1975 280 M110 Engine Whatzit??

[rump]

Hello all,


I have a large oil leak coming from this plastic tap piece located on the left side of the engine between the head and the intake manifold. It normally has a very loose metal pipe connected to it. What is it and how can I get a new one/repair it to stop the leak?



https://ibb.co/Jp2cWM3
https://ibb.co/fY85LbL



Thanks!

[fonzi]

Seems like positive crankcase ventilation to me. It should probably be connected to the air cleaner to be sucking all that stuff back into the intake instead of spraying it all over the motor. I don’t know.

[Idle]

From the photos this appears to be on the exhaust side of the engine. If so then has to be a part of your EGR system.

First look at your EGR valve. Is there a hose missing? If so this is likely where it is supposed to go.

But if your exhaust manifold has no EGR valve then some previous owner has swapped your exhaust manifold for a Euro version which has no EGR valve. This is a popular thing to do on the M110 if you can find a Euro manifold. They came to the US on gray market cars so they are not everywhere, but a lot of 280sl were imported this way and none of them had EGR valves. So when they hit the scrap yard savvy Mercedes owners know to grab the exhaust manifold.

If this is the case then just plug the hose. If fumes are not being sucked from it then it serves no reason to be there. And the engine would run fine without the EGR valve. Many people think they run better without them and that's why they go to the trouble to swap the manifolds.

[Frank Reiner]

Originally Posted by rump

tap piece located on the left side of the engine between the head and the intake manifold.

Originally Posted by Idle

From the photos this appears to be on the exhaust side of the engine. If so then has to be a part of your EGR system.

First look at your EGR valve. Is there a hose missing? If so this is likely where it is supposed to go.

But if your exhaust manifold has no EGR valve then some previous owner has swapped your exhaust manifold for a Euro version which has no EGR valve. This is a popular thing to do on the M110 if you can find a Euro manifold. They came to the US on gray market cars so they are not everywhere, but a lot of 280sl were imported this way and none of them had EGR valves. So when they hit the scrap yard savvy Mercedes owners know to grab the exhaust manifold.

"and I want to be a paperback writer"

Just more of the usual fiction. As always, an Idle mind is the Devil's Playground.

[rump]

Here are a few more photos of the connection and where the line goes from there. (I have drawn a red line along the route.)

https://ibb.co/5GHHvg8
https://ibb.co/zZrMFzX
https://ibb.co/F8BcGPt

There is a bent metal tube that loosely sits inside the plastic piece between the head and the intake manifold. The metal pipe tees into two ends. One is capped by a short rubber hose and a bolt(!), and the other end goes to the evap canister purge valve. SO, I believe that this connection is supposed to be a source of vacuum so the engine draws in the vapors in the charcoal canister when the evap purge valve is opened. I can't currently verify this because I have most of the front of the engine disassembled for cleaning and service.

I don't have a good diagram of how all this is supposed to be connected (I'm waiting on a copy of the service manuals). I do have a copy of 14.2-050 Operation of the emission control systems, but the connections are a bit vague.

Any thoughts?

As always - thank you!

[Idle]

Originally Posted by Frank Reiner

"and I want to be a paperback writer"

Just more of the usual fiction. As always, an Idle mind is the Devil's Playground.

You don't work on M110s it appears.

Perhaps if you did you might learn a few things. Like when to shut-up.

[Frank Reiner]

1) Directly above the plastic elbow, in the cam box, is located the PCV orifice. Originally a steel pipe (which fitted tightly in the plastic) ran aft alongside the cam box, made a 90 deg. bend behind the original Solex carburetor, and was connected to a fitting in the throttle base of the Solex carb. That was the source of vacuum.
2) The steel pipe had a tee in it just behind the carb. The evap canister draw-off hose was connected to that tee via the purge valve.
3) Since the Solex carb has been replaced with a Weber, the original vacuum source no longer exists in your car.
4) If your conscience is not troubled by it, delete all of the evap control nonsense, and all the EGR nonsense.
5) The PCV can be connected to any convenient point on the intake manifold as a vacuum source.

[rump]

Originally Posted by Frank Reiner

1) Directly above the plastic elbow, in the cam box, is located the PCV orifice. Originally a steel pipe (which fitted tightly in the plastic) ran aft alongside the cam box, made a 90 deg. bend behind the original Solex carburetor, and was connected to a fitting in the throttle base of the Solex carb. That was the source of vacuum.
2) The steel pipe had a tee in it just behind the carb. The evap canister draw-off hose was connected to that tee via the purge valve.
3) Since the Solex carb has been replaced with a Weber, the original vacuum source no longer exists in your car.
4) If your conscience is not troubled by it, delete all of the evap control nonsense, and all the EGR nonsense.
5) The PCV can be connected to any convenient point on the intake manifold as a vacuum source.

Thanks for the info, Frank. The more I look into the emissions equipment on this car, the more I find faulty. I've been removing a lot of it.



That PCV fitting (part no. 1109972682) seems crooked and loose. Only problem is, it looks like the only way to replace it would be to remove the intake manifold. I'm going to see if I can snug it up and get a vacuum line connected to it.

[Frank Reiner]

Originally Posted by rump

That PCV fitting (part no. 1109972682) seems crooked and loose. Only problem is, it looks like the only way to replace it would be to remove the intake manifold. I'm going to see if I can snug it up and get a vacuum line connected to it.

If you have not done so already to adjust the valves, remove the cam cover; the top of the PCV orifice is visible with the cover removed. That orifice is screwed into the cam box, and if you are fortunate, you will be able to unscrew it. With the orifice removed the elbow can also be removed for replacement (the body of the orifice extends into the elbow).

[rump]

Originally Posted by Frank Reiner

If you have not done so already to adjust the valves, remove the cam cover; the top of the PCV orifice is visible with the cover removed. That orifice is screwed into the cam box, and if you are fortunate, you will be able to unscrew it. With the orifice removed the elbow can also be removed for replacement (the body of the orifice extends into the elbow).

Oh, that sounds much easier! I will do that when I get around to the valve adjustment.

[rump]

Originally Posted by Frank Reiner

If you have not done so already to adjust the valves, remove the cam cover; the top of the PCV orifice is visible with the cover removed. That orifice is screwed into the cam box, and if you are fortunate, you will be able to unscrew it. With the orifice removed the elbow can also be removed for replacement (the body of the orifice extends into the elbow).

I have the cam box cover off, and I can see the orifice, but it's not budging. I need to find a wide enough flat blade to turn it. Any thoughts as to where I can find one?



In the process, I think I discovered why I had such a bad oil leak - one of the studs for the cover nuts is stripped and the PO just popped it on there for looks. It certainly wasn't sealing up anything. I think I found the part number for the stud, but how do I replace it? I'm guessing it's just screwed into the cam box housing?

[Frank Reiner]

rump:

If this seller is willing to part with the exhaust manifolds and down pipes, make a deal; they are a good replacement for the catalyst & its manifold.
http://www.peachparts.com/shopforum/vintage-mercedes-forum/413705-73-280c-sale-parts.html

[rump]

Hey Frank,
I have found someone to buy the non-cat manifolds from, but it looks like I would need to get the down pipes and front muffler as well to hook everything up. Is that correct?



Here are diagrams of the two systems...
https://imgur.com/a/At7aUk2

[Frank Reiner]

r:
The diagrams are correct; manifolds from a W114 ('73-'74 Federal, & '73 California) are a direct fit. Manifolds from W116s, W123s, W126s, and probably R/C 107s can be used, though the head pipes (down pipes) would have to be custom.
What are the manifolds that are available to you?
If you cannot find any other head pipes, I have a new set of W116 pipes which could be reworked for your application.

[rump]

Oh! I see. I'm checking with the seller on the vintage and model. I'm a little confused, though: The first diagram I posted is from a 1973 280 (W114), but that has a different front muffler?