Re: rough running 1987 560SL

Paul McKechnie wrote:
> Maybe the PO had the chain and guides changed as maintaince before it
had 
> time to cause a problem.

Yes, that is exactly what happened....apparently, those plastic guides 
go bad & become brittle with age, not just miles...and when they go bad, 
  a piece can break off & wedge itself in the timing gear & cause the 
chain to skip a cog.  I have viewed the receipts and the prev. owner did 
have the tensioner & the tensioner guide replaced as well along with the 
timing chain and guide.

I removed the spark plugs & checked compression.  Even though the 
compression is good, I noticed that one spark plug (#4 cylinder) was 
black & fouled.....I am wondering if this is oil fouled or carbon 
fouled...there is no oil on the spark plug, there is a bunch of bubbly 
flat-black stuff on it.  Any ideas ?

I am told that sometimes the rockers &/or cam lobe can go do to lack of 
lubrication.

Any ideas or suggestions would be great !

Thanks,

Brian
> 
> "Tiger" <tiger0002@[EMAIL PROTECTED]
> wrote in message 
> news:477a5516$0$13861$607ed4bc@[EMAIL PROTECTED]
> 
>>Agreed on timing chain... No way on such a low mileage. Going from good 
>>running car to crappy the next is most likely timing chain... probably
due 
>>to the fact that the tensioner probably never changed.
>>
> 
> 
>