Valve Adjustment Clarification
 

I've decided to tackle on the valve adjustment on my 1984 300D, I read the tutorial from diesel giant. the way I am interpreting it, if the #1 cylinder Exhaust is at 90 degree or so, every valve in the same position can be adjusted. Am I correct with this understanding? I've adjusted valve clearance of solid lifter ICE before, when the #1 cylinder is at TDC. Other cylinder in the same orientation and can be adjusted.

is this something similar?


Please advise. Thank you in advance.

I always do them one at a time. Turn the engine until the cam lobe is pointed straight at the oil tube (would be about the 1oclock) position. Adjust that valve. Turn the engine again then adjust the next valve that comes into position. Repeat until all ten valves have been adjusted.

You have to move the cam for every valve.

Rotating the crank is the easiest part of the job. What i did was first the intake valves then the exhaust just to stay away from any confusion.

Thank you everyone for the inputs, the car sat overnight. Hence I will attemp this after work today.

I have to use the valve adjustment cheat sheet that DieselGiant has in the tutorial: http://dieselgiant.com/5Cylinder%20valve%20sheet.pdf

It helps me keep track of what I've done and what I haven't. I put a circle around the ones I've done and then when I go back around to double check them I put an X through the circle.

Good luck with yours!

I cheat. I adjust every valve that is not pointing at the follower, then rotate 90, and do the rest.
Unless the cam is damaged, anywhere other than during lift is on the base circle of the lobe, and ok to measure clearance.

Reading this thread because I too should be due for adjustment before long.

What I recall doing, is something like vstech suggests, but I would mark valves done both on sheet and on engine itself (dab of paint or ??) to avoid confusion. Using a 1 at a time methodical approach as some have described might reduce errors.

I have never had luck turning crank directly. I have the socket, but it seems to me extensions came off and it was hard to reach. If it is easy, I must be missing something. I have always used a crescent wrench on PS pulley plus a little hand tension on belt. I have one of those electric starter hand switches somewhere too, but never tried it.

I use the remote starter switch, or just jump the bolts with a screwdriver/pliers...

Yeah, do all the valves you can, as vstech mentions.

I also use a remote momentary switch.

Print out or draw the image in the attachment and mark off the ones you did.

Well that sure makes things a lot easier... makes sense too.

I'll try it that way next time.

Last time I did it was with the injectors out when I was doing a compression check, and that was a whole lot easier to rotate the engine without compression.

I have always done it following the firing order. I start with #1, and then to #2, to 4 then 5 and last 3. I do both exhaust and intake with both lobes pointing up (approx. 10 degrees). I thought this was the approved method, but now that I understand that this way may be easier/faster, I will try it as well. I DO know that doing each of the 10 valves one at a time is not the best way.....Rich

The FSM specifically FORBIDS using the PS pulley nut...
Because that is a tapered fit and you will have it way too tight should you ever need to take it off...

I have seen a warning in Maintenance manual not to use the camshaft sprocket nut, but they don't mention the PS nut in MM.

DieselGiant says to use the PS nut and that is what I have always done. It is hard to see how the nut could get overtightened because it is already tight and the wrench just turns the engine over quite easily. (BTW, you need to pull up on the underside of lowere belt - then belt doesn't slip.)
From DG site:
http://www.dieselgiant.com/valveadjust19.JPG

Ohh, thanks for the tip. I should try that when I do the 'SD.

Graham,
I have the paper manuals and have read them... but I am not going to get them out for this question... so let me put it these ways... one.... the FSM says to use the crank nut... that is not the ps nut...and not the cam nut...
Two... TCane and I worked for an hour getting a ps nut off one time... and had power equipment and oxy acet... it is TAPERED ... therefor you can over tighten it... but it is your car and you can do what you want with it... my obligation is to raise red flags for those that have not gotten caught by some PO's actions or have the FSM to read themselves....

I checked both the Maintenance manual and the FSM and neither said anything about not using the PS pulley nut. If you have MB reference that confirms that we should not be using the PS pulley nut I would like to read it and would certainly take note if what you say is confirmed.

It SAYS use the CRANK NUT...
it does not have to also say ... ' do not use the steering wheel nut, the rear axle nut, the radio nut '.....
But I am telling you that due to its being a tapered fitting... it is not legit to turn the entire engine over with it.... I actually think it does say ' do not use the ps nut'... but do not have time to look it up ...

Link to FSM section on valve adjustment:

http://www.startekinfo.com/StarTek/outside/12265/disc_2/program/Engine/617/05-210.pdf

Notes to use crankshaft bolt. Says specifically not to use camshaft nut. No mention of power steering nut.

Feel free to use the PS NUT.... it is your car.... I assume....
smarter people will read the instructions to USE THE CRANK NUT...and USE THE CRANK NUT...

I was thinking of throwing a few lit matches down the dip stick tube instead of pulling the drain plug at oil changes. The FSM does not say you shouldn't do it that way. By the way do you (or anyone) know the torque spec on the radio nut?

The FSM does say to use the crank nut, and specifically not the cam nut. Maybe it is the cam nut shaft that is tapered and not the PS pump? I see no reason why the PS pump shaft would need a taper. That said, I don't use what the FSM recommends. I do not use the PS nut simply because it will over torque it in the process. I use a remote starter switch which is the easiest and quickest way. I adjust what ever set of valves that are pointing up and mark each on a sheet of paper to keep track. When done, I check each valve again just to be certain.

If I follow the FSM, I would have to add at least an hour of time. For those who use the crank nut, do you do it from below (it is not possible for me anyway to do it from above)? That means having a helper or add more time if you don't have a helper by having to get up and down many times to point the valves up. Good exercise but no thanks.

The CAM NUT is stong enough to rotate the engine with....
The REASON not to use it is that the whole system is designed with respect to keeping the timing chain tight between certain points in the rotation... the slack being addressed on the passenger side of the engine by a combo spring,ratchet and oil pressure.
This is why the FSM specifies that when ' rolling in' a new chain pressure is to be kept on the combined chains...
If you use the CAM NUT then you are PUSHING A CHAIN... thus not keeping the designed tension on the side of the engine meant to keep the chain in contact with the sprocket of the timing pump and things like chain rails.
We have had many reports from people who thought they ' just replaced' the chain... and found the timing pump a tooth off afterwards...
But some people do not believe the FSM.... after all it was only written by the people who built the car...
TCane and I spent an hour taking a PS nut off a car he bought ....with oxy acet and many heatings and lots of force..... that is when we found out it was tapered...

OK so you have verified the PS nut is tapered. Usually a taper is used for an application where precise timing is needed such as in a VW camshaft or injection pump shaft. Why was a taper used for the Mercedes PS pump?

I don't know what the big deal is about using the PS pump pulley. I have never had to remove a PS pulley, and don't ever plan to do so. It is not worth the effort to rebuild a PS pump when there is so many good ones available. Like most everything else on these cars, it is designed and built very well, and should last the life of the car (in most cases they do). I have had almost 30 of these cars, and only once have had a leaky PS pump that needed fixing/replacement. I have several laying around, so finding a replacement is not hard. I would not bother removing the pulley for any reason, I would just replace the entire pump. As far as using the crank pulley over the PS pulley, most always I am able to use my 27mm deep socket on a 1/2" ratchet just fine. If I do it just right, it stays on the bolt and does not fall off while I am adjusting valves. In fact, it has happened several times that I left it on the crank bolt and started the engine minutes later after putting everything back together. I have gotten the valve adjustment down to about a half hour total now. The times I can't use the crank bolt, I used the PS pulley and it worked just fine. I see no problem with doing it whatever way works best (easiest). I am not going to NOT use the PS pulley bolt for fear that I won't get the pulley off, because I probably will not ever have the need to remove the pulley in the first place........Rich

I do use the "CRANK NUT".

I was just relaying what the FSM actually says since there was a lot of speculation going on and you "do not have time to look it up" (though you do have time to respond and berate).

You said you believed it stated explicitly not to use the PS nut. I was simply correcting that. It does not say that.

That was not a suggestion to use it.

I will choose not to take offense at your low-blow at my intelligence. :)

Actually I think that where precise timing is needed a key is more often used..
A tapered (friction ) fit is often used to protect something in the power line...as with using the friction of a Morse Taper in a lathe... where you WANT it to give way under certain drastic situations and limit the damage by letting the power go on down the line..

For timing a VW diesel engine, the cam nut is left loose while engine is rotated to TDC before the cam nut is tightened. In the VW, the taper on the cam is for precise timing, not for protection of the cam, which bends valves and breaks the cam if the engine goes out of time for whatever reason. The taper IMO is for precise alignment of the pulley for less pulley run out and wobble, same reason the morse taper is used in morse taper drill bits.

I'm with ROLLGUY on this one. I've got a spare pump (actually an entire spare engine) so dealing with a failed pump is a simple swap...nothing to do with swapping a pulley.

Well, you don't believe the Mercedes people who wrote the FSM...
and you have not been reading the same books on machine design that I have.. or you did not believe them either...
I can't help you under those conditions.

Hi Everyone!
Regarding the valve adjustment procedure, the base circle on these camshafts is Not really a circle at all. This means that you cant really set the valves with the lobe pointing randomly away from the follower (ie the 90deg method). It needs to be in a specific position.
I set mine one lobe at a time with the lobe pointing at the oil squirter tube.

I would suggest that you prove to yourselves my statement about the base circle not really being round, and it is very easy to do. First, Set the valve clearance with the lobe pointing at the tube. Then rotate the cam untill it is pointing Straight up or about 11 oclock. Check your valve clearance again! It will be quite different! Then turn the cam slightly past the tube, say 2 oclock. Once again, check the clearance, and it will be different. Please don't just take my word for this, but rather actually do the experiment next time you set the valves. I wish the FSM was a little more specific about EXACTLY what position the lobe should be in to set the clearance, but, sadly it is not.

I hope this helps!
Cheers!
Chris

OR they could just assume that the Factory Shop Manual specifies a certain procedure for a good reason... LOL

You are correct, on a worn cam there will be various degree wear that is why I said "on a cam that is not damaged" the reason the FSM doesn't specify position is because when the car is built there is a perfect base circle for the cam...

Help? I did not ask for help. Maybe you are confusing me with someone else? We were discussing why a taper was used on the PS pump and you go on a rant that I do not believe in the FSM and that I have not read the same books you have been reading.

Whenever I check valves clearances, I always check a few at different points of the base circle (valve pointing up or at the oil rail) and found no difference. This was with cars in my sig. Small sample size but data nevertheless.

With proper clearance, the base circle never makes contact with the follower. A cam base circle would have to wear unevenly to become an imperfect base circle. Does that always happen with tight valves? You would think it would wear evenly and maintain a perfect base circle.

You asked me why a taper was used on the PS Pump.

and I said I do not know specifically about that..but that in machine theory books I have encountered... one use of the friction taper involves protecting the tool from unexpected problems in the material being dealt with... as an example you can see that a set of Silver and Deming drill bits used by the typical post drill of old times.... all the drill bits had the same size shank.. and a flat on one side... this fit quickly and accurately into the hole in the drill shaft... which had a lock bolt to keep the drill bit in place... a fast and accurate change of bits was thus accomplished..
BUT... if you hit something hidden in the drilled item... it broke the drill bit... or stripped cogs from a gear... or burned a flat on the drive belt...
Most people who need help do not realize they need help.

Here is one possible guess as the the thinking of the MB engineers.... they saw the ps pump as something which could lock up... and ruin the belt driving it... and did not want the ps pump to be an Achilles Heal in terms of the car making it home... or to safety... as the car can be steered ( with great effort )without the power steering pump working...
So they put a emergency slip clutch into the drive line of the PS pump.

I've never heard of anything that's under spring tension under varying loads like a cam to wear evenly...

So, with proper lubrication, the cam base circle should remain perfect even with tight valves?

If the tapers spin relative to each other, both halves are ruined. I'd rather the belt slips then to ruin 2 expensive pieces. A taper is used in machinery for repeatability and quick change, not to protect the work. Are you forcing help on those who are not asking for it? :D

It is ok if the tapers are ruined..
the bigger objective is the safety of the people in the car.

There is a new safety device available on some table saws... it will stop the blade so fast if your finger touches the blade that very little injury will occur...
but it pretty much destroys the table saw and the emergency shut off equipment..
You have to be able to sort out your priorities in life... some people never do.

... that is precisely opposite to what I said...

I saw that ...and started to say that...
but he appears to be upset by anything I say... so I refrained.....LOL

OK, I went back and read your post again and note that I read "evenly" as "unevenly". Typically, how uneven is the base circle wear? I observed no uneven wear on the 3 cars in my sig. What are your observations?

none of the ones I've serviced had any uneven wear either. I'm guessing all the ones I've serviced had regular adjustments, and never had base circle contact.
I have read numerous posts from members that have found their cams to have different clearances at different parts of the base circle. they must have had cars with excessive Oil change intervals, or extreme infrequent adjustment of the valves, or both...

My 83 240D @ 200k and 83 300D @240K had tight valves when I acquired them, the 85 @ 157k had properly adjusted valves. None had uneven cam base circle wear.

How could they? It would take something pretty bizarre like variable tension springs, or variable length valves or little creatures with microscopic dremels to create uneven wear on the base circle. And if they were uneven any contact would tend to even the base circle, not make it uneven.

Well, some people are saying they do wear unevenly. I didn't think so and my observations agree with what I think.:)

To others who do not understand the object of this base circle discussion....

It only makes a difference to people who ARE TRYING to TAKE a shortcut in terms of setting the valves. If you follow the FSM instructions this does not affect you.

AND I would suggest that trying to accurately determine if the base circle IS ROUND... with any meaningful accuracy.... would take more time than actually setting the valves according to the instructions in the FSM...

The ' N ' in your ' survey' is too small to have statistical relevance.... therefor it is by definition ' anecdotal '.... and can not be trusted for generalizing.
But it is nice that you agree with what you see... otherwise I might have to offer you some more help....