Milodon Oil Pump Issue

Losing oil pressure at end of run relief valve stuck open.

I’m running a complete Milodon dual pickup oil system with swinging pickup.
At idle I have 70 lbs, finish line 100+ at 7200 rpm using 20w50 oil.
At the end of 2016 I had the same this same issue, I replaced the Milodon 21206 cover which fixed it.

No issues through the 2017 season.

First race out 3 weeks ago lost oil pressure at the end of the run. Took relief valve cover off and valve was stuck open again. Shut engine off at finish line and towed back. Popped cover and “unstuck” valve each pass.

Returned home and removed cover, removed relief valve then chucked it up in lathe to radius the edge of valve. Polished the leading edge of the valve but I could still feel the valve clicking as it slides over the inside relief valve bore to seat. There is to much clearance between the bore and valve allowing the valve to drop down and the leading edge of the valve catches on the bore opening thus hanging it up.

I thought radiusing the valve would fix it but it didn’t. Another thought would be to make a stop to prevent valve from opening as far and catching.

I called Milodon prior to buying this one and was told they have never heard of this issue. Just my luck, I'm the only one..lol

3000.00 to put a dry sump on it would fix it but since I’m a bracket racer it just doesn’t make sense. Hell any of the other wet sump pumps cost half or more of dry sump, Titan, System One, P&P ect.

Anyone else had this issue and if so what is the fix. 285.00 to buy another cover to repair this for maybe 2 seasons is not economical plus it’s stupid. Anything out there other than a Milodon?

Thoughts"

Dave

Does the Milodon adjustable pressure relief kit come with a new valve. I've run Milodon pumps forever and never had that issue. Maybe you need to find an "Old" pump due to some oddball production changes.

Have you checked for flatness of your block to the pump housing. Maybe there is something causing a twist and bind.

Insert a 660 bronze sleeve (get it as a tube from MSC, Grainger etc.) in the cover, bring it back to the (new) valve OD). Easy access: it has a plug in the end where the passage was drilled, just follow that, alignment doesn't matter.

Sounds like the bore of the relief is your issue
and that could be cleaned up.. with a 100+ on
oil pressure you could afford to lower it some..
the valve tipping would be my concern

Or a slight oversize valve may be practical. How complex is the shape?

Titan has had the same issue, from what I have heard.

Maybe when stuff is tightened down it distorts that area causing it to stick

Maybe an Indy cover. I've put 500 passes on a used part. Never had any issues. Single line 7200 rpm.
Doug

OP, how old is that cover?
I've used over 50 Milidon of the older pump covers over the years and never had a problem like your having with yours
I have three motors with the new style pump covers for the remote mounted oil filters, one is being used on my bracket engine now with no issues so far, one is on a customers 800 HP pump gas Hemi motor that came off a engine dyno last week with no issues
I do have one motor that has the Hughes brand single piece pump cover with the oil filter mount built onto it with no issues either

the adjustable valve does not come with the pump cover - are you using the Milodon Billet pump or a factory pump - 99% of the time the pump cover is over tightened and it makes no difference with the old or new style cover - both can distort enough to create the issue

I agree...

I personally prefer the pumps that Wescott made but they are kinda hard to come by. I did have a relief valve issue with a KB pump twice. I have also had good luck with Titan but after the fire I am not sure they are available now either.

Believe it or not I k
had an adjustable valve in it Saturday. Backed out to it's lowest allowable. It blew the o-ring out of the filter. Ended up going back to the original valve.

The issue isn't in the pump itself it's the cover. Seems there is to much clearance in the valve to bore..

Dave

Sorry that isn't the issue. I can make the valve hang up with the cover sitting on the bench.

Dave

I like that idea..
And I do still have my old cover..

Dave

The valve tipping is the issue in my opinion.. I did go to a lighter oil to lower the oil pressure. Haven't looked at data to see where it is now.

Dave

Hope this works...

Relief Valve kit

Dave

I thought Indy used the Milodon cover. I was interested in their indy maxx pump but could not find any info on it. Is the cover like the Milodon?

I used to have on of the 2 piece milodon cover and only issue was keeping the gasket for the filter adaptor from leaking.

Dave

This is the second Milodon part # 21206 cover I have had this one has less than 2 seasons on it. First one had maybe 3. So in 5 years I have had 2 of these same issue..

Dave

I have had good luck with the Indy covers too. Use them for a lot of engines actually.

Do you kill the engine at the stripe or not?

It is the billet pump. Not overtightened, not warped. It will stick on the bench..

Dave

Yes, I always kick it to neutral and kill the engine..

Sounds like Indy may be the way to go..

Dave

I don't know that this plays into anything at all but I am the same, kill the engine in the lights. We speculated that my issues may have had something to do with it as well. Mind you my issue was with a KB pump but still wondered if it was a factor at all...I had it happen to two different pumps and we tried various remedies. Finally just changed the pump never had an issue after that.

I have a new Indy cover that I don't need. I will send you a photo. If you can give me 75% I'll be happy.

I would also inspect the area of the relief port (leading from the retracted valve position either to the LP side or to the pan). I suspect many aren't large enough to dump quickly especially with high viscosity and pressure. Some automotive pumps allow the piston to retract way past the port edge, meaning the port could be extended backward (examine the casting to be sure there's enough metal, duh). I wouldn't try to enlarge the circumference for exactly the reason mentioned: stability in the passage may be compromised.
In the Chevrolet L6 pump I'm working on now, the port is only 61% as large as the passage, the piston's OD is about 80% covered by the casting.

There has been some back & forth about why/when to dump excess back into the feed side as opposed to right into the pan: relief oil to the LP port causes turbulence at the inlet and may aerate flow? Not sure when this happens.

[quote=rickseemanI have a new Indy cover that I don't need. I will send you a photo. If you can give me 75% I'll be happy. [/quote]

Rick, very interested.. Is it the one with the spin on filter adaptor? Also, I assume it will work with the milodon billet pump?

email: dcovey1@hot.rr.com

Thanks

Dave

I can't see killing it in the lights would have any affect on the relief valve sticking, plus I have also let it drop back to an idle and it still stuck.

I think I may have 2 issues going on here # 1 is I think the bore is to large as it doesn't keep the valve centered allowing it to drop/tilt and catch when it try's to seat. # 2 may be what polysphere alludes to. If the reliefs in the valve were larger to allow it to start dumping the valve may never open far enough to clear the front of the bore and drop/tilt as it would be supported on both ends.

By the way I just downloaded my data from the weekend oil pressure was 97 lbs at the finish line.

Dave

I actually was considering opening up the three reliefs in the valve. But wasn't sure it was a good idea 2 days from raceday. Do you think that could contribute to my oil pressure trace on my graph looking like pressure oscillates10 pounds or so as I go down the track? I have never had a nice smooth pressure trace.

Dave

IMHO it's possible, lots going on.
OTOH it's reading from the sender - how far is that away from the relief valve? Even if it makes you nervous it may not reflect any change in the main gallery.

Oil pressure sensor is at the rear of the block, mounted on frame rail (dragster) -3 line feeds it.

I'm going to take my extra plunger/valve and rework the three reliefs to start opening sooner. I'll take the other in case it doesn't work out. Good thing this is a mopar, taking the valve in and out is simple..lol

Thanks for the input..

I bought the indy pump cover from Rick but will probably not see it before I leave Friday.

Thanks

Dave

You're very welcome, please LUK anything you discover?
Thanks.