Engine: Tips on increasing oil pressure

[Studeguy61]

I have removed the engine from my 61 Lark Wagon. It had a noise that was diagnosed as a cracked piston skirt or piston possibly hitting head. When the bearing caps were removed the bearings were worn bad. The engine was rebuilt by a reputable Studebaker shop 20000 miles ago. The oil pressure was always low, 20 on the highway, less than 10 idling. I will have the crank turned .0001, it has been turned once according to the numbers on the bearings. My question is what can I do when reassembling to try to ensure increased oil pressure as I think the bearings did not receive enough oil.

Thanks for any responses.

[DEEPNHOCK]

A few things that come to mind (and I am sure there are more)

Have you serviced your oil pressure relief valve piston?
Is your relief valve spring new?

Cam bearing clearance can also affect oil pressure.
To add... Camshaft bearing surface dimensions never get any attention (ie: no 'new' camshafts) so increased clearance can lead to lower than OE oil pressure.
Hard to measure, for sure...

[Mrs K Corbin]

at this point, I'd go for a complete rebuild if I could afford it....

Being a CASO myself, I don't do it. Just keep adding 20W50..

Seriously tho:, Mains, Rods, Cam and bearing clearance, oil galleries, relief valve, pay careful attention to rockers and lifter clearance.

It's a pain, but if rebuilding, don't get in a hurry.

[Mike Van Veghten]

One thig that helped a bunch is trimming the oil pump housing for a tighter cover to gear clearance. Less internal leakage.
I used .004", no gasket. Pressure builds faster also.
Also in the pump housing, radius both the inlet and outlet inside the housing. Works exactly the same as "porting" the intake and exhaust ports....more flow...!

Thin rods will decrease pressure, more leakage. If you have a hand full of rods, pick the wider/thicker (big end) rods. Even .001" or .002" x 2 = less gap, less leakage, more internal pressure.

Mike

[christophe]

Never assume automatically that the bearings correspond to the crankshaft. Your problem may be due to incorrect bearings. Measure the crankshaft first. Don't ask me how I know...
Your reputable Studebaker shop did a bad job. You don't have to use special tricks to get a good oil pressure. A TRUE rebuilt (where each part is controlled and within specs.) will give you plenty. By the way, 95% of the necessary info is given in the shop manual.
Best of luck.

[Mrs K Corbin]

OOOOh I forgot about the oil pump housing and plate stuff... That's a Good one. did it to my 2R5 ...

[Mike Van Veghten]

christophe -

Most of the things mentioned...are called "blue printing".
Which IS a slight misnomer. In actuality, it should be concidered making each and every part the dimensions the "book" says it should be, and "then some"..!

Mike

[StudeNorm]

When push comes to squish, plasti-gauge, when used CORRECTLY, does not lie... and all the above stuff!

[altair]

Some years ago I worked on a 6 Dodge that had failing oil pressure the dealer ship sold me a device called camshaft restrictors I think there were three pieces. They were inserted into the oil plug gallery on the lower side of the block. There purpose was to restrict oil to the cam and therefore deliver more oil to the remainder of the engine. The inherent design is to deliver oil to the cam first then the rods if the cam is leaking then the rods get what is left over.

[kxet]

My 49 Champion has a fitting with a .060 orofice where the line that goes to external Fram filter.I have no idea how the 61 engine is set up.You can use a .045 orofice I've heard some where to raise oil pressure.

[jackb]

mic your journals, buy your bearings (do you have .001 inserts ?) to match journal turn...

[StudeRich]

It appears no one has asked, we are dealing with a 170 OHV Six right?
The Six Oil Pump is going to be radically different than the V8.

I don't think you mean you will have the Crank turned ONE ten thousandth.
Quote: "I will have the crank turned .0001, it has been turned once according to the numbers on the bearings."

If the Bearings and Crank are .010 (Ten Thousandths) undersize now, you will be going to .020 Bearings and Crank undersize, of course if the crank's condition/size allows.

[rockne10]

mic your journals, buy your bearings (do you have .001 inserts ?) to match journal turn...

When I had my 289 crank polished, the machine shop matched each journal to a bearing, not all the same. Along with new cam bearings and everything else that went with the rebuild.
If anything, I have too much pressure. I dropped from a 15-40 to a 5-30 oil and still idle at 35-40 psi.
Pushing that kind of pressure may not be healthy for an engine that hasn't been totally refreshed.

[swvalcon]

Best to just have the crank reground to .010 under and get the right bearings. The shop that grinds the crank should be able to get you bearings or get them from SI. Polishing and adding .001 or .002 bearings is a hit and miss.

[Tom Bredehoft]

Post ten (install a .040 or .045 restriction in the oil line before the filter) will help a lot. The only down side is that the oil won't be filtered thoroughly as often. It will be filtered. I filled the of the elbow on the downstream side with solder and hand drilled a .040 hole through it.