Intermediate shaft: binding with oil pump gear?

[ShelbyMopar]

Issue:

Went to prime the engine today, everything seemed to be going smoothly, oil pressure built great.

But there is a spot I noticed the distributor wants to move upward out of the spot it rests in, and the intermediate shaft gear is noticably stiffer at this turning spot as well.

I'm thinking some of the teeth of the intermediate shaft aren't meshing as nicely with the oil pump gears in this spot. The oil pump is new (Melling), the I-shaft is used of course. Nothing seemed out of ordinary between either of them, until this point anyway.

New bearings for the I-shaft as well, and it spun freely when I tested it after having my machine shop put the bearings in.

Distributor turned freely, so did the oil pump. Something must not be right though.

Thoughts?

[black86glhs]

Did you try putting grease on the gear teeth? I do this on mine to keep it lubed until it gets running. Try it and see if it helps.

[shackwrrr]

any burrs anywhere at all on the oil pump gear or inside the oil pump.

[135sohc]

possible combination of the new pump still being brand new and not 'broken in' yet and the teeth on the I-shaft having just enough wear to cause slop when mated to new unworn teeth on the pump ? just a guess anyways.

I have a new oil pump sitting here for my next engine and I'm about 50/50 on using it vs reconditioning the original oil pump that came with the block & shaft since the teeth on both are worn/matched together.

[inmyshadow]

Perhaps your oil pump isn't completely flush to the block.

[turbovanman²]

Perhaps your oil pump isn't completely flush to the block.

+2, I've seen this more times than I can count, they even put a note in the box telling you that you might have to trim the pump mounting ears.

[ShelbyMopar]

What ears are these?

Must have lost the note in the box =/ Those parts have been sitting a while.

I don't wanna drop the pan again, but whatever, better then having an issue down the road.

[turbovanman²]

What ears are these?

Must have lost the note in the box =/ Those parts have been sitting a while.

I don't wanna drop the pan again, but whatever, better then having an issue down the road.

Where the bolts go in.

[ShelbyMopar]

Well heres the news, not sure what to think:

dropped the pan, pulled out the oil pump. It did look like the one ear was a little too long, so I grinded it down so it didn't sit over that little lip.

Put it back in, exact same thing.

Tried a different pump (used stock pump, alum. housing), exact same thing.

Tried a different intermediate shaft (had a spare kicking around), exact same thing.

This is a weird situation, and the pump looks to be sitting flush. Now heres the stranger issue: It only seems to be harder to turn when the distributor is on. Tried 2 different distributors, same thing again.

When I leave the bolt loose on the distributor hold down, and turn the I-shaft, you can easily see the distributor wanting to move up and down.

Thoughts now?

[puppet]

When you spin the pump by itself there must be a spot in the rotation that is creating some friction. That would account for the gear wanting to ride up.

[HoverFish]

If it only seems to be a problem with a distributor mounted... is it possible the oil pump isn't centered on the distributor hole? I'm not sure how that could happen, aside from elongated mounting holes on the pump or incorrectly mounting holes in the block, both of which sound a bit far-fetched.

[ShelbyMopar]

When you spin the pump by itself there must be a spot in the rotation that is creating some friction. That would account for the gear wanting to ride up.

No, there is no excess friction while spinning the pump by itself.

The oil pump turns freely on its own. The intermediate shaft turns freely on its own. The dizzy turns freely on its own. The intermediate shaft and oil pump spin just fine together. As soon as the dizzy is bolted down, binding somewhere.

And the oil pump looks centered... I am stumped here. Like I said, there is no stiff spots while the oil pump is hooked up w/ intermediate shaft in place, and only happens while the dizzy in in place. There is some casting flash up in the oil pump area that I am going to try trimming up, see if that helps at all. Otherwise, all input is appreciated.

[shackwrrr]

what happens if you shim the dizzy up a little bit? Your pump may have been cast weird or something.

[black86glhs]

what happens if you shim the dizzy up a little bit? Your pump may have been cast weird or something.

I was thinking the same thing. Get a couple gaskets for a small block and put them under it and see if the problem goes away.

[shackwrrr]

and if that does fix it I dont see a problem in keeping it that way

[turbovanman²]

Did this engine chew up the int shaft before?

[ShelbyMopar]

Did this engine chew up the int shaft before?

No, never had any intermediate shaft issues prior to this one.

The engine was running decent before, but had a few issues with ring lands on high boost before, so I ended up getting it machined + overbore.

[turbovanman²]

In that case, try another dist, if that doesn't help, I would redo the int shaft bearings.

[ShelbyMopar]

In that case, try another dist, if that doesn't help, I would redo the int shaft bearings.

I've tried a couple dizzy's, no difference there either.

I was reading though, if the distributor moves/wants to jump, sometimes it can mean a slightly bent/warped intermediate shaft. It only wants to do it in 2 spots all the way around (full rotation of dizzy/rotor).

So perhaps this spot is where there is a slight bend? I could be wrong, who knows. Both those intermediate shafts had been sitting a LONG time, one on a shelf for about 2 years. The other in a box of parts, maybe they aren't much good anymore just like cranks aren't after sitting flat for quite awhile. Although there are no counterweights on an I shaft, really.

[turbovanman²]

I've tried a couple dizzy's, no difference there either.

I was reading though, if the distributor moves/wants to jump, sometimes it can mean a slightly bent/warped intermediate shaft. It only wants to do it in 2 spots all the way around (full rotation of dizzy/rotor).

So perhaps this spot is where there is a slight bend? I could be wrong, who knows. Both those intermediate shafts had been sitting a LONG time, one on a shelf for about 2 years. The other in a box of parts, maybe they aren't much good anymore just like cranks aren't after sitting flat for quite awhile. Although there are no counterweights on an I shaft, really.

Seems kinda far fetched that 2 shafts are tweaked. Do you know anyone with a lathe? They can mount it up and then you can check to see if they are true.