Engine seals - boy I must have done something wrong!

[Wayne 962]

Yes, it does sound like a piston / spring problem. Triple check everything against the Engine Rebuild Book...

-Wayne

[T77911S]

Originally Posted by ischmitz

Oil pressure should never be higher than 5 bar - that's when the oil pressure relieve valve is designed to open. And the safety valve is designed for 10 bar. I remember with my 74 engine the oil pressure would go up with RPM when cold and then suddenly the needle jerked downward (oil pressure relieve valve opened) when hitting around 60 PSI.

This only happened with the engine cold - I sometimes tried to not rev the engine to this point as a simple means to "wait until properly warmed up" The RPM when this happened was as low as 2500 at start and then it gradually "went up" as the engine warmed up.

Have someone hook up a mechanical oil pressure gauge to confirm your pressure readings of 100PSI. If that is the case take out the safety valve and inspect the piston and the bore. Hope you can fix this without another tear-down. Good luck,

Ingo

i dont mean to hi jack, sorry
mine does this too. i see the needle drop some around 80 psi but then continue to rise to 100+ psi. i do as you do, i hold the rpm around 2k (100psi) and watch as the pressure drops. is this something i need to look into?

[KevinG]

Ingo, Wayne - Thanks for the input.

T77911S - welcome. I couldn't tell from your post if your pressure readings were on a fully warmed up car or only when cold. If your pressure returns to normal when warmed up I don't believe you have a problem.

Update on my car.

I drained the oil and lifted the car last night. I removed the plug for the relief valve that is on the passenger side of the car, and is positioned vertically in the motor. I do not know whether this is the oil pressure relief valve or the safety valve. It is the one that has the spring guide. Upon removing the plug, the spring, guide and piston fell out on their own volition.

Important note to anyone trying this at home - just because you drained the oil doesn't mean that there is no oil in the motor. Enough came out of this hole to completely overwhelm my puny roll of paper towels.

Obviously, the piston wasn't stuck, and I couldn't figure out any way to make sure that it is moving freely in the bore. Upon re-assembly, 25mm of spring was protruding from the bore. If anyone can tell me if that is correct, or some other means of verifying proper installation and operation I would appreciate it. I don't recall if the rebuild book has any detail on this, but I will review this morning.

I have to remove the driver side heat exchanger to get to the other relief piston assembly - the one mounted horizontally. This was the one I had difficulty with when I assembled the bottom half many moons ago. I will get to it this morning and post results here.

Thanks for all your help.

[ischmitz]

Kevin,

it is such a long time ago that I had both my oil pressure relieve and safety valves appart. I don't remember if there are different springs or other ways to screw up. I hope others with more experience can chime in here.

Anyway, here is a post with a nice cross-section of the pressure relieve valve. Oil bypass modification Just thinking, what would happen if the vent passage was blocked. It woud actually increase the spring rate seen by the piston but the piston would still drop out when you open it up....

Ingo

[KevinG]

Ingo -

Just speculating here, but if the vent passage was blocked, I would assume that if the blocked passage was filled with air it would some effect on increasing the spring rate - if it was filled with oil (more likely) you would be lucky to get any movement of the piston at all.

Anyway - I need to correct something in case a future reader comes across this posting. The bypass modification type oil piston relief kit USES TWO DIFFERENT LENGTH SPRINGS. What I posted earlier was not correct. Get Wayne's book and read it - it explains things very clearly.

The horizontal oil passage uses the shorter of the two springs (67mm, 18 coils), while the vertical passage uses the longer of the two springs with a guide. The longer of the two springs is 86mm with 19 coils and appears to use slightly smaller diameter wire. I have no idea what the spring rates are.

I have not gotten rid of my old 2.2S case yet, so I did some comparisons to the 2.4 case I am now using. Everything matched between the old and the new so it doesn't appear to be a case problem. In case anyone wants to know:

Horizontal oil passage / piston information:
Depth of machined piston stop in passage - 55mm
Depth to bottom of piston seated in passage - 52mm
Spring length - 67mm
Spring protrusion from side of case - 15mm

Vertical oil passage / piston information:
Depth of machined piston stop in passage - 63mm
Depth to bottom of piston seated in passage - 60mm
Spring length - 86mm
Spring protrusion from bottom of case - 26mm

Even though the number of coils on the longer spring are the same and the diameter of the wire used appears to be smaller, it takes a bunch of strength to get the plug installed.

Since it's easy to get to, I am tempted to install the smaller spring to see what effect it has on oil pressure. Would I be risking major damage (or even minor damage) by doing this?

Thanks,

Kevin

[KevinG]

Can anyone come up for alternatives for cause of high oil pressure? I really think that this is the issue as it doens't leak when at idle but does when run at higher rpms. I would think that bad seals would leak at any rpm.

Thanks,

Kevin

[3.2 CAB]

A seal may not leak at lower RPM due to less oil pressure in the system. Once it gets fully pressurized(high RPM) it can then push oil past or through bad gaskets and other sealing areas. While it is at a lower oil pressure(idle speed) the gaskets or seals may be effective enough to be able to keep the oil from passing through. I saw this on the last leaking front seal on a late model Crown Vic, while it was at idle speeds, the seal would seal, but as engine speed rose, the oil would then start to pass the seal.

Kevin, hopefully you will be able, with not too much work involved, get to the bottom of your cause for the leakage problem. Good luck!! Tony.

[911quest]

A couple of other possiblites faulty thermostat and what about the oil cooler how long did it sit while you put the motor together. I know this is out in left field but I have seen wasps etc. build nest in strange places. On the pressure spring you could loosen the plug slowly and see if you get a pressure drop you will get oil an oil leak but might yeild a clue...also the #8 main bearing did you get the bearing aligned with dow pin correctly so the oil passage didn't get blocked..