Milidon oil pump problem

[Hemi GTS]

Ok heres the deal, I got the 493 in the bracket car and I got an older Milidon dual line pump with a remote filter on it. Problem, oil pressure goes way over 100 lbs when reved, idle pressure is 70. I have an adjustable regulator on it and its backed out. I checked the pump bore for hanging the valve looks good. It is also a new valve, I am using 30 wt oil in it, any ideas?

[GON_RACIN]

I had to cut a coil or two off of the spring for the adjustable reg. on mine to get the pressure down to acceptable levels.

[ksdartguy]

I had one of those way back. It was like that cold and still on the high side with
hot oil. I never turned the adjuster in. hot was about 55 and 80 as I recall.
Id cut off a coil. You can always turn it back in a bit.

Rick

[bigtimeauto]

I had 91lbs cold with my stock spring and 20/50. I to took 2 coils off and now have 80lbs cold. Why on earth are you using straight 30? get that lawn mower oil out of there.

[chryco]

How tight did you build that motor?

[andyf]

If you put an oil pump designed for a Funny Car on an engine with stock bearing clearances you get a ton of oil pressure.  Even if you take the spring out of the bypass you might have too much oil pressure if the internal clearances are tight.

[Hemi GTS]

Big time Ive always run straight weight oil in the race engine, of course I never ran a pump like this.

 Andy, this pump was on my Hemi that was out of a drag boat. How can I tell if its a pump for a Funny car,is there some way to identify it?

[chryco]

Check this out , it only describes one pump . If your mains and rods are a little on the tight side , you`ll have to take some spring tension out of the reg. I know , I`ve popped a few oil filters off with that same scenario in the past. A race pump is meant to run on a loose race engine .

http://www.milodon.com/oil-system/oil-pumps.asp

[Hemi GTS]

Thanks Chryco I did look at that. I sent an email out to the Guy I bought My Hemi from and see what the pressure was on the motor when he had it, thats where this pump originated. The clearances in the Hemi and this engine are the same.

[bigtimeauto]

I run that same pump without any issues. Just use normal oil and get the cold setting to 80 and you will be fine.

[Hemi GTS]

What do you mean by normal oil?

[bigtimeauto]

20/50 10/40 crude or if you have enough miles synthetic

[chryco]

My Barton pump reads 80# cold them drops down to 65# hot. With 20/w50 valvoline .
   Take some spring out , she`ll be fine.
       C

[andyf]

That doesn't look like a Milodon pump to me.  It looks like a Melling HV pump with a Milodon cover.  If it is just a HV pump then put the standard spring in there and your pressure will go down.  Or better yet, replace the pump body with a standard passenger car body rather than the HV unit.  The fact that your pressure is so high is telling you that you're pumping more volume than the engine needs.  Putting a softer spring in there just bypasses the oil which isn't really a good solution.  There is no reason to just pump the oil around and around inside the pump since all it does is heat up the oil and place drag on the camshaft drive.

[Hemi GTS]

Thanks every one, Andy its possible thats what the pump could be it does say Milidon on the cover.

[andyf]

Easy way to verify is to see what material it is made from.  The Milodon pumps are aluminum while the regular pumps are cast iron.  In the picture you posted that appears to be a Melling HV pump with Milodon covers.  The Milodon pump has the block side inlet cast into the pump but in your picture the block side inlet appears to be a separate plate.

Look in the Milodon catalog and I think you'll understand the difference.

[NYrr496]

I have a pump that I bought from Dick Landy a long time ago.  It's in a Milodon box, but it's iron.  I'll look at it when I get home, but I'll bet it's a Mellings that they repackaged.

[Thin White Duke]

Straight weight oil resists breakdown much better than multi-viscosity oil.  It's the best protection assuming you have narrow operating temps (not over the winter and into the summer). 

[ojaidart]

Just for discussion, why is high oil pressure a problem?  I have 100 lbs cold and 70-80 lbs hot using a 10-40.  I use a Wix oil filter because the casing is heavy and will not blow out.  I also tried to adjust mine down and it is as low as it will go.  I can't think of a reason to stress over the higher pressure.  Any comments?

[NYrr496]

If nothing else, you're stressing the cam gear and timing chain with nothing more than bypassed oil. 

I noticed in the late 80's that Cat industrial engines were operating with lower oil pressures.  Cat had a bulletin that explained the oil ran cooler AND the engine burned less fuel because it wasn't pumping all that extra oil, thus creating less drag.

[Hemi GTS]

Andy, been doing some thinking and I was wondering about taking the inside line off and the plate, running just the outside line. I do have the shorter drive shaft for it. The engine is set up for 7500 RPM. I would still be pulling oil through a number 10 line.I put a stock spring in and it brought it down to 70, but when you rev it the pressure jumps to 140 which leads me to believe what you said about the supply to the pump being so much more, any thoughts?     Mike

[bOb shingler]

use both lines.

[Hemi GTS]

Bob the problem I got is excessive oil pressure, like Andy said it appears I have more volume to the pump than I can use causing the excessive pressure 140lbs. I can live with 90-100 , 140 is a bit too high.

[NYrr496]

140?  Jesus... Epoxy a piece of black pipe over the oil filter...

Don't do that.

[bigtimeauto]

your bypass is not working. Take it apart and clean it it is stuck. Don't start it again till you fix it. I can't believe you didn't expload your oil filter!

[Hemi GTS]

Its not stuck I already checked that, I believe its what Andy said about the pump being a high volume unit with the Milidon covers. When you increase the supply to the pump such as what I have, and a long pump gear such as mine, your oil volume is such that at a higher rpm it is delivering more than the bypass can handle. As far as the filter, its a mobile 1 same as K&N, they have a burst pressure of 500lbs plus. I have changed the oil to a 10-40w. I have to warm it up and see what happens.

[chryco]

Its not stuck I already checked that, I believe its what Andy said about the pump being a high volume unit with the Milidon covers. When you increase the supply to the pump such as what I have, and a long pump gear such as mine, your oil volume is such that at a higher rpm it is delivering more than the bypass can handle. As far as the filter, its a mobile 1 same as K&N, they have a burst pressure of 500lbs plus. I have changed the oil to a 10-40w. I have to warm it up and see what happens.

Cutting the volume to the pump will not drop the pressure. Just make it harder to receive oil from the sump. I did the opposite and added the secondary line . Little if no change in oil pressure , But I know I have the ultimate in volume now.
    Chryco

[bigtimeauto]

There has to be something wrong with the bypass if the pressure keeps building. I have the funny car pump and still run it at 80psi cold.

[GLENNP]

Since you guys are the brains on this I'd thought I just through this out there....is that a carpeted garage floor?   You rule!

[Hemi GTS]

Yeah it is indoor outdoor grey carpet. Whe I redid the garage it was a hell of alot cheaper than anything else. It cleans up pretty good, and if You screw it up just roll it up can it get another piece. I like it.

[Hemi GTS]

Well I pulled the pump off the engine and took it all apart, didnt see anything wrong with anything,and then I started thinking about the relief circuit.I put the relief valve back in, the spring and the retainer cap. I then took a screwdriver and pushed the relief valve back until it stopped and I discovered that the cap was not letting the valve back all the way only alowing 1/4  of the window on the valve to open the pressure side back to the suction side. So I backed the cap off and discovered I needed another .135 thousands more to open the window all the way.I put the adjuster cap in the lathe and cut.135 off the end that the valve was contacting. Put it all back together fired it up went to 90 lbs cold and 80 at a rev hot, idle is 50. We ran the car, with a shit burn out due to a line lock problem it ran 9.92 @135 shift speed 7000 RPM.Cam range is 5500-7800, we got a lot left, it crossed the traps at 7400. I have to get a tighter convertor, what a ride though!
Watch the pass. Theres one of My Dart leaving a Family reunion, sorry no sound on that one.   


http://s455.photobucket.com/albums/qq280/426dart/?action=view&current=20081005111842.flv

http://s455.photobucket.com/albums/qq280/426dart/?action=view&current=20081005141146.flv

http://s455.photobucket.com/albums/qq280/426dart/?action=view&current=DartBurnout.flv

[chryco]

Awesome ! Thanks ! Glad to hear you got the oil pressure issue licked !
  Chryco

[Hemi GTS]

Thanks Chryco, I was really going nuts with this.

[bigtimeauto]

 Glad to see you worked it out.