Valve adjustment
 

I Just checked my Intake valves, they are about .15mm (cold) they should be .10mm(cold),My question?would this make a big -if any differances to the operation of the engine?.:confused:

Well, they will tighten up over time, but yes, you want your valves to be at the right gap or else they will open/close too soon/late. You should make them as close to spec as you can get and keep them there.

What intervals are people adjusting their valves?

15K miles should be right.

If you've already popped the valve cover, I'd go ahead and adjust them...

Mine were all too tight and after I adjusted them I got about 22 mpg 90% city driving with a pretty heavy foot... was getting barely 20 before that...

I HAVE A 85 500sel, WwHAT SHOULD THE VALVE ADJUSTMENT BE AND AT WHAT INTERVAL.
HOW ABOUT THE TIMING CHAIN. I HAVE 117000 MILES ON IT.

THANKS
JOHN1

John -

I don't believe you adjust the valves on the M117 motors. They're SOHC hyd lifters I believe...

At 117K mi, I don't think the timing chain should need to be replaced. I'd consider popping both valve covers to check the chain stretch.

SELL 500SEL.

BUY 300SDL.

RETURN HERE FOR ADVICE.

:D

I have no idea where you are from or what the temperature is/was when you did the check. In cold areas having a valve clearance a little over the high side of the tolerance is not a bad thing. Loose is much less bad than being too tight.

Jim

Valve Adjustment
 

Engine cold,Local Temp @ 70 F, location Hawthorne(Los Angeles) CA 90250

Actually on older engines slightly opening up the gap from factory specs on Exhaust valves will boost performance and slightly increase compression for more complete combustion. This is true because exhaust valve timing sets the length of time that compression builds up before being released.

But with intake valves the same benefit is not necessarily true. And the engine might actually be fighting itself at not getting enough air for the combustion stroke. Of course with normally asphixiated diesels the amount of air the engine inhales on intake is practically neglible.

And I agree with Jim, loose valves are always better than too tight. Thats my take on this, borrowing from experience mostly with gasoline engines.

I'd take a nice Euro 500SEL, 265hp I believe they were. In fact, I scored the Euros for the SDL off one. :D As well as some crazy German Becker -

http://img.photobucket.com/albums/v4.../Becker611.jpg

im,

I know the manual and many people say 15,000 for a valve adjustment, but I'm convinced that is too often. I do it every 25,000 miles.

On one of my 300SDs, none of the valves needed to be adjusted aftr 25,000 miles, I.E. all were within the factory specification.

The last time I did it to the same engine, only about 1/2 of the valves needed adjustment. That's why I believe adjustment at 25,000 miles is sufficient. A theory I have is that in older engines the valve seats get work hardened and the clearance doesn't change as much as in new engines.

P E H

What was the status of your exhaust valves? Were they also a little loose, right on the money, or tight?

The answer probably indicates the maintenance strategy of the previous owner. As was mentioned before, the usual thing people find are tight valves, because most owners either don't know the valves have to be adjusted (and never have it done) or don't pay to have it done often enough.

I have some idea your car's valve clearances have been maintained, and perhaps the maintenance strategy was to leave them just a bit loose. If they are all the same and all just a bit loose, I would tend to leave them alone.

Tell us if you see any wear trails on the camshaft lobes where they contanct the rocker arms.

kenk3z