[carsten svensson]

I had the valve covers off to check the valves on my 1975 450sl and I go to check the marks on the camshafts - and they are off by one tooth I am estimating. The car have had the timing chain and tensioner replaced a couple of years back so all of that should be fine. The question is - what is the best way of rectifying this? Short of redoing the timing chain? I was thinking of getting the chain joint over the left bank opening it at turning the camshaft before putting in a new chain joint? Assuming the slippage would happen on the left bank and this is an old issue before the chain replacement.

 

[CousinMB]

Hows the car running?
Any problems?

 

[H20ham]

Would some give more advance on intake, less timing?

 

[AlterSchinken]

I had the exact same on my 380. It was that way when I got it. The car seemed to run fine but I didn't drive it much in that condition. I removed the tensioner and was able to adjust the chain by one tooth, both marks then lined up correctly.

My guess is that it somehow jumped when starting at some point in the past. I have since replaced the guides and tensioner and so far it has been ok after 8k miles or so.

 

[carsten svensson]

Hows the car running?
Any problems?

It is running remarkable well, it idles perfect at 750 rpm. Maybe there is a little hesitation in the middle range and runs really well above 2500. My ocd tells me to fix this rigth away… and the voice of my mechanic granddad says if it ain’t broken don’t fix it. So now I will leave it to the forum

 

[Tom86951]

I would think you could ziptie the chain to the cam sprockets to secure the chain, then remove the tensioner, then carefully remove the zip ties (one at a time) to rotate the cam pulleys one at a time. Been a while since I replaced my chain but from memory, it seems like that would do it.

 

[RaceDiagnostics]

I don't think that has jumped a tooth, it's not off far enough, probably just wear and tear of the sprockets etc. These marks are estimates only. The only way to check your valve timing properly is to use the 2mm lift method outlined in the workshop manual.

 

[Tom86951]

I don't think that has jumped a tooth, it's not off far enough, probably just wear and tear of the sprockets etc. These marks are estimates only. The only way to check your valve timing properly is to use the 2mm lift method outlined in the workshop manual.

I missed the pictures on my phone, but agree now that you point that out. In my aging memory, a full tooth off was more obvious than that. Since it's running great and isn't obviously off, I'd consider it fine myself.

 

[Gogi]

First of all since you’ve already removed the left side valve cover I would, remove the driver side valve cover. Disable the fuel pump and ignition. You need to crank the engine so that the chain tensioner if filled with oil and extended to tighten the chain. Now turn the engine from the crank bolt in the direction of rotation of engine. Align the 0 mark on the crank pulley to the indicator mark on timing cover. Look to see if the passenger side cam mark is aligned on the cam if not turn engine to align that mark and check to see how close the driver side cam is to its mark. If all three marks are spot on you’re ok. If not you be a tooth off. With both cams aligned take a look at the crank reading and see what that says. That is how many degrees of stretch there is in your chain. With a new chain and guides and a MB tensioner you should be spot on 0 zero.

 

[KoboldWrangler]

looks fine to me.

 

[AlterSchinken]

I don't think that has jumped a tooth, it's not off far enough, probably just wear and tear of the sprockets etc. These marks are estimates only. The only way to check your valve timing properly is to use the 2mm lift method outlined in the workshop manual.

Mine looked just about like this with the RH cam off by one tooth. Unfortunately I didn't get a picture of it. The camshaft sprocket is 10 degrees/tooth. The washer where the mark is is about 44mm diameter, 10 degrees translates into approx 3.8mm at the circumfrence.

 

[RaceDiagnostics]

Ok so that is in your case, before the OP makes any assumptions, the correct way forward is to make the measurement as per the workshop manual. I can dig out pics of my engine looking just as bad at the pics above when there is no jumped tooth.

Best to make measurements not assumptions.

 

[carsten svensson]

Thanks to all! I went back and measured at I have 2mm so not a tooth but some stretch, I could do the w??? Insert, but maybe it is not worth it for just cruising around

 

[AlterSchinken]

Thanks to all! I went back and measured at I have 2mm so not a tooth but some stretch, I could do the w??? Insert, but maybe it is not worth it for just cruising around View attachment 2807881
View attachment 2807880

When you put the right side cam marks aligned, what do you read on the damper?

 

[RaceDiagnostics]

Thanks to all! I went back and measured at I have 2mm so not a tooth but some stretch, I could do the w??? Insert, but maybe it is not worth it for just cruising around

No need to worry. The workshop manual recommends that the valve timing is corrected (using offset Woodruff keys) after ~ 10k miles from new or after a new chain. However I don't know anyone, not even Mercedes dealerships who ever did this. Early chain wear/bed in stabilises after this time.

Also please note that the marks are approximately only and do not look bad at all. The pin on the water pump for example has at least a +-1 degree free play when being mounted.

FYI, here are some pics of my newly built engine which has perfect valve timing. New chain, new cam sprockets, new intermediate sprocket, new crank sprocket, new tensioner, new upper and lower guides etc.

US driver side.

US passenger side.

That's at zero miles from rebuild.

I'll dig out a couple of videos showing how to correctly determine your actual valve timing.

 

[RaceDiagnostics]