78sc temp / oil pressure question

[Brtuffli]

I searched the forum and did not see any that address this problem.

Car is a 78 sc with a 3.0 liter motor. 36,000 miles on it. Problem has occurred 2 or 3 times over the past 20,000 miles. Each time was after a highway drive of 45 miles or more in length.

When I am driving, I normally have normal oil pressure and engine temps. Then I look down and see the oil pressure at one bar and the engine temp almost in the red. Clutch in, pressure goes down. Slow down to nurse the car home and in a few miles, the temp is much lower and oil pressure is back up to just about normal.

Not sure if this is oil pressure bypass related it the ostrau related or other?

One other related comment, sometimes after about 8 miles the oil pressure is just a bit low but then after 1 mile, it just pops up normal.

All comments and thoughts welcome. By the way, this was my uncles car and when I bought it from my cousin, there were spare parts. One of them was a bypass spring so I guess hat means the original was replaced.

[Jdub]

From a thread you may read using this link. Not sure this is your issue but you should be sure to perform this upgrade on your early SC if it has not been done already. The jist is that the orientation of the bowler style "new" screen detailed below must be oriented correctly to the oil pan, etc. If you have recently removed any of this you may have this issue. Again, you certainly want to fetch these parts off of the Classifieds and get them in on your next oil change.

EXCERPT FROM THE LINK ABOVE:

Regarding the oil screen and relief valve updates:

On my 1979 SC, the oil drain plug was originally at the rear (fan) and of the sump plate, in line with the case seam. When I installed the updated screen, there was no way to put the drain plug back
in that location, as the updated screen is different. I ended up with the
drain plug rotated 90 degrees towards the left side of the car. So I think
it's safe to say that if your drain plug is where mine originally was, you
can't have the updated screen. However, if your drain plug is already
rotated to the left side, that's no guarantee that you have the new screen.

The old screen looked like a bowler hat. The brim of the hat is the flange
that allows the screen to bolt to the case. The rest of the screen is all
wire mesh, with a hole to allow the oil pump pickup through. The updated
screen (PN 930.107.314.00) is similar, except the wire mesh part is only
around the perimeter of the flange. The top of the "hat" is now solid
metal, again with a hole
to allow the oil pump pickup through. The top is also concave, which is
why the drain plug won't fit in the same place. There is a large dimple in
the plate for the plug, but it's offset to the left. The new screens aren't
cheap, maybe $85. I managed to find a used one, but they seem to be rare.

According to UpFixin Volume VIII, "The 911 Lubrication System" by
A.L.Caldwell, you should be able to tell if you have updated pressure
relief valves by the screw cap you have. The original is round, 25mm in
diameter and has a slot across it for a large screwdriver. The first
update used a 23mm diameter screw head, with a groove machined around its
perimeter near where it contacts the case. My 1979 SC has this type. The
current version of the update uses a screw cap with a raised 17mm hex head
machined onto the 23mm circular base. The update was incorporated at the
factory beginning with SC engine numbers 6282539 (49 state) and 6581060
(Calif.).

BTW, this article also has a photo of the updated sump screen. This is a
reprint of the original article that appeared in the April 1989 Pano.

Hope this helps!

and:

SC's built prior to 1980 model should update;

1 oil screen 930.107.314.00
1 oil pressure relief spring 930.107.531.01
1 guide spring 930.107.533.00
1 screw plug 999.064.016.02


Update:
999.064.016.02 superceded by part # 999.064.026.02.


There are a few more thereads on this out there also.. But that is the nut of it..

[Harpo]

I just ordered all the parts so I can try this out as I have low oil pressure

Thanks

David

[Flat6pac]

The springs are two different lengths on an SC/Carrera
Bruce

[juanbenae]

a 78 with 36k miles would seem to have possibly set for a time with out running? even if treated well upon reincarnation after a long sit things like the three oil pump to case O-rings can perform less than expected in high temp conditions. if one of them is leaking during thin, hot oil usage it could introduce air rendering the oil being pumped to frothing & less effective.

sure, ive been drinking. but, if you have replaced all the oil bypass pistons & springs in addition to confirming the oil thermostat is opening pumping oil to the trombone when hot something is strange. s this a recent phenomenon or a long time reoccurring issue?

[Mark Salvetti]

Originally Posted by Jdub

From a thread you may read using this link. Not sure this is your issue but you should be sure to perform this upgrade on your early SC if it has not been done already. The jist is that the orientation of the bowler style "new" screen detailed below must be oriented correctly to the oil pan, etc. If you have recently removed any of this you may have this issue. Again, you certainly want to fetch these parts off of the Classifieds and get them in on your next oil change.

EXCERPT FROM THE LINK ABOVE:

Regarding the oil screen and relief valve updates:

On my 1979 SC, the oil drain plug was originally at the rear (fan) and of the sump plate, in line with the case seam. When I installed the updated screen, there was no way to put the drain plug back
in that location, as the updated screen is different. I ended up with the
drain plug rotated 90 degrees towards the left side of the car. So I think
it's safe to say that if your drain plug is where mine originally was, you
can't have the updated screen. However, if your drain plug is already
rotated to the left side, that's no guarantee that you have the new screen.
.
.
.
.

Wow, I wrote that maybe 20 years ago......

Mark

[Brtuffli]

Thanks for the link. I will read it thoroughly. I will also pull down the strainer, etc. if I remember correctly, (I am away from the car right now), the drain plug is in the center of the car, not left or right.

I did not mention that I have pulled the motor recently to replace broken head studs so many of the engine seals (top end) have been replaced.

As I said, when I got the car, there was an oil pressure relief spring in a bag with a part number on it. I will have to check that out against the numbers listed above. I will also check the head of the valve to see if I can determine which one is installed on my motor.

Again this problem has only occurred a few times, each and only time happening when on the highway. The recent time was after pressing the car a bit 4,000 RPMs for maybe a mile or so.

I always run 20-50 in it

[Brtuffli]

Oh and one more thing, I guess my uncle had replaced the original trombone cooler as this car has an oil cooler in the passenger front wheel well ( right in front of tire). Don't know if that changes anything or not

[Brtuffli]

Ok I am back from vacation and here is what I found:
Oil drain plug is in the center, not to the left or right
Looks like my uncle updated it in 1981. Is that recent enough to have the best parts?
At that time, looks like he updated oil pressure spring etc.
see pics

[Brtuffli]

[LIRS6]

Drain plug is not oriented correctly. It should be at a 90 deg angle to the centerline of the case, on the 1-2-3 bank side.

Jason

[Brtuffli]

Thanks for the reply.
I guess next steps are to pull the sump and make sure it is the updated bowler hat and rotate it correctly.
Any other thoughts?

Comments on the oil pressure relief spring?

I did run the car up to temp and checked the oil line to the front cooler. One was 153 and the other was 113 or so. Seems the thermostat is working

[Brtuffli]

It is finally time for an oil change. I pulled the sump and here is the screen that is installed.


Is this the correct part? If so, does it seem as if it was installed correctly? I ask as it seems that all the other posts say the drain plug needs to be in the 1 2 3 side of the engine and mine was towards the front of the car.

[Brtuffli]

Here is the pickup. Does that look right?

[Mark Salvetti]

That's the correct updated sump screen.

Reinstall, and you'll have that dimple on the 1-2-3 side of the engine. Orient the sump plate to put the drain plug under the dimple.

Mark

[Superman]

Yup. I believe that is the updated (later SC) screen. There is only one way to install it.

There are two ways to install the sump plate. If you install the sump plate so that the drain plug sits right under the oil pickup tube, then your engine can starve for both cooling and oil pressure.

[Brtuffli]

I took a photo of the bottom of the engine. Based on this photo, it would seem I still have the old set up. But it seems that my uncle did replace it in 81 or so. Do I need to take it apart to check spring length?

[Brtuffli]

Seems like it was updated

[Brtuffli]

Thanks superman and mark. I thought all previous post were saying that it would only fit one way but I think everyone is really saying it needs to go a certain way to avoid problems!