Oil Pressure Regulator Question

[Dave Payne]

My 250 engine seems to have excessively high oil pressure, well over 100 psig cold, and 80 psig warm idle. I've adjusted the regulator, however it looks like the regulator spring is binding up in the regulator piston cup. It appears the spring outside diameter is too large, causing the binding problem. The spring measures .4020 inches on the outside diameter. The cup inside diameter is .3920. The spring is very tight in the cup. I believe I have the wrong spring(?) Does anyone have the correct dimensions for the regulator spring? Any advice is appreciated. Thanks, Dave.

[250GT]

My 250 engine seems to have excessively high oil pressure, well over 100 psig cold, and 80 psig warm idle. I've adjusted the regulator, however it looks like the regulator spring is binding up in the regulator piston cup. It appears the spring outside diameter is too large, causing the binding problem. The spring measures .4020 inches on the outside diameter. The cup inside diameter is .3920. The spring is very tight in the cup. I believe I have the wrong spring(?) Does anyone have the correct dimensions for the regulator spring? Any advice is appreciated. Thanks, Dave.

I presume youre engine is freschly overhauld?
than the pressure is always so high
after 10000km it will come between 40-45 idle
80-100 cold( in winter thick oil.)
ortherwise test with seperate mano meter on he block (without the narrow connector)
those old instruments are not very accurate.
i would EVERYBODY advice to replace the cheap (china ? )produced org.FRAM oilfilter .
To replace by
MANN filters those are black but are quality filters. Made in Germany
otherwise you cam blowup the org orange one. Fram schit
well it all up to you.

its only a hobby here.
C.

[kare]

Which Mann filter do you use? Does it have a valve in exit passage (center hole) or a stand pipe?

[250GT]

Which Mann filter do you use? Does it have a valve in exit passage (center hole) or a stand pipe?

Hi Kare ,
those have an so called; Rücklaufsperre; valve witch keep the oil inside the filter,
Even at vertical place filter this means by the next start the oilpressior is immidiatly where it belongs to be
it nr W 940 it an DIESEL filter!
the person who has a by paper bypass filter as in the pic- below- cars before 1958 do not to have sorrow,
the pressure there is relativ low.
A Ferrari 250/330 has no real torque. Yeah we must admit this.
even a GTO or SWB has no impressive preformance till 4000 rpm.
So after this border something happend, that means in this regio higher than 4000rpm till 8000.
The pressure is there allways 80-100 almost
that why you need quality filters.
the armchair-specialist among us, only reach this feelings in there dreams I hope.

only a hobby here

Cornelis

P.S fore the decal specialists this top lid is org 1957/8

[kare]

I have actually held such a filter in my hand wondering if it might fit. Also used on some VW Turbo engines if I recall right. In vertical position the stand pipe should also work, so I ordered a case of Baldwin B253 for my car.

[250GT]

I have actually held such a filter in my hand wondering if it might fit. Also used on some VW Turbo engines if I recall right. In vertical position the stand pipe should also work, so I ordered a case of Baldwin B253 for my car.

I have my-- know how --from those specialist who prepare
the racing cars Breadvan ,GTO , SWB.
what fore those cars is good it can be wrong for mine.
they will have there reasons.
even when used on dieselcars.
Fore those who loves there wife more than there car, can stay at the org. shit.
(this is humor)
Kare, you can have mine org. Fram for free, if you wish.
its deco at my place.

C.

[kare]

I am very happy with Baldwin as they offer full line up for Ferrari including oil, fuel and air filters at a very reasonable cost (everything priced around 10 euros per piece) Best wishes, Kare

[330GT]

To get back to the original topic, I pulled out the oil pressure regulator for my PF coupe, intending to measure the spring. Well, there is no spring in mine, so once we figure out what size it should be, I'll need one too.

[Dave Payne]

To get back to the original topic, I pulled out the oil pressure regulator for my PF coupe, intending to measure the spring. Well, there is no spring in mine, so once we figure out what size it should be, I'll need one too.

Kerry - Thank you for trying to get the spring dimensions, I appreciate that. I found a few different springs at our local ACE hardware store today. I bought a spring that was 1.75 inches free-length, .040 wire diameter, and .375 inches on the outside diameter. This spring fit perfectly into the piston cup on the pressure regulator. The spring rate was slightly lower than the one I removed, and the spring was about .500 inches longer than the original. I don't think the original spring was the right one, it was too large on the outside diameter and fit super tight into the piston cup, and someone had ground down one end. Anyway, I ran the engine and the oil pressure was about 70 psig "cold" and around 55 psig at idle, exactly what I was hoping for. Plus I have plenty of adjustment left on the regulator. The engine seems to have improved throttle response with the lower oil pressure. I bought two of these springs, I can send you one if you want, no problem. Dave

[250GT]

To get back to the original topic, I pulled out the oil pressure regulator for my PF coupe, intending to measure the spring. Well, there is no spring in mine, so once we figure out what size it should be, I'll need one too.

Kerry - Thank you for trying to get the spring dimensions, I appreciate that. I found a few different springs at our local ACE hardware store today. I bought a spring that was 1.75 inches free-length, .040 wire diameter, and .375 inches on the outside diameter. This spring fit perfectly into the piston cup on the pressure regulator. The spring rate was slightly lower than the one I removed, and the spring was about .500 inches longer than the original. I don't think the original spring was the right one, it was too large on the outside diameter and fit super tight into the piston cup, and someone had ground down one end. Anyway, I ran the engine and the oil pressure was about 70 psig "cold" and around 55 psig at idle, exactly what I was hoping for. Plus I have plenty of adjustment left on the regulator. The engine seems to have improved throttle response with the lower oil pressure. I bought two of these springs, I can send you one if you want, no problem. Dave

Hi Dave,
The way you descripe youre repair means that you have created youre own-- good???-- oilpressure.
without any evedence or to be sure ,its the real pressure.
When Kerry write he can not find a spring this has a secound meaning I think.
he knows there is a spring in side.
A spring can be replace while it was broken.
but more likely is this :
They (dealeror last owner??) try to manipulate.
So :
real pressure test.
compression test.
valve clearance.
sping adjusting distribution chain etc
smooking engine etc
you must find out to RELAXE.
better trottle response ?? NO, NO, its imagination

P.S Its only a hobby here

C.
good luck

[330GT]

When I rebuilt my 330 engine, I was a novice, so I subscribed to the 'if it's not broken, don't touch it' theory. So I never took apart the oil bypass pressure regulator.

Now I find out that I'm missing the spring in the one for the coupe. I figured it was time to understand how it works.

P1010162x.jpg (41.35 KiB) Viewed 10104 times

To the left of the missing spring is a piston. It fits into the part to the left and can obstruct the holes you see in it. To the right of the missing spring is an adjustment screw. As it is screwed in, it puts more pressure on the spring and hence the piston. So the oil pressure has to be higher to push the piston to open up the holes leading to the bypass filter.

Here you can see it assembled with the piston partially obstructing the holes.

P1010164x.jpg (40.7 KiB) Viewed 10105 times

In Dave's case, his old spring wasn't correct and didn't fit into the end of the piston nor the end of the adjustment screw. That kept too much pressure on the piston, so probably no oil was going through the bypass filter, thus causing too high of oil pressure.

[250GT]

When I rebuilt my 330 engine, I was a novice, so I subscribed to the 'if it's not broken, don't touch it' theory. So I never took apart the oil bypass pressure regulator.

Now I find out that I'm missing the spring in the one for the coupe. I figured it was time to understand how it works.

The attachment P1010162x.jpg is no longer available

To the left of the missing spring is a piston. It fits into the part to the left and can obstruct the holes you see in it. To the right of the missing spring is an adjustment screw. As it is screwed in, it puts more pressure on the spring and hence the piston. So the oil pressure has to be higher to push the piston to open up the holes leading to the bypass filter.

Here you can see it assembled with the piston partially obstructing the holes.

The attachment P1010164x.jpg is no longer available

In Dave's case, his old spring wasn't correct and didn't fit into the end of the piston nor the end of the adjustment screw. That kept too much pressure on the piston, so probably no oil was going through the bypass filter, thus causing too high of oil pressure.

Kerry ,
just found your spring,
It fitts perfectly in piston and adjust screw.
Its a rather stong spring, I dont have the equipment to check the pressure,
but place between direction finger and tumb I hardy can press this 10 mm together.
when you are working on an european car you must forget inches, feet and pounds.
total lenghs is in mm.

C.

[330GT]

I visited a local PF coupe (outside plug engine) today and was able to measure the spring:
Length 1.440"
OD .390"
Wire size .053"
# coils 9
Spring rate 25 lbs/inch

Sorry Cornelis, but US measurements since that is how the spring places over here specify their springs.

I tried something for the spring rate that worked out fine. I just used a digital postage scale and pushed down with a finger on top of the spring until it was 1/4" shorter and read 6-7 lbs. Then went for 1/2" and read 12-13 lbs. Nicely linear and yielded ~25 lbs/inch. No need for specialized equipment for a simple spring like this.

Out of curiosity, I also measured Dave's 'Ace Hardware' spring. Its rate was 10 lbs/Inch, so quite a bit weaker.