Bill ... You are making me feel paranoid ... like I am not sensitive to my car or something. I run Bosch Platinum plugs at .030 or so and can't recall ever having any problems. Robby is sensitive about resistance; soldering a bypass wire across the resistor in the rotor. Copper wires etc. I run "historic" wires and connectors (recycled from my 230SL). My plugs do run clean and slightly gray.

On the offset key, you can put them in in both directions; that is plus or minus 5 degrees. So the total adjustment can range up to 10 degrees for a single chain link.

I didn't ask if your chain sprocket was warn? I replaced mine when I rebuilt my engine. The top of the teeth should have a flat spot; if they are "sharp" (no flat spot), replace the sprocket.

Bottom line, if the sprocket is good, I would drive it.

__________________
Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

No, Jim, you shouldn't be paranoid. If MY plugs had nice clean deposits on them and my car ran "fine" I wouldn't be screwing with it.

Now I have to remove the d*%# valve cover AGAIN. If the cam sprocket is worn, wouldn't the intermediate and crank be worn as well? the cam sprocket is EASY to change (relative to the other 2...). Guess I'd better check it tonight before Star Quality ships the rest of my order on Friday...

As for platinum plugs... everything I've read about them and my experiences with them (on several different cars) would make me want to think twice about putting them on another car - especially a vintage car. But, if it ain't broke... I'll try a "narrower" gap with these and see how it runs better. Right now I'm suspecting that maybwe I'm not running rich as much as I'm not getting complete combustion and/or the plugs are occassionally missing, giving me dark brown/black deposits on the plugs??? Hey so far in trying to fix this I've been wrong every time...

__________________
Bill Streep
San Antonio
'57 190SL (toy)
'08 S5500 (mine)
'09 CLK550 (wife's)
'06 SLK350 (daughter's)
'11 GLK350 (daughter's)
'03 CLK310 (spare)

You are correct. The top sprocket is easy to change, the bottom sprocket wares the most and is hard to change, the distributor drive sprocket and the chain tensoner sprocker do not ware (very hard to change).

I was surprised when you mentioned that your chain had not streched; when I replaced mine, the new one was about a half inch shorter.

Since this thread has gone to two pages, maybe time to start another.

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Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

I suspect the reason the chain hadn't stretched is that it was replaced when the engine was rebuilt, about 15K or so ago. The chain now has about 5K on it. If you drop the oil pan, can the bottom crank sprocket be replaced, or is it a bigger deal than that. Could it be that worn sprockets (top and bottom) are contributing to my chain-hitting-the-pan problems? I guess I'll find out tonight when I look at the cam sprocket.

Thanks again - hey, this is the 1st "flaming" thread since December!

__________________
Bill Streep
San Antonio
'57 190SL (toy)
'08 S5500 (mine)
'09 CLK550 (wife's)
'06 SLK350 (daughter's)
'11 GLK350 (daughter's)
'03 CLK310 (spare)

Changing the bottom timing sprocket on the car should be real fun. As I recall, the timig chain cover whould need to be removed which would require pulling the chain guides. Could be done on the car but a lot of work.

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Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

OK, looked at everything last night. Cam sprocket looks brand new. Flat spot on the top, you can still see the ridges in it from where it was ground. From the "looks" of it, it really looks like it was just put in the engine. Put NGKs in it gapped to about .27 last night. I should get some good runs in it this weekend. See how long these last and how it runs. Thanks again!

__________________
Bill Streep
San Antonio
'57 190SL (toy)
'08 S5500 (mine)
'09 CLK550 (wife's)
'06 SLK350 (daughter's)
'11 GLK350 (daughter's)
'03 CLK310 (spare)

Woodruff keys are available for corrections of 4,61/2,8,and 10 Degrees. With this selection and the fact that a chain link is 18 degrees,you can correct any timing problems.
Bill Lewallen

Bill,

When I talked to Star Quality, they told me 0 - 5 degrees in even increments... They are sending me both 4 and 5 degree offsets (at about $4, why not...).

__________________
Bill Streep
San Antonio
'57 190SL (toy)
'08 S5500 (mine)
'09 CLK550 (wife's)
'06 SLK350 (daughter's)
'11 GLK350 (daughter's)
'03 CLK310 (spare)

Bill Streep, and others,
Mercedes parts has four off-set keys. Your dealer may have to order them. Few people use them. If the timing is off, the owner is told he needs a new chain and their goes $600 when a $4.00 off-set key would have corrected the timing.
The available keys part number is as follows:
621 991 04 67 0.7mm. 4 degree correction at the crankshaft
621 991 02 67 0.9mm 6-1/2 deg. correction at the crank.
621 991 01 67 1.1mm 8 deg. correction at the crank.
621 991 0067 1.3mm 10 deg. correction at the crank.
With this combination of off set keys and the fact that a chain link is 18 degrees, you should be able to get the timing exact. Good luck..
Bill Lewallen Lexington,Ky.

Bill Streep, and others,
Mercedes parts has four off-set keys. Your dealer may have to order them. Few people use them. If the timing is off, the owner is told he needs a new chain and their goes $600 when a $4.00 off-set key would have corrected the timing.
The available keys part number is as follows:
621 991 04 67 0.7mm. 4 degree correction at the crankshaft
621 991 02 67 0.9mm 6-1/2 deg. correction at the crank.
621 991 01 67 1.1mm 8 deg. correction at the crank.
621 991 0067 1.3mm 10 deg. correction at the crank.
With this combination of off set keys and the fact that a chain link is 18 degrees, you should be able to get the timing exact. Good luck..
Bill Lewallen Lexington,Ky.

Wow, Bill, thanks, you saved my tail... Called up Star Quality, and had them look into the part numbers. Sure enough, their 1,2,3,4,5 degrees is at the CAM, and not at the CRANK. They looked in their notes, and sure enough the note said this translates to 2,4,6,8 & 10 degress... So I ordered a 4 and a 6. That way, when I make my "final decision" I can decide if it's really closer to 4 or 6. This is getting REALLY nitpicky - Any opinions as to whether I should go 1 over or 1 under... ;-)

Thanks again, everyone.

__________________
Bill Streep
San Antonio
'57 190SL (toy)
'08 S5500 (mine)
'09 CLK550 (wife's)
'06 SLK350 (daughter's)
'11 GLK350 (daughter's)
'03 CLK310 (spare)

Bill and others,
I doubt if you(or your engine)will be able to tell if the timing is off one degree,plus or minus.It could vary that match by the way you hold your head when you read the marks on the crankshaft.To get the timing exactly on the mark you need to us a dial micrometer and a graduated disk attached to the camshaft gear.Don't worry about your timing. You will be okay doing what you are doing.
Bill Lewallen Lexington,Ky...