[gtofreek]

Well, I found the problem almost right away. I continued on to disassemble the entire engine just to put my mind at ease. This has been driving Joe and myself out of our minds trying to figure this out. I started by turning the engine over as it was and listened. Every now and then, with no rhyme or reason, I would hear an unusual click noise. Almost sound like the oil pump drive shaft dropping 1/4" inch and hitting the pan. Something to that sort, or maybe the sound you might hear if there were no rockers hooked up to the lifters and the lifter didn't stay in contact with the cam lobe and then dropped and hit it. Something like that. So I pulled the intake and valley pan off to take a look. Also the valve covers. I saw nothing unusual. Everything looked fine and normal. So I turned the engine over some more, and every now and then it would make this click noise, but without rhyme or reason. It just did it when it wanted. Sometimes I turned the engine over 4-5 times before it would do it, sometime 2. But it sure sounded like it was coming from the distributor area. So I look at the distributor to see if there was a gap between the reluctor, and the magnetic pickup. There was what looked to be about a .030" gap. So I turned the engine over and watched it. There was always a gap but the gap changed slightly as it turned around. I attributed it to the reluctor paddles not being exactly the same length. So not seeing anything there, I pulled the distributor to take a closer look. Spun it by hand and the gap looked about the same as it did in the engine. I turn the distributor on it's side, and now that the reluctor is not shadowed by the rotor, I can see it paddles were shiny on the top 1/8" or so. So I look back at the reluctor to pickup gap and the reluctor is touching it! Turns out the lower bushing of this new distributor is extremely wore out in less than 200 miles. Really after a few dyno pulls. I took some not so great videos with my camera phone with a scratched lens but you should get the picture. I figure the uneven load of the oil pump is making this gear jump all over the place and randomly hitting the magnetic pickup. There is no wear whatsoever in the shaft. Just the black oxide coating has been rubbed shiny. It's like this bushing is extremely soft. It's not bronze. It looks like some sort of iron, that may not have been carborized? The composite distributor gear has some minor wear to the top 1/4 inch that was taking all the load but otherwise it looks great, considering. Says something about those gears. I'd say it has about .005" wear on it. Just barely enough to try to catch a fingernail on. The cam to dizzy gear contact pattern looks perfectly centered to, with about 3/4 tooth engagement. I could find no other reason for the bushing to wear like that as it was not like that when I pulled it apart to change the gear, and re-curve it. I've seen bronze bushings wear the shaft of the distributor pretty severely yet this shaft has no wear that can be felt, it's perfectly smooth. We checked the shaft to see if it was bent, but it was real straight. Also the wear on the teeth of the dizzy gear was even all the way around the gear.

Has anyone had an MSD dizzy gear wear out this fast? I'm wondering if they got a bad batch of hardened bushings.

BTW, the piston skirts look beautiful! Also, I stand corrected, the piston skirts had .0047" clearance!
Here is a link to some videos on youtube. The second video is the best.
https://youtu.be/0QOwVaJcQ_Q
https://youtu.be/soh91OYexBM