308 oil pressure should be ? @ idle @ 2000

Unknown

With the engine at operating temperature and a pressure guage measuring oil pressure at the opening just above the oil pressure regulator valve, located on the driver's side (down low),



what should the oil pressure be idling? ______ psi



What should the oil pressure be at 2000 rpm's? _______ psi



PS: this is a new engine with only 100 miles on it, and if that will make a difference what should it be 1) NOW and 2) after it has 2000 miles on it??



TIA



54 HSWH

[Deleted User]

Cannot help much, I do have a book that says the 6 cylinders should have 45 lbs oil pressure and should have a light come on if it drops below 13 lbs.

Unknown

oil press should be at least 30 psi at idle and approx 40 at 2000 rpm, if engine is in good shape BILL ALBRIGHT

[Deleted User]

54 HSWH



I don't know how Steve plumbed your oiling system, but I know its been amended by at least a "full flow" oil filter. The oil pressure is controlled normally via a by-pass system consisting of a spring and a small plunger located behind a rather flat looking nut on the lower-rear driver's side of the engine block. You may want to call Steve and see how he dealt with the original by-pass, he may have plugged it.



I know the manuals say its not adjustable, but they didn't count on 50+ years of oscillation in the spring either. I had to adjust mine by placing shims in the recess of the retaining nut and tightening the spring down a tad. Keep shimming until either your oil pressure gets up to normal or you lock the plunger down(in which case you've got bigger problems if the pressure won't come up!).



You might want to make sure your new oil filter unit doesn't have a similiar by-pass system also, as some aftermarket remote filters have them in the housing. A redundant by-pass system will make your oil pressure "swing" at low rpms and be erratic at cruising speed. One of the by-passes needs to be disabled and "locked down". Again, this is why you need to call Steve and get the low-down on how he plumbed your updated oiling system.



Hope this helps,

Mark Hudson

[Deleted User]

Oh, I just re-read your original post! I'm sorry I missed the guage location.



You have your oil pressure guage reading the by-pass pressure and not the galley pressure. That would be cause for panic - I can imagine your worry.



You need to "T" into the line going from your remote filter back into your block, I think you'll be happier with the reading you get. And, that answers one of my questions, your original by-pass is functional if your guage is wafting back and forth with some low reading pressures.



Mark Hudson

Park_W

To clarify, where's the optimum point to connect a direct reading gauge? I have mine tee'd off the same point as the oil light sender unit. Describe in terms of where on the engine, not relative to connections for a remote filter.

Unknown

I've been told that at idle it should be 20 #'s (min),



and at 2000 rpm's it should be 40 #'s (max). i.e., too much will cause damage to the oil pump gear!



Do these numbers and the rationale sound reasonable??



TIA

Geoff

Park is correct with the location for the oil pressure gauge - in a T-juntion with the oil pressure sender unit on the right side of the engine, under the manifold.

Geoff.

[Deleted User]

I apologise for not explaining better.



54HSWH has a doctored oil filter system, its NOT a stock Hudson and NOT in the stock location. His oiling system was changed to a "full flow" filter, meaning it filters the oil direct from the pump so that no oil enters the galley that hasn't been filtered prior to reaching the bearings etc. The oil supply direct from the pump to the galley is blocked and the oil supply from the pump is redirected to the filter, from the filter back to the oil galley under full pump pressure. I like this setup and will do it to my own when the modifications commence.



The original filter system only filters oil that makes it past the by-pass plunger. In the original configuration, the galley is supplied with non-filtered oil direct from the pump and the 'waste' pressure is fed through the filter. The small plug on the driver's side of the block, where the original oil filter is attached/supplied, is a port into the "backside" of the by-pass plunger and any pressure reading is one of the by-pass oil and not the pressure in the galley supplying the cam/mains/rods. The original filter system takes the by-passed oil and then returns it directly to the oil pan.



So, it shakes out like this:



an oil pressure guage located in the original oil filter's discharge line (driver's side, near the oil pan rail), will result in no pressure reading at all.



an oil pressure guage located in the original oil filter's supply line (driver's side nearest the by-pass retaining nut), will result in a very low reading that is not steady.



an oil pressure guage located in a "T" at the original sending unit location (passenger side behind exhaust manifold) will be the correct pressure from the pump to the oil galley - this is the true pressure your bearings are living with.



In 54HSWH's oil system, A guage is needed between the filter and the oil galley, not between the pump and the filter, so as to catch any pressure drop that may be occuring in the filter and be reading the "true" galley pressure. He has external lines to go from the pump to the filter - then from the filter directly into the oil galley on the passenger side of the block. He DOESN'T have a STOCK filtration system.



Bill's oil pressure numbers are good ones. But, if your newly rebuilt engine doesn't have that pressure (once you get your guage in the right place) - it doesn't mean your engine is bad or bearings out of tolerance. Shim the by-pass plunger spring a little at a time until it gets within range before making assumptions about the engine's condition, or replace the spring outright with one of proper factory tension (which I have no idea what it was and doubt there are any specifications on it). Those by-pass springs are very old and have been actuated millions of times in the 50+ years they have been standing guard over your oiling system.



I had to adjust my own stepdown's by-pass spring - and it didn't take much to get it back into the 25@idle and 50@2500 range. My guage is located via a "T" in the sender unit position.



sincerely,

Mark Hudson