AUGH! Please help me with valve adjustment tips! = broken valve guide
 

Hi guys,

I'm having a HORRIBLE time adjusting the valves (well, ONE valve) on my buddy's 240D.

Here's the deal - using Diesel Giant's guide, I laid out all my tools (by the way, I've done this on many a gasser, I'm pretty familiar with the procedure).

Everything went very smoothly until the Exhaust Valve on Cylinder #2.

The clearance is REALLY tight- I can't even get the .3 mm feeler gauge in there (all the rest were tight too). I've tried backing off the lower adjusting nut by like 5-6 turns, and then I try and turn the top nut clockwise to open up the clearance. I hold the bottom nut while turning the top one clockwise. To my understanding, this should open the gap. I keep turning the top nut while holding the bottom one still, but no matter how much I turn it, I can't get .3 mm worth of gap on it.

No matter how many times I do this - Hold top nut still, turn bottom nut 5-6 turns, then hold bottom nut still, while turning top nut 5-6 turns clockwise, the gap just seems to be the same!

Augh! What am I doing wrong? The other valves seem to adjust just fine!

Sincerely,

PE

P.S. OK, Now that I came inside and calmed down and had a cold drink and I'm thinking about it, I think that I have a stubborn valve that spins while I am trying to turn the nuts. I don't have one of those fancy wrenches that hold the hex cap of the valve spring still. How can I get around this?

I determined that the stubborn valve that spins while I try to turn the nuts is indeed the case. I don't have a hex-cap valve spring wrench, so I hit the valve, spring and cap with some penetrating oil, and then used a needle nose vice grip to hold the hex cap still while I turned the adjustment nuts.

Not perfect, but it did the trick, enough to finish the job.

Both valves on cylinder #4 were similarly spinning. Hmm. Maybe I should have sprung for a hex-cap valve spring wrench.

Still, anybody have any tips for this that would keep from buying a hex-cap valve spring wrench?

Thanks,

PE

Indeed - there are three wrenches in the valve adjusting set => two for the lock nuts and one for the hex head cap that sits on top of the valve spring.

Someone mentioned to jam a screwdriver through the spring to keep it from turning. I had one do that one time, and it worked.

Here is the 3rd wrench on e-bay.


HAZET-NEW --MERCEDES -VALVE ADJUSTING WRENCH--30MM--# 2769-3 | eBay

charlie

Yes, if you are able to wedge a screw driver against a cam tower, go that route.

I always jam something against the spring retainer... I've never had an issue with it not working...

OK, thanks for the hints. If I understand this properly, you insert a screwdriver through the valve spring so that the spring holds the screwdriver and the screwdriver is braced against a valve tower so that it doesn't turn?

Anyone have a photo?

Sincerely,

PE

I gonna have to say this - I can't stop myself - I think it is fair to warn you and others that wedging foreign objects in the valve gear is potentially dangerous. I can't prove it - but I see no other way in which the so called Mercedes expert managed to break a valve guide on my engine but I guess it was done by not using the correct tools.

http://www.peachparts.com/shopforum/...alve-guide.jpg

So my warning is be careful if you decide to wedge stuff in there - I think the cost of 3 wrenches is cheaper and a lot less hassle than head off and off down to the machine shop if the worse case scenario "happens"...

WOW! That's horrible!

I think that a Hazet valve spring cap wrench is in my future...

Thanks,

PE

Thanks for the Pic Army, never thought it would/could/possibly do that.

That wrench I posted is $59, I have see them cheaper. this guy wants $59 for each one of the 3. :eek: that is pricy. there was a guy a few months back that had them for $20 each for the bent one`s.

I picked mine up a few years ago, along with 3 other MB tools for $58. was in the right place at the right time with that deal.

Charlie

Please note - the picture shows an end result of...


...well I don't know exactly what - I can only assume some monkey used the wrong tools and was too rough. How rough? I don't know. My suspicions do fit in quite well with other stuff I found on the car - including the rocker arm sets being installed incorrectly on the head - put the group of two over cylinders 4 and 5 and both of the shafts bow making the rocker arms run on their corners (not on the flat) on the cam surfaces...

Army, Isn`t it about your bedtime over there? :rolleyes: 8:25am here and the sun just got over the tree tops.

I remember that thread where you had all the fits about the rockers being wrong.

Charlie

Valve adjusting wrench
 

I found some cheap wrenches, $20.00

Hazet Valve Adjusting Wrench | eBay

$15.00

Hazet Valve Adjusting Wrench | eBay

$35.05

HAZET 2769 - 1 Valve Adjusting Wrench | eBay



Charlie

Hi Charlie,

Thank you, you're always very helpful.

I actually have the correct adjusting nut wrenches, that's not the problem.

The problem was that I had a stubborn valve where the valve kept turning when I was trying adjust the clearance. That's what the "Valve Spring Hex Cap Holding wrench" is for.

I haven't found anything else that is designed to address the problem I just described. Looks like they are around $50.

Sincerely,

PE

wow...
I must say, I do not WEDGE or PRY on anything I have jammed against the retainer... I merely set something in the path of the rotation that prevents the nut from loosening...
care is a must!

Bed time? Nah it was just lap top in the kitchen cooking dinner for the children time... I'm only 9 hours ahead of you Charlie. We're closer than you think - you have been warned!

Does the 240D have valve rotators? Is it possible that I messed one of them up by rotating the valve during adjustment?

Thanks,

PE

They have that star looking thing visible in the pic on the right.

HI there, I don't see the pics... what is the star-looking thing?

What picture?

Sincerely,

PE

In post #8, I've included that pic and just the star.
Also, an illustration with a red arrow pointing to it, but it's difficult to tell.
Lastly, a shot from the FSM.

Sorry. I'm confused. My question was does the 616 engine have any auto valve rotation devices that could be thrown off by my rotation of the valve? I read a post that indicated that certain MB engines have valve rotators, and that by NOT using the "3rd wrench", you can disable the rotators, and mess up your valves.

Can anyone clarify?

Thanks,

PE

i actually had planned on doing a valve adjustment tomorrow on my 240D and also was using the Diesel Giant guide (which doesn't mention any of this). just made my two bent 14mm wrenches tonight. but now i'm all confused. is the 'screw-driver-jam vs. valve-spring-cap-wrench' decision one that i will definitely have to make, or do the valves only spin in some scenarios?

The valves only spin in some scenarios. Apparently the vast majority of them never spin, and it's only some of them that have this issue. It manifests itself as when you try and adjust the clearance, the valve spins (you can see it), and if you aren't thinking about what's going on (like I wasn't), then you won't realize that you cannot adjust the gap unless you keep the valve from spinning around.

The Hazet wrench kit has the 3rd wrench, which pretty much looks like a 30mm socket that's been chopped up and has a handle welded to it (that's the concept anyway). It serves only to grab onto the hex head cap on the valve springs, and keeps the valve from spinning as you adjust the gap. The FSM shows the use of the wrench clearly a couple of posts above.

Sincerely,

PE

I hope this helps
 

The OM616 and OM617 engines have some common parts. One of these shared parts are the "rotator" bits that are fitted beneath the valve spring - I've added some more lines to the picture posted by toomany...

http://www.peachparts.com/shopforum/...1&d=1329293335

There aren't many ways to mess up these little rotating things at the bottom of the valve springs. They are most likely to suffer from a build up of crud as they sit in a recess in the head and there isn't any flow of oil going past them - not that really matters in most cases as far as I can make out. If you were rebuilding the head then it would be a good idea to clean them out - but under normal routine maintenace nobody is going to bother with them.

I'm sure that in 99.9999999% cases it is difficult to mess them up whilst adjusting the valve clearance so long as you aren't jamming great bit bits of metal down through the valve spring!

I think it is most likely that you will damage the valve guide by jamming foreign objects down through the valve spring.




Now please don't let this get out of hand. Be careful and I'm sure you are all going to be OK =>

What happened to my engine was undoubtedly caused by a total f$%^%^^&&ing idiot. I think that this is a really REALLY RARE OUTCOME

Army, THANK YOU!

That is a brilliant post, and explains the answer to my question perfectly, concisely, and accurately.

I now have a tiny bit more knowledge jammed in my head, thanks to YOU!

Sincerely,

PE

I forgot to post these up again

They show the dimensions (well each square is 2.5 cm) of the wrenches so that the more adventurous can make their own!

http://www.peachparts.com/shopforum/...ve-wrench1.jpg

http://www.peachparts.com/shopforum/...ve-wrench2.jpg

Occasionally these sets come up for sale quite cheap. I think I paid something like 30 euros for mine => you have to be patient and wait though.

Those rotaters are called Rotocaps. You cannot damage them by rotating the valve, but what does happen is that the rotocaps stop working over time. The valve stays in one position and wears in one position. If you turn the valve, the valve doesn't close anymore.

It is advised that you change them if the engine has a lot of miles:

http://i185.photobucket.com/albums/x...ilversum13.jpg

http://i185.photobucket.com/albums/x...ilversum35.jpg

http://i185.photobucket.com/albums/x...ilversum36.jpg

http://i185.photobucket.com/albums/x...ilversum38.jpg

Some of my old rotocaps didn't work anymore when I replaced them, some of them still worked to some degree.

so... on the MULTITUDE of motors on this site, when the valve does NOT rotate, it's a sign of stuck rotators? worn valve faces/seats? HMMM...

anybody with the FSM know if the spring wrench is supposed to TURN the valve face during adjustment? interesting...
maybe on a newly purchased car, or one that's been too long between adjustments, set the gap, then rotate the valve, then start the motor, then repeat... hmmm....

I have several 30mm sockets, I could cut a few sections off of it, and weld them to a handle...

@Govert - at how many miles did they stop working on your engine?

Do you think that if they weren't trapped in those muck capturing recesses and were kept cleaner they might have lasted longer?

When I spoke with the machine shop / engine rebuilder who did the work for my engine I think he said that in his experience they didn't fail that often. So long as they move freely they're good.

EDIT - some perspective perhaps? Mine were all good at about 100,000 miles

As far as I can see the FSM doesn't say that the 30mm cap should turn. Even chapter 05-250 which says that the rotorcaps should be replaced on high mileage engines does not specifically say make sure that they still turn. Well it doesn't say so in the English version. I understand Govert uses the original German version quite a bit. I have a copy too but need to start Windows to access it. I usually save up my German FSM reading so I only have to suffer microsoft products once in a while! (I'll put it on my list)

I don't know if a non-turning valve is a sign of a non-working rotocap. It depends on the friction force of the valve adjusting nuts vs. the valve spring force.
The spring wrench should not turn, but I usually see it moving a bit until it blocks against a injector, cam tower or thread of the valve cover.

My engine has run about 200,000 km (roughly 125,000 miles) for certain, probably more. Even the working rotocaps didn't feel as springy as the new ones. The non-working ones weren't springy at all, but they all could rotate. I did a compression leak test on my engine and you could hear when you rotated the valves that some of them weren't worn evenly. I could hear air leakage increasing and decreasing when I turned the valves, so the non-working rotocaps did have an effect.
They would probably last longer if they weren't in those recesses, where there is an oily-soot build up, I've heard that from an W123 expert too.


I have to start Windows too for my German FSM. It doesn't say so either, it is sort of implied if the FSM says that they should be replaced on high-mileage engines. The only question is: what is high mileage according to MB? The original service booklet goes up to 200,000 km, so perhaps that is considered high mileage.

O to have access to all of those service bulletins... may be there is some post official FSM-like advice there? I doubt if I'll get to see them.

Here is a DIY on making the third wrench.
http://www.peachparts.com/shopforum/diesel-discussion/180280-valve-wrench-info.html

Charlie

Post-FSM advice on what exactly?

Well they may have, for example, decided that after so many miles as in XXXXXX miles rather than "at high mileages" you are no longer advised to change the rotorcaps but instructed to change the rotorcaps - I don't know - things get revised - recommendations change. The instructions in the FSM get superceded?

Don't forget that the advice is part of the replacing the valve springs. The rotocaps are easily checked once you remove the valve springs. In general it doesn't really matter if the valve stays in one position, as long as you don't turn the valves during valve adjustment. At the engine overhaul (for late OM61X-engines at 400,000-500,000 km) valves, valve seats and rotocaps could be changed. Don't forget the dealer usually didn't see the really high-mileage engines, fleet owners did their own maintenance, second or third owners went to independent garages, people who drove a lot, went to specialised overhaul companies.

I found this piece of information in the FSM of the Heckflosse:

"Bei undichten Ventilen erst nochmals das Ventilspiel kontrollieren und bei Ventilen die eine Ventildrehvorrichtung (Rotocap) haben, die nicht mehr funktioniert, genügt es vorerst eine neue Ventildrehvorrichtung einzubauen. Die Ventile dichten sich durch des Drehen wieder ab. Um mit Sicherheit einen Erfolg oder Mißerfolg festzustellen. ist eine weitere Dichtheitsprüfung nicht vor ca. 3000 km vorzunehmen. Wurde keine zufriedenstellende Besserung erzielt, Zylinderkopf abbauen und Ventilpartie bearbeiten." (0-05/3)

It means: if you have a leaky valve which has a non-working rotocap, replace the rotocap first. The valves will stop leaking because they will start turning again. After 3,000 km check again. If it still leaks, do a valve job.

The advice that you have to change the rotocaps on high-mileage engines was also in the W114-115 FSM. That leads to the conclusion that "high mileage" is more likely to be 100,000 km than 300,000 km.

This is a good thread..... lots of good information...
One thing it shows... since rotators are cheap... anyone who does a valve stem seal job... should put a new set of ( cheap ) rotators.... and I recommend SPRINGS... as they are also cheap compared to the labor of getting all the stuff off to redo the valve stem seals.....
Army = Stretch .. I think both show up in this thread... maybe not... but ' Army ' still shows in some old posts..
Valve rotators were a wonderful invention... as the heat valves are subjected to varies across its surface.... rotating them each time they are activated keeps the valve SEATS round also...

Some important facts about the valve adjustment wrenches...

the third wrench WITH the little stand... which keeps it in place for those who only have two hands... is very helpful when things get hard to do.. like the back cylinder in my 617 wagon... I had to button up everything.... to drive to the dealer to get the proper wrenches to finish the job..

THIN wrenches...
of the PROPER ANGLES..

these are important considerations for the valve adjusting wrenches due to the thinness of the nuts...
AND you may need to pull one wrench against the other..

THUS is becomes important that they slide past each other ...