What tools needed for 2.3-16 valve adjustment?
 

What Tools do I need for a 2.3-16v valve check and adjustment? I have the manual on CD, a decent torque wrench, and will be replacing the valve cover gasket. Part numbers/tool manufacturers would be welcome as well!

cheers,
dan

Shim over bucket designs usually are accompanied with a special tool for depressing the valve in order to change shims, but the Mercedes (Cosworth) design uses shim under bucket (a little button between the valve stem and tappet), which requires that the cam be removed to change. The old Jag inline six was the same.

My Cosworth Vega is a shim over bucket design (re-engineered by Chevrolet from the original shim under bucket design of the Vega-based F2 engine), and I have the special tool to depress the valves to change shims.

One of the reasons I bought a 2.6 five-speed instead of a 16V was that bloody shim under bucket design. I didn't want to remove the cams to swap a shim.

Bottom line is that you don't need a "special tool" - you just have to remove the cams to change shims!

Duke

Groovy...sounds like an interesting design. What do I use to measure if the valves are out of clearance in the first place?


dan

Once the valve cover is removed you need a set of feeler guages to measure the clearance. MB offers a sheet that supplies the recommended clearances &
all of the sizes of valve shims/part numbers. That sheet is in the maintence manual.

I got the valves checked. After getting a set of mm feeler guages, I also needed to find a 27mm socket to turn the engine with. 1 1/16" does the job in a pinch, the engine must be turned CW if you are standing at the front of the car. In other words, it likes to be 'tightened.'

My next question is-

Where do I get the shims from? My local dealership says that they may take up to a week to get from germany, depending on what ones I need. Of course, I won't know what i need till I have the exhaust cam off! I'd rather just do the job once and not have my car opened up for a week. Are these something that a machine shop might have or could easily fabricate? Or how much is the "Kit" that mercedes sells?

thanks,
dan r.

MB doesn't sell a kit, only individual shims & there are 19 sizes. However most likely you will need shims between 2.65-3.0 mm. Doubt if you could get a hardened shim like that anywhere but MB. IF the valves are too tight then a "really" good machine shop could make them thinner.

You might only need one or two shims. After you measure, you can usually juggle around the ones on the motor to correct the tight/loose valves.

My local dealer stocks a "shim kit" that has an assortment of sizes and I just picked out the two I needed the last time I adjusted mine.

Make sure you loosen the cam retainers evenly so you don't damage a cam.

Tinker

Doc and Tinker,

Thanks for the replies guys-this board really is amazing.

1. I probably won't be able to "switch out" different shims as the only valves that off spec are too tight-also all on the exhaust side as well as being a fairly uniform .05-.1mm off. I will call around to local dealerships.

2. I will try to take the retainers off evenly. I'm supposing this means loosen them in a pattern a little bit at a time? The manual just says "remove retainers." Its things like this that make me wish I had some basic training... :book:

dan r.

Dan,

Having done this a number of times now, the procedure is not that difficult. The scariest part for me is loosening the sprocket connection to the camshaft and worrying about dropping a screw into the chain box or getting one of the screws jammed against the head (lots of "features" in the area the head of the bolt can get caught on while you turn the engine over and then bend the fastener - I know from personal experience, and the fastener is a pretty common metric size, including length so it will be available locally on a Sunday, if you know what I mean). The exhaust side is particularly tricky. Do the job in good light so you can see what you are doing clearly.

You need a micrometer to measure the existing shim if the original thickness value has been blurred or worn from friction. The first time I did this I checked them all to make sure the etched values and measured values were the same. They were and now I only measure the ones I cannot read clearly.

I also made up a record sheet to enter measured clearance between the camshaft and the tappet/bucket for each valve, and a formula that, once I enter the known shim size, calculates the final shim size. Unfortunately not all the 19 cited sizes are always available. The range of clearances can be accomodated though, and I aim for the high end of the tolerance (largest allowable clearance) if the shim I need for the middle value is not available. I record the shim thickness of the new shims for each valve and then reassemble.

The camshaft to sprocket flanged connection has four bolts and the holes are not symmetrical so the joint only goes together one way. I usually take a digital shot of the area for memory help to avoid cranking it over a bunch with the flats provided for that purpose on the camshaft.

I liberally coat the camshaft, camshaft supports, tappets and camshaft support caps with oil (Delvac 1) upon reassembly. The sequence of bolting the camshaft bearing caps down (or taking them off) depends somewhat on the position of the camshaft when you begin the camshaft bearing cap disassembly. I suppose you can try to control the camshaft position but I have not since I typically do both camshafts (take one off at a time, then put one back on at a time) in one event to minimize the waiting time for the shims. Anyway, I loosen the cam bearing cap fasteners slightly on all bearing positions in a sequence to minimize the bowing of the camshaft. It is visually apparent when you are doing this, and if you take your time the sequence works out kind of by itself. The same at reassembly - I bring the cap fasteners (nuts as I recall) down snug by hand,which is not really much force, then move around on the ones that are closer to the valves being opened as the camshaft is drawn down into position, and continue tightening the easier ones by hand. Once the caps are all seated, I use the torque wrench and go from the inside (middle) to the ends a couple times to make sure everything is ok. Then I turn the camshaft by hand with a cresent wrench (big one) on the camshaft flats and check the bearing cap torque between every set of valve actuation positions.

I then line up the sprockets and the sprocket to camshaft connections and make up that joint. You have to turn the camshaft with the engine to access to the bolts/bolt holes on disassembly and reassembly. At least I do.

The rest is straightforward. Remember to be very careful to keep things very clean. I have used nothing but synthetic motor oil on my car, or my son's car now, and as of the last few years, nothing but Mobil Delvac 1. The inside of the engine is very visually clean, and when you take things apart it is amazing how clean it actually is. Dirt (typical junk inside the engine compartment, like sand, hood pad debris, grease with road dirt and so on) needs to be kept out when the engine is open. I typically use a clean shop towel to cover everything while I wait for the shims, or go to the hardware store for a fastener, etc.

By recording the shim dimensions in each valve location the next time you can order the replacements upon measuring the clearance, or, if swapping ones you have will work. I never throw shims out. Good luck, Jim

Dan,

Yes, Just as Jim described. The cam sprockets can be tricky.

From your post it sounds is if you are under the impression your existing shims will all the same thickness. That is not the case. They will be all over the range. As Jim stated, since you have no reference point on the existing shims, you will need to take it apart after the measurement or read the markings on the shims to find out exactly how many replacements you will need. Remember to replace the shim with the marking up so the valve stem does not wear off the marking.

My bet is will have to purchase less than four shims. The factory spec provides a range so there is always a way to distribute the shims you have to minimize the amount you need to purchase.

Yes and always save those old shims, as Jim stated.

Tinker

By the way,

As for tools are concerned you must get a suction cup, because those buckets are very hard to fish out.

Alex

This job spun out of control=>http://www.peachparts.com/shopforum/showthread.php?p=804855#post804855

But I would not be afraid to adjust the valve spec again. MBNA had all the thicknesses I needed in stock and had them the next day, so no worries there. Just be bloody sure not to drop any of the cam-bearing washers or sprocket screws down the timing chain cover. On this job, there is no chance of loosing the timing of the car, unless you somehow manage not to align the sprockets with the cams correctly.

cheers,
dan

Dan,

Curious how many shims you ended up purchasing?

Tinker