SL/R107: timing chain
Thread Starter
Member
Joined: Dec 2011
Posts: 109
Likes: 0
From: Toronto
CL55, S550, 450SL
timing chain
Is it necessary to change the timimg chain on my 1980 450SL with 126,000km as preventative maintenance? I think it is a double chain but have yet to take off the valve covers to confirm.
If so, do I need to replace the cam sprokets as well?
Is IWIS a good brand of chain?
If so, do I need to replace the cam sprokets as well?
Is IWIS a good brand of chain?
Senior Member
Joined: Jan 2010
Posts: 330
Likes: 26
From: Middle of Nowhere, USA
450SL
It is double row. IWIS is OEM so it is fine.
Pull the valve covers. Line up the right side cam marks (US passenger side). Check the left cam marks. Look at balancer to check where the timing marker is. If more than 8 degrees off zero replace chain. The main thing that causes failure is a broken upper guide rail. At this mileage they need to be changed. The tensioner is probably also weak. Replace it. After market cam gears are around $30.00 each so why not change them.
Pull the valve covers. Line up the right side cam marks (US passenger side). Check the left cam marks. Look at balancer to check where the timing marker is. If more than 8 degrees off zero replace chain. The main thing that causes failure is a broken upper guide rail. At this mileage they need to be changed. The tensioner is probably also weak. Replace it. After market cam gears are around $30.00 each so why not change them.
Senior Member
Joined: Jan 2010
Posts: 330
Likes: 26
From: Middle of Nowhere, USA
450SL
Up to you. That is the suggested limit. I would go ahead and change it while you are doing the job. Also replace the cam oiler tube plastic fittings. There are sites with DIY info, including pictures and video.
