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Originally Posted by Davidless
… 2weeks ago … after we timed and tuned the holley 750.
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What did you set the timing on the Holley 750 at?
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Originally Posted by Davidless
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. |
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?
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Originally Posted by Davidless
I wasn’t comfortable with this and sent the video over to Ford racing. They … said the oil pump can be adjusted for the bypass spring force.
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What they told you is correct. It can be.
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Originally Posted by Davidless
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.
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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.
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Originally Posted by Davidless
The following week I built a test stand so I could see how the pressure behaves after the oil temp reached proper temp.
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This is always a good litmus test.
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Originally Posted by Davidless
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.
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What was the engine oil temperature at that point in time?
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Originally Posted by Davidless
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.
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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.
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Originally Posted by Davidless
… my Ford manual … 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.
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That is marketing material that you are entitled to either believe or disbelieve. That call is entirely yours.
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Originally Posted by Davidless
After contacting Ford again they agreed as will, said never had a problem like this selling crates for 20 years…
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That seems to be a pretty good track record — No?
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Originally Posted by Davidless
Well now I’m removing all of my parts to send back for their inspection, not sure what else to do.
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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?
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Originally Posted by Davidless
I don’t think it’s my responsibility to drop the pan and check, especially for what I paid.
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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??
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Originally Posted by Davidless
Any how I’m glad I tested before putting in my car, will keep updating once Ford has a look at.
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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 …
Some info to share about my SB 427 high oil pressure problem
Linear Mode
