Engine seals - boy I must have done something wrong!

[KevinG]

Engine seals - boy I must have done something wrong!

Cross Posted from Engine Rebuild forum - didn't get any help there, so I thought I would try here
--------------------------------------------------------------------------------

I recently completed the rebuild of a 2.4 high comp S motor (9.6:1), and have a big leak problem. I have leaks from the flywheel area, the crank pulley area and the left side heat exchanger near the front of the car.

To me, this translates to main seal, pulley seal and MFI drive seal.

How in the world could I have gotten all three wrong? I lubed the seal lips before install, and put a bead of curil t around the outside after install.

The only other thing I noticed was that oil pressure shows at 100 psi (indicated) on the gauge at around 5.5Krpm. I only noticed because I felt it was a great improvement over what I used to get before rebuild. I chalked it up to the new 3.2 pump with bypass.

Also - the leaks only happen when it is running and warm. I can get under it and clean the bottom of the motor, and no leaks will occur while it is parked.

Any assistance greatly appreciated.

Thanks,

Kevin

[dtw]

Some argue against using any Curil-T on the crank/cam seals. I used it on my 2.4 on everything and didn't have leaks, so YMMV. Sparing application seems to be key. Based on the info you've provided I'm wondering if oil pressure isn't the issue. Seems as though your relief pistons should be opening up around 60-70 psi, check the books for the actual number. May be compromising the seals if you're hitting 100 psi.

[Gunter]

Kevin:
That's very disappointing.
Different people use different methods to install the seals.
If I remember correctly, JW doesn't use any Curil-T on the outside, just oil on the lip.
Same here.
For the main seal, it's important to install it square to the case and flush. (Not deeper than the edge)
The bore has to be smooth and round meaning: the case-halves have to match precisely.
Sometimes the area on the crank where the lip runs shows a little wear and needs to be polished?
The other end has the pulley seal but also the large O-ring.
To make sure where the leaks are coming from, some people use color dye.
For both seals, they can leak from the outside, or inside, or both.
Unfortunately, the engine has to come out again but then you could see the dye in the leak-area.

[LuftWaffle]

Hi Kevin,

Sorry to hear of your troubles - very discouraging! Two thoughts and I apologize if they seem over simplistic. Are the seals are installed facing the right direction? The other thought is crankcase pressure. Your breather isn't plugged up is it? A crankcase with inadequate venting can sure push a bunch of oil past the seals! Don't ask me how I know this...

Good luck - keep after it, you'll get there.

John

[myfast911]

dont what to sound dumb,but did you use the right main seal?this happened to me on my 2.4 a while back.put in one for a newer car and it leaked very bad.

[JeremyD]

Are your rings properly seated? did you check your ring gap?

Mine did this when I was getting some blow by and it was pressurizing the case. Get some crankcase PSI and it is amazing where the leaks will come from...

[Rot 911]

Originally Posted by JeremyD

Are your rings properly seated? did you check your ring gap?

Mine did this when I was getting some blow by and it was pressurizing the case. Get some crankcase PSI and it is amazing where the leaks will come from...

That is the first thing that popped into my head also. Broken ring, incorrect ring gap or one or more ring that didn't seal.

[KevinG]

Per Jeremy D -

Are your rings properly seated? did you check your ring gap?

A simple compression check will tell me, won't it?

When I read this, I mentally said "Oh, sheet" - I took the air cleaner housing off to check for leaks on the top of the motor while the engine was running, and smoke was coming out of the breather hose. I remember thinking that it shouldn't be that hot - temp gauge was only at 180.

Time to break out the compression tester.

[Zeke]

That is a shame and would be my worst fear. I don't know how your crank and cam looked AFA having a groove, but some install a seal slightly deeper or lightly proud of the case to get the seal to run on a new surface rather than the one form before. This is one trick I learned when doing the 914 motor. Not sure if it applies directly to a 911 motor, but I thought Id throw it out for consideration.

Worst case (sorry) scenario is that you will lose some time and have to purchase a new gasket kit. I hope the solution is contained somewhere in the above posts so it doesn't come to that.

One more thought: with that high of compression, you might be getting the blow by mentioned. Some say to first break in the cams for 20 minutes, let cool and then run it very hard w/o hitting high RPM's. The combustion pressure will help seat the rings. What do you have to lose? Worked for me on a 4 cyl.

[DW SD]

Kevin,
I think a leak down test would give more definitive results than compression. At least you would hear if the air is entering the case (and not the valves)?

pressure out of the crankcase breather is not a good sign.

How does it run?

Doug

[911quest]

How were the oil pressure relief bores? Could the oil relief pistons be stuck in the bore...excessive pressure

[KevinG]

Thanks all!

The oil pressure relief pistons were new, and are the correct ones for the oil bypass mod. The 2.4 case is new to me but obviously used, as are all of the internals. I had Henry do the bypass mod on the case, so I'm sure that it was done properly. Doesn't mean that the pistons aren't stuck though.

The pistons, cylinders, heads, cams and MFI are all from my old 2.2S motor. Rings are used, so I don't believe they need to be re-seated do they? Cams were fine per my machinist, he didn't even think they needed polishing. Rockers were re-faced, so I'm going easy with the revs for a while.

I pulled the plugs and ran a compression check - all cylinders clocked in at 140#, which I believe is correct for an engine with early s cams. Plugs had a fairly heavy coating of fine dry soot, so I guess I'm running rich. No oil on the plugs, though.

[Wayne 962]

Did you take photos when you installed the seals?

-Wayne

[KevinG]

Nope - no pictures of the install. I took lots of pictures of the dis-assembly in case I needed them, but not of the assembly process. Guess it works both ways, huh?

[KevinG]

Thinking back on the oil pressure relief pistons (it was a while ago that I did that part of the assembly).

I remember that the piston kit I got had the proper pistons, but had two unequal length springs (same as my pre-bypass modification setup). I compared the longer spring of the used setup with the longer spring of the new kit, and found them to be the same so I made the substitution.

I also remember having a difficult time installing one of the piston/spring sets.

Before I pull the motor, I will put it into the air and check the pistons for free movement.

[3.2 CAB]

Hi Kevin, I went ahead and copied my reply from the engine forum.

I don't know if this applies to your problem, but I have seen many seals, mainly the front crank seal leak, due to the way it was installed. I have had to repair many(foreign and domestic) timing cover seals because of the design of the sealing area. The actual sealing area is somewhat like a "V" in its shape. I have found where some people have installed the seal and the inner lip of the "V" was rolled back towards the outer lip of the seal. I have found that when installing seals, once you have the seal on the shaft, I then pull it outward, toward the end of the shaft just enough for the inner lip of the "V" to flip back to the direction that it should be, instead of being curled against the shaft, towards the outer sealing lip of the "V" once the seal is pull back a little, it make the seal lay down correctly, so the sealing lips are in the correct position around the shaft to seal it up and make the seal surface area back into a "V" shape again. Hopefully I am being clear on this. Good luck!! Tony.

[fbarrett]

Are you sure you put the seals in the right way around? The inner lip should point inward, toward the high pressure. I did it wrong, twice, on a 912 front seal replacement!

Frank

[KevinG]

I'm sure I got them oriented correctly. Whether or not I managed to get the seal lip to fold over on itself as in 3.2's suggestion remains to be seen.

[The Turk]

Hi Kevin,
If you have 100 PSI oil pressure when the motor is warmed up to running temps there is definitely something not working correctly with the pressure relief pistons.
You should remove them and make sure they are correctly installed and that they move freely in the bores.
I would think that excessive oil pressure would force oil by seals that would normally not leak.
Good luck.

[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