Increasing oil pressure

[flyinlow]

Can you shim the relief spring to increase the pressure of a 440 pump? How thick to increase 10-15 psi?

[elacruze]

Yes you can, but why not buy a new spring?

How much pressure do you have now, and why do you want more?

Oil pressure is generally a problem at low RPM, and shimming the spring will not help if pump volume is low due to wide clearances.

[BrianShaughnessy]

You can shim it I suppose.  I'm guessing you want to increase the pressure now with the oil cooler?   There are higher pressure springs available tho.

Do you know if you have a regular volume oil pump or the high volume (M63HV ) ?.   

With the added lines and cooler volume to fill up, I'd go the HV route myself. 

I ran some of the old MP oil coolers on my old Shelby Zs.   They used an adapter to circulate engine coolant through them without adding so much volume for the oil pump to have to fill.   Another version of this type was stock on
old late 80s/early 90's TPI 305 / 350 3rd gen Camaro/Firebirds.

[flyinlow]

The engine has 18k on it ,Melling HV pump. When it was new I ran a mechanical gauge. About 60-65 psi above 2000 rpm and 35-40psi at 800 rpm idle ,warm engine. I went back to the stock electric gauge and an idiot light for the last three years. 5/8 Th's cruise and 3/8Th's at idle.

Yes I am trying to recover the pressure loss with a cooler. I am thinking AN10 or AN12 lines instead of AN8. Less restriction thru the fittings and a header  style cooler instead of a plate cooler.

I did measure the oil filter temp with a laser thermometer. After 30 mins of freeway driving (2000rpm) the oil filter was 210*f on a 65* night . This is without the cooler installed.

[Challenger340]

yes,
just add a .030" washer behind the Relief Spring.

[John_Kunkel]

Adding shims to the relief valve won't increase the OP if it's below the relief valve setting.

IOW, if the relief valve is set at 65 psi and the warm pressure is 50 psi all the shims in the world won't raise the pressure because the low pressure is caused by lack of volume.

[flyinlow]

yes,
just add a .030" washer behind the Relief Spring.

Thanks

Adding shims to the relief valve won't increase the OP if it's below the relief valve setting.

IOW, if the relief valve is set at 65 psi and the warm pressure is 50 psi all the shims in the world won't raise the pressure because the low pressure is caused by lack of volume.

The oil pressure rises until a fast idle, then stabilises. I will put a mechanical gauge back on and check the pressure. I was happy with the engine until I started playing with the oil cooler. I want to have a cooler that has less then 5psi oil pressure drop if possible.

[BrianShaughnessy]

Yes I am trying to recover the pressure loss with a cooler. I am thinking AN10 or AN12 lines instead of AN8. Less restriction thru the fittings and a header  style cooler instead of a plate cooler.

Going to bigger lines would probably decrease the pressure even more.


Do you have 1/2" pickup installed or just the 3/8?    There's a few other tricks that increase the oil intake to the pump...  aside from ditching the internal pickup and going external but that's another story.

[flyinlow]

3/8 pick up.

Woundn't larger diameter hoses from the engine to the cooler reduce the resistance and pressure drop?

[BrianShaughnessy]

3/8 pick up.

Woundn't larger diameter hoses from the engine to the cooler reduce the resistance and pressure drop?

It would increase the volume that needed to be filled and pressurized.   Since you're already having a volume problem,  it should probably make it worse. 

[flyinlow]

3/8 pick up.

Wouldn't larger diameter hoses from the engine to the cooler reduce the resistance and pressure drop?

It would increase the volume that needed to be filled and pressurized.   Since you're already having a volume problem,  it should probably make it worse. 

I must be missing something.  The HV oil pump puts out enough volume to keep the the oil pump on relief at any speed above a fast idle. It is pressurising the oiling passageways.The hydraulic lifters, the cam ,main and rod bearing are all leaking (as the should be) as the engine runs. The gauge at the far end of the engine shows good oil pressure. Now I ADD few feet of hose and a cooler,that do not leak and I get large pressure drop?

[elacruze]

To clarify, your problem here is not low oil pressure, but that your pressure has been reduced by an added oil cooler.
If so, that can only be due to added restriction. To eliminate restriction, obviously the cooler body must have adequate flow capacity, then you must use hose and fittings which are large enough not to restrict.
90* fittings are no good, if you have any make sure they're aircraft style tubing with nice radius. The tubing and hose must be at least the same size ID as the smallest inlet/outlet hole of the cooler, preferably a size larger. The volume of the cooler and lines will not by itself affect pressure, a hydraulic system without restrictions will see equal pressure throughout regardless of volume.

[flyinlow]

Putting larger AN 10 hoses on with a header style cooler seams to have fixed the problem . I put the mechanical gauge back on and I have 75psi at start up drops to about 70psi at a fast idle  after about 10 minutes it drops to 5o psi at idle, 70 psi above 2000rpm.. With the new cooler set up , I can't really see a pressure drop. 

I also ported the adaptor housing to help flow. 

Thanks for the input.