Oil pump driveshaft related to spark scatter?

[cv67]

SBC melling HV pump (not the hd one)

Always had an issue with timing light marks fluttering..car doesnt miss at all.

Noticed when I pull the distributor the shaft falls off to one side making restabbing the distributor a friggin pain.

This normal, or could the (arp) shaft or coupler have something wrong with it? Everything down to the block is brand new.

Could this be the cause?

BTW timing keeps advancing over 3k. Had it on 2 different sun machines they insist the distributor is fine.
Any other car Ive had the shaft stayed fairly straight when pulling the distributor..may move a little but not flop to the side like this?
Pulling the engine isnt gonna happen right now, car just sits anwyays

[allencr267]

..falls..., ...flops to the side...

?????
Mechanical advance releasing or tremendously out of balance?
What do the teeth look like, riding on the middle with like a 1/3 of the tooth showing a nice smooth wear, but not worn, smooth polished pattern and the advance twists smooth & free?

[Old School]

Did you use the shaft with the steel collar or the plastic one? The only time I have seen what you describe is a plastic collar broke and let the shaft flop around. If that is the case it is not good. Can you get a scope and see if the shaft has a collar centering it on the oil pump shaft? If not I would pull the pan and replace the collar.

[cv67]

I supplied an ARP shaft, so it better have the steel one. Never thought a plastic one could have been stuck in there, Ill have to get a scope. If so thats a scumbag move on the machinists end, hes long gone though. Cant help but wonder.

Advance mechanism last time i had the cap off seemed ok. ITs been sitting a few yrs will double check.
Took it in to have a little more initial put in it rather than locking it out, guy advised me to leave it as is...Jeff at AED assured me its good as is.

That would suck to have to tear it down nowhere to work on it.

It keeps advancing over 3k, shouldnt?

On flopping it leans to one side big time when you pull the dist out. Sounds like a converstaion I once had with a chick named...nevermind.

The teeth are pretty decent. I did have a lot of angle milling done and use a moroso plastic washer, maybe it needs a slip collar. Its close meaning if I really tightened it the oil pump may be getting loaded up to hard. Hard to lean over the hood for more than a few minutes.

[MadBill]

... Sounds like a converstaion I once had with a chick named...nevermind..

Don't tell us it was Eileen...

[BOOT]

The shaft is fine, most aftermarket use the skinny 400 style shaft while 350cu or smaller sbc oem shaft were thicker and wouldn't lean over. A HEI dist drops in my 350 fine but both MSD dist I have I have to jack one side of the car just right to get the shaft to stay where I need.

Spark scatter is via oil pump, a HV pump and thick or aerated oil could cause it I believe BUT be sure your timing light is hooked up good, wire isolated and good plug wires also separated. A MSD box has multi spark below 3000rpm and it's not recommended to check/set your timing below that rpm.

[Newold1]

Real moderate spark scatter would most times definitely show up as misfire at higher rpms. You say you have no misfire so the problem sounds like the timing light pickup or connections. Try a different timing light and move it to a different plug wire just to see if its the same on another plug.

Use a scope and good light to look at the top of the oil pump shaft. I've seen one or two where one of the top ears broke and that will allow the distributor to pump shaft to lean like crazy when the distributor is pulled.

Remove the shaft off the pump carefully and have a magnet tool ready to pull it out so it does not fall down into the bottom end if you can.

[cv67]

Ill get a scope and check..tried different lights, and yes it runs strong as high as I wanna go.
Thanks, will report back when I can check it.