OM617 manifold oil = broken valve guide - Page 2 - PeachParts Mercedes-Benz Forum

Stretch · #16 08-12-2010, 02:57 PM

Here are some pictures of the manifolds after a really short time of use. The engine has only been run at idle (more or less)... 0 miles driven and just look at it now:- everything was all smart and ready to go.

You can see that cylinders 1, 2, and 3 are the culprits... and that the oil hasn't gotten as far as the air centre of the inlet manifold under the air cleaner. I guess because the engine was only at idle for a short time the oil on the exhaust didn't get a chance to burn off. See the picture of the manifold to down pipe joint - engine oil was dripping out.

funola · #17 08-12-2010, 03:17 PM

How much have you driven this car? If it sat for a long time, or if it was babied by the PO, maybe all it needs is a dose of good ol Italian tuneup! When I bought my 83 300D turbo, it was slow, sluggish, and the exhaust was smokey. Changing all the fluids and filters and driving it hard cleaned it up good and the engine became more and more responsive with more power over time.

Stretch · #18 08-12-2010, 03:26 PM

Quote:

Originally Posted by funola

How much have you driven this car? If it sat for a long time, or if it was babied by the PO, maybe all it needs is a dose of good ol Italian tuneup! When I bought my 83 300D turbo, it was slow, sluggish, and the exhaust was smokey. Changing all the fluids and filters and driving it hard cleaned it up good and the engine became more and more responsive with more power over time.

I've driven it for about 3500km - but it has been out of action since April or so. However I don't hang about when I'm driving... I was hoping that a bit of pedal to the metal would help with the car's behaviour but in this case it seems as though it has been sat for too long (even before I bought it) and so I guess every rubber component needs to be replaced.

I've just renewed every rubber part underneath - looks like the engine is next.

SirNik84 · #19 08-12-2010, 04:45 PM

this may be a long shot. but engines that have sat for a long time can have issues with the rings not holing as tightly as they could. the trick and old motorcycle mechanic tough me is to pour Marvel Mystery (MM) oil in the cylinders and let the rings soak overnight. this will loosen any old oil that may prevent the rings form making good contact with the cylinder wall.

The engine I bought for my SD sat for years and had poor compression when I first tested it. after a night of MM oil it had much better compression.

ATF can be used if you have no MM oil. I've used ATF mixed with Diesel Purge before as well.

Stretch · #20 08-13-2010, 01:07 PM

Quote:

Originally Posted by SirNik84

this may be a long shot. but engines that have sat for a long time can have issues with the rings not holing as tightly as they could. the trick and old motorcycle mechanic tough me is to pour Marvel Mystery (MM) oil in the cylinders and let the rings soak overnight. this will loosen any old oil that may prevent the rings form making good contact with the cylinder wall.

The engine I bought for my SD sat for years and had poor compression when I first tested it. after a night of MM oil it had much better compression.

ATF can be used if you have no MM oil. I've used ATF mixed with Diesel Purge before as well.

Thanks for the tip SirNik - I'll give it a go... I'm taking it apart anyway as I need to re-align the upper oil pan and sort out the front and rear crankshaft seals. Most importantly I need to check to make sure that the "Mercedes Expert" I bought it from hasn't done anything really stupid to the engine inside.

Stretch · #21 08-31-2010, 02:40 PM

Update on the ATF trick:-

Well I filled the bores with ATF (no Marvel here). All of them drained through eventually - it took longer than 24 hours - except cylinder number 2 where the oil is still there on day 3!

Stretch · #22 08-31-2010, 02:43 PM

I've found the cause of the oil leak.

A valve guide on cylinder two is sheared in half - see photos

The underside of the valves were pretty gunked up too

SirNik84 · #23 08-31-2010, 02:53 PM

Damn, that'll do it! Sorry it wasn't something simple.

Stretch · #24 08-31-2010, 03:09 PM

Quote:

Originally Posted by SirNik84

Damn, that'll do it! Sorry it wasn't something simple.

I have a nasty feeling that some one has been adjusting valves with normal spanners... better off doing stuff yourself with the right kit rather than letting a "Mercedes Expert" loose on your car.

Stretch · #25 09-02-2010, 01:32 PM

Update:-

I went and had a chat with my friendly dealer - who has been very helpful even though the car is now nearly 30 years old - and they put me onto some chap who "has been doing it for years". I'm getting him to replace all of the valve guides. Then he's going to re-grind the valve seats and re-grind the valves so I get a really good fit. The head is being skimmed too - and he's going to check and replace the pre-chambers as well.

He says that I should adjust the valves on the larger side as they tend to go tight with use - has anyone ever heard about this before? Have I missed this? I've not seen any reports here before...

StaggerLee · #26 09-02-2010, 02:49 PM

I believe these do tighten with time and use; unlike other engines. I usually adjust to spec but I do it way more often than necessary. If I were going to let it go for a year or two I would adjust to the "looser" side.

Yak · #27 09-02-2010, 08:38 PM

Quote:

Originally Posted by Army

Update:-

He says that I should adjust the valves on the larger side as they tend to go tight with use - has anyone ever heard about this before? Have I missed this? I've not seen any reports here before...

I think this is consistent with other advice. For valves that were not regularly adjusted it seems to be: adjust, drive about 1500 miles, check & adjust, repeat, then get a regular schedule. It may be a case of how they're adjusted, e.g. using the 3 wrench set to hold them from rotating vs. two wrenches.

I don't think being a "little" loose will hurt, but I vaguely recall a post by WHunter on the topic. Maybe another search will turn something up.

Stretch · #28 10-20-2010, 01:27 PM

Well that took some time - the head is back!

(When the block has been honed and I've got the new pistons I'll be putting it all back together again)

82B3NZ · #29 11-03-2010, 10:34 PM

Any Progress?? Looks good

W124 E300D · #30 11-03-2010, 10:54 PM

Quote:

Originally Posted by Army

Well that took some time - the head is back!

(When the block has been honed and I've got the new pistons I'll be putting it all back together again)

OIL THE LIVING CRAP out of everything on reassembly with fresh lube oil... it will make the start smokey, but prevent damage on the initial start up...

When you get the engine back together, leave the injectors out, as the very last thing, then connect battery charger, crank 60 seconds, wait 3 minutes, and repeat 3 times, last two times should give you good oil pressure, insert injectors, connect up, and away you go.

Use any revs you like for running in ONCE THE ENGINE IS WARM, when engine is cold keep revs to 1/3rd max, but for first 500 miles keep to 1/3 rd throttle, next 500 miles 2/3 throttle, then new fluids and filters, then you'll be good to go.