What is the correct interval for timing chain replacement (86 300E). Should the tensioner or anything else be looked at/changed at this time? I am quickly approaching 200K km!
Thanks,
Nick

Replace chain, rails(?), and tensioner IMMEDIATELY.

Some say you can wait until you hear it, but you are risking bent valves or more.

100K Miles is the interval. Cost is $400-500. Depending on what other things you have done.

I've posted a note below from a fellow list member of his points.

Regard,
Eli

>>>>>>>I have a 1988 300TE and I changed the timing-chain (and sprocket;
tensioner; upper cam-cover gasket; valve-cover gasket; cam seal; &
updated the oil-tube) at about 115K.

I changed it out of FUD (fear, uncertainty, & doubt) & PM (preventative
maintenance), even though when comparing TDC on the crankshaft and that
on the camshaft it was less than 6-degrees off. I believe anything
greater than 6-degrees is the magic number, please someone correct me if
I'm wrong.

I got my parts through Randy Steele of European Parts Specialists
(www.epsparts.com / 805.683.4020) and his prices were very competitive.

I believe all the above parts came to *under* $250, with about $60 in
sealants alone (two different MB's sealants, silicone-based &
anaerobic). If you just do the timing-chain & tensioner, I bet you can
do it for under $125.

You will need to rent a chain crimper-tool as well (Randy has this).
Definitely get the factory manual, and study it. You will need another
person's assistance to feed the chain so it won't slip (my wife helped),
and remove the spark-plugs to ease turning the crankshaft in the
CLOCKWISE direction (during re-assembly coat only the spark-plug threads
with anti-seize paste & coat spark-plug boots with dielectric grease).

CAVEAT- mark position of cam-shaft sprocket when crankshaft-pulley is at
TDC. This will be your reference point.

Good luck,

:-) neil
1988 300TE
>>>>>

Thanks Eli,
I neglected to mention that this service has been done once before on my car by the dealer, several years ago by the previous owner. You mention "rails(?)"?
Nick

[This message has been edited by Nick Jamal (edited 02-14-2000).]

Hope you don't mind my asking a question or two along the same lines. I own a 1980 450SEL, 129k miles. I've never changed the chain etc. I have been advised by two very conservative MB mechanics that the weakest link in the chain, tensioner, rails is the tensioner. I will know that it is going when I hear what is basicly chain slap for a few seconds at cold start up and then it goes away. That is suppose to be the chain tensioner, that is normally tensioned one direction hydrauliclly from the oil pressure, now only being tensioned with an operating engine.

Although MB has never officially endorsed the 100k swap out, there are enough horror stories and recommendations from the MBClubA that prudence dictates that a FUD/PM based R&R is warranted.

I've had three different recommendations from three other MB shops:
#1 swap out the chain and tensioner. (least expsensive).
#2 Swap out the chain, tensioner and tensioner rail.
#3 swap out chain, tensioner and ALL of the rails (very expensive $2000+, very labor intensive since the front of the engine must be dismantled).

Okay, this is were I can't muster enough neurons to find the answer. What's the best answer? #2 seems to be the most prudent since swapping out the tensioner rail is a no brainer since the chain swap is happening at the same time and it doesn't require tearing the front apart. I know this is like starting a discussion about oil change intervals, lots of opinions, but thoughts and advice are welcome. Any long term MB mechs want to tackle this one?

S, J.R.
1986 280GE LWB
1980 450 SEL
1981 Volvo

Always replace the guide rails..
They become brittle with age .
I've seen them snap from chain whip and jump teeth.

First Hand!

So are you guys saying that with about 147K miles I should change the T Chain although i got the belt tensioner replaced at 133K ???

Mine is a double row chain which sheds a slightly different light. Or does it? Thoughts?
J.R.

JR
We suggest timing chain replacement with tensioner (MB OEM ONLY) at intervals not to exceed 100000 miles. We always replace the tensioner rail and the other 3 rails in the cylinder heads at the same time. These rails fail at least as frequently as the chain does and cause the same disaster. Should not run you more than $700.00 U.S. or so.