Oil Pressure Relieve Valve Spring

[Snoopy1971]

Related to my overheating issue, I decided to check my oil pressure relief valve...

H case, single relief case ...

Got the plug off no problem. Spring fell out, plunger was stuck in the top of the bore. I tried tapping it a bunch of times with a long thin screwdriver to see if it would jar it loose ... no dice. I tried my magnet ... no dice there either, magnet wasn't strong enough to pull it down. Had to wedge a bigger screwdriver into it to get it to come loose a little. I came down the bore some, but not all the way. Now I used my magnet again, and it pulled it out.

The bore didn't really look dirty to me, but I wiped the spring and plunger off.

After clean:

I bent the tip of a piece of metal coathanger and put it up the bore to see if there was anything in the 4 or 5 ports coming off the bore. Didn't get anything.

I then took a piece of shop towel, wrapped it around a screwdriver, and used that to wipe and clean the wall of the bore.

Lubed up the plunger with oil, pushed it all the way up to the top of the bore ... didnt get stuck, came back out when I pulled the screwdriver out.

I was getting ready to put it all back in, but decided to measure the spring first.

Here is the page from my '66-'69 Bentley manual:

So it says the spring is supposed to be 62-64mm long unloaded.

Here is mine:

So did the spring get stretched ... is it the wrong spring ... is it one from a high pressure application, etc???

I know a dual relief case has a long spring at the crank pulley end and a short spring at the flywheel end. Is the long spring in a dual relief case the same size as the spring in a single relief case? Or is it longer? If it is longer, I wonder if somebody put the wrong one in.

Does anyone have a pic of the page from the Bentley manual for the years with a dual relief case that shows the spring dimensions??? I'd like to see if the dimension is the same as mine or different.
_________________
1968 Bug

[chrisflstf]

Cb has good springs

https://www.cbperformance.com/product-p/1766.htm

[Nitramrebrab72]

You can see it has been stretched from the middle to the left hand side of the pic the gaps are larger and irregular, it also appears bent at that point where as the right side appears regular.

You say it got seized in there, the first thing that comes to mind to cause that would be fuel drenched oil, that and possibly overheating.

[Snoopy1971]

[Snoopy1971]

[glutamodo]

[Rome]

Snoopy, the plunger you have is the aftermarket style substitute for the factory original '1500 S" type 3 plunger. Yours has a tapered transition from the lower section up to the groove. The original ones had a simple groove (QuentinRN gallery)-

That plunger was usually sold in a small kit along with the long spring, though the replacement kit spring was usually a bit longer and had slightly thicker wire coils than the factory spring.

If you can find an original factory spring, even a used one which you can measure, I'd prefer that over the aftermarket one which you appear to have. I'd also recommend running some 400 wet grit sandpaper around the plunger right at the transition from the lower section into the groove, to break that sharp edge. But the cleaning you did to the bore is already helpful.

[kreemoweet]

[Multi69s]

If it was my engine, and since the parts are cheap, I would just get new ones (or good used ones), those score marks are not doing the case bore any favors.
_________________
69 road Bug 2110
73 Squareback - 2L, T4, Automatic W/ AC
Gone, but many fond memories 69 Baja Bug 2010 - 5 Rib Bus Transaxle
Gone but not forgotten 72 Baja Bug 2010
My builds
T4 into Squareback http://www.thesamba.com/vw/forum/viewtopic.php?t=458944&highlight=
Auto Trans Rebuild http://www.thesamba.com/vw/forum/viewtopic.php?t=516066&highlight=
AC in Squareback https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight=

[Snoopy1971]

[Nitramrebrab72]

If you ever have a stuck pressure relief piston again, with a cold engine run the engine just 30 secs stop it remove the spring refit the cover or not with an oil pan under it (or not if cover on) start bring the idle up slightly don't over do it the oil cooler won't like it...
The advantage of not putting the cover on it will shoot any of the dirt that was possibly wedge in there without going back through the system, and second you will hear the piston hit the oil pan especially if it is metal.
Though personally on this occasion I believe it to be more a case of diluted engine oil than dirty engine oil as marks are quite deep and more consistent with metal on metal, loss of shear strength in engine oil's main cause is fuel dilution, and it is the a main cause of a hydraulic piston getting stuck in a cylinder.
Before fitting the new oil piston removal of any heigh points of scoring in the bore might be in order with some fine emery cloth and a good cleaning after(no compressed air though)

As regards overheating, I had a slight problem that was resolved when I used a thinner engine oil, something I was totally against at first. I even tried pimping the pressure relief valve but what really helped was the engine oil viscosity.
Also check your oil cooler for external debris blocking air passage.