Engine: high oil pressure

[DMB-8]

I have a 62 t cab that has a fulflo 289 engine in it.The former owner said that it was overhauled. I installed a set of external gauges on it so I could know
what was going on.The oil pressure is 80# at idle and goes over 100 as you rev it up.I tried another gauge and it gave the same readings.We then pulled
the oil pressure relief valve out and cleaned it and changed the spring,to no avail as the pressures are still the same.Can anybody give me any ideas as what else could cause the oil pressure to be this high.Thank You for any advice that you can give me.Don Borger

[GinettaG12P]

Pull the relieve valve out, put the plug back in and start the engine. If you still have high oil pressure, the relief port that the relief valve normally uncovers (when there is high oil pressure) is clogged. That is, the relief port may be clogged. I have no idea how to clean it if it is clogged.

[StudeRich]

A sticking relief Valve in the Full Flow Oil Filter Adapter is the only other source of that kind of Pressure in addition to the Post above.

[studegary]

I agree with the above responses. Of course we are all assuming that you are using some reasonable viscosity oil (not more than 30).

[DMB-8]

We replaced the oil filter adapter with no difference.I am using 15w 40 oil.We then took the bypass out and put just the plug back in the oil pressure dropped
but would go to 0 at idle.I have used the 15 w 40 in all my other studes and have had no problem with oil pressure on them.Thank You For your responses so far. Don

[StudeRich]

/Cut/We then took the bypass out and put just the plug back in the oil pressure dropped
but would go to 0 at idle./Cut/

You took the Bi-Pass OUT? Does that mean the Piston in the Pressure Regulator Assy. at the Timing Gear?

All it needs to work properly is to be able to open and close freely, if it is smooth and maybe lightly greased or Oiled, installed center hole outside and with the proper Spring and thin NOS Copper/Asbestos Gasket on the Nut, it should be fine.

Throw away the Thick Copper Ring replacement Gasket now sold with the Repair Kit and get a thinner one.

[GinettaG12P]

You took the Bi-Pass OUT? Does that mean the Piston in the Pressure Regulator Assy. at the Timing Gear?

All it needs to work properly is to be able to open and close freely, if it is smooth and maybe lightly greased or Oiled, installed center hole outside and with the proper Spring and thin NOS Copper/Asbestos Gasket on the Nut, it should be fine.

Throw away the Thick Copper Ring replacement Gasket now sold with the Repair Kit and get a thinner one.

OK, now you have determined that the bypass port is not blocked, so you are ahead of the game. This means that the plunger of the oil pressure relief valve is not moving far enough under oil pressure to uncover the bypass port. This could be because the spring is too strong - you never can tell what a previous owner might have done - or the plunger may be hanging up on a ridge in the bore (unlikely, but possible). I don't know what the spring rate is for the relief valve spring and I don't know where to find that information. So, operating out of ignorance, I would take the spring out and run down to your hardware store and find one the either has the same spring rate but is a bit shorter (same wire diameter and number of coils), or has a lower spring rate (smaller diameter wire and same length and number of coils - more coils make for a lower rate, so in this case more is better.) That test will tell you if the spring that was in the car is the wrong one. Alternatively, you could just assume that the spring in the car is the wrong one and buy a new one from one of the studebaker vendors. Personally, I like the empirical approach where you make and test assumptions, such as the spring rate is too high.

[Dwain G.]

The springs vary in length slightly, but should be right around 1 3/4" at rest.

[GinettaG12P]

The springs vary in length slightly, but should be right around 1 3/4" at rest.

Spring length is important, but spring rate is critical. If you buy one the correct length and OD, it should have thinner wire or more coils, or both, so the spring rate is lower.