Ticking time bomb balance shaft M272

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Here's the comparison between knackered ones and new ones.... View attachment 86273 View attachment 86274


I recently purchased a CLK 350 with a balance shaft issue not that i new at the time , your Balance sprocket still has teeth ! when i removed mine the teeth were completely gone !

I purchased a kit , it came from the states with all the parts need to change the shaft although didnt include the timing chain so i got one of those here

im just about finished repairing the engine and hope to put it back in the car at the weekend

its not a difficult job to repair it , although having the right tools helps, its definitely a diy job if your confident with engine work , and of coarse taking the engine out !!

ill post up a picture later of my balance shaft so you can see how worn it is
 
I like the sound of this! - I don't really have any way of taking the engine out, but I think I'm competent enough with tools to pull the front cover off, lock the cams, swap the shaft, and stick it back together.

If it's not too much hassle, can you post some links to the parts you bought?

The bad news is that if and when I need to change mine, you're now going to get pestered for information and advice.
 
Thought you have to get to the rear of the engine to get at the balance weight attached to the other end of the shaft.
 
If the car is OK apart from the suspected balance shaft issue, do count on the cost
and make the deal if it is within your wallet. Then put aside the amount needed for repair.

It could still be a good deal.

The only way to think about this is to expect the worst and act accordingly.
 
320 still has a balance shaft but I presume they are more reliable engines but with less power and less gears? It's only a Sunday summer car for the Mrs but we don't want a 4 grand paper weight sat on our drive. Anyone know of any mechanics in Yorkshire who have done the balance shafts? May consider if I'm satisfied the work can be done without stealer labour charges as happy to do some spannering myself? Never had issues with our old slk.

The M112 Engine (3.2 and 2.6L V8) is very strong and smooth with (certainly for the 3.2) strong low down torque. They do use the previous generation gearbox and yes it does have fewer gears (5 against 7) but again the gearbox is very strong (it was used in many of the 500 plus hp high torque AMG models) and smooth.

Performance wise there would be virtually no difference in day to day driving with the 320 Vs a 280, as always, buy on condition.
 
There is obviously either a design or materials quality issue with premature timing chain/sprocket wear. I have an M271 engine with similar concerns about cam drive wear although thankfully it doesn't have a balance shaft at all.

You can't cure the above problems through choice of oil but there is some consensus that soot in the oil causes chain wear and stretched chains wear the sprockets. My response to that is more frequent oil changes which is cheap insurance and for me it's easy as I only do 4-5000/year. What I definitely wouldn't do is exceed 10,000 between changes. I think MB's previous regime of 15,000 miles and up to 2 years was madness.
 
All cam chains wear and need replacing at some point but it seems the 3 valve heads as longer lasting and a better bet at higher mileage. Had the design been better the replacement cost labour wise would have been more reasonable. I'm looking for a 320 now.
 
Check out the teeth on mine
 

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I like the sound of this! - I don't really have any way of taking the engine out, but I think I'm competent enough with tools to pull the front cover off, lock the cams, swap the shaft, and stick it back together.

If it's not too much hassle, can you post some links to the parts you bought?

The bad news is that if and when I need to change mine, you're now going to get pestered for information and advice.


It’s straight forward really I think some of the hardest parts to do are getting the power steering pump off and some of the bolts on the bell housing
Apart from that a engine hoist and engine stand , and take your time , take it apart , fit the new bits put it back together
Get a good impact for the crank pulley that thing is in there tight !!

I’ll check which supplier the parts came from , it was on eBay USA , around £400 genuine parts kit shipping tax’s included
 
Performance wise there would be virtually no difference in day to day driving with the 320 Vs a 280, as always, buy on condition.
True enough. - The 280 will reach peak torque sooner, and hold it for longer (due to variable valve timing)... but power-side they're about the same (the 280 is technically ~10bhp higher).

Other than the balance shaft, it is an improvement over the M112.
 
Well Ive just put down a deposit on a 2005 Black with cream 320 cab. Looks very nice but needs a few jobs sorting. I noticed oil on both rocker top boxes and coils to fix. The wheels and tyres are a little poor as are the front discs but I can sort them. Until I get it home next Saturday I won't know what else will need work but hopefully not too much. I paid the same as the 280 I looked at but think it's only 1 year older and in better nik too same miles. Cheaper to tax hopefully too.
 
Welcom to the CLK club! I bought a low mileage 02 320 back in March and am pleased with it so far. I did have the dreaded crank position sensor go but at least it got me to where I was going.

The engine is nice and smooth and seems to have plenty of grunt if required, which isn't often in my case. I bought it mainly for long M way trips and I am impressed with the lack of wind noise. I expected the window seals to be tired but they seem fine. It may be 17yrs old but still nice on a long journey, which it will be having again tomorrow.

LG.
 
Welcom to the CLK club! I bought a low mileage 02 320 back in March and am pleased with it so far. I did have the dreaded crank position sensor go but at least it got me to where I was going.

The engine is nice and smooth and seems to have plenty of grunt if required, which isn't often in my case. I bought it mainly for long M way trips and I am impressed with the lack of wind noise. I expected the window seals to be tired but they seem fine. It may be 17yrs old but still nice on a long journey, which it will be having again tomorrow.

LG.
What's the crank sensor issue then? Now I'm wanting to check that out?
 
What's the crank sensor issue then? Now I'm wanting to check that out?

As said, the Crankshaft Position Sensor is a common failure on these engines especially at higher mileages. Symptoms are non starting when hot although it can also happen with a cold engine or misfires.It usually produces a fault code

If it happens then buy the MB Part and not a cheap aftermarket one, the only issue when they fail is that they are difficult to get to (situated at the back of the engine just above the gearbox housing) and can also be stuck in place.

I had one fail on my previous C320 at 150,000 miles, the part was £104.
 
What's the crank sensor issue then? Now I'm wanting to check that out?

Oops, didn't mean to be alarmist there. It's something that isn't even marque specific, let alone model. I had one go on an old Citroen CX.

I had read about it during my researches so wasn't too surprised by it. I've no idea if it's high mileage, age or a combination of the two which causes them to throw the towel in. My car only had about 52K on the clock.

Any half competant mechanic should be able to change one, unless it's well and truely stuck in. Admittedly, after 2 failed attempts myself I took it to an expert who had probably changed dozens of them. However, having watched him do it I think that I could do the next one myslef, (given long enough tools!)

And I may have to, because I bought a "cheap" one, albeit a Bosch one, so I could be sitting on a "crank position sensor time bomb!"

LG.
 
Ok thanks I know what they are and can change them so thanks for the head's up. Car starts ok at present! I would like to look at upgrades for the car as it's got the earlier style bumpers and other bits and bobs. Registered 2005 elegance without sat nav but not what options will retrofit? Not keen on the 17"wheel design.
 

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