Valve Adjustment - PeachParts Mercedes-Benz Forum

#1 07-22-2002, 04:32 PM

Can anyone tell me how to turn the engine when adjusting the valves? Also, in which direction should the engine be turned?

SW · #2 07-22-2002, 05:23 PM

I usually turn it using a wrench on the bolt on the power steering pulley. I turn it clockwise. Many will disagree about using the power steering pulley, but I've done it plenty of time with no ill effects.

Fisherman · #3 07-22-2002, 06:35 PM

Or get yourself a 27mm or 1 1/16 inch deep socket and put this on the crank end. Always turn the motor in the direction of normal rotation.
You can tell by looking at the fan blades and seeing which way to turn the motor and make the fan "pull" air.

Ken300D · #4 07-22-2002, 06:43 PM

I'm in the process of doing this now on the '82 300D along with the task of replacing the air cleaner rubber block mounts. I bought the car at 296K and it now has 325K and I have to admit not doing the valves before now. They are all tight. Intakes have little or no clearance, and the exhaust are tighter than spec.

If you buy the injector socket tool from Performance Products (something like $25) that also fits the big nut on the crankshaft pully. This should be a more sturdy place to turn the engine from than the power steering pully. Plus you may need to do some injector work in the future. PP sells a Hazet socket as their "injector socket" and it is a good quality part.

The engine turns clockwise as viewed from the front.

Be careful not to turn it over so fast it starts - just kidding.

Ken300D

Fisherman · #5 07-22-2002, 06:53 PM

If you do not have the larger socket and want to use the P/S pulley then I would recommend removing some glow plugs first to relieve the pressure.
The first time I used the pulley I thought I would break it off when approaching TDC on some of the cylinders. I guess you could consider that a poor man's compression check... or maybe not.

leathermang · #6 07-22-2002, 07:51 PM

That same socket is $8 from Sears.....

P.E.Haiges · #7 07-23-2002, 09:41 AM

Although I use the deep socket to turn the engine via the crankshaft pulley ( just because I have one), you can use a regular 27mm or 1 1/16 inch socket and a short extension.

P E H

dsmess · #8 07-23-2002, 04:34 PM

The 'hit and miss' method works if you are patient....just bump the engine around with the starter key....watching the cam lobes. just a short hit or it will start!

JimSmith · #9 07-23-2002, 04:48 PM

I have a gentle slope on my driveway, so I can just put it in 3rd or 4th gear and gently pull the car towards me to get the engine to turn over, then stop it when the lobes are in the correct position for a particular cylinder, and use the emergency brake to keep it there. I make the adjustments, then pull it towards the next cylinder. The firing order is cast into the valve cover (Zuendfolge) so you can just go from cylinder to cylinder in that order. My driveway is pretty long and I have two teenage boys to help me push it back if I have to, but I can make adjustments then check each one after going through a couple of complete engine cyclings in a car length or so. In other locations I turn the engine with the 27mm wrench on the crank pulley fastener, or I use the power steering pulley fastener. I lean towards the power steering pulley fastener these days since it is so accessible.

Good luck, you have lots of choices that all work. Jim

#10 07-24-2002, 12:14 AM

Thanks everyone for the info, but I still have one question... where exactly is the crankshaft located? :p

P.E.Haiges · #11 07-24-2002, 12:50 AM

The crankshaft is located in the bottom of the block just above the oil pan. The lower drive pulley for the fan belts is located on the end of the crankshaft. In the center of this pulley is a 27mm nut that holds the pulley on the crankshaft. To turn the engine by hand, you put a 27mm or 1 1/16 socket wrench on this nut and turn clockwise (facing front of the engine) with a ratchet wrench.

P E H

JimSmith · #12 07-24-2002, 12:55 AM

The crankshaft pulley is the one that has all the belts running on it. It is located at the bottom, center of the engine, just below the water pump/fan pulley.

The belts are all driven by the crankshaft, with the alternator and water pump/fan driven by the innermost (closest to the block) belt, then the power steering pump which is a little higher than the waterpump/fan pulley, and off to the driver's side (US model), while the A/C pulley and belt are on the outermost position, and the A/C compressor and pulleyare below the power steering pump, also on the driver's side. Hope that helps. Jim

McRoth · #13 07-24-2002, 08:50 AM

I thought I'd let everyone know that I found Valve Adjustment wrenches over at Performance Products for $61.60! That includes the third one. Here's the address for the ones for my 240D: http://www.************************/product_page.asp?attFlag=0&appFlag=0&productname=Valve+Adjustment+Wrenches&productfamily=Valve+Adjusting+Tools&subcat=Engine+%26+Electrical+Tools&category=Specialty+Tools&make=MERCEDES%2DBENZ&model=240D&submodel=+&series=123&year=1982&vehicletype=CAR&keyword=&vendorid=&search=

Ken300D · #14 07-24-2002, 09:36 AM

This seller on EBay has the bent wrenches.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1846066934

That's where I got mine - does not include the special wrench to hold the valve spring in place. If I have need to hold the valve spring somewhere I hope a pair of sliding jaw pliars will work.

Ken300D

engatwork · #15 07-24-2002, 09:55 AM

Thanks Ken, unfortunately I did not see they were for the unimog until after I purchased them. I'm sure I can make them work and they will probably work better than the straight Craftsman wrenches I have been using.