Guys you may have noticed an earlier post today that I took the car out for its first drive with the new 406. Well, I encountered a problem. When I was driving I noticed my oil pressure dropping very low so being close to home I brought it right back and shut it down. If I start it again oil pressure is fine at an idle and goes up with rpm. Is it possible it is running out of oil at a higher rpm when driving? Its a stock pan and a high pressure pump. I researched on here and someone had a similiar problem. It was suggested maybe the pickup was too low or too high. Mike Lewis suggested adding a little more oil then trying again. That way you would be able to tell if it was running out of oil or if not the pickup might be too close to the bottom of the pan. If I try another 1/2 qt of oil it shouldn't hurt the engine should it?

Thanks

Jerry

To much oil will cause the crank to fling excessive amount of it on the cylinder walls which can end up fouling plugs or cause carbon buildup behind the rings. I don't think I 1/2 quart is gonna hurt anything though. Usually if the pickup is to high and/or not enough oil, the oil pressure will drop when you drive around a corner.

I think I know what is happening. I used a windage screen and screened of the drain back holes in the lifter valley. It seems like it is running out of oil, like the oil is taking too long too drain back to the pan. Does these seem like a logical explanation?

When the pressure dropped were you driving normally or in the throttle? What are the pressures, cold and warm idle? How quickly did it drop? What viscosity oil?

Jerry,

Adding an extra quart short term to test will not hurt anything.
If it takes longer for the pressure drop then it is a good indication the oil is not getting back to the pan or the pickup is too high.
In a rat it could mean the pickup is laying in the bottom of the pan.
In a small block this isn't the case.
To add to Pat's questions, what kind of screens, how close is the pickup to the pan, was it welded or bolted???
From your initial discription it sounds like an oil return problem. :(

Are you sure you haven't overfilled the crankcase, as this will froth or aerate the oil and cause a pressure drop after driving a little while, after you shut down for a little bit, the pressure will be ok until it starts aerating again..

The pressure was dropping to below 20lbs at a cruise about 2500rpm. When I got it stopped and checked the oil it seemed low but after a bit the dipstick showed it was full. I added about 2/3 of a qt more oil and took it out again. The pressure did not drop this time. I am using 10-30 wt oil. Pressure at cold fast idle is about 50-55lbs. When driving at about 2500 - 3000rpm engine hot I have about 45lbs now. However at a hot idle now I am below 20lbs.As soon as I hit the throttle it goes up to a max about 45lbs. I have only reved it to about 4500 rpm at this point. It maybe looks like I maybe have my clearances on the bearings too loose graemlins/clonk.gif I like to learn things the hard way I guess. Anyway I not sure what you fellas think but I believe the oil is taking too long to drain back. I used a Milodon diamond stripper windage tray, the one that is actually a big screen. I also screened the drainback holes in the lifter valley. I am using a melling 55a high pressure pump and stock style pickup. When I set the pickup I installed it on the pump and set my pan on with no gasket. The pan pushed the pickup until the pan was seated. I then raised the pickup about 3/8" more. I am using a felpro 1 piece pan gasket which is a little bit less than a 1/4" I should be about 1/2" from the bottom of the pan.
One positive thing though, holy crap does this pull.
Right now I have to try and figure out my problem. I am going to pull my intake in the next few days to make sure there is nothing blocking the drain back holes. Then I guess I will have to pull the motor so I can pull the pan to take a look.
Any thoughts???
I should add I did tack weld the pickup on with my mig welder and i did take the pump apart before welding

Jerry

Jerry, are you dead sure all oil galley plugs are in? That pump should be producing at least 60-65 lbs at cruise. I would guess there's an internal oil leak somewhere, maybe one of the plugs behind the timing gear. Is that an HP pump or a HV/HP version? I've used that windage tray several times and drainback screens hundreds of times. Never had any drainback issues. Is it a stock oil pan and dipstick combo?

Tom

Originally posted by Tom Mobley:
Jerry, are you dead sure all oil galley plugs are in? That pump should be producing at least 60-65 lbs at cruise. I would guess there's an internal oil leak somewhere, maybe one of the plugs behind the timing gear. Is that an HP pump or a HV/HP version? I've used that windage tray several times and drainback screens hundreds of times. Never had any drainback issues. Is it a stock oil pan and dipstick combo?

Tom Yes its a stock pan and an aftermarket dipstick Tom. Tom, I am dam sure I have those front plugs in good, butttt, I have made mistakes before. :D
If one of those front plugs came out would that explain my situation? Would that explain my lower pressure problem? You know, when I first fired this up to break in the cam I had close to 80lbs pressure eventhough I had straight 30 wt oil.Maybe you have a good point with a front plug missing. I would kiss someones behind till they barked like a fox if they told me that was the problem and it indeed turned out to be.
I do really appreciate everyone insight into this before I start tearing everything apart

Jerry,
What kind of drop are we talking about here?
Is it 60 to 45 after hot or is it heading towards no pressure while driving?
45lbs at 2000 or so I would consider normal with your pump, oil & lifters.
Could be a plug came out but I doubt it as this would not cause the drop in pressure that seemed better after adding more oil.
With your lifters, 20 lbs hot idle is not unusual but 45 above 3000-3500 seems a bit low for the 55A pump.
This is one application where I prefer a hi vol (M55HV) pump in a small block as you have 16 extra "oil leaks" added to the system.
If adding a half quart cured or delayed the pressure drop it still sounds like a drainage problem of some sort.
Don't know why as the screens shouldn't cause a problem unless you got epoxy over half the hole or used very fine wire or something??
Did you install the plug under the rear main cap that diverts oil to the filter?

Originally posted by Wolfplace:
Jerry,
What kind of drop are we talking about here?
Is it 60 to 45 after hot or is it heading towards no pressure while driving?
45lbs at 2000 or so I would consider normal with your pump, oil & lifters.
Could be a plug came out but I doubt it as this would not cause the drop in pressure that seemed better after adding more oil.
With your lifters, 20 lbs hot idle is not unusual but 45 above 3000-3500 seems a bit low for the 55A pump.
This is one application where I prefer a hi vol (M55HV) pump in a small block as you have 16 extra "oil leaks" added to the system.
If adding a half quart cured or delayed the pressure drop it still sounds like a drainage problem of some sort.
Don't know why as the screens shouldn't cause a problem unless you got epoxy over half the hole or used very fine wire or something??
Did you install the plug under the rear main cap that diverts oil to the filter? Mike, right now with an extra qt of oil I have about 55 lbs pressure when cold. When it get operating temp and driving the max pressure I get is about 40-43lbs when revving about 3000rpm - 4500rpm at this point.
With the extra oil it no longer seems to drop drastically like it did earlier when cruising.
At a hot idle now I am below 20lbs idling at 1000rpm. It seems like the oil pressure will go no higher than the 40-43 lbs when hot. I am probably starting to ramble here and confuse everyone
Thanks

Originally posted by blumont:
</font><blockquote>quote:</font><hr />Originally posted by Wolfplace:
Jerry,
What kind of drop are we talking about here?
Is it 60 to 45 after hot or is it heading towards no pressure while driving?
45lbs at 2000 or so I would consider normal with your pump, oil & lifters.
Could be a plug came out but I doubt it as this would not cause the drop in pressure that seemed better after adding more oil.
With your lifters, 20 lbs hot idle is not unusual but 45 above 3000-3500 seems a bit low for the 55A pump.
This is one application where I prefer a hi vol (M55HV) pump in a small block as you have 16 extra "oil leaks" added to the system.
If adding a half quart cured or delayed the pressure drop it still sounds like a drainage problem of some sort.
Don't know why as the screens shouldn't cause a problem unless you got epoxy over half the hole or used very fine wire or something??
Did you install the plug under the rear main cap that diverts oil to the filter? Mike, right now with an extra qt of oil I have about 55 lbs pressure when cold. When it get operating temp and driving the max pressure I get is about 40-43lbs when revving about 3000rpm - 4500rpm at this point.
With the extra oil it no longer seems to drop drastically like it did earlier when cruising.
At a hot idle now I am below 20lbs idling at 1000rpm. It seems like the oil pressure will go no higher than the 40-43 lbs when hot. I am probably starting to ramble here and confuse everyone
The plug under the rear main cap was installed by the machine shop
Thanks </font>[/QUOTE]

Sorry to hear about your troubles. I have a filter cutter and will be home from Ecuador tomorrow night if it will give you peace of mind that you didn't hurt it - highly unlikely.

It does sound like you have an internal leak. What were your main and rod clearances?

I think the best solution is to pull the engine and check it over...

I'll bet one of the lifter galley plugs popped out. That's not nearly like the center one coming out, that will really kill your pressure.

You have those lifters with the oil hole in the bottom? I don't see where you mentioned that in this thread. Did you get them from Mike, so he knows about them?

It's possible you have a volume problem when hot, I don't know, I've never used those lifters so I don't know exactly what to expect in terms of pressure/volume lost. Are they Isky? Do they recommend running an HV pump with them?

Are you getting any valve train noise from one side or the other?

Tom

Well I have been sitting here with my rum thinking about all these responses and scratching my head.
I performed a little test but am not sure if it means anything. I kept thinking about what Tom said about an oil gallery plug coming out.So this is what I did. I removed both valve covers. It seemd the rockers on 1 bank had less oil on them whether this means anything or not , not sure. I fired up the engine with the covers off, engine pretty cool and about 50lbs oil pressure.
The rockers at the back started getting some oil fairly quick but the further to the front it took a bit. I am not sure how much oil should be coming out , I kinda thought it would, well basically come squirting out with a fair bit of pressure.
I guess my first question is how much oil should be pumping out the push rods? If the answer is lots then maybe the missing oil gallery plug might make sense as it is at the front and those rockers were getting little oil, so the pressure could be minimal there.Make sense? Actually the more rum I drink the sensier it gets. jokin
I should have added these are Crane gold rockers
Thanks again

Jerry

Tom,
Yes,Jerry has the direct lube lifters & my experience is they will drop the idle & lower RPM numbers with a 55A pump & decent bearing clearances about 10 PSI or so.
Still should have full pressure at higher RPM though unless the bearing clearances are excessive.

Jerry,
Don't guess :rolleyes:
I personally wouldn't drive it or run it until you can look it over as Ryan suggested just to be sure.

Could be as simple as too much clearance along with the direct lube lifters, a core plug or even a loose pump but you need to take a look ;)

Just for info, I do not like plugging the valley & screens with a stock 4 quart pan.
You probably only have a couple of quarts in the pan at RPM under normal circumstances & slowing down the return probably isn't the best plan.

BTW, you didn't answer but did you put the plug in under the rear main cap?

Jerry,
It should be making a pretty good mess running it with the valve cover off. If not, something is probably wrong. I did a Ford 351 once and missed a "hidden" galley plug and it had similar oil pressure. If yours was ok when you first started it, and now it has dropped ... something has gone wrong. Our Matco tool guy had the same problem with a new engine (not one of mine ! )just last week and it turned out to be a broken rocker stud that let a roller lifter jump out of the hole and dropped oil pressure significantly. He claims it still ran pretty good, but I think it has a pretty heteful cam so he may not have noticed it at idle.
The moral is....find out whats wrong before running it any more.

Thanks guys. I have no intention of driving it again until this problem is resolved. I was fortunate to get a chance to drive it in early March to begin with because of our very warm weather. I think the first thing I will do is pull the balancer and drop the pan a bit with the engine in the car.I will check to see if possibly a front plug has come out. If not that, she will come out.
Tomorrow I am going ice fishing before its all gone.Its hard to catch ice when its 70 above :D

Mike, the rear plug was installed by the machine shop. Just another note on the lifter valley screening. I bought a kit and when I went to install it, there were screens (4)for the large drain holes at the ends of the valley and I installed them. It turns out there were plugs to block off the drain holes over the cam so I didn't put them in. I assumed it was all screens in the kit. I was going to epoxy some screen over those holes but never found a suitable screen to use so I just left them out.

Once again thanks fellas