Brad Boggess

So I finally had to replace my OEM Opti. Removed old Opti fairly simple, opened new msd box got Opti out and started to install it and it wouldn't full seat.. Removed orings just to see if they were holding it out ~.150". Nope so I checked pin to make sure it was in correct slot, yes it was correct, checked it three times, measured pin installed height its correct, used a white paint pen and marked inside slot to see if pin was bottoming out, nope not that. So I took measurements and that's when I noticed msd radius that started .150" before shaft meets larger round part. So conclusion is the radius on the msd unit is bottoming out in the timing gear hole. So someone if they have contacts at msd, please relay that it needs to be countersunk similar to the OEM Opti or it will cause failure to Opti.

Injuneer

You might want to contact MSD directly and tell them you may have received a defective unit. Hundreds (if not thousands) have installed the MSD over the last 10 (or is is 12) years, and this is the first report of such a problem I have seen on this and 3 other LT1-oriented forums over the years. Lots of other problems with the MSD, but not this one.

GaryDoug

All the photos I see of the MSD pin drive Opti look to have that radius on the shaft. Is it possible your cam sprocket is aftermarket and does not have the countersink in this photo in the MSD install sheets?

Brad Boggess

I am using gm sprockets.

Brad Boggess

Alright, update as of now. Radius has no issues with sprocket. So out came the voodoo bump stick.... Measured pin dia. It was correct on first try at the end .2488" and then I noticed that its tapered... Why idk. But .2527" just won't fit in the MSD slot of .2509" so cam going to work with me tomorrow and swapping pin out.