GT500 3V Oil Pump Questions...

[Samos3]

I seriously doubt that a high mileage 4.6 3V will generate anywhere near 100psi oil pressure with a GT500 pump.


Factory spec minimum oil pressure is 10-15psi at hot idle and 30-40psi at 2000rpm (doesn't specify if it's 5W20 or 5W50).
In the real world a healthy 5.0 will be holding around 25-30psi hot idle and 80-90psi above 2000rpm on 5W50. With 5W20 or 5W30, oil pressures will be lower.

A high mileage car might not, but not all of the cars out there are high mileage, many with fresher rebuilds in them.
Or, maybe worst case case, some of the cheaper rebuilds with non-oem parts in them.

 

[Samos3]

It seems the o-ring listed on Rockauto for the 4.6 3v pickup tube (oil pump seal) is for the 4.6 2v. Or mispackaged.

It's just a simple neoprene o-ring, right? Ford sells them.....$39 for ten.

 

[Badd GT]

Don’t change anything, just put it in right out of the package it comes in. Your over thinking it, you will be fine

 

[JC SSP]

Always thought the GT500 oil pump was the best all around for any 3V.

 

[Samos3]

Don’t change anything, just put it in right out of the package it comes in. Your over thinking it, you will be fine

That's never happened before.....

 

[Samos3]

Okay, ......looks like you guys win. But not for the reasons we've been discussing.

Contrary to info posted in an older thread, the GT500 housing is not exactly the same as the 4.6 3v. It was posted by someone that took apart and measured both oil pumps. According to his measuring, the spring depth difference was .020". Maybe then. Not now. Revised housing? Don't know. And his pics won't load for me, so I can't even judge by that.

I will have some fairly accurate measurements tomorrow night.
For now, the cap plug is identical. So is the valve cup. GT500 spring is longer.
The valve bore section of the housing a significantly different length. Shorter, too.

Pics:


GT500 pump and parts on left. My original 4.6 3v parts on the right.

Last two pics are of the two different springs in the GT500 valve bore.

All things being equal, which they obviously are not, the GT500 spring goes back into its respective pump, then into the car. The change in valve bore length changes spring preload. Changing to the 3v spring is not an option unless you are an engineer and can do the math to even find out if it's workable.
If it was just a change in springs, that would be one thing.

Now, to find the correct o-ring and an answer on that pin....

 

[JC SSP]

What “pin” are you referring too?

 

[Samos3]

What “pin” are you referring too?

Go to this link and scroll thru the pics til you find the pic that includes two o-rings. Inside one of the o-rings is a metal pin. On Rockauto some of the other brands of pumps show the pin as well. Haven't found any reference to it. The two o-rings are different sizes, so I am guessing the smaller o-ring is for 4.6 2v applications that have the smaller diameter pickup tube. Maybe the pin is for 2v motors (EDIT: Nope, that ain't it).

https://www.tascaparts.com/oem-parts/ford-oil-pump-9l3z6600a

 

[Samos3]

Logic would say that the 3v spring being installed into a pressure relief valve bore that is shorter than the one it came from would increase the preload and in doing so, result in a higher pressure relief than it did in its original longer bore.
The springs feel about the same rate (unscientific testing), even though the GT500 one is longer, but it gets compressed even more than the 3V spring.

Found some more old threads discussing the higher pressure potentially being a problem in a 3V.

Not to mention I am also using the improved rockers with the smaller squirters. That would improve pressure a little, too, I think.

 

[Dino Dino Bambino]

Found some more old threads discussing the higher pressure potentially being a problem in a 3V.

If its a fresh engine build with the same tight tolerances as from the factory, there's also the option of the Mellling 340 HV pump (higher volume but not higher pressure).

 

[Midlife Crises]

When I built my 3 valve I used the Ford Racing high volume pump that is no longer available from ford. Using Mobile 1 10-30 synthetic in have 100 psi oil pressure at cold idle and when the engine is warmed up it has 30 psi at idle. Having a higher volume of oil is beneficial to the operation of the VCT and maintaining pressure and flow when the oil is hot will help the VCT and tensioners do their job. The cams and followers should also benefit from the increased oil supply. If I were purchasing a new oil pump today for a 3 valve it would be the Melling 360 HV without question.

 

[Samos3]

If its a fresh engine build with the same tight tolerances as from the factory, there's also the option of the Mellling 340 HV pump (higher volume but not higher pressure).

Not a rebuild, so looser...how much?...good question.
I've been considering the Melling option. Or just going with a stock 3v pump.
Really wanted higher volume and a factory part, but not crazy about higher pressure. Really should have done a pressure first.

 

[Midlife Crises]

You are making this harder than it needs to be. You have a new GT 500 pump in hand that will do the job with stellar results. Nobody running that pump has washed the Babbitt off the bearings in their engine. Insufficient oil is known to be a problem for the valve train when the stock oil pump is stressed.