Timing chain and sprockets

[wisnia07]

Hello!

I'm rebuilding a 280sl engine and I'm wondering should I change the timing sprockets along with the chain.

Before I took the head off, the timing wasn't correct. When I've set the camshaft on it's marking, I was 8 deg. off at the crankshaft. That would mean that the chain is stretched a lot, and it should have destroyed the sprockets.  But when I took everything apart I was surprised how good the teeth on the sprockets actually look.

Below are photos of cam, aux and tensioner sprockets.  I wonder how bad does it look to you? Do you think they should be changed?

Thanks for any tips!

[ja17]

Inspect them all for damage or bad wear. Replace any damaged or badly worn. Change the crankshaft sprocket and the camshaft sprocket always, they are fairly inexpensive and get worked the most. The sprocket that drives the injection pump and distributor is good to replace also but can be pricey. The other two small sprockets are less critical. The new timing chain will last longer with good fitting sprockets. Each chain link equates to 18 degrees of timing. If your head has been cut, then your engine camshaft timing will automatically be a bit late. Off-set camshaft keys are available, but set-up is complex since you cannot use the "visual method" once off-set keys are installed. A new chain, should get you within a few degrees and that will be fine.

[Benz Dr.]

Those gears look worn out to me. When they're new the top of the tooth is about 3 mm wide and those are far from it.

[mbzse]

Those gears look worn out to me. When they're new the top of the tooth is about 3 mm wide...

To illustrate Dan´s comment, I offer this pic (borrowed off the web)

[Benz Dr.]

Yup. And the one on the right isn't as bad as some I've seen.

[wwheeler]

I had one on my 220SE that was almost pointy. Virtually no flat at all. Replacing that was a no brainer. And yes along with the new chain, made a huge difference in timing.

That is a great visual to see a new sprocket side by side with an old one. It really illustrates the point.

[wisnia07]

Thanks for your replies!

The picture with new and used sprocket was really helpful to assess the wear on the wheels. After seeing how the new wheel should look, I will change all the sprockets along with the chain of course.

Cheers!