That's not how it works.

Adjusting the cap nut effectively changes the length of the valve stem. Turning the cap nut CW increases clearance by reducing the length of the valve. CCW reduces clearance.

Unlocking the top nut and holding that position and turning the bottom nut cw then locking down the top nut does increase the clearance to the feeler gage. I just did 10 of them and got them perfect. Idles like a caddy now.

We shot a DVD of the valve adjustment last week to show people how its done.

The statement about the valve moving was to help somone imagine what the clearance is doing.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

OK, you got me. Different vehicle.........different specs. I'll amend the post.

No big deal. I like to think of you as the accuracy watch dog.

Its all good!

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

Thanks. There is nothing worse than having a new mechanic get a well written procedure wrong due to misinterpretation. It's quite easy to do.

We went through several iterations of Danny's check for chain elongation until it was understood under all conditions. It's in the DIY section now.

Ok. I finished the valve adjustment and rechecked the timing chain. The front left edge of the metal marker on the engine block lines up dead on with the line between the upside down one and zero on the harmonic balancer.

What does this mean as far as stretch??

__________________
1982 300SD Light Blue
2002 Honda Accord SE
1974 Toro Wheel Horse Tractor
2000 Toyota Tundra Pickup

That's zero stretch..........almost unbelievable for a worn chain.

You would need to do the test several times to ensure that the procedure didn't give you any error (not permitted to back the chain up slightly if you pass the mark).

In any case, the stretch is very low.

I hate to play the "accuracy watch dog" deal, but...

Isn't it the other way around? Top nut is the adjusting, bottom is the lock nut.

No its not.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

You are correct. Apparently some folks think they are adjusting the valve spring with the lower nut.

Here is what the 167 Service Manual says WRT valve adjustment:

Loosen cap nut while applying counterhold to the counternut on valve by means of valve adjusting wrench.
(In English, that means hold the lower nut and turn the top nut CCW.)

Adjust valve clearance by turning cap nut.
(Translation: Turn the top nut to set the desired valve clearance.)

Following adjustment, secure cap nut with counternut.
(Translation: Hold the top nut and tighten the lower nut by turning CCW.)

Check valve clearance once again.

Well, the car was purchased by me from the original owner who bought it new. Same mechanic for 18 of 22 years. I have had it two years. I have driven it 30k miles.

Maybe he had the chain replaced??

I know I set the valves correctly because I checked them twice -- right after the adjustment and then I turned the crankshaft one rotation and checked again.

It checked a few degrees of stretch before I had adjusted each valve, but after each was adjusted it checked at Zero then.

I guess that's pretty good for 273k miles.

__________________
1982 300SD Light Blue
2002 Honda Accord SE
1974 Toro Wheel Horse Tractor
2000 Toyota Tundra Pickup

Reverend, that's due to a higher power having a positive effect on the outcome.

Adjusting the valves won't have any effect on the elongation of the chain.

But aren't you supposed to adjust the valves before checking the chain or at least make sure they are in spec?

Maybe there is about one or two degrees of stretch. Even so, isn't anything under 6 degrees ok? The uppper guide looked fine. The tensioner was doing its job ok. It looked fine. I looked down in the engine with a flashlight and the sprockets on the vacuum pump looked good and not worn that I could see. The top sprockets looked really good.

Should I go ahead and replace the upper guide and tensioner?? Or just have my trusted mechanic at the dealer take a look and see what he thinks?
Mark at Leith MB in Raleigh, NC has been there over 20 years and is the only one who works on my car. He is tops. It might cost me $85 for him to have a look, but might be worth it.

Tell me what you think?

__________________
1982 300SD Light Blue
2002 Honda Accord SE
1974 Toro Wheel Horse Tractor
2000 Toyota Tundra Pickup

The adjustment of the valves has no effect on the elongation of the chain and won't affect the results of the check for stretch. Remember, you align the marks on the tower and check the damper. The valves play no part in this test.

As for the slide rail, I wouldn't bother with it. It's the tensioning rail that suffers the most wear from the chain and you need to remove the tensioner and the camshaft sprocket to take a look at it.

It's a fairly lengthy job to change the tensioning rail. I decided to leave it when I removed the cylinder head. It had some wear......maybe .040" or so, but nothing that I'd be concerned about considering the thickness of the lining.

Kent Bergsma of ************** says the chain and tensioner should be replaced at not later than 200k miles.