low oil pressure

[Rick Rockey]

Looking for some feedback. I have a 351W stroked to 427 with about 400+/- miles on it. My oil pressure, when warm (175), is 28 lbs. at idle (800 rpm's) and about 38 lbs. at 3000 rpm's. I've checked using two different gauges so it's not the gauge. I'm using 10/30 oil, oil pump is a Melling HV. Any thoughts on this? Oh, cold pressure is 42 pounds.

[Rick Parker]

Doesn't sound like enough Rick. Should be 50-70 with a HV pump on it with .0025 clearances. Maybe the relief valve is stuck? What filter are you using? Cooler? Electric Gauge????

Rick

[nanard289]

Hi Rick,

Don't worry, usually, a low oil pressure means a good oil flow! At least, you don't spend needlessly mechanical power to drive your oil pump faster. Usually pressure switch (that monitore the red "too late" lamp) is adusted to swith on below 20 to 30 PSI.
It is a common practice for Nascar engine builders to adjust oil pressure at 10lbs per 1000rpm to be about 40 lbs at 4000rpm to 80 lbs at 8000 rpm (with external dry sump oil pump system you can easily adjust the oil pump rotation speed ratio). However, if you can listen some valve train noises, you can use an higher oil viscosity as propose Rick (W40 for winter looks OK). You have to check also the oil pressure gauge location. Oil pressure value may change according to the control point that can be before the main crank input or after the cam bearings. If you have an electrical oil pressure indicator, don't forget to check the oil pressure sender. Last issue, in case of doubt you can bring an oil sample to the chemist for analysis. He will be able to find any suspicious metallic particles.... if there is!

[Ron61]

Rick,

I have a 351 stroked to 416 and I run lower oil pressure than most and have had no problem since I had the engine built in 1996. When cold it is about 50 pounds. On a 118 degree Summer day it will run around 40-45 pounds at 3,000 RPM and around 28-35 pounds at idle depending on how long I have been running hard. I am running a remote filter and oil cooler also. I have changed oil after just one run several times to check for any suspicious stuff in it while it was nice and clean and have never found anything. Used a magnet and very fine mesh nylon screen to pour the oil through. So now I don't do this and I don't change oil after every drive. I have also tested with a remote gauge hooked right into the sender and it reads the same.

Ron

[Mr.Fixit]

38 psi is plenty to keep the motor alive and well

[Rick Rockey]

Thanks for all the replies to my thread. I'm using a direct pressure gauge off the block. Now as another check I think I'll take a reading at the remote filter block just to see if there could be some difference in pressure. Also going change oil to 10/40 and use a better filter, I was using a Fram PH8A.

[Bruce Edwards]

Rick,

The rule of thumb for engine builders is 10 psi for every 1,000 rpm the engine is made to turn. If the egine will go to 6,000 rpm your pressure should be 60psi. If your engine will never see the high side of 4,000 rpm than 40 psi is fine.
As a builder I would remove the front timeing cover and check to be sure all of the lifter galley plugs are still in place. If one pops out the pressure will drop but because of the engine oiling system you will still show pressure and the lifters will not make noise at lower rpm.
You could also drop the pan and see if anything is in it, say like a galley plug. We use the Melling HV/HP pumps in our engines and have never had a new engine with oil pressure that low.
Be on the safe side and check it. You really do not want to rebuild it due to lack of pressure at speed.

[RACER X #99]

Rick, I am by no means an engine expert but everthing I have read and heard lately is that the 10 lbs. for every 1,000 rpms is old school engine thinking.
I know that the Clevelands and the FE's because of their poor oiling systems need lots of oil pressure to insure oil is getting throughout the engine.

I read where the Nascar cup guys will actually lower thier oil pressure for qualifing down to 25 psi and then raise it up to 35 psi for race conditions. Or course they rebuild after each race so those numbers might not work for longevity on the street.

In my 408 Dart which has the best oiling system of any Ford block, I run about 45 psi at 7,000 rpms running 20-50 dyno oil. Im gonna go to 10-40 synthetic this year as I now have about seated the rings.

I think you oil pressure is just fine.

Cranky

[Bruce Edwards]

Rick,

Just to put in my last two cents. I have been building engines the "Old School" way for almost 30 years and have NEVER had an engine I built come back for more than an oil change.
If one of my new engines fired up with that kind of oil pressure it would never make it out of my shop.
Also for the record the 4.6 Supercharged engine in our demo car pushes 80 psi at cold idle with a factory Ford race oil pump and I never messed with the bearings on the donor engine as it came out of a wrecked car with only 24,000 miles. I would not call the 4.6 "Old School"

Just and old school kind of guy

[wilf leek]

Might be worth checking the clearance between the oil pickup and the bottom of the oil pan if everything else checks out. Or if some silicon or whatever is blocking the pickup mesh.

I am with some of the other posters here - that low a pressure on a new engine merits investigation. Could just be a stuck relief valve, could be something more serious.

[CowtownCobra]

I started with a HV pump. Cold it pegged the gauge (80+). Warm at idle it was about 45. I went back to a standard pump. The lowest I think I've ever seen hot is about 25.

You may have a wiring problem.

[Hal Copple]

having any number of friends with stroked Windsors, it is my observation that the strokers just run a bit lower pressure than the standard stroke engines. Probably a number of reasons.

I would not pay much attention to "idle" pressures, i can drop to 20'ish at 700 rpm, and bump it to 900 rpm, and get 35 or more. A no-load engine at low rpm does not need much pressure.

I used to run for many thousands of miles, at my own standard condtion (hot, 2000 rpm steady), about 48 psi, went up a bit with increasing revs. Never had any problems at all, and i know of some guys with even a bit lower, whose engines have many thousands of miles with nary a problem.

But you might seek out a few extra pounds just to feel better. Try a really good filter, and try a slightly more viscous oil, say a good 15-50 or 20-50, if your pressure drops, you have too much resistance in your lines and filter, if it goes up, good. Be sure and be easy with your motor until you have some heat in the oil, by the way.

I put a full AN 12 system (including a Setrab oil cooler), with as few turns in the lines as possible, with an oil return straight into the block, plus some other things, like a huge NASCAR racing Wix filter, etc. Modified high volume Melling, cranked up all the way, enough to spin off my distributor gear, too. Was pretty expensive to do this, but I did gain about 5-10 psi, now my hot cruise is about 55ish, and it goes up nicely with rpm.

You have now various opinions, but short of dropping your oil sump, easy to do once you do it a few times, try the change in oil and filter first. Of course, the first thing to do is to call yourengine builder, for their specs and opinions.

[Mr.Fixit]

A stroked windsor will live just fine at 40 psi. I know a few shops that warrantee their stroked high-HP windsors, and they only make 40 psi. If a galley plug came out, it wouldn't make pressure, let alone 40 psi.

[Cal Metal]

Also, changing to 10W-40 might not be the best idea. The more additives it takes to widen the viscosity range, the less oil there is for real lubrication. Narrow that up a bit. Too many polymers run counter to good lubrication. Very few manufacturers recommend 10W-40 and will, in some cases, void the car's warranty if used. Mobil I (synthetic) is the exception, as they use no viscosity improvers in their 5W-30 or 10W-30 oil.

All synthetics are not created equal, however. Some do use polymer enhancers on the wide viscosity oils. Mobil 1 is the exception, however.

[Bruce Edwards]

We had a Windsor engine come in our shop with low oil pressure after some other shop built the engine and refused to help the guy with his complaint. They told him it was normal to have low pressure on a new engine and not to worry about it.
Pulled the pan and found a front galley plug. Pulled the cover and timing set and found were it went. Installed a new plug and the oil pressure went up to the area it should have been. Our new customer was happy that he found someone that knew something about Windsor engines.

[Mr.Fixit]

What kind of pressure did that motor show?
Last windsor I dealt with that had a galley plug come out couldn't get any pressure on the gauge. Went to 55 hot after replacement.

[Bruce Edwards]

It was showing 25 psi at 3,000. and 15 psi or so at idle but it did not have any lifter noise until you got it over 3300 and the pressure would start to go away.
Not much question something was wrong with the build but the builder was a high volume outfit that did not take much pride in the work they put out.

[Cracker]

Recently, trying to isolate an oiling problem I backed out an oil plug from the main galley towards the rear of the valley and then primed the motor. I had SO much oil coming out that it shot over the fender! It happend so fast I didn't even look at the gauge but there is no way I was registering much at all. The difference is this is an FE but from what I've heard from a few knowedgable folks is that it would be extremely noticable if a galley plug came out. You'll still move plenty of volume but at little/no pressure.

[Bruce Edwards]

The Windsor has three galley holes in the front of the block. One is partly covered by the cam spacer/ thrust plate. The plug that came out was behind the plate. The plug was driven in side ways and was so bent it got past the plate. The edge of the plate was just big enough to block off part of the galley hole giving the engine some pressure.

[DAVID GAGNARD]

Bruce;


I'm familar with the three plugs on the front of the engine you'll are talking about,I have a question..... Do you recommend removing these and tapping the block and using screw-in plugs or are the " factory style freeze plugs" good enough for a performance engine?????? I have heard both ways from different builders,just wanted another opinion.....

I just went in the shop and looked over a 1972 351-W block,it has two freeze plug looking plugs on the side of the cam (front face plate) and one screw-in plug deeper in the block in the front were the oil drains back near the cam and distributor gear,and one rather large "freeze plug looking" plug in the rear of the block and right next to it it also had a smaller screw-in plug.....

I know you could not tap and thread the large one on the rear of the block,but how about the small ones in the front..... Is it worth the time and trouble or not really necessary??????

David