Oil pressure low in 427 C/O
 

My 427 C/O got new rod, main and camshaft bearings recently, with the crankshaft reground also. All done by an experienced machine shop. The engine got a new camshaft, lifters and new Dove rocker shafts. An oil restrictor to the rocker shafts has been installed in the Dove F5 aluminum head also. It has a remote oil filter with a FRAM HP1 oil filter, an oil cooler and oil thermostat in between. The oil pressure pickup measures the pressure AFTER the oil filter and oil cooler, actually the pressure going into the engine.
The engine runs fine. At first I used 15-40W Castrol oil, and the pressure was 15psi at idle(800rpm) and 50psi above 2000rpm. I wanted to improve that , changed oil to Shell 15-50W but now I have 10psi at idle hot and 45psi above 2000rpm,
It has a Melling MV57HV high volume oil pump, which is almost new,and a bafled Canton Oil pan. 8 liters of oil total
Outside air temp here is around 95ºF.
I am worried about the low oil pressure, especially at idle , and do not want to rev up above 4000rpm until I am sure 45psi is enough for that.
I have read of some 427 owners reading oil pressures of 30psi at idle and up to 80psi at 3000rpm , and all that with 30W oil !
What can be wrong with my engine? Is my oil pump no good? Are some of the 80psi guys reading oil pressure before the oil filter? Is my oil gauge faulty?
Need help from all of you!:rolleyes:

Hey again!

The oil pressure should be between 32-35 psi at idle and I have been told to use single viscosity oil - I use 40 wt in my car. I have 32 psi at idle and 93 psi at 6200. Oil pressure is controlled or set with the regulator/spring in the back of the block/oil galley - sorry I don't know the exact name but that is what is used to set the pressure throughout the engine. Best wishes!

Here is a site with some very good information for all!

www.Melling.com/highVol.html

Cracker,
you make me turn green of envy !
How do you get those oil pressures ?
Where do you have the pickup for the oil pressure indicator ?I see that you have Jesel Roller Rockers & Chevy oiling system through. Might that be the reason?
The oil pressure relief valve in the back of the block may prevent the engine from attaining higher pressure than the maximum set. But I reached 80psi cold when I first fired up the engine, and on idle the relief valve is probably not operating anyway, so that is hopefully not the problem (I say hopefully because I don´t feel like taking out the engine AGAIN!)
I have followed another lead (Leadertape) with the same problem I have, and the answers are of all kinds. Mr.Fixit says 10-15psi at idle and 45psi at speed hot is fine, which makes me feel good, but then you suggest minimum 28psi hot at idle.
Lifter galley problems are out of the question in my case,
since my block doesn't have any.
Is 10psi enough pressure at 800rpm (oil temp about 195ºF)?
Is 45psi enough pressure at 3000rpm?
Is 50psi enough pressure at 6000rpm?

At this point I am starting to think as follows: I will drive the car, enjoy it and if the engine ever develops problems because of the oil pressure, well then I´ll take it out and fix it. That may take a long time in happening, and in the meantime I´ll have fun driving.
The engine has been too long resting in the garage doing nothing. No excuses now !

ElJaro,

Going to a higher viscosity oil might actually give you lower oil pressure as measured after the filter. There will be slightly higher pressure out of the pump - but more pressure drop across the filter.

*Toss the Fram filter! Do a search on this site for "oil filter".

With the oil cooler and thermostat, 15W-40 is probably a better oil choice.

It does sound like your clearances are a bit loose and you could stand a slightly stiffer bypass spring in the oil pump, but things are not too far off. I would drive it for a while and see whether the pressure remains constant. Put some miles on and check the rod bearings for wear.

Bob,
I agree with you, higher viscosity isn´t going to increase pressure in the engine, and what happened to me is exactly that.
I´ll have to go back to 15-40W oil, and will check on the oil filter issue. Maybe there are a few psi'i in there too.
Thanks for the tip !
Steve

My builder used the pressure relief valve to adjust/increase my pressure. Just a thought, when I put my engine back in the car my Smith's oil guage read 20 psi at idle hot. Obviously I was concerned and brought the car back to the builder and we ended up sticking an pressure gauge in the same port and discovered mine was reading 12 psi low! So now I have to simply add 12 psi to whatever the guage reports. This might be the case with yours and is relatively easy to check. Best wishes!

Hello,
Nearly all 427 center oiler blocks have a small (1/4") hole under the oil filter adapter pad that should be plugged. I'm not sure what the hole was for but I believe it was for some drainback to the pan when FEs were used in undustrial applications. Normally, when using a passenger car adapter the hole is covered by the adapter and gasket. But in Cobra applications where a remote oil filter and/or cooler is used, nearly all of the adapters have an open area over the hole that is only covered by the gasket. If the gasket blows out or leaks, oil pressure will bypass internally right back into the pan. Depending on how bad the tear in the gasket is, this will result in low or no oil pressure at idle when warm. I'm not saying this is your problem, but I have seen it happen plenty of times and it is easy enough to check out and fix. See photo, an allen plug is installed in the hole.
HTH,
Mike

I generally see 5-8 psi more with 20/50 than 10/40 but my climate is mild. 55-85 degrees, I don't drive my car much at 95-100 degrees but ambient temp makes a difference.
Try a mechanical gauge for kicks. It picks up at the block where the oil line adapter is. If it is still low you may have a bad oil bypass spring in the pump or in the block.

Was this an engine you owned prior to the rebiuld? You say the oil pump is almost new??? What does that mean? Was it on the engine before with low miles to prolong the life of the engine before the build? or was is something someone had lying around. It could be the pump. Are you sure it is a HV? What was the oil pressure on this engine with this pump before the build (did you have good pressure with this pump before the build)

I had similar problems with a standard pump that was on my car when I bought it. It could be the bypass spring in the block was improperly reinstalled if it has one (not all c/o's do) it is behind the fly wheel above the cam freeze plug.

This is a solid cam engine now, I will assume this as you indicated the rocker arms are adjustable.

Was this a solid cam engine before it was built?? If it was a hydraulic lifter engine and if the machine shop didn't plug the oil galley to the lifters that could be your problem. The lifter design for the hydraulic lifters takes into account the need to maintain pressure, solid lifters are the opposite. they are designed to scavenge oil off the valley pan and will allow oil to flow around them freely. This isn't something the machine shop will know or care about (they should, but may not) especially if you bought your heads elswhere and only had them do the short block???

I hope this helps.

I spoke with the builder of my 427 Center Oiler (Accurate Machine in Arizona), they built the motor originally for one of Bob Bondurants cars......He told me that my oil pressure is right where it should be:

Cold fast idle 1,200rpms 40lbs

All the rest are hot

15-20lbs at 800-900rpms (idle)
40-45lbs at 1,800-??????



Hope this helps..........


Yours In Fords,

Bill S.

SCOBRAC,
the engine is original without hidraulic lifter galleys. A solid lifter HP engine throughout.
I replaced the filter today with a Purolator, but when starting the engine, oil pressure would not shoot up instantly as before, now it creeps up slowly,
I'll take the Melling HV pump out tomorrow and check if it is drawing air from somewhere. I remember that the pickup was touching the windage tray when installing it, and it may not be bolted down flat on the pump surface.
More news tomorrow.

If the windage tray was touching the pickup there may be a hole in the pickup tube by now.

Good Luck

I'll have to bang up the windage tray a little to make place for the oil pickup.
But since my rear main seal is leaking, I took out the oil pan again, replaced the seal, and I am waiting for a new Melling HV oil pump to arrive to be put into the engine.
It may be that the scars I see on the two rotors in the actual pump are not so normal and oil pressure is leaking out there. The Melling HV oil pump I have right now went trough the munching up of a cam lobe, a lifter and several bearings, so it may have been worn excessively by metal particles. Well, it's only just about $35 to find out if that is the culprit of low oil pressure.
I'll keep you posted on this.

Mr. Mustang / Bill is right on.

15-20 psi at idle and 50-60 psi at cruse is perfectly normal.

Anything higher is a waste of horsepower and provides absolutly nothing in return.

mines 15-20 idle 50-60 down the road too no problems

25LBS at Idle and 50-60 cruiseing :)

SFfiredog was right
 

I installed a brand new Melling HV pump, and the pressure is still very low. 10psi at idle hot and 40psi at 4000rpm.
Today I took out the oil filter adapter and there was this 1/4" hole which I had never bothered about or had never really seen, but which was mentioned as a possible cause by SFfiredog.
The gasket over the hole was blown
( that probably happened when I saw 90psi the first trime I fired up the engine after the rebuild, but never again thereafter), so the oil was pumping right back to the oilpan, reducing the oil pressure.
That is most likely the culprit. I bet that when I get the hole plugged I will get decent oil pressure.
I'll fix that this week and will probably get back with good news.
One thing that worries me though is that I did about 50 miles today with that low oil pressure. Even at 5000rpm the oil pressure never got above 40psi.
I hope I didn't ruin the bearings.
Thanks to SFfiredog, whose suggestion I did not consider initially, because I had never SEEN that hole. But there it was !!!

Oil pressure ok
 

The misterious hole in the block right where the filter adapter goes has been plugged, and oil pressure hot is now 25psi at idle and 60psi above 2500 rpm.
Thanks again to SFfiredog for the tip:D

Good for you! That might have saved your engine in the long haul. If there is such a thing as a long haul with an FE!

Back to Basics
 

We purchased our car second hand in August of this year and it came with 33 near perfect photos but looks can be deceiving. It looked good but no one had done the maintence.
We were experiencing low oil pressure and jumped to concluision about the pump being bad. The forums confirmed our fears and we were ready to pull the engine but a closer inspection showed the pan bolts were loose. Problem solved "Have oil you will have pressure."
Track the problem, test and eliminate each component.

I am beginng to sound like Mr. Fixit :JEKYLHYDE