617 Valve Adjustment for Dummies
 

Hey everyone ok so its time to do my first valve adjustment on my 85 300sd. Its been a looooong time since theyve been adjusted, at least 90,000 mi since iv had the car and iv only recently realized how important this is. the car has been smoking like black/grey like whoaaaaa lately so i hope this fixes it...

Iv read through the archives and I had a few questions in piecing all of this together:

Tools- I understand the Hazet tools make the job much easier. However if i have an extra set of hands on the job, would using standard wrenches be ok? Could somebody clarify the "screw driver jamming" technique used instead of the third wrench?

-When it comes to actually adjusting the valves, how tight am i supposed to tighten the adjusting valve and locking nut together?


-When it comes to replacing the valve cover, how tight am i supposed to torque it down? What is the correct procedure for this? Order?

Can either of these be "played by ear"? Any last min advice for a new kid on the block?

First, go and get at least the Haynes manual for you car.
It is not totally complete...but has better pictures than the Factory Shop Manual on many things.
It has a list of the torque values you are to apply to those bolts you asked about.
If you check the archives you will find lots of discussion about the screw driver compared to the ' third wrench' .
The time you will wish you had the third wrench is if one of your valves adjusting nuts is stuck. It is a wonder you have not burned a valve neglecting the valve setting that many miles.
I think while I was in there I would replace the valve stem seals. That could be the cause of some of that smoke.
If I did that I would also put new adjusting nuts and locking nuts on.... that really makes a difference in those staying tight without excess force needing to be applied.
My first valve adjustment was on a weekend... after four hours I put it all back together so I could drive it to town on Monday and buy that third wrench... then had to start all over. Only three of my adjusting nuts were stuck... but if they are stuck you are depending on the friction provided by the springs... not enough in many cases...

How often shohuld the valves be adjusted? Max is the first diesel car I've ever owned. Are valve adjustments based upon a maintenance schedule of are they predicated by certain symptoms (noises, smoking, etc.)?

An extra set of hands won't eliminate the problems associated with the use of straight wrenches. Access is the issue.

15 Nm.

Every 15,000 miles, or every year, which ever comes first.

Actually I think the interval is every 15,000 miles with no time interval, although every year isn't a bad idea depending on how much you drive it. I drive my 240D maybe 500 miles a year now, so I'm probably on an every ten year interval whether it needs it or not. :)

Screw driver jamming... I prefer to use a wrench, put it between the spring nut and the cam tower. 17mm works for me.

It is every 15,000 miles. I added the or every year, since human nature is to make it out of sight, out of mind when mileage is not accumulated. A car driven 1000 miles per year, some would just change the oil every 3 years :eek:.

According to...?

All the posts I have read about valve adjustments... I do not have the FSM CD handy right now, nor the Haynes Manual.