300E timing chain installation.HELP!
 

Hi everyone,
Here's my dilemma. My brother and I,mostly my brother are doing the head(valve guides[done by machine shop],seals injectors and seals,chain rails,fan clutch,fan). I also want to change the timing chain since we are at this point(the head is back on[with new head bolts], the rails are on, the injectors are in), he's from the school that the chain won't break. I have over 200k on tne motor. He says I'm being paranoid. I'm from the school of if we're there we might as well change it now do NOT want to get caught out there later and have to pay out my butt for something that should've been done earlier . He's being hardheaded. I ordered the chain and the tensioner, since he won't do it, I figured what the hell, I'll do it myself, the chains right there. Is this a hard change? Can I be walked through this process from you guys on the site? Does this chain have to be marked or lined up or anything like that? You guys haven't let me down before, this is why ask this of you:D:D. If this procedure is already in the achives I'll do a searh there.

TIA

For the cost involved, I would replace the chain. The parts are an update for 1986 300e engines which is a bonus. There is an oil pump chain and rails, too. This is an extra $15.00 from Fastlane. All told, the parts are about $200, right? Cheap.

FWIW, I just replaced both chains on my M103 at 240,000 miles and the new chains look "worse" than the ones I took off! If I had to do it over I would have left the chains and replaced just thr tensioner and guides.

I believe the procedure is in the archives. The procedure essentially involves breaking the old chain with a Dremel or small hack saw, connecting the new chain to the old chain, feeding the new chain by rotating the engine and closing the new chain with a special tool. The archives will tell you where you can rent the special tool and possibly a workaround.

Your borther has a point. The M103 timing chain failures I've read about were caused by other internal failures or foreign items inside the engine. They tend not to break on their own unlike V8 timing chains.

Good luck.

Sixto
91 300SE
87 300SDL
81 300SD

I'm from your brother's school:D

I had the opportunity that you had, but given the circumstances I passed and only replaced the tensioner guide and chain rail. My chain appeared in perfect condition, much like Capn's.

I figured, if it aint broke, why fix it? Too much at stake to mess up, and that crimp tool is a pain in the a$$ to find and is way too expensive to rent/buy.

As Sixto said, in almost all likelihood, only foreign matter will cause it to break (catostrophic tensioner/chain rail breakage), NOT the chain failing itself.

It's your call, but if the chain looks good, I wouldn't fool with it. It's a tricky replacement.

Good luck!

~Paul

_____________________
'91 300E, 210K miles

We do 103 head and timing cover reseals about 3-4 a month. These chains dont need to be changed . I always change the rails and reset the tensioner. Now if the car had a timing problem like said before here yes I would change the chain.In other words leave it alone, nothing wrong with these chains.:D

timing chain replacement
 

Thanks all for the reply. Looks like I'll leave the chain alone. I'm definitely not going to mention this to my brother though.

Tell him you thought about his sage advice and reconsidered your foolish notions. Then get him to replace the guide and tensioner while you watch :)

Sixto
91 300SE
87 300SDL
81 300SD

Now I hope that damn chain doesn't break and make us all look like idiots !!:D

Just my 2 cents....... for the cost of the chain, I'd do it. I know its a pain in the proverbial a** but, look at it as cheap insurance. If nothing else chains stretch and will throw the cam timing a bit which may or may not be noticable.

I've replaced several and found that it takes all of 20 min. to replace it once you are there. The oil pump chain oughtta be fine but, look hard at the tensioner rail for it and replace it if its worn. (odds are its grooved)

The big trick is cuttin the old chain off and I will use nothing more than a punch and hammer to breaked the old one. Stuff a rag to keep debris out of the oil pan

Joe