Quick question about 1990 300SEL - PeachParts Mercedes-Benz Forum

nickofoxford · #1 06-08-2009, 03:07 AM

Quote:

Originally Posted by pawoSD

A V8 W126 with an original chain at those miles should have it replaced immediately, along with the guides. Its a time bomb at those miles. Ideally they should be replaced every 100-120k.

On hilly roads you'd get annoyed by the M103 in a W126.....its a revving engine....not big on torque....up in the 3000-6000rpm range its a blast, and can move the car very quickly.....but on takeoff and around town it does lug a bit. In the 300E its not an issue as its quite a bit lighter....but the W126 is heavy, torque is needed.

I sure hope it's not on the original chain then.. Stupid question, but the V8 uses one chain for both heads? Or does it require two chains? I've done the chain on my 240D, it was intimidating but I got the job done, how much of a PITA is it going to be on the 420?

Looks like i'd really want the M116, Im about done with the constant struggle and downshifting thanks to Betsy. I mean she's a great car to toy around in, but it's just not my style to always be turning down my tunes so I know when to drop it back into D

Thanks for your input pawoSD!

pawoSD · #2 06-08-2009, 11:17 AM

Quote:

Originally Posted by nickofoxford

I sure hope it's not on the original chain then.. Stupid question, but the V8 uses one chain for both heads? Or does it require two chains? I've done the chain on my 240D, it was intimidating but I got the job done, how much of a PITA is it going to be on the 420?

Looks like i'd really want the M116, Im about done with the constant struggle and downshifting thanks to Betsy. I mean she's a great car to toy around in, but it's just not my style to always be turning down my tunes so I know when to drop it back into D

Thanks for your input pawoSD!

Yes they use one chain, it runs up and down and across between the heads....it is a pretty long chain and there are a number of sliders/guides....which is why its so important that it all be in perfect shape, if a guide breaks off.....

I'm thinking it'd be a lot more of a pain than on the 240.....might be best left to a dealer.

Hit Man X · #3 06-08-2009, 02:55 PM

Chain failure itself isn't the issue, it simply stretches over time. This hurts performance as cam timing is off. Not a huge deal, but the guides are the key and the driver side ones are the ones that fail causing the big boom. There are three main ones at the heads on the M116 and one for the tensioner arm (you can replace just the sleeve on the arm to save a few bux), the lower guides really don't have issues. I would change them if you have the front cover off but not until then as it'll disturb the head gaskets.

V8 chain is easy to put in, I have the MB chain guide tool and chain crimper if you need to bum it.

The trans thing just senses ABS pulses to make it start in first gear, I'm not smart enough with electronics yet to give more in-depth information. I'm in process of teaching myself the intermediate stuff... I mean I can rewire, find drains, know the principals of alternators, etc, etc, etc.

nickofoxford · #4 06-10-2009, 01:41 AM

Quote:

Originally Posted by Hit Man X

Chain failure itself isn't the issue, it simply stretches over time. This hurts performance as cam timing is off. Not a huge deal, but the guides are the key and the driver side ones are the ones that fail causing the big boom. There are three main ones at the heads on the M116 and one for the tensioner arm (you can replace just the sleeve on the arm to save a few bux), the lower guides really don't have issues. I would change them if you have the front cover off but not until then as it'll disturb the head gaskets.

V8 chain is easy to put in, I have the MB chain guide tool and chain crimper if you need to bum it.

The trans thing just senses ABS pulses to make it start in first gear, I'm not smart enough with electronics yet to give more in-depth information. I'm in process of teaching myself the intermediate stuff... I mean I can rewire, find drains, know the principals of alternators, etc, etc, etc.

Sweet thanks for the offer! I might have to take you up on that, It would be my luck that I'd get the trade done with and a week down the road the chain goes. I don't know for sure yet if I really want to tackle the chain or leave it to a dealer.. At the same time I've seen some real dumba$$es working at dealerships. I'll sleep on it.

Electronics is nothing to be proud of knowing

I've been in votech schools for electronics for 3 years now (finally graduated this year). I mean if you're learning for automotive stuff it's great stuff to know, just don't take it up as a career choice

. It makes me want to be an Amish

nickofoxford · #5 06-10-2009, 01:32 AM

Quote:

Originally Posted by pawoSD

Yes they use one chain, it runs up and down and across between the heads....it is a pretty long chain and there are a number of sliders/guides....which is why its so important that it all be in perfect shape, if a guide breaks off.....

I'm thinking it'd be a lot more of a pain than on the 240.....might be best left to a dealer.

Agreed, Im not scared of doing it it's just more the "what if"..