The engine has been together for several years with no issues. I did the annual oil change and no pressure on start up. Pulled the distributor and tried priming the pump manually. Pulled the oil filter (dry). Tried partial fill of the oil filter, no luck. Pulled the pick up line and filled the pump, no luck. Pulled the pump apart and found this. Milodon single line pump. Had good pressure before the oil change. Any ideas as to what caused this?

Untitled by Greg Ault, on Flickr

Untitled by Greg Ault, on Flickr

Untitled by Greg Ault, on Flickr

Untitled by Greg Ault, on Flickr

I'm surprised that you'd spin on a dry filter. It wasn't a FRAM PH 8A, was it?

Cut the old filter open and see whats inside. You either had a clearance problem or some trash is moving through the pump. A dry filter is not the end of the world in a scenario like this i wouldnt think.

That damage didn’t just happen.

You had pressure before the oil change because the system was full - pickup to pump. Once you drained the oil the pump wasn’t able to get prime.

What does the pocket of the pump housing look like?

^ Agreed

Untitled by Greg Ault, on Flickr

Machine the face of the cover and new rotors and you should be good. Check face clearance of the pump rotors to housing. Should be a couple thou.
If you can find someone to anodize it after machining that would help durability.

Put a dial indicator on the shaft at the distributor end, zero it. Then install the pump. If the shaft moves up you have an issue.

Looks like the inner rotor is digging in to the cover. Might be just due to the debris.

Looks like abnormal downward force on the gear, thus into the cover. Do you have a an old-school rubber hose on the distributor shaft to prevent intermediate gear (timing) movement? What does the intermediate shaft bushing top side look like? Check the to see if the shaft has slipped and walked down the gear.

I don't think it's garbage related. It looks assembly related of something has moved around. Do you have the correct intermediate shaft installed? Is it possible you have a longer Milodon shaft installed?

Wedge and Hemi using Milodon Oil Systems with a steel high volume oil pump or Milodon #21814 and dual line spacer:
#21001, #21150, #21160.
Overall length 8.562", 7" of shaft out the gear.
-Steel Gear
21500
-Bronze Gear
21520


Wedge and Hemi using Milodon aluminum pump #21815. Use with Milodon Oil Systems #21175, #21185, #21190, #21195.
Overall Length 8.187", 6 5/8" of shaft out the gear.
-Steel Gear
21503
-Bronze Gear
21523


Wedge and Hemi using stock-style pan and tube pick-up. Also used with Milodon Oil Systems #21000, #21010, #21100,
#21110 and systems using a stock, Keith Black or Milodon #21814 pump.
Overall Length 7.875", 6 5/16" of shaft out the gear.
-Steel Gear
21505
-Bronze Gear
21525

I agree, that looks like a set up issue. Not enough clearance. I spoke with Milodon when i did mine and they gave me the specs. I dont remember what the spec is at the moment, but a call to Milodon will get it done with the proper shaft length. Before the oil was drained, the system was full of oil and would pull a prime, but once drained there was too much clearance and not enough oil to prime.

I dug a little deeper. Milodon cover, unknown pump. Bronze gear also showing significant wear.. I agree on the set up issue. I ordered a new Milodon billet pump and cover, and correct shaft with new bronze gear.

Annual oil change. I take it you don’t race very often or put many miles on. Get yourself an oil cutting tool from summit and make a habit of using it. That whole engine needs rebuilt NOW!!!

If you have a good oil filter you are probably OK.

The below pics are my oil pump that was super ugly, and the rod bearings. The ole Mopar M090 oil filter did its job.

something i've been doing when preparing a pump for install is de-burr the the ends of the rotors. some of them are pretty crummy and they'll even damage an iron cover. excessive pressure could be a contributor and a worn intermediate shaft bushing could create some wobble.

I run Milodon billet oil pumps. In my experience you can't fit these with the same torque settings as the iron ones (bolts to block), they will bind. If my memory serves me correctly, we torque ours to some thing ridiculous like 15 inch/pounds (yep INCH/pounds). Needless to say we always use some sort of studlock on the bolt threads. I don't know what the manufacturers recommended torque settings are, I tried to find them online but haven't been able to. Previous to all this, a buddy of mine had the same issue, he had problems priming the oil on a rebuilt motor and warned us about this.
I've also tried gently snugging the pump up when the motor was on the stand and winding the pump with a priming shaft by hand. It doesn't take a lot of torque to put these pumps into bind. I have them on two engines, fitted with a gasket to block and it's the same with both pumps. I have had no issues otherwise, they work fine.

Yes definitely a setup issue. Something weird with the shaft bushing and shaft engagement in gear was going on here. Or internal clearances. .004 is the minimum gear clearance. Make sure to check that when it goes back together.

I have been using the same Milodon system for years and several block combos and never had an issue like that.

I always give it the "finger twist" with my priming shaft to make sure everything in the pump is happy before I prelube it too.

Bad340fish -

What kind of cover did you have on your pump? A flat one or a recessed cover like a Milodon? How long did that pump last ?

Milodon or ANY aluminum pump cover - you're going to have issues if you use stock torque specs. To get my pump to spin freely with an aluminum cover the bolt torque is so low it makes me nervous that the bolts will fall out or that the pump will leak like a sieve. And I have no choice because of external oiling! I haven't done it yet but my intention is to drill and safety wire the bolts.

What you see in the photo is a thick cover made by Muscle Motors. Thickness didn't matter, it would bind with stock torque. retry with a stock iron cover ... no problem. Put this one back on ... it binds.

If you look closely you can see the bypass valve is stuck open in that cover
I've seen aluminum Milidon pump covers like that also I think the oil pump drive is forcing the rotor down into the pump cover making metal that gets stuck in between the bypass valve and the cover.
I've had that happen and unstuck the valve and the pump work normally after that

Man that sucks Greg…. Hope you find a remedy

If you look, the wear on the cover, it's from the drive gear and not the driven gear. looks like there was downward pressure on the gear. I would look real close at the intermediate shaft and the shaft bushing. also take a look at how much clearance you have between the distributor and the intermediate shaft (will need to look with intake off).
If you know someone with a mill, that's a easy fix.

Joe
PS if your not going to fix it, PM i will buy it from you.

PPS I just seen you found the issue.

My comment was more to say that the oil filter probably got most or all of that material. Mine was a small block Melling High Volume that chowed down some needle bearings from a rocker arm failure. I should have take a picture of the pump taken apart it was ugly but it fit lots of needle bearings through it lol.

Mill or no mill, there is no "easy" fix. To the best of my recollection those pump covers are all hard anodized. Mill it and run it and you'll have the same issues in a very short time. You have multiple issues to fix, the pump cover is just one of them.

65 A-990 race Hemi used aluminum pumps without being anodized. Never saw one go bad as long as the engine was built properly and didn’t experience a failure.
But like I said earlier, anodizing does help durability and allows the pump to digest some particles.

Beyond checking all clearances for the pump, I would pull the pan and check some bearings. That missing metal is a lot, and it went somewhere.

Problem solved! Recommended intermediate shaft and installed shaft were different lengths. Pump primed and fired up with more pressure than it's ever had at idle. I let it get to ~110 before shutting it off as I thought the pressure was excessive (it dropped once it warmed up). Per all the comments above; I contacted Milodon about the torque specs. I was told "Spark plug tight. Snug plus 1/4 turn." Also from the above comments; after following the Milodon directions, I spun the pump by hand with a screw driver and intermediate shaft with no gear. Next I spun it with a drill and monitored oil pressure. Several over precautionary steps in between and it's happy!

Untitled by Greg Ault, on Flickr

Untitled by Greg Ault, on Flickr

Untitled by Greg Ault, on Flickr

Untitled by Greg Ault, on Flickr

Untitled by Greg Ault, on Flickr

Untitled by Greg Ault, on Flickr

Good deal!

how much too long was the previous shaft ? the pic makes it look like about 1/4"ish ?
it's amazing it went together and functioned at all.

~1/4in.

Any idea why the diff lengths? Guess I got to assume some aftermarket race blocks use that???

Did you cut the oil filter open?

Come on Jay don’t spoil the party. The oil filter caught all that metal. Lol 😂
Next years post. Why do my bearings and pistons look like this.

I hope not, but at this point it is what it is. The damage was done at start up. This was a scheduled oil change and the car was running fine. The first oil filter would have been the one to cut. That was last year and no I did not open it up.

There are three length shafts to accommodate the different pumps.
The shortest shaft goes with a stock style pump.
The middle length is used with the Milodon 21815 pump.
The long shaft is used when you’re running the sandwich plate between the pump and the block.

Thanks Dwayne….

….and if that was my W8 mill I’d tear it down. If it was my iron headed “Bracket Betty” I’d RUN IT!

I call BS on that Jay. Not your style.

I'm going to do some more inspecting this weekend. If it's bad, it's going to sit for quite a while (shoulder surgery in a couple weeks).

Your speaking of a guy that has rolled rod bearings into an engine after a poor nitrous decision….
That has gorilla taped parts together in a trans to make next round….
Don’t underestimate me!