Engine: Location of 289 oil filter restriction

[HHI Hawk]

[BobPalma]

Here you go, John:



That's a photo of the filter base for the newer, spin-on, partial-flow filter(s). If you don't see that exact restriction right there in your filter base (with the filter removed, of course), you need to find one....or make one with the .046" restriction. It screws in from the bottom. BP

[Mrs K Corbin]

I just plugged mine off and change oil more often. If you're having oil pressure issues, just plug it off temporarily as a troubleshooting measure.

[HHI Hawk]

Bob, that was exactly what I was looking for. Although the archive threads on the topic of sufficient oil pressure vary, I find it difficult to believe that it should be on the low side of the shop manual tolerance of 20 to 40 rpm at 40 mph (about 1700 rpm) on my 1958 Silver Hawk with auto transmission. It reads 25 psi with coolant temperature of 175F. I verified it with an external mechanical gaugeAccording to my Shop Manual, the timing gear only gets oil through the hole in the regulator piston until 40 psi when it opens to get normal lubrication.
The suggestion of capping the line off as a troubleshooting procedure sounds like a good idea.
I appreciate the advice - thanks.

[BobPalma]

Bob, that was exactly what I was looking for. Although the archive threads on the topic of sufficient oil pressure vary, I find it difficult to believe that it should be on the low side of the shop manual tolerance of 20 to 40 rpm at 40 mph (about 1700 rpm) on my 1958 Silver Hawk with auto transmission. It reads 25 psi with coolant temperature of 175F. I verified it with an external mechanical gaugeAccording to my Shop Manual, the timing gear only gets oil through the hole in the regulator piston until 40 psi when it opens to get normal lubrication.
The suggestion of capping the line off as a troubleshooting procedure sounds like a good idea.
I appreciate the advice - thanks.

John, if you have 25 psi at the gauge at 1700 rpm fully warmed up, you have nothing to worry about, assuming the oil pressure relief valve has been cleaned properly as you indicate. Many Studebaker V8s run forever at that pressure; everything sounds fine.

Make sure you have that restrictor, or the equivalent, in the pressure line to the oil filter base, however. BP

[Mrs K Corbin]

yeah, 25 psi is ok.... mine gets down to 5psi as the pistons swap holes....

[HHI Hawk]

yeah, 25 psi is ok.... mine gets down to 5psi as the pistons swap holes....

Today, I capped off the input line for troubleshooting purposes. Unfortunately, it made no difference. I don't understand how eliminating a 1/8 inch "leak" will not affect oil pressure.
My concern derived from the Shop Manual's statement that, below 40 psi, the timing gear is only lubricated by oil through the small hole in the regulator piston. Higher than 40, the gear gets oil directly. I certainly didn't want to damage my recent rebuilt engine - big $$$!
Also, as a professional pilot for 42 years, it is difficult to relax when the oil pressure gauge has questionable readings. I hope I don't have to take a photo of a gauge with good pressure and tape it over mine.

[StudeRich]

/Cut/Make sure you have that restrictor, or the equivalent, in the pressure line to the oil filter base, however. BP

Today, I capped off the input line for troubleshooting purposes. Unfortunately, it made no difference. I don't understand how eliminating a 1/8 inch "leak" will not affect oil pressure.

If you followed Bob's instruction in Post #5, I am sure you would have found the .046 Restrictor hole in your OEM Oil filter Base (See Post #2), so that would be why it made NO difference.

Also, there should be a similar size Safety Backup Restrictor in the PB50 Fram or equivalent Oil Filter.

If a fresh, newly rebuilt Engine has below 35-40 PSI Oil Pressure, I would suspect improperly Installed Cam Bearings with TOO much clearance or a similar Oil pressure loss at Rocker Arms etc.

I am sure those who report less, have worn Engine Bearings.