603 valve seating - Page 2 - PeachParts Mercedes-Benz Forum

wwii · #16 10-27-2018, 11:15 AM

This looks like it works: Model 124 Maintenance Manual Index

And this looks like the same thing: http://www.w124-zone.com/downloads/MB%20CD/W124/Main.html

Also on the Startek site itself: https://www.startekinfo.com/StarTek/outside/12264/?requestedDocId=12264 - Engine is on Disc One

dieselbenz1 · #17 10-27-2018, 12:49 PM

Excellent startek had the info I was after thank you WWII

PERMISSIBLE CLEARANCE OF VALVE STEM END TO CAMSHAFT BASE

20.4 – 21.4 VALVE CAN BE REUSED
21.4 – 21.97 INSTALL NEW VALVE LENGTH 106.4 MM
19.5 – 20.3 INSTALL REPAIR VALVE LENGTH 105.5MM

dieselbenz1 · #18 10-27-2018, 02:33 PM

I'm measuring 20.4 which due to my equipment thin square bar is on the longer side, I'll try and find a dowel to sit in the cam bearing so i have less error. I suppose used lifters may have a bit of crud inside which don't allow them to fully collapse? I'll try again to disassemble them to clean the internals. The intake valve length appear to be .1 mm longer so perhaps the exhaust valves aren't closing at lower rpms?

dieselbenz1 · #19 10-27-2018, 02:58 PM

Found my precision dowel exhaust measurements

20.52
20.32
19.92
19.91
19.98
20.24

I believe that identifies the smoking problem but I don't understand why compression tests were good.

I suppose its not a good idea to cut a bit of length off the end of the valve stem shouldn't be sodium filled but its likely hardened?

I havent measured the intakes yet..

barry12345 · #20 10-27-2018, 03:10 PM

I had this nagging in my head from the start that something going on here was probably not right. You have no ideal of tests I design to find out what I want to know. It is just the way I do things. Mentally challenged does not even describe some of them.

Anyways as I started to think about one for you to apply. Attempting this It all came together. You do not have a valve problem really. It may not be the best valve job in the world but it is not the issue. I put all you have posted together. So how could I design a test for a non existent condition?

That diesel with a thirty percent leak down as say a mean average on almost all cylinders. I remember something you mentioned that the number one cylinder was different somehow but not the specifics.

Combined with if you had done the percentage of leak down at the normal 100 pounds. The percentage of loss would have been substantially greater. I doubt the engine could even have run with that much loss being a diesel of the 603 type. I am pretty sure that your 603 would have exhibited real problems to even get started as well. If even possible.

I do think you may not have put each and every cylinder at it's top dead center and that is not the easiest to do when you did the leak down test.

Another issue was . Four hundred pounds is fairly good compression for that engine. You could not obtain it with perhaps a sixty percent leakage factor with a hundred pound test. I may be wrong as it does happen.

If I am right post it so the white smoke can be dealt with. Did you dead top center each piston in turn when you did the leak down test? If not the chances are very high that each cylinder may have had a partially open valve. If it had been performed at 100 pounds input pressure there would have been a lot of noise of air escape. I should have caught this possibility earlier. At 76 and really busy right now I just was not thinking things through well enough.

Do not feel bad if I am right. Us humans are really good at getting things messed up periodically. I have had my share over my lifetime. This would not be the first for me either. In you video if you consider it. The bubbling is not enough to let thirty percent of the constant volume of air present escape at 50 psi. That valve is not passing very much volume of air at all at about the twenty plus pounds pressure showing in the video. Some but not much. I doubt you would even hear it on a proper leak down test.

This is just one of those cases. If you were a lady working on this engine. I am not sure if you would still love me or not in the morning.

Just an attempt at a little levity to lighten things up. Your problem was getting a little heavy.

dieselbenz1 · #21 10-27-2018, 04:10 PM

Perhaps I'm a bit confusing when I first had the head come back it was smoking real bad so I did a compression check no. 1 was 375 the remaining around 400. I did a leak down at 50 psi because I had no way to keep the engine from rotating on me and it is a home made leak down tester that I have used for a while so accuracy is definitely in question. All cylinders were tested with each being at TDC. I did hear air escaping so I added oil to the intakes and bubbling was tremendous. I then removed the exhaust manifold to witness the same. Then I had removed the cam and the bubbling was similar.

The shop never did anything to the head in the 3 weeks they kept it for saying it passed vacuum test therefore it is good and all it needs is run time. I used a blueing to see a faint ring around the valve and seat then lapped each valve to see a wide seating area. Reassembled and ran the engine for 4 hours hoping that run time would seat as I was told. The video was then taken and as observed the bubbling has been reduced but I have no idea what normal or good is.

barry12345 · #22 10-27-2018, 05:55 PM

The more information the better. That nagging feeling is back. That something is being missed.

You seem reasonably able. Plus have been at this for some time. Any history on this engine? Did you ever hear and see it run before doing the valve job? If the engine sat around for some time any ideal of how long? Before you got it.

It is just me perhaps but I would have to check with working mechanics near that machine shop. What their general reputation is and if they use them. If not why not of course. Until that is done perhaps stop for awhile.

You mention when you put it back on the first time there was a lot of smoke. White smoke I assume? Many possibilities where eliminated when you tested without the cam installed so they can be disregarded. Although thankfully a leak down test performed without the cam installed.You do have some latitude of position and it still be a valid test. I think it is far more important to find out about that machine shop. Than anything else before moving on.

dieselbenz1 · #23 10-27-2018, 06:36 PM

I picked up this engine at a 50% off day at pick n pull last January. It had a ton of leaks fuel, oil, coolant but it did start will a few replacement parts however ran poorly. I pulled the 14 head and found it cracked. I stripped the engine checked rings, bores and crank bearings all were within spec. I decided to reinstall rather than refresh as 45 yrs ago when I had last rebuilt an engine the rings would not seal. A member sold me the 18 head so I had it rebuilt. Ever since it has smoked white diesel smelling exhaust. This has been just something to fill some time for me and I don't have an application for it but do have all the parts to drop into a w124.

I think this pretty much ends this project putting in new seats I may price out but can't find any, paying 50$ each for shorter valves would be more than I'm willing to spend.

tjts1 · #24 10-27-2018, 07:58 PM

I think you have a prechamber problem. Does it have straight or angled injectors?

dieselbenz1 · #25 10-27-2018, 08:17 PM

I am using the straight prechambers I spent a lot of time making sure they fit correctly after I had them shaved using blueing to make certain there was no interference. Upon firing and running the engine the first time and several other times I sprayed soapy water to ensure a proper seal. After the head was shaved I needed to add .03 mm spacers to bring the prechamber into specifications.. Before firing the engine the first time I had rotated it to further insure no interference. The only leak was one injector needed more lapping which I had done.

Strange with a misting of starter fuel it behaves better emitting a small amount of black smoke.

dieselbenz1 · #26 10-28-2018, 02:05 PM

Last evening I took apart the lifters cleaned them no real crud found lapped the lifters for what little material that would remove and reinstalled them dry. Upon startup quieter engine but still smoking as usual set the rpms to 2000 not much smoke at that speed. Went away for a coffee came back 20 or so minutes later dropped the speed back to 500 rpm engine temp was 95 degrees I didn't turn on the portable fan I use to cool the rad. Smoking was significantly less. Now what?

barry12345 · #27 10-29-2018, 12:58 PM

Run it longer. It has been getting better. So perhaps an hour at at a time and let it rest for about 5-6 times.

Because the seats are deeper and the valve faces where ground. The lifter pistons might be slowly adjusting to their new areas of internal operation.

If you can depress the lifter a little while it is under the bottom of the cam lobe radius. It would be harder as you have the valve spring load. There would still be operational room in the lifter. If not the lifters are bottomed.

Check with a machine shop. I know I could use some of my water cooled diamond granite working tools to do the stem ends. Just with no water as it could result in an explosion with it, I suspect the sodium passage may end low enough in the stem. Machine shops may alter the stem ends of sodium filled valves. They do cut the faces remember. They are hollow tubes essentially but to block them off I would expect it to be done before the cuts for the valve keepers. How this was done would be important. Again assuming the ends would have to be machined originally to get the valve lengths right. After they were filled with the sodum.

I know they are considered dangerous. Have to talk to a machine shop if they can and do this. Would be cheap enough if they do. Fifty dollars a valve I agree is out of the question. Even worse it may not be the whole issue.

As for the lifters. Mercedes was very late in adopting the use of hydraulic lifters. The lifters I am at least superficially familiar with have quite a lot of internal operational room. Mercedes specs to me indicate theirs might be different.

The white smoke has to be generated by unburnt fuel getting past the exhaust valves. Or leakage past the turbo bearing seals. Or a cylinder is not firing.

I was wondering if an engine out of the car with perhaps no exhaust hooked up. This could be missed. You have done so much I was reluctant to go there. You have at least loosened off each injector line in turn to verify all the cylinders are on line? As usual I suspect you probably have already been there. Or running with the exhaust manifold off you know they are. I might read the glow plugs surface temperatures otherwise after the engine has run awhile.

The 603s presented a major increase in power and efficiency. Over the 617s with identical displacements. Since the combustion chambers remained similar. At least to my knowledge.

It never has been discussed. Just how they did this. A good 603 is perhaps not a rocket ship compared to the 617s. Yet it is substantially better. Both are indirect fuel injection engines.

I know they always stated they thought hydraulic lifters were poor performers for public consumption. Before they adapted them. I think your engine type may have been the first of their diesels to adopt them. There are some reasons to suspect their internal range of operation is less than the average hydraulic lifter.

dieselbenz1 · #28 10-29-2018, 02:05 PM

I did crack each injector and with each cracked the engine misses so I do know every cylinder and injector are firing. I did clean the injectors and nozzels in a ultrasonic bath using acetone they all have decent spray patterns and were adjusted to open at 1950 psi. My experiences with worn injectors is smoke on startup, reduced power but when the engine is up to temperature no smoke and adequate power. Zip movement on the hydralic lifters by pressing but darn that test should have been done after I cleaned and never refilled the lifters right after cam installation. This engine does not have sodium filled valves at least according to the manual but I will double check. The intake manifold is still off so I know the turbo is not contributing oil to the combustion cycle.

Diseasel300 · #29 10-29-2018, 02:09 PM

You may just need to run the engine in. Unless you're having massive losses through the valves (which you'd sure notice) your smoke is unlikely to be valves as the culprit. You certainly wouldn't be getting good compression numbers if the leakage was significant enough to cause operational issues and poor combustion.

You are installing the lifters in a collapsed position correct? If you pump them up prior to installation it may take some time for the oil to leak out enough for the valve to fully close. The lifters used in the Mercedes are just hydraulic bucket lifters. Very similar to those used by other manufacturers. There's nothing special going on with them.

To Barry above:
The 603 makes better power and more efficiency with the same displacement due to the head design. The 617 is a reverse-flow head, the 603 is a cross-flow head. Better breathing leads to an increase in efficiency and better power for a given displacement. This is why the 606 makes so much more power than the 603 with nearly identical displacement and block design. The head has 4 valves instead of 2 and allows much better breathing.

dieselbenz1 · #30 10-29-2018, 02:11 PM

I think it maybe worth the effort to drip time this machine. I again played with timing first went to 17 degrees which doubled the smoke, 15 degrees less smoke 12 degrees least amount of smoke but still bad. The IP does not show any evidence of veggie oil, I resealed delivery valves, the oil gaskets and rebuilt the lift pump. Turning on the glow plugs when running a warm engine does not change the smoke nor changethe sound of the engine.