guess you're right, I gather the restriction was in front of the pressure sensor.

Bob

My experiences with oil pressure
 

I have a windsor but my experiences are similar and I thought I might share thejm.

My motor was build by a well known engine builder for fords on this site. My oil pressure is 40 to 45 psi when warm and engine speed above 2000 rpm. This seems low to me as I expect 60 psi or better on a fresh professionally build engine. Old rule of thumb is 50 psi plus 10 psi for every 1000 rpm over 5000 rpm. I have 60 psi when cold at idle no matter what oil.

My build shteet says 0.0035 inch clearance on mains which is 0.0005 over stock maximum allowed. I have a 25% high volume pump and have tried 5-30wt up to 20-50 wt. The number I site are for 20-50 wt. The engine builder did not seem conserned about the oil pressure or the bearing clearance and suggested I turn up the pressure relief valve spring.

As a mechanical engineer this did not make sense to me so I called Melling tool company about their pump. They agreed that turning up the relief setting would not improve pressure once warm.

I have chosen to stay with the 20-50 and just drive the thing and not worry about it.

I would like to know what others expect and have for oil pressure once the motor is warm and at speed. I suspect my old rule of thumb has no engineering basis and that anything over 40 psi for a motor that stays under 7000 rpm is not a real problem other then it bothers some of us ( including myself ) to look at the gage and see lower then expected oil pressure on an expensive motor.

How about 0.0035 main bearing clearance? Why would a compentant engine builder purposely install such clearance on a street/strip motor? I do not know but it sure runs good......

That rod clearance does sound on the BIG side for a Windsor. It's common knowledge the FE's like more clearance, but I'm surprised at a Windsor going that much. Hmmmmm...

My side oiler, hot, idles at 40, runs 70 or 80 at speed, 10-40 synthetic. All though I think I'm going back to Shell Rotella standard oil shortly. Don't know why for sure, synthetic just doesn't 'feel right', it's a mental thing.

Oh, and no oil cooler or external filters, just 'stock' stuff with a HV pump.

On my 289 I originally used .0025 clearance for rods and .002 for mains, with oil restrictors throughout. The current Oil Pump is a Precision Pumps (reworked Melling) Hi Volume, High Pressure unit; the newer design with the shaft extending into the bottom cover. This was installed when they became available as I thought the extended shaft was a definate design plus, that had been missing in the Ford pumps. Per Melling the bypass is set at 80#. Using Kendall GT-1 10-40 oil the engine develops 80#+ at cold start up. When warmed up it has a solid 70# at road speed above 2000 RPM and 35#-40# at idle. It has been bullit proof for 14 years. Although it is not a high mileage engine, it routinely get reved above 6800 RPM.
http://www.precisionoilpumps.com/ima...ace%20Pump.jpg

I have a Shelby aluminum block and heads. My oil pressure can easily go above 100 lbs cold and I am real careful until the temp comes up. Once the oil gets warm it drops to 55 at 2000 rpm and 20 at idle, the max pressure hot is about 60. I spun the gear off the dist once cause I got carried away before it was warmed up but that was about five years ago. I have a high volume pump with oil restrictors in the head a cast T pan and a Canton windage tray. If I hold above 4000 long enough, well over 100 mph, my pressure will start to bobble. I am convinced that I am pumping the oil up into the motor faster than it can return. The FE heads have a very challenging time trying to drain oil back to the pan and over use of silicon for the end seals can interfere with this. If you pull the dist and the rear breather you can see these drain backs with a mirror. I am always amazed at the number of people who think that a stronger oil pressure relief spring will help low oil pressure. It can make the high higher but the low will be unchanged.

I had my engine modified to a dry sump system. Something you might want to consider if running high RPM's for extended periods of time. I use to watch my pressure guage bounch all over the place; now it stays pretty steady, except at idle.

RDI in NC made mine for me.

TL :MECOOL:

Fyi
 

ED
Your oil is up in the motor, at higher rpm's. But mainly wrapped around the crank. My oil restrictors are brass screws cut about 5/16's long slotted and drilled with the smallest drill bit ACE hardware carries.062 was too large.Couldn't find it but it was the smallest bit they had. still flows plenty for my Dove rollers. You cant imagine how much oil your engine moves I was shocked when I spun the oil pump with an cordless drill motor. Plastic catch pan under a friend spun it while i watched. It has to move more while running. So keep filters ,coolers fed with an-8 line min. I'll be using an-10 line to reduce friction,and let oil flow unrestricted with a bypass line for the cooler. Your correct let that oil warm up. Excessive oil pressure uses horsepower, More's Law doesn't always apply enough is enough. When my system is full I have almost 12 quarts oil with the oil to the bottom of the windage tray.Knowing that will drop some when the motors fired up. Can you Imigian the turblence all those pistons pumping on the bottom side. a little vaccume on the crankcase doesnt hurt, keeps the seals from leaking,gaskets too. A nice an dry FE what do you know? Thanks All Jimmymac;)