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How to check timing chain stretch on a V12?

2147 Views 5 Replies 3 Participants Last post by  pcmaher
I'm looking for some "easy" ways to check timing chain stretch on my 95 S600 (140,000 miles). I do not know if the timing chain was changed on the car, and have no way of finding out. I was having trouble with my beater, a 1987 Olds wagon with a 307 V8. I suspected timing chain problems. So I removed the distributor cap, and hand-turned the crank the opposite direction while watching the distributor rotor. The rotor should rotate almost immediately if the timing chain is in good shape. On the beater, it didn't. There had to be at least 20 degrees of crank rotation before the rotor began turning. Disassembly confirmed an incredibly stretched chain and worn cam sprocket. Can this method be used on the V12? Are there any other methods I can use? I'm trying to avoid as much disassembly as possible. I'd sure appreciate a good tech's advice / opinions.
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Do not rotate the crank in the oposite direction on a V12, Big problems if you do...I have seen a posting dealing with that situation and the effects..Not at all pleasant..

And the V8 engine is an entierly different beast...

There is a way to do it with a twin beam scope using the flywheel sensor and the cam sensor.. and looking at the trace... however I am sure that the engine adaptive system will have compensated for any stretch you might have..So possibly the best way would be to get MBstealer to get you the printout and have a look..
If you can find a friendly MBstealer.. he will be able to tell you if that chassis number ever had chain parts assigned to it.. here in the UK I understand that MB keep records of all the replacement parts fitted to our cars..That way they have a complete history of manufacture..That is why a MBdealership will always ask you for your vin number when ordering parts..
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