up a retard box. I called msd again and he said the box is probably bad.

Well crap! That sucks! I had a difference of about 10 degrees switching from an al-2 to an al-3 so I had seen something like that before...

I can adjust the crank trigger back up to adjust for the drop in timing but I'm worried if something is wrong and it goes back up when I decide to bottle it and I melt it down

If MSD says it's NFG, can they fix it?

Call Pat Collins at TechWest Racing in NC. He repairs MSD products and is great to deal with. 704-995-4286

I'm not 100% sure (been a while), but I think I had the same thing happen to mine and everyone I asked said it was OK. I use the same 3 stage retard box w/ a 6AL and crank trigger.