OM603 Valve Guide Seals - PeachParts Mercedes-Benz Forum

Diseasel300 · #1 08-20-2017, 10:00 PM

The OEM valve guide seals for the OM603 are brown and green with no designator showing what is supposed to go where (a piece of paper isn't that expensive...). Which is intake and which is exhaust? I see information posted in various places (this site included) saying both ways and that can't be correct.

FSM says green is exhaust and brown is intake. Does that still apply today? Who knows because there's nothing included with the new ones?!

My car currently has green on intake and brown on exhaust, and if that is incorrect, I strongly suspect that is my oil consumer. If I take the car out on the highway, I'll suck down a quart ~500 miles. Bottom end is solid, almost no blowby to speak of, certainly not enough to lift the cap even if the breather is blocked up. Turbo pipe is dry. Head gasket isn't leaking and compression is good. I'm out of ideas and notice that this evening when I had the cam out to swap lifters (old ones were getting noisy).

Of course the $64M question - can the seals be changed with the head still installed on the engine? Is there a good writeup somewhere how to do it without screwing everything up in the process or dropping a valve down in the engine?

Diesel911 · #2 08-20-2017, 11:03 PM

If you know who made the valve stem seals go to the makers website and ask their techs.
Also what company mand them would allow someone who has previously done the job to say what they did.

Do the Exhaust and Intake Valves have the same diameter? Do the Valve Stem Seals have the same size inside diameters and is the part that slips over the Valve guide the same inside?

rreeuuvveenn · #3 08-21-2017, 12:10 AM

did not try it yet,

eager to hear from you,

good luck,

Diesel911 · #4 08-21-2017, 12:06 PM

I poked sround at the Alldata site and found this stating tht the seals are black and brown and giving the part number

http://www.alldatadiy.com/alldatadiy/DIY~V67820085~C46810~R0~OD~N/0/34870063/56621018/56621031/142971815/34853741/100411974/34853743/34872041/34851431

Part of the issue is that if you by aftermarket valve stme seals like Meistersatz the color can be different and some even have a different design.

I read through the alldata .pdf and while I am not a carful reader I did not see any reference to what color of seal goes where.

Also the Instructions are for the Cylinder Head removed from the Engine. If you sre doing this on the Engine you need the Piston of the cylinder you are working on to be at top dead center and you only work on one Cylinder at a time.

rreeuuvveenn · #5 08-21-2017, 12:12 PM

someone did post the different seals, and said that Mercedes did improve the seals,

see attach

Diesel911 · #6 08-21-2017, 12:26 PM

Quote:

Originally Posted by rreeuuvveenn

someone did post the different seals, and said that Mercedes did improve the seals,

see attach

Good if that guy is still around maybe he can be contacted as to which is the Exhaust seal.

In the pic the green seal looks like the inside diameter is larger then the brown seal. Unless it is just the camera angle.
On other dieseles sodium filled exhaust valves are often fatter then the intake valves. The Larger inside diameter of the green seal could indicate it is for the fatter Exhaust Valve.

Help the guy out because I have no specific experience with his engine.

rreeuuvveenn · #7 08-21-2017, 12:38 PM

some more information,

Diseasel300 · #8 08-21-2017, 06:58 PM

The seals I used were OEM MB from the dealer. When I had the head redone last April, I left them with the machinist and requested they leave the head disassembled. They went ahead and assembled it and I trusted they did it correctly without checking first. My mistake, my fault.

Seems they are indeed backwards. I have brown on exhaust, and green on intake. Given the difference in valve stem diameter, I can't see there being a fantastic seal on the intake side.

So now that it's established that the guide seals will be changed this fall, how does one go about keeping the engine on TDC on the 3 pairs of cylinders and also keeping the camshaft in time? This is an OHC engine with direct-acting tappets unlike the OM617, so the camshaft has to come out to get to the valve guides. I have a spring compressor so that isn't an issue, I'm more concerned with keeping the engine in time as it's rotated 120˚ twice to do the various pairs of cylinders at TDC.

Diesel911 · #9 08-21-2017, 08:07 PM

Quote:

Originally Posted by Diseasel300

The seals I used were OEM MB from the dealer. When I had the head redone last April, I left them with the machinist and requested they leave the head disassembled. They went ahead and assembled it and I trusted they did it correctly without checking first. My mistake, my fault.

Seems they are indeed backwards. I have brown on exhaust, and green on intake. Given the difference in valve stem diameter, I can't see there being a fantastic seal on the intake side.

So now that it's established that the guide seals will be changed this fall, how does one go about keeping the engine on TDC on the 3 pairs of cylinders and also keeping the camshaft in time? This is an OHC engine with direct-acting tappets unlike the OM617, so the camshaft has to come out to get to the valve guides. I have a spring compressor so that isn't an issue, I'm more concerned with keeping the engine in time as it's rotated 120˚ twice to do the various pairs of cylinders at TDC.

I have never seen it done on Diesels. But, back in the 1960s people would get and adapter for the spark plug hole and fill the cylinder with continous compressed air. That was supposed to hold the valves up in their seats.

But you need an Air Compressor and it would be best to have one with a water seperator type Filter.

Diesel911 · #10 08-21-2017, 08:30 PM

I forgot to mention that the use of compressed air in gasoline engines was usually to replace a broken valve spring. Stock valve stem seals on old cars were very minimal with most just deflecting the oil.

Maxbumpo · #11 08-22-2017, 04:53 PM

Well, I'm not so sure that's your problem. At speed, your turbo charger is keeping the intake manifold pressurized, so there would be airflow up the valve stem and guide. I don't see how oil would flow down very easily. Same on the exhaust side - turbocharger puts slight back pressure on the exhaust manifold.

However, I would love to hear that I'm wrong!

Diseasel300 · #12 08-22-2017, 05:35 PM

Cruising along on the highway, you're only running 4-5 PSI boost, and when going down hills (which there are a lot of here) the manifold is in a slight vacuum with foot off accelerator. At those conditions, I can't imagine the small amount of pressure in the manifold being enough to prevent oil dripping down the valve stems. We'll find out this fall when I change them how much the valve stem seals are contributing to the oil burning factor. The bottom end is way too tight to be causing it, especially with the cross hatching still present in the cylinders.

The question remains: How to do the job with the head on? I'm really not eager to pull the head or screw up a bunch of stuff by doing it wrong. I'm very wary of doing the compressed air method. When I tried that last year before pulling the head, it tried to spin the engine over and broke a chain guide. Luckily I was able to fish all of the broken pieces out without pulling the front timing cover.

dieselbenz1 · #13 08-22-2017, 10:58 PM

Compressed air will work fine if you lock the fly wheel with the special locking tool or an improvised one.

Diseasel300 · #14 09-01-2017, 11:17 PM

So I did the deed today and it wasn't a terrible ordeal.

Compressed air didn't work to break the valve springs loose from the collets. They were ON THERE. Ultimately what I wound up doing was taking a piece of string and wrapping it around the crank pulley and marking the diameter. I had a helper mark the TDC spot and we measured the diameter and divided it into 3, wrapped the string back around the crank pulley and lined it back up on the TDC mark and filed 2 marks in the outer rim of the harmonic balancer to designate 120˚ and 240˚. We then worked on cylinder pairs 1&6, turned 120˚ and did 2&5, turned another 120˚ and did 3&4.

Having the pistons at TDC made it easy to pop the collets loose to get the springs off. When done, we turned it another 480˚ back to TDC and reassembled the top end.

The seals that were installed were backwards on every cylinder. The intake valves were so loose in the seal that they'd drop with no resistance whatsoever. With the new seals installed you could pick them up and they'd stay, despite being lubed with oil.

The end result is that the oil burning seems to have stopped.

Maxbumpo · #15 09-05-2017, 11:56 AM

Excellent! Please follow-up with a long term report.