What does adjusting the valves actually do? i.e., better milage? run smoother? quieter? etc?

I am not too mechanically inclined, but I do love to play with diesel engines. In this case, I will take the car to a mechanic, but what if he does it incorrectly? Will it destroy the engine? What damage can be done to the engine if it is done wrong?

Thank you.

Worst possible case scenario is that you completely undo the lock and reg nut on the valve and the valve drops into the engine. Chances of this happening are small if you are aware it can happen.

Basically if the valves are to tight they can actually stay open and never fully close. A proper gap also allows for better oiling of the cam lobes.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

A mis-adjusted valve will be prevented from closing or opening fully, resulting in the loss of compression and/or inadequate breathing of the affected cylinder. Symptoms are typically excessive smoking and difficult starting. The job of adjusting the valves is pretty straightforward if you have the right tools (like the special bent wrenches) and a good manual (like the Haynes W123 manual). If you're gonna pay someone to do it, make sure it's someone who's familiar with these diesels and has done the job before.

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

Do not have your valves adjusted on your diesel by a shop that is not BOSCH Certified. Also don't let them charge you more than $120.

__________________
1985 300sd Burgandy - Palomino. This ones a keeper.
1986 Isuzu Trooper II Turbo Diesel 5 Speed Red/Grey.
1995 Mustang GT 5.0 5 Speed Black/Gold.
----------
1985 300sd Silver - Blue/Grey Custom. Sold!
1984 300sd Green - Black/Green MB Tex. Sold!
1991 Volkswagen Jetta ECOdiesel 5 Speed White/Grey. Sold!
1995 F150 5.0 Auto Green/Gray. Sold!

BOSCH had nothing to do with the valve system...why would a shop need to be certified by them to work on it?

If the valves are too tight (which is how they tend to get over time) they can hang open and be burnt (eroded) by combustion gasses. If they are too loose you will not get ideal mileage, and will have some valve noise.

It does take some practice, but is not rocket science. Buy your self a feeler gauge, manual, and if you want the fancy bent wrenches (I have never needed them, but it would make the job easier) and dive in!

__________________
1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

It's basically caused by the hammering of the valve and valve seat as they open and close many times per second. Over time, this hammering wears them down and reduces the gap between the valve stem and the tappet. It's not much wear (Hundredths of a millimeter change) but it does make a difference.

If you are doing a valve adjustment yourself for the first time, remember to make sure if you are adjusting an intake or exhaust valve and double/triple check your adjustments before you put the valve cover back on.

im not sure if i would suggest taking off the cam to do this procidure. (takes a second and thinks about what he just said) lol... carefull not to bust your knuckles.

__________________
Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?

As long as they would add one additional commandment for you to keep thy religion to thyself.
George Carlin (Wonder where he is now..)

1981 240d (engine donor 1983 240d) recently rebuilt engine hurray! - No more.. fought a tree and the tree won.

pearl black 1983 240d 4speed (Converted!@$$%) atleast the tranny was rebuilt.

Hi does anyone here know how to get my otherwise very powerful wagon to iddle stronger? already tried the knob at 7.

It would be better to start a new thread to ask such an off-topic question rather than taking over this one.

If you would take the time and go to your library......look for a book that explains how internal combustion engines work.....and read up on the how and why of any 4 stroke internal combustion engine.

One must walk before one can run.......

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

Now, now Brother Billy.

Remember how that one kind old gentleman encouraged us to find a way back when we were young whippersnapers just getting our hands dirty? Well, we've gotta be charitable and encourage them and pass it on. My boy laughs at me and my advice but I notice that in practice, he falls not too far from the tree...I've even learned a few things from him.

Anyway! Enough of the touchy, feeely stuff..

Damn boy, like Shorebilly said ...go search the threads and check out the library, use yore head son! THIMK!

Goood '03 Chianti tonite

__________________
Bama1


2008 SLK 280, Firemist Red - "Hurricane"
2001 F150 Lariat 4x4, Black on Black - "Badboy"
1982 240D 4 speed survivor -"Pearl" - Donated to Vietnam Veterans
1962 Oldsmobile Dynamic 88 -"Gertrude"

1954 model original owner - ~2.5M
Gray softtop/solid exterior/modified chassis

If you like too play with diesels, adjusting your own valves is an ideal place to put some time and energy. Owning one of these cars isn't such a good deal if you have to pay someone else too do every little thing. Might as well just drive a Camray or Subaru as its a whole easier too find someone competent to work on them.

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"