84 fuel pump
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Unfreaking believable! Next I'll be teaching the Otto four stroke cycle engine.
You are correct that a relief valve is not needed. As you activate the ram the pressure will be minimal until the wedge on the end of the ram contacts the log. The pressure on the gauge will rise as the ram meets resistance. once the wedge starts splitting and the ram resumes movement, the pressure will drop until the ram reaches the end of it's travel where the pressure will spike again as the ram is filled and hydraulic oil and has nowhere to go. A relief valve is not needed as long as the pump isn't capable of moving fluid at a pressure high enough to damage the system components. On your log splitter, install a tee at the cylinder where the oil from the valve enters and run a hose from that tee back to the tank and see how well your log splitter works now.
I never said that a relief was necessary to create pressure. I said it was the resistance to (fluid) flow that creates pressure. The "cylinder increases effort ( work )" provides the resistance to flow that creates the pressure. I hope you wake up before you have to apply any of your engineering acumen to a work related or commercial product or project.
RACE ON!!!
Originally Posted by A88FXRS
last time for me. if you take a simple logsplitter circuit that has a pump, tank, valve and double acting cylinder only and NO RELIEF VALVE and make it operate the cylinder the pressure and flow made by the pump will show on gauge.
Originally Posted by A88FXRS
as cylinder increases effort ( work ) pressure will increase. since there is no relief valve to create pressure as you say, what is making pressure ? the pump, the only component that has the capability of doing this. have a nice day.
RACE ON!!!
Racer
Joined: Jun 2006
Posts: 461
Likes: 0
From: ilion ny
the pump causes the flow. the fuel pressure regulator creates the resistance which increases the pressure. Its the same principle as putting your thumb over a garden hose. don't block the hose with your thumb and the water just comes out of the hose with little pressure block it off with your thumb and it is pressurized. your thumb is the resistance causing the increase in pressure.
Burning Brakes
Joined: Sep 2006
Posts: 1,202
Likes: 3
From: MD
To the original tangent-starter, here's why a lot of 84's wind up with 85 fuel pumps. The 84 fuel pump wore out, and the 85's was new and made it run better. A stock 84 really doesn't need the extra pressure. That being said, I put an '58 pump in my 84 as well. If you start modding it and need more pressure the '84 pump won't deliver as solid a pressure at 15psi+. The 84 pump was nearly maxed-out in the original system calling for ~13psi. If you're replacing it, may as well go with the '85 pump. Doesn't hurt anything, costs teh same, and if you start modifying your motor and want more injector pressure it's already there waiting for you.
And, yeah, CFI is right. Resistance to flow does make pressure (I are a mechanical engineer).
And, yeah, CFI is right. Resistance to flow does make pressure (I are a mechanical engineer).
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by JLeatherman
To the original tangent-starter, here's why a lot of 84's wind up with 85 fuel pumps. The 84 fuel pump wore out, and the 85's was new and made it run better. And the reason it runs better is because it NEEDED a new pump. It doesn't run any better with the new 1985 pump than it would with a new 1984 pump.
A stock 84 really doesn't need the extra pressure. That being said, I put an '58 pump in my 84 as well. And changing to an '85 pump doesn't change the pressure.
If you start modding it and need more pressure the '84 pump won't deliver as solid a pressure at 15psi+. The 84 pump was nearly maxed-out in the original system calling for ~13psi. My stock pump was tested through the 1/4 mile at 17 psi. The pressure never dropped wound out at WOT and shifting at 6000 rpms, but I can't say other '84 pumps will pass that test.
If you're replacing it, may as well go with the '85 pump. Doesn't hurt anything, costs teh same, and if you start modifying your motor and want more injector pressure it's already there waiting for you.
And, yeah, CFI is right. Resistance to flow does make pressure (I are a mechanical engineer).
A stock 84 really doesn't need the extra pressure. That being said, I put an '58 pump in my 84 as well. And changing to an '85 pump doesn't change the pressure.
If you start modding it and need more pressure the '84 pump won't deliver as solid a pressure at 15psi+. The 84 pump was nearly maxed-out in the original system calling for ~13psi. My stock pump was tested through the 1/4 mile at 17 psi. The pressure never dropped wound out at WOT and shifting at 6000 rpms, but I can't say other '84 pumps will pass that test.
If you're replacing it, may as well go with the '85 pump. Doesn't hurt anything, costs teh same, and if you start modifying your motor and want more injector pressure it's already there waiting for you.
And, yeah, CFI is right. Resistance to flow does make pressure (I are a mechanical engineer).
RACE ON!!!
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
Once I clicked, it all became clear
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by jhammons01
I had to ask myself when I saw a 2 page thread on changing the fuel pump...."how does that Happen?"
Once I clicked, it all became clear
Once I clicked, it all became clear
RACE ON!!!
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski