Some info to share about my SB 427 high oil pressure problem
 

I bought a Ford racing 427 long block in this past May to go along with a new SF mk3. I had a blast buying stuff to dress it out and must say a very rewarding experience, it allows you to bond with your engine and personalize it. But that’s just me

Anyway when I got the LB I primed the oil system with a drill, what I noticed was that the oil pressure jumped to 100 psi, didn’t think much about it and being a novice at engine building but a mfg engineer by trade so I don’t feel I’m not a total dummy with most stuff, lol.

2weeks ago I found someone to run it on their test stand for cheep, after we timed and tuned the holley 750 we both noticed that the oil pressure jumped to 85 psi and pretty much stayed linear with the rpm increase, from idle to a brief 5000.

I wasn’t comfortable with this and sent the video over to Ford racing. They weren’t either but said the oil pump can be adjusted for the bypass spring force. I then called Melling and talked to Brain, he agreed with me and said you can’t turn down the pump force that much with turning the adjustment screw CCW.

The following week I built a test stand so I could see how the pressure behaves after the oil temp reached proper temp.

After just running at idle a few minutes and watching my gage read consistently at 85 psi I still felt something definitely not right with this pressure. Oil pressure should not be linear with RPM. If it was running at 85 at 6000rpm and went back down to 10 to 20 psi at idle I’d be ok with that but this is not the case.

I did some review reading in my Ford manual and it states that the oil pressure should be at 60psi running 4000rpm, this is more like it imo. Nothing is stated in the build list about using a high volume/pres pump either.

After contacting Ford again they agreed as will, said never had a problem like this selling crates for 20 years, l agreed with him, doesn’t make sense I got the only lemon of the bunch.

I had him check my serial number for any non conforming blocks that may have been made around that time, nothing

Well now I’m removing all of my parts to send back for their inspection, not sure what else to do. I don’t think it’s my responsibility to drop the pan and check, especially for what I paid.

Any how I’m glad I tested before putting in my car, will keep updating once Ford has a look at.

What did you set the timing on the Holley 750 at?


Oil pressure on a cold engine will always read high until the engine comes up to operating temperature, usually 180 ˚F to 200 ˚F.

What do you mean when you say the oil pressure 'pretty much stayed linear with the rpm increase, from idle to a brief 5000.’ Are you saying that each time you doubled engine rpm from idle to 5000 rpm, the oil pressure doubled?


What they told you is correct. It can be.


I am not certain why he would say that. It is absolutely possible to turn the observed engine oil pressure down to almost zero at idle by adjusting the oil pressure bypass/relief.


This is always a good litmus test.


What was the engine oil temperature at that point in time?


It is not clear that what you mean by linear with rpm when you say the words is what is actually meant by linear with rpm. Once again, did the oil pressure double when you doubled engine rpm, or did it do something else?

In the sanity check space, fluid flow (and pressure) is a second-order function and goes up as the square of the increase in flow. Double the flow, and you will see four times the pressure. Double it again, and you will see sixteen times the pressure.

Engines maintain a lower oil pressure at elevated engine speeds by controlling the size of the pumping mechanism, the speed of the mechanism (when using a dry sump, which you are not), the flow capacity and opening pressure of the pressure relief valve, which as it’s name implies relieves pressure.


That is marketing material that you are entitled to either believe or disbelieve. That call is entirely yours.


That seems to be a pretty good track record — No?


Just a thought — instead of repackaging an entire engine and then paying to ship it back to wherever, have you ever considered that it might be easier just to pull the pan and oil pump to inspect it for simple whoopses like a stuck oil pressure relief?

It is not only easier and cheaper, it is also a shorter and faster path to the solution!

BTW, why would you be, “removing all of your(my) parts to send back for their inspection,” I thought it was their parts you were concerned about — no?


But you do think it is your responsibility to repackage the long block and pay to ship it back to Ford, where it will probably sit for some time before anyone even thinks about touching that hot potato, to investigate your issue — if they do that at all! More than likely, they will simply ship you a replacement engine (if they are nice) that behaves the same. What do you do then??

This is equivalent of the carpenter who accidentally hits his thumb with his hammer as he fabricates something and says, “I’m glad I only broke my thumb! A couple of inches to the left and up, and I could have broken my entire hand!”

In the FWIW bucket, when you go to Summit and check Melling oil pumps for a 351 (I presume that is the base for your 427), every pump listed is specified as a high-volume pump. That doesn’t mean they may not have more proletariat pumps, but they certainly do not show up for 351-based engines on one of the largest aftermarket performance retail sites.

Sort of makes you wonder …

Eschalder thanks for taking the time to respond I will try to answer