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After picking my car up from the second shop in a row that couldn't do the job b/c they thought they had the tools but didn't, and talking to 8 other Indy shops that can't replace the chain/tensioner b/c they don't have the tools for an M271, I sit down at the dealership to which I'm told by the SA that the timing chain's "unserviceable" because it's functioning. They only do the job once the chain jumps time and costs thousands.
They always ask me the same question, "Why replace it if it's working?" If it wasn't for the few people on this forum whom I've read had this problem, I'd be getting pretty unsure of myself for wanting to do this as 'maintenance' which seems crazy to every mechanic I've talked to. If this is such an important thing to do, why has NO mechanic in South Western Florida ever done it on an M271? Do M271 owners just drive the car until it breaks and sell it for scraps, or does everyone know how to DIY even though it's complicated as ***** and requires expensive tools? Super pissed about the whole process of this procedure right now.
You can probably find one cheaper somewhere else, but the basics of the process is:
1) take off airbox and cover
2) take off ignition coils and plug wires
3) remove valve covers to expose cams and timing chain
4) loosen chain tensioner
5) manually crank the engine (be sure you don't crank backwards!!!! very important) until you get to the point where the chain is bolted together
6) once you unbolt the chain, you hook one end of the new chain onto it and keep manually cranking the engine pulling the old chain out until the end of the chain comes out the other end, then you connect the chain together. This is where it gets tricky and I don't know the exact instructions, but you will need to use the camshaft alignment tool and crank the engine to align everything together. If you have access to the STAR manual it will give you more specific instructions and specifications on how to align everything.
It can be done. You may have to just DIY it yourself, but man that cam alignment tool is a lot of $$$$
In the industry I work in (not automotive), there's been a major brain-drain. I've been at it for 9 years and in that time a lot of the intelligent and experienced individuals have left or been pushed out. It's getting tough to find anyone who knows what they're doing and when I do, I find it to be a refreshing surprise. The products used in this industry now cater to this new dumbed-down norm.
Is the same happening in automotive repair?
BTW, here is the KillerPancake approved cam alignment tool (worked like a charm!!). I'm not a mechanic and I did my own timing chain. Any indie who claims to know Benz should have no issue doing this job and be happy to take some $ for it.
$680 later... it's done BUT I don't know. Some tubing keeps popping out that makes it feel like it's about to stall out, so I have to pop the hood and put in back. I'll get something to get it to stay in place, but still. I swear the car sounds different too, I don't remember the engine vibrating, but it does now. Maybe it did, but I feel like something got phucked up during the procedure and it sucks that this is the guy's profession. I actually don't think it's a brain drain as much as guys just not giving a *****.
I replaced the timing chain and cam gears this weekend past. An I have also noticed that the engine sounds different (except for the absence of chain rattle on startup, that is) The engine seems to have a deeper sound at lower revs when the gear changes occur. Is this your experience also?
I am planning to recheck the cam timing this weekend.
Last edited by leonrsa; 10-15-2014 at 06:42 AM.
Reason: Add info
No special tools needed. They will help, but aren't required. If your hearing the "rattle" on start up, change your chain NOW. I waited until it jumped time and bent valves. You want to talk about expensive.....
No special tools needed. They will help, but aren't required. If your hearing the "rattle" on start up, change your chain NOW. I waited until it jumped time and bent valves. You want to talk about expensive.....
My chain jumped when I started the car. I suppose I was very lucky as there were no bent valves
I replaced the timing chain and cam gears this weekend past. An I have also noticed that the engine sounds different (except for the absence of chain rattle on startup, that is) The engine seems to have a deeper sound at lower revs when the gear changes occur. Is this your experience also?
I am planning to recheck the cam timing this weekend.
Interesting observations. Mine seems to sound identical as it did before... Only difference is I notice it a bit smoother now, but I had to replace the crank damper so its most likely due to that.
2017 GLA 250, 2011 C63 P31 (p30 w/ lsd) (in repair), 2005 C230 Sport Eurocharged, 2003 C320~sold
Check and make sure your balancer 0|T mark is lined up with the keyway. If it's not your balancer is no good and the car is out of time. This is what happened to jpman but his was about 60° off so couldn't even spin the engine. You have to pull the crank bolt out to do this and retorque it if everything's fine.
You should post a video so that we can see what your saying. There is a slight chance that your timing is off. If the timing was right before the timing chain job and when they replaced it they left it right, there should have not been a change in how the car behaves or sounds...
I replaced the timing chain and cam gears this weekend past. An I have also noticed that the engine sounds different (except for the absence of chain rattle on startup, that is) The engine seems to have a deeper sound at lower revs when the gear changes occur. Is this your experience also?
I am planning to recheck the cam timing this weekend.
Recheck tdc mark with top of piston at compression stage. My pulley had moved position and I had to replace it. If this is a similar case, your timing could be off. The engine should have not changed behavior assuming your timing was right from the beginning.
After reading about the problems jpman had I am definitely checking if the pulley is correctly aligned with TDC.
Some observations: (Some of this may be obvious)
When I adjusted the can timing after I replaced the gears I found that for each tooth the chain is moved on the gear the crank moves by 20degrees.
The chain tensioner must be installed before checking / adjusting the timing of the cams.
The engine must be rotated in the normal direction of rotation to take up any possible slack when checking the timing.
And lastly, a new chain can easily be pulled through by joining it to the old chain and rotating the crank pulley (carefully!) without the cams rotating. If resistance is encountered, the cams can be turned about 90 deg and you can continue rotating the crank. Once the chain is through turn crank to TDC, align cams with timing marks and crimp the new chain together.
You should post a video so that we can see what your saying. There is a slight chance that your timing is off. If the timing was right before the timing chain job and when they replaced it they left it right, there should have not been a change in how the car behaves or sounds...
Okay. Here's the video- cold start in my one-car garage. It sounds deeper than it was b4 the timing chain/tensioner replacement. The deep sound lessens as the video goes on. Does it sound like the timing is off?
Okay. Here's the video- cold start in my one-car garage. It sounds deeper than it was b4 the timing chain/tensioner replacement. The deep sound lessens as the video goes on. Does it sound like the timing is off?
That doesn't sound too bad. But then it might sound different on the video than in real life...
I would check the valve timing for sure - it is so easy to be 20 deg out (1 tooth)
u might be right. I got a battery/starter light come on about a week ago, but didn't come back on. So how do I know if I need a new battery or starter?
Check the battery voltage after car has sat overnight (via dyno mode or with a voltmeter).
Below, say, 12.2v, means it's getting there.
Then I'd try to give it a charge for a couple of days with a battery charger and see how it holds the charge afterwards etc.
See the pic: http://4.bp.blogspot.com/-3I_NhSukbM...teofcharge.png
09-09-2014, 12:55 PM
) The engine seems to have a deeper sound at lower revs when the gear changes occur. Is this your experience also?
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