Oil pressure relief valve

[jallen]

Looking for cause of low oil pressure, started with oil pressure relief valve. The plunger will not come out, even tried starting the engine, no luck. Shop manual suggests cleaning yearly. Any
ideas? This is a 62 V8. The pump will be next, but wanted to start with the easy stuff first. Don't want to rebuild the engine at this
time, am hoping for a cheap, easy solution for low oil pressure.
20 lbs at start-up, mechanical gauge believed to be accurate. Thanks

[gearhead49]

I had one that was real stubborn and gave it a few shots of carb cleaner and sprayed Seafoam Deep Creep then let it set for a few hours and it came out after some muscling. I then replaced the plunger and spring with a new kit from Studebaker Int. after a good scrubbing of the cavity with a small engine bruch and re-assembly it has pressure in the 40 to 50's idling. My Lark sat for about 20 years before I got it.

[DEEPNHOCK]

I just did one that took me an hour to get the plunger out, even with some carb cleaner.
I could get it to move about a quarter inch.
Made a hook pulling tool out of a dental pick gizmo.
Once it was moving I knew it would only be a matter of time.
Alternate 12oz. lubrication helped lower personal temperature
Persevere!
After you get the plunger out, take a new 1/2" drill bit and run the bore by hand with it to clean the crud out.
Change your oil afterwards, especially if you have a fibre gear.
HTIH..
Jeff[8D]

quote:Originally posted by jallen

Looking for cause of low oil pressure, started with oil pressure relief valve. The plunger will not come out, even tried starting the engine, no luck. Shop manual suggests cleaning yearly. Any
ideas? This is a 62 V8. The pump will be next, but wanted to start with the easy stuff first. Don't want to rebuild the engine at this
time, am hoping for a cheap, easy solution for low oil pressure.
20 lbs at start-up, mechanical gauge believed to be accurate. Thanks

[Tom Bredehoft]

Oil pressure and the pressure relief valve. Here's my take on it.

The plunger and its spring are open to the full pressure of the system. When the oil is cold, it pushes the plunger back so that the oil can dump the excess pressure into the pan. As the oil warms up, it is thin enough to go thru the hole in the plunger, allowing the plunger to close off the dump to the pan in normal conditions.

If I understand it correctly, if the plunger is stuck, there will be godawful high pressure until it warms up. If the hole is plugged, the plunger will stay open when the oil gets hot and continue to dump pressure into the pan.

My 53 232 lived for many years with a 5/8 inch spacer behind the plunger, giving me a false high pressure until the engine got warm, when the pressure dropped to about zero at idle, 20 at road speed. I removed the spacer and put a .040 restriction in the line to the filter, now it runs at 35 lbs at road speed hot.

[img=left]http://www.alink.com/personal/tbredehoft/Avatar1.jpg[/img=left]
Tom Bredehoft
'53 Commander Coupe (since 1959)
'55 President (6H Y6) State Sedan
(Under Construction 617 hrs.)
'05 Legacy Ltd Wagon
All Indiana built cars

[StudeRich]

Well I guess a reality check needs to mentioned also, if the Cam Bearings were overlooked on last Overhaul/Rebuild or are just worn original and Rod or Main Bearings, you will not get consistent Med/High correct Oil pressure, some have driven many miles this way but I would NOT like the fact that it is a time-bomb with an unknown due date! [:0]

StudeRich

[DEEPNHOCK]

I can tell you firsthand that shimming the piston is risky..BTDT
Step one:
Shim spring.
Step two:
Drag Stude home when fibre gear tells you that sucked and replace with nice aluminum gear.
Step three:
Drag Stude home after shearing distributor roll pin.
Step four:
Fire up newly fixed setup and watch oil filter split and de-rust everything in eyesight.
Step five:
Remove spring and return to a normal life.

If you have chronic low oil pressure, and you have replaced 'everything'... Ask yourself if your cam bearing to cam clearance is within factory specs. That's the first place oil has a decent chance to leak out bad.....
Just thinking out loud...
Jeff[8D]

quote:Originally posted by Tom B

<snip>
My 53 232 lived for many years with a 5/8 inch spacer behind the plunger, giving me a false high pressure until the engine got warm, when the pressure dropped to about zero at idle, 20 at road speed. I removed the spacer and put a .040 restriction in the line to the filter, now it runs at 35 lbs at road speed hot.

[jallen]

Thanks to all who have responded. Thankfully there is no oil filter. Plunger remains stuck. Looking for Alternate 12 Oz lubricant. Will check fridge.
Good news is it's a truck, so no prolonged HiSpeed driving. Have no
accurate history of vehicle so oil pan will come off next.

[nvonada]

"Thankfully there is no oil filter"

Never thought I would hear that

_______________

http://stude.vonadatech.com

[DEEPNHOCK]

Help me out here with my limited comprehension...
If your plunger is stuck, how will taking to oil pan off help?
Can you 'push' the plunger out from the cam gear side?
(I need a cutaway to envision the oil passage in there)
Here's a swag solution to your stuck piston plunger..
Get a 1/2" end mill (long), or grind a 1/2" drii bit so the end is flat.
By hand, use it to clean out the bore right up to the piston plunger edge.
Maybe this would allow you to work the piston back and forth and get it out.
I spent a half hour moving the piston in and out an eighth of an inch before victory on that last engine.
It had low low oil pressure when hot.
Plunger and bore cleaning made all the difference in the world.
HTIH
Jeff[8D]

quote:Originally posted by jallen

Thanks to all who have responded. Thankfully there is no oil filter. Plunger remains stuck. Looking for Alternate 12 Oz lubricant. Will check fridge.
Good news is it's a truck, so no prolonged HiSpeed driving. Have no
accurate history of vehicle so oil pan will come off next.

[PackardV8]

Does anyone have a plunger on the bench to measure the ID? Once, when I had a stuck plunger, I used a drill bit just a fraction larger than the ID of the plunger bore. By hand, I tapped and turned the drill bit into the plunger bore. It grabbed the inside edge of the bore of the plunger enough to rotate the plunger, helping the PB Blaster to better do its' work. After a few rotations and wiggles, the drill bit pulled the piston out.

thnx, jack vines

PackardV8

[Tom Bredehoft]

The two shop manuals I have, 53 and 55 both say to twist a No. 12 drill (.189) into the bore in the plunger and keep twisting as you pull the plunger out. A No. 12 drill is enough bigger than a 3/16 that the smaller one won't work. I've done it, it works. It's kinda hard getting the No. 12 drill out of the plunger, once it's out of the hole, but it can be done by unscrewing it, backing it out.

[img=left]http://www.alink.com/personal/tbredehoft/Avatar1.jpg[/img=left]
Tom Bredehoft
'53 Commander Coupe (since 1959)
'55 President (6H Y6) State Sedan
(Under Construction 617 hrs.)
'05 Legacy Ltd Wagon
All Indiana built cars

[jallen]

Thanks again to all who have replied. Plunger inside diameter is
.197 plus or minus .001. If anyone had a length for the spring
that would be helpful. After cleaning and re-assembly oil pressure
is better but still low compared to other studebakers i've owned.
Plan to order a kit tomorrow, will post dimensions for new parts.