I just refilled my 240D tank for the second time since doing my valve adjustment. The first tank gave me right at 30 MPG, so I didn't believe it. Today, I got 29.8, and I've been running with the A/C most of the time.

Before the valve adjustment, I was getting 25. I guess those three intake valves with no clearance really was killing the engine.

Joe

Greetings Joe,

I am glad you are experiencing an increase in MPG, we'd all like that one with the price of fuel these days. I Know MB recommends 15,000 mile valve adjustments, but in some cases the change of weather has some bearing on where the gap may fall on our adjustment. This being probably one of the cheapest, not time wise that is, things we can do to our older Benzes, to keep then performing well. I'd suggest adjustments on the valves with extreme weather changes like from Winter to Summer even though the mileage doesn't call for it. You would be surprised what each little MM in adjustment actually means as far as tight sealing valves and added power and MPG.

Great Job,

Charles

__________________
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan

Can-do,

I spent about one c-note on my '79 300SD in the last 3 years(33 K miles) and it is ready to go every day. I bought it as a parts car 3 years and all the parts are still running.
The body is getting bad but it might last a few more years. I bought a better body on Ebay so when the '79 dies, it will really be a parts car.
P E H

... Hello.
Do you know if there is a thread detailing just how to adjust valves? I'm only finding references to an adjustment needed, one just done, or an aspect or two about adjusting them. Are there instructions on the whole process on our wonderful MB forum? I'll appreciate help. Thank you.

Debi,

It is a very simple job, but tedious. I will give you a synopsis on how it is done and what tools you need.

Tools:
2 14mm open end wrenches, a 27mm or 1 1/8" deep socket wrench and ratchet, and 4 feeler gages .003", .005" .013" and .015". There is a special set of wrenches available(~$75) but they are not necessary. You also need a general set of tools to remove the valve cover.

Procedure:
Turn crankshaft until one of the camshaft lobes is 180 degrees (lobe pointing up) from the position where it fully opens a valve. Then determine if this is the intake or exhaust valve. You can tell which valve it is by the location of the valve that is closest to the intake or exhaust manifold. If it is the intake valve use the .003" and .005" feeler gages, if exhaust valve use .013" and .015" gages. Intake and exhaust are adjusted same way, just using the different size gages. Check with your 2 gages between the cam lobe and the cam follower to see if one will go and the other one won't. If this is true, this valve won't need adjusting. Usually the valves will be tight because of the valve wearing into the seat. Loosen the acorn nut and lock nut on the valve stem and adjust the acorn nut until the gages go and don't go. Then hold the acorn nut and tighten the lock nut securely. Then recheck with the gages. You will probably have to re-adjust a few times until you get the feel of it. Make sure you tighten the lock nut as tight as possible and recheck with gages.
Now turn the crankshaft until the another valve is in the 180 degrees position. Once you find how far to turn the crankshaft it will be the same amount each time. I think on my rachet it is 16 clicks actually 4 clicks 4 turns.
Now do the next valve the same way. Keep track of the cylinder number and which valve was done so you know when you are finished.
Other mechanics may do it differently but this way works for me.
Check for cam timing, not more than 3 degrees on the vibration damper on crankshaft when cam timing marks are aligned and check the chain tensioner to make sure it keeps the chain tight. Install a new valve cover gasket and reinstall the valve cover.
You should be able to do this job in 2 to 3 hours. Any questions e-mail me.

P E H

Greetings PEH,

Thanks for your input to my signature line, but if you have only spent that much on your car in three years, then only the oil and filter have been changed every 3K and nothing else. There are still some of us that commute quite a distance and easily do your three year average miles in less than a year.


Charles

__________________
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan

Can-do,
Nope, oil and filter get changed every 10,000 miles with Castrol Syntec. Changing the oil more often is a waste of time, oil and money. The only repair was to rebuild the front calipers. Its a winter car. My other 300SD stays in the garage all winter. No rust on that one.

P E H