Valve adjustment 1985 300SD - Page 2 - PeachParts Mercedes-Benz Forum

Joe Marroso · #16 04-22-2009, 12:17 AM

Gentlemen,

May I repeat my difficult situation. I can't finish my valve job till someone demonstrates the "secret handshake." How do I adjust the jamnut when the valve "spins?"

Is there a "3rd wrench" that holds the valve in place? An eBay for such a tool url is non-functioning.

Will I do damage if I push between the coils of the valve spring with a needle nose and pinch down on the valve stem while I turn the jamnut?

Help!

Joe Marroso

aaa · #17 04-22-2009, 07:21 AM

There is a third wrench, just look for "mercedes valve wrenches" or whatever, you'll see a big third one along with the curved 14mm ones.

I didn't need it though. I encountered your problem on two valves, and somehow managed to figure it out by poking a screwdriver at the spring. I did not touch the valve stem.

leathermang · #18 04-22-2009, 08:42 AM

Since you are dealing with three items... the top nut, the locking nut and the spring retainer nut.... the legit bought ' 3rd ' wrench to fit the lowest item is very handy ( as compared to using a screwdriver , etc )... since most of us have only two hands....and that legit lower wrench has a leg on it to hold it in place.
If you search ' bent wrenches' on this forum you should see lots of discussion on this...
I was caught like you are... all except a couple of the valves adjusted just fine my first time... I tried making the lower wrench just like I did make the two upper ones... but finally just bought the lower one...

funola · #19 04-22-2009, 10:12 AM

Don't know if this will work for you. When I adjusted the valves in my 240D, I first inserted a feeler gauge that fits the old clearance (good to know what it was). With feeler still in, hold the top nut steady and loosen the lock nut just a little (maybe 1/4 turn or less?). Next, insert the correct feeler gauge and turn the top nut slightly till the correct drag is felt. Then while holding the top nut steady, turn the bottom wrench to lock the lower nut. The idea is to keep feeler contact pressure on the cam and follower at all times during the adjustment. It may or may not help you but my valve retainers never spun with the procedure above.

Joe Marroso · #20 04-23-2009, 02:41 PM

The bloody deed is done. That is to say; each exhaust valve is .35mm but not .40mm, each intake valve is .10mm but not .13. Nice huh? The Diesegiant dvd was a big help to an old mechanic whose last valve adjustment was on a roller cam!

I ran into a problem that was not fully anticipated even after all my research, i.e., the valve that spins during the adjustment procedure. I referred to the solution of this surely common problem as the” secret handshake.” I had already been aware that one stalwart described this problem and suggested using a large flat screw driver. Another ground out a piece of a 30mm socket to form a wrench and braised on handles!! These be some manly men or at least clever mechanics. Nevertheless, just how I was to use this screwdriver or where I could buy this “3rd wrench” was not altogether clear.

So, the next morning I tried the adjustment ordeal again. The “large flat screwdriver “did just fine, thank you. At the risk of pissing someone off, I really don’t see the need for a third wrench. Now, I am going to explain; the valve assembly (involved in the adjustment procedure) has 3 parts not 2, as leathermang pointed out. There is, off course, the top nut or adjustment nut, the jam nut that compresses the valve spring, AND the hexagonal valve spring retainer. Every once in a while, by my reckoning, when the jam nut is being adjusted to create more clearance (lash), the valve retainer will also turn. To stop this spinning, take a large flat screwdriver and align it with the cam bearing mounts so one of the points on the hexagonal valve retainer is impeded from turning. With the valve retainer will no longer turning, the jam nut can now create the proper gap.

My crankcase was immaculate and the entire overhead valve assembly looked in very good condition (the varnish colors in the pictures are reflections). My SD has 231K miles. From the deadness of the valve cover gasket (it felt like a greasy rope), I don’t think the valves had been done in a while (at least +20k miles). 3 of my exhaust valves had ZERO clearance!! Yet, she ran beautifully. Started right up. With the new valve adjustment, the ol’ belcher sounds like one of those expensive sewing machines did in the 1960’s.

As a point of order; surely to arouse passions: My diesel uses a two tank WVO system (Golden Fuels). There have been concerns stated in a cohesive and scientific fashion in this forum that stated WVO fuel will contribute to the polymerization of the lubricating oil. The appearance of the startlingly clean valve cover and cam assembly indicates the motor oil is in robust condition (even at 3K miles). I tried to freeze the engine oil (Rotella) overnight. Contaminated oil would freeze, thus contributing to the destruction of a cold started diesel. My crankcase oil did not freeze. I use Lucas every oil change. I splash a small amount of dry gas and biocide in the WVO settlement barrels. I add cetane booster (3oz for 12 gallons) every WVO fillup. That’s it. I switch over to WVO when the engine is at operating temperature. The car runs much better than it did when I bought it (11K miles ago). I use it exclusively for city slogs generally at 20-21 miles per gallon.

I do try hard to properly filter the WVO, but I can’t possibly have the best system. There are fabulous systems that retail for $1000. My DIY gravity/heat filtration system cost less than $100 and is only 18 inches wide.

So, let’s review the bidding;

1) I use WVO
2) My crankcase is not contaminated. Hardly, it is perfect.

So, it is possible to escape the “polymerization of engine oil” death sentence for a WVO Greaser because…

I don’t know. But, I love the way my baby runs. And when I go to sleep, I am secure in the knowledge that I didn’t send as much money as I could have to the people who try to kill our soldiers.

Joe Marroso

leathermang · #21 04-23-2009, 03:32 PM

Quote:

Originally Posted by Joe Marroso

I ran into a problem that was not fully anticipated even after all my research, i.e., the valve that spins during the adjustment procedure. I referred to the solution of this surely common problem as the” secret handshake.” I had already been aware that one stalwart described this problem and suggested using a large flat screw driver. Another ground out a piece of a 30mm socket to form a wrench and braised on handles!! These be some manly men or at least clever mechanics. Nevertheless, just how I was to use this screwdriver or where I could buy this “3rd wrench” was not altogether clear.

So, the next morning I tried the adjustment ordeal again. The “large flat screwdriver “did just fine, thank you. At the risk of pissing someone off, I really don’t see the need for a third wrench. Now, I am going to explain; the valve assembly (involved in the adjustment procedure) has 3 parts not 2, as leathermang pointed out. There is, off course, the top nut or adjustment nut, the jam nut that compresses the valve spring, AND the hexagonal valve spring retainer. Every once in a while, by my reckoning, when the jam nut is being adjusted to create more clearance (lash), the valve retainer will also turn. To stop this spinning, take a large flat screwdriver and align it with the cam bearing mounts so one of the points on the hexagonal valve retainer is impeded from turning. With the valve retainer will no longer turning, the jam nut can now create the proper gap. Joe Marroso

Not exactly the secret handshake yet... and this stuff IS in the archives if you look good enough... where to find the wrenches, everything....

But the description for the secret handshake is that the valve is threaded on the top, either of the two nuts used to adjust the valve lash can be stuck so that the VALVE turns ( the retainer only turns because it has a cleat which goes into the mortise in the valve ) when you try to move those nuts. So if one or both of the nuts are really stuck then you can use the retainer to hold the VALVE with enough force to unstick either of the nuts which are tight.
You seem to be giving the impression that the screwdriver is an acceptable tool for this job and that those suggesting the third wrench are somehow spendthrifts or unable to use a screwdriver well... when in fact you have dealt with very few stuck nuts on these engines and it may be that the amount of abuse a stuck nut has had in the past may put the force necessary to move it in a different league from the ones you have experienced first hand.

Phil · #22 04-23-2009, 03:56 PM

I made all three wrenches but I have also read about people holding the valve spring retainer in place with a screw drive. My feeling is to do what ever works with out damaging anything. I made the third wrench because it was easy to make and I thought it might help which it did the first time I adjusted the valves. If you do a search for valve wrenches you will find what I made plus what a lot of other people made.
When I turn the engine to adjust the valves I hold the stop lever down and turn the engine with a start button. As long as you hold the stop lever you should not have any problems.

Joe Marroso · #23 04-24-2009, 12:36 AM

Quote:

Originally Posted by leathermang

Not exactly the secret handshake yet... and this stuff IS in the archives if you look good enough... where to find the wrenches, everything....

But the description for the secret handshake is that the valve is threaded on the top, either of the two nuts used to adjust the valve lash can be stuck so that the VALVE turns ( the retainer only turns because it has a cleat which goes into the mortise in the valve ) when you try to move those nuts. So if one or both of the nuts are really stuck then you can use the retainer to hold the VALVE with enough force to unstick either of the nuts which are tight.
You seem to be giving the impression that the screwdriver is an acceptable tool for this job and that those suggesting the third wrench are somehow spendthrifts or unable to use a screwdriver well... when in fact you have dealt with very few stuck nuts on these engines and it may be that the amount of abuse a stuck nut has had in the past may put the force necessary to move it in a different league from the ones you have experienced first hand.

As usual leathermang is right. My diesel experience is limited, but in my defense I never hid that fact. Apparently I got lucky with the screwdriver and the valve retainer. It didn't seem so at the time. By all means, purchase the 3rd wrench. I am not sure where to do so, however.

Joe Marroso

leathermang · #24 04-24-2009, 12:49 AM

People just need to know they may need that lower wrench.... only three of mine did...but since I was not expecting that I started my job on a Sunday... the MB house is closed on Sunday... so when I found that I did need it.... I had to wait till Monday to go get it... and had to put everything back together to use the wagon to go get it... Had I known I might need it I would have started the job Friday night so I could get the wrench Sat morning if needed in order to finish by the end of the weekend...
On the five cylinder most people find the rear valves hard to get to....