Valve Adjustment: Don't Procrastinate - PeachParts Mercedes-Benz Forum

diesel don · #1 09-28-2002, 01:58 PM

I finally did my first valve adjustment ('85). I had put it off because it sounded like a monster. But like most other repairs so far, its fairly straight forward. I'd encourage you newer guys to not wait as long as I did (I've put 28k on since purchase).

All valves were tight with the exhaust valves being extremely tight. Former symptoms were:

Increased oil consumption
Increased smoke
Rough idle upon cold start

As suggested, I did it when stone cold and notice the following improvements:

Perfect idle
About 1/2 the former smoke
Somewhat quieter

After a test drive, I concluded that it runs very smooth but that performance didn't change all that much. Perhaps 500 miles down the road or so.

It took me about 2.75 hours and I found the lower 27mm crank bolt to work fine.

Don't wait.....

Don

Stevo · #2 09-28-2002, 05:24 PM

I bought a "78" 240d for my daughter almost a year ago. The car was very clean, a stick, and had been garaged "most of its life" actually he bought a new MB and sorta forgot to keep up on the valve adjustments on the "78" We got it home and when we went to adjust the valves they were VERY tight. A couple of cam lobes were quite 'dished in" and the rockers very worn.

So dont let that happen to you, Keep those valves adjusted folks.

ck42 · #3 09-28-2002, 06:01 PM

This is something I've been wanting to learn how to do myself for a while now.
Problem is, there doesn't seem to be too many online instructions for the DIY'er.....especially mechanically challenged DIY'ers :p

Something I'd LOVE to see is someone actually make a video and show step by step the whole procedure.

From the very few instructions I've found so far, there seems to be a lot of assuming being made.....like I'm suppose to know what a gizbamo is already...or that I was suppose to do something else first....or that you're not suppose to turn the motor backwards....or even KNOW which way is backwards!!!

I'd REALLY like to learn this procedure! But, I seriously don't feel comfortable attempting it with ANY of the instructions I've found so far.

Anyone in the Atlanta area wanna make a movie?

You adjust my valves and I'll hold the camera.

jcd · #4 09-28-2002, 08:26 PM

However,

I had a local tech do it, $100, and I could really tell a difference in performance, sound reduction and starting.

JCD

P.E.Haiges · #5 09-28-2002, 10:22 PM

I was going to adjust the valves on my '79 300SD after 25,000 miles. However, I checked them all first and I found that not one of the valves needed adjustment. They were all within spec. I checked them with go nogo gages .001 inch smaller and larger than nominal. I do try to set them on the highside (maximum clearance) so maybe that is why they were all OK.

Has anyone else had this experience?

P E H

P.E.Haiges · #6 09-28-2002, 10:32 PM

C42,

Isn't MB Autoworks in Atlanta? Maybe they would show you how to do the valve adjustment. Its not rocket science and should only take a short time to learn

P E H.

PS. Looking at the engine (NOT MOTOR) from the front, you turn the engine clockwise by using a 27mm or 1 1/16 socket wrench and ratchet placed on the head of the bolt in the center of the front of the crankshaft.

franklyspeaking · #7 09-28-2002, 10:33 PM

I checked mine last week, since it had been about 15k miles since the last adjustment. All valves were okay. I'll probably check them in another 10 or 15k. I am not surprised some may go 25k with no adjustment necessary. I have only adjusted mine once since I bought it in 1994 - have put on about 55k.

Stevo · #8 09-29-2002, 11:30 AM

P E H

Whats a go nogo gage ? I set mine at .016 & .006 and use the nut on the steering pump to turn the engine. I also have the valve arangment drawn out on a sheet of paper so I can keep track of which ones I've done.

P.E.Haiges · #9 09-29-2002, 08:22 PM

Stevo,

Go and nogo gages are gages that are .001" more than nominal and .001" less than nominal. After you adjust the valve the go gage (.001 less than nominal) will fit between the valve nut and the cam follower and the nogo gage (.001" more than nominal) will not go between the valve nut and cam follower if the setting is correct. This eliminates the "feel factor" of just using the nominal size gage.

This way there will be no error and the valves are all set nominal +/-.001 inch. I always set the gap so the go gage is loose so the clearance is very close to nominal +.001". It is also an easy way to check the valve clearance before adjusting them. Some valves may not need any adjustment so checking them first will save you time. This is how I checked the valve clearances when I found they needed no adjustment after 25,000 miles of service.

The gages needed are .003", .005", .013", .015". I use Starett precision gage stock.

P E H

leathermang · #10 09-29-2002, 10:17 PM

Stevo, I suspect from the evidence you have read " How to Keep your Volks alive.. etc" by Muir. For what you are setting your valves at you need .015 and .o17 and .o5 and .o7...
But I really suggest you learn to use the crank bolt to turn the engine... you may have real problems with that steering pump nut and pulley should you ever need to take it off... ask TCane how much trouble he had with his when the PO did that...

BWatson · #11 09-30-2002, 05:41 PM

I confess...I had it done...I'm lazy, what can I say! I still attempt DIY projects but I decided to get this one done by an old pro. I'm sure it's probably not rocket science but I just love my car too much to experiment on. The timing chain is good!
Maybe I'll attempt the starter, which locks up on occasion. I can usually bang it with the tire iron to get it to start but I don't want to have to lie down on the ground when I'm dressed. Although, once this same thing happened to my 70 Caddillac when I was on a date and I did the old Fonzie bang and it started right up....her pants came right off....maybe I'll wait to fix the starter since I just met someone and this tactic might come in handy.!

Stevo · #12 09-30-2002, 09:25 PM

Thanks for the info on the Go and nogo gages, thats a new one on me and it sounds like a slick idea.

Leathermang ...Ya Muir and I are ol buddies, hes been on a shelf in my shop for allot of years. My wife had that 64 bug when she was in collage, wont sell it either.

Using that steering pump bolt sure makes life easier. So thats why using the crank is recommended and not the steering pump bolt, ok it does stand to reason if it was ok to use it the book would say so.

BWatson ... If you have found a good procedure concerning underwear,dont change it and thanks for sharing

At this point I can use all the tips I can get

P.E.Haiges · #13 10-01-2002, 01:43 AM

Leather,

Aren't the nominal valve clearances for the MB Diesel engines .004" (0.1 mm) intake and .014" (0.35mm) exhaust?

P E H

engatwork · #14 10-01-2002, 07:59 AM

PE - it is based on whether it is a turbo engine or not. I don't have the numbers here in front of me but there is a difference.

muybweno · #15 10-02-2002, 10:50 AM

hey fellas...

where do i get the neccessary parts in order for me to do the valve adjustments. I figured i'd do it soon because i need to do an oil change and water pump change soon...mind as well throw in a little experimentation with the valves and cams.

I know that P.E mentioned something about nominal valve clearances for the MB Diesel engines .004" (0.1 mm) intake and .014" (0.35mm) exhaust......is this the correct openings for a normal 300D '78?

I found some wrenches off of ebay that this one guy is selling and he claims that they work even better than the original wrenches meant for the job....whats tipsy about it is that he makes them himself.....dont really know about this

your opinions are appreciated
allen