Just finished adjusting the valves for the first time.

[Highway Star]

It really needed the adjustment, I couldn't fit a .0001mm feeler gauge in:eek:. It wasn't idling right, it took too long to warm up, and the fuel mileage was about 12 mpg. All conditions of valves not seating all the way.

It wasn't easy, all I had was two 14mm wrenches and the injector fuel lines got in the way, so I had to remove them. That helped quite a bit. Next time I'll order the specialty tools so it won't take me 6 hours to get a 1 hour job done. After saving myself $200 at the shop, I think I can afford to splurge on some tools.

[AnthroProfessor]

Wouldn't it be nice to get the MB tools for the valve adjustment?

Maybe someone here can get us the part numbers. My dealership told me they can get me any tool if I gave them the part number.


I think valve adjustments can be done by the hobby mechanic. Its something I want to learn.

[Maxbumpo]

I don't have the part numbers in front of me, but the Hazet wrenches do make the job soooooo much easier. The part numbers for all 'special tools' are contained in the MB service manual, in the procedure that calls for the tools. I think that I paid $65ish for mine, had a discount from Performance Products. MBCA membership gets you 15% off, not sure what the prices are these days but they have them and their price is pretty fair (and unlike the dealership they will be shipped to your door).

Also get the crow's foot for the fuel injection lines if you plan to remove those.

[Zill]

Is there a thread that describes the valve adjusting procedure?

Thanks,

Zill.

[Maxbumpo]

Procedure is in the factory service manual, available from MB for about $20 on CD. Call 1-800-4-MERC.

Basically, remove all the linkages to the valve cover, and remove the valve cover.

I make a diagram like this to keep track of which valves I've adjusted:

[front] I E E I I E E I I E [back]

(I'm not sure if I've got the order correct, could be that first valve at front is E (exhaust) not I (intake), will be obvious if you look where the intake and exhaust manifolds attach). You'll need to know correct gap for Intake and Exhaust, should be on sticker on the valve cover. Certainly will be in the factory procedure.

Rotate engine clockwise by crank bolt until one of the lobes points at the oiler tube that runs across the top (never rotate engine by camshaft, and ONLY turn the engine in clockwise direction). Determine if exhaust or intake, apply appropriate feeler gauge. If too tight or loose, loosen the nuts (14mm) that adjust the spacing between follower and cam, correct gap and tighten. Double check gap. Mark off that valve as adjusted, then rotate engine clockwise until next lobe lines up (won't be next to the one you just did), and repeat. If you use the diagram and work the valves in the order that they point up rather than going cylinder by cylinder, you only turn the engine over one revolution (saves a little time and effort).

Also, check the chain stretch while you are there.

Here is the procedure for checking the timing chain stretch submitted by the esteemed Dr. Marshall Booth some time ago.

With the valve cover off, turn the engine clockwise (viewed from the front) using the crankshaft bolt (27 mm or 1 1/16" deep socket) - don't use the cam bolt! - until the scribed mark right behind the camshaft sprocket lines up precisely with the molded line on the front cam tower. This alignment is critical as an error here (say from parallax) will translate into twice the error in reading the timing chain stretch. If you miss - run the crank around again twice to bring the marks back into line - don't back up.

Then read off the flywheel damper the amount of chain stretch. There is a pointer and it will be pointing to the damper somewhere between the "0T" mark and the "10" mark (unless your chain is REALLY in terrible shape). A reading between 0T and 3 degrees is fine. Between 3 and 5 degrees indicates modest wear and anything beyond about 5 degrees should be a suggestion to change the chain. At 7 or more degrees the chain should be changed NOW! At about 10 degrees the pistons and the valves can begin to collide! Injection pump timing will be off by about 1/2 the amount that cam timing is off so if the chain is stretched 5 degrees, the pump will be off about 2 1/2 (if it hasn't been adjusted to compensate for the chain stretch - not usual, but some people do it). Setting the pump timing is a bit more involved.,