500E M119 timing chain rail replacement question
 

Hey guys,

I was working on getting my spare 500E motor ready when I noticed the top of one chain rail was snapped off - see attached photo. It's the upper, inside rail, the one which is the same on left + right sides, part number 119-052-11-16. My question is, what is required to replace these rails? I can't find the procedure anywhere in the W124 CD-ROM, nor the WIS. I assume it's one of those things that MB thinks is so simple they don't have to explain it, but for someone like me who has never done this, I could use a little guidance.

Do I just need to remove the camshaft gears / adjusters, pull the chain out of the way, remove the locating pins, and the rail pops out? I really do NOT want to pull the timing cover on this engine if I can avoid it. From what I can tell, there is only one rail that requires timing cover removal, and I'm going to hope that one is ok; and just replace the others. I searched both 500 forums and PeachParts, seems that most people either just replace the top rails (above the camshafts), or pay the mechanic to do everything. A couple folks pulled the timing cover and changed all of them but that's not in my plans for this motor right now - that's a separate project for next year.

If anyone has tips about how to R&R those inside/upper rails, and also the long curved rail on the passenger side, I'd greatly appreciate any assistance... thanks!


:euro:

To replace rails #8 & # 14 you must remove the upper cover on that side. also set motor at 45 deg BTDC compression stroke and pin & remove the intake cam gear.

MB Doc, thanks for the reply! I was able to pin the cams and remove the sprockets, and get all 3 chain rails removed from the head (the ones held in place with dowel pins). I've been taking photos and I'll update this thread with more info & pics when I get it back together.

One more question: Do the M119 chain tensioners really go bad? I thought the typical complaint of the "chain rattle" was almost always due to the faulty check valve in the oil filter housing (which I do plan to replace), not a bad tensioner. This is an early-build 1992 motor, btw, with 77kmi on it - the chain tensioner is original, it's date-stamped 1991. I've also heard there was a recall/upgrade to the original tensioners, but can't find any info on that. If you recommend that I replace the tensioner, is the aftermarket "SWAG" brand tensioner acceptable? I don't know if that is OEM or not. It's significantly less expensive than an OE tensioner from the dealer.


Thanks again!

:kid:

Hi,

It has happened to my engine at 90K. The parts are really very cheap- all you need is to take the valve cover off and replace the broken timing chain guide.

Anyway, all the replacement parts that I've seen are MB. I guess that it's best to make it a regular maintenance part- every 50K sounds good.

And, just has bad, are the cam oil tubes. 1992 and earlier engines have aluminum ones so there is no problem with them; later 119s have plastic ones and they definitely go bad- but you can get replacement ones make out of aluminum.

Attached is my engine with a replacement timing chain guide installed- and you can also see the oil tubes, too.

Peter C. Sessler

Hi,

I just realized that I hadn't answered your question! Yes, they go bad- look at how cheapo the original ones are. The high heat location makes them brittle and so they break.

Peter C. Sessler