Long story short, My my timing chain jumped quite a few teeth due to the camshaft teeth being worn out. So I removed the cylinder head to check for bent valves, and thank god they look ok.. But I will do a valve job since I already have everything apart.. Now my problem or lack of knowledge is that when the piston (Cylinder #1) is in the TDC position, the crankshaft pulley T/D mark is not aligned.. What are my missing here? see photos for reference.. Any feedback is appreciated because surely something is wrong, just can't figure out what it is... Thanks in advance..

 

Hi.

How many miles on your engine? Did you clean the piston tops already? They look to be in good shape.

Get some Acetone, and plenty of paper towels, and clean the piston tops. Replace the oil before you start the engine. You should do that regardless. Run the engine for a few hours, then replace the oil again. Or, say **** it. I'm not going to spend $30-$90 on the oil, screw the bearings and the engine!! :-)



Oh yea, turn the pistons over again, a full cycle. You're on the intake phase of the 4-cycle engine.








Check out the youtube video.
https://www.google.com/search?q=four...e+how+it+works

 

185 k miles. I just do not understand why when piston #1 is in TDC, it does not align with the Crank pulley markings..and yes I cleaned everything so i t looks pretty good. Before I remove the valves and do all that work, I need to understand if I have a defective crankshaft or not...

 

You're on the wrong stroke to check the alignment of the balencer. You need to turn the pistons over another full revolution.

However, what it looks like is that the balencer is off by ~30 degrees??
Where you have the piston now, the balencer should be 180 out of phase with the timing mark on the timing case.

If you turn the pistons over again, and the balencer mark doesn't line up zero, then it's likely that the outer ring has slipped.

The inner part of the balencer is bolted to the crank. Then, there is a rubber piece, then there is the outer part of the balencer that has the timing marks on it.

The outter rings of balencers slip all of the time. That's why racers, etc, will often out a white paint line between the outer ring and the inner ring. It shows if the outer part of the balencer has slipped.

 

Btw, the #1 piston is at TDC twice in the 4-stroke cycle.

Once at the start of the intake cycle.
And, once at the start of the power cycle.

You have the #1 piston at TDC, and the crankshaft at the start of the power cycle.

For the timing mark on the balencer and the timing case to align, you need to have the #1 piston at TDC, and the crankshaft at the start of the intake cycle.



FYI,
http://www.hotrodders.com/forum/tdc-...ke-205908.html

http://www.mgaguru.com/mgtech/engine/cs111a.htm

 

Note the the photos, look at piston #1 with the pulley at TDC

 

I don't remember any problem with my balencer like that.
Unless someone else knows otherwise, I'd say that the balencer has slipped, and you need a new one.

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this explains why my valves did not bend when my timing chain skipped..

 

I noticed the pdf you send me, at TDC on the pulley the piston is at the top. this was my worry because with my pulley at TDC, my piston is on the bottom of the cylinder... GREAT!!!!!

 

>My my timing chain jumped quite a few teeth due to the camshaft teeth being worn out.

Why did you say that your timing chain slipped?
Was it because of the timing mark on the balencer?
Did you have any errors or engine problems before that?

It seems like your balencer may have slipped, and you removed the timing chain and heads.

If your timing chain gears look fine (no missing worn teeth) and you didn't have any OBD-II errors, I'd say that the problem was a slipped balencer outer ring. That happens a lot on older high performance engines.

 

Correct, the balencer timing mark should be at zero when piston #1 is at the top, and the crankshaft is at at the end of the exhaust cycle and the start of the intake cycle.

 

oh, my intake cam sprocket teeth are badly grinded!! when I pulled the valve cover off, they were not aligned, i would say the intake sprocket was advanced at least 6 teeth! And the original problem was a loss of power, 3 days later would not start, then discovered the sprocket which I ordered a new one and a chain.. just siting here questioning the TDC on the pulley not aligned when the piston is in TDC before I continue

 

Btw, this comes up very often in forums where the engine has a separate distributor that goes into the engine.

Often the distributor needs to come out to change the intake, heads, cam, etc. So, people take out the distributor, don't keep track of how much and the direction they turn the crank, and plug in the distributor incorrectly. Then the car's timing is off, and the car either won't run at all, or runs like crud.

An older distributor I found quickly through Google.

 

More bad news. You'll likely need to pull the timing cover and change the gears on the crankshaft. Iirc, that ends up being even more of a pain, because of the balance shaft and that chain.

 

so I can not just align the cams with the pulley and get true TDC since there is another problem here, and you believe I need a new Crankshaft? IF thats the case, Id be better off finding a low miles engine or a rebuilt!! Not good for me

 

Surprisingly the gears on the crankshaft look great... I was thinking how reliable this car would be if I just remarked the new TDC on the pulley.. and aligned the cams with that... it would be all aligned, I just do not know if the crankshaft problem will progress.. And now I know why my car always vibrated on idle, I thought it was from bad motor mounts

 

That's good.
Did you check all of the teeth? If not, the timing chain gears on the crank shaft would need to changed. But, not the crankshaft.

I just thought of something. :-P
The metal from the camshaft gears had to go somewhere. They are in the oil pan. So, you really really really should remove the oil pan, make sure the oil pickup doesn't have have anything in it's screen pickup, and put it back together.

Otherwise, any piece of metal left in the oil pan would bang around and cause metal particles over time. How long it would take before the engine is garbage is anyone's guess.
With metal particles in the oil, that will score the crank and rod bearings, score the crank and connecting rods, score the camshaft bearings in the cam shaft housings, and score the bearings on the camshaft, and so on. In other words, the engine and it's parts would be scrap metal.

Fwiw, it might be easier to lift the engine with the head back on. Use bolts/studs on the exhaust and intake. Make sure that you do not gouge either the intake or exhaust making surfaces. Use an engine support (ebay ~$100), support/lift the engine (remove the engine supports).


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Thanks a lot, you gave me a lot of useful information... I need to order head bolts and the gadget kit and most likely a new harmonic balancer..Il let you know the results in a week or so when its done.. Thanks....

 

Good luck!

 

I found a picture of my engine that shows the correct relationship between the #1 piston and the timing mark on the harmonic balancer. See the attached picture.


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come across another problem, does the camshaft housing have a gasket? or just use the mercedes black silicone?
Anyone know this? can't wait to finish up here....

 

BTW, my harmonic balancer was defective, slipped about 120 degrees.. new replacement was ordered..

 

Yup, that's what I figured. I'm glad that you'll get that fixed.

 

That's a good question!
I really should do a FAQ for the M271 head gasket in January or so.

You must use MB Part number: 003989982010
Do not use anything else made by anyone else. If that gasket leaks, you'd need to remove the timing chain and cams again. Imho, do not risk getting a leak in 10K miles, don't cheap out.


Also, I know the industry pretty well. Fake parts are a very big deal. Such as, a large percentage of wheel bearings are fake! :-P

So, for many things, I buy only directly from a Dealer.
Sorry, Pelican. :-( But, I did buy over $1,500 of parts from Pelican.
Still, I bought $2,500+ directly from dealers (not including the new head and supercharger). Including that silicon.

On ebay, for ease of buying, I'll buy from mbofdurham.
http://stores.ebay.com/mbofdurham

Fro many parts, *I* like mbwholesalepartsonline.com. They are in NYC. I bought well over $2,000 in parts from them. :-O
Also, I've bought from southatlantamercedes.com.


I'm not saying any of those are the best, or the cheapest, or the fastest. I'm saying that from looking, I felt they were safe to buy dealer parts from. After a close inspection when I got the parts, I don't have any reason to believe that they are not 100% MB parts.
Although, the fakes cloners have gotten so good, even top Microsoft sales people and execs could not tell a fake Windows OS package from an original.

So again, imho, buy many parts only directly from a Dealer that you trust!


I also attached the document that says where to put the silicon bead and the bead width. Follow that exactly. Redo a bead if it's too wide, or off center.
Do a repair once correctly, and be done with it.

Also, you must get the head and the lower cam housing. 100% clean of any old material. MB lists a cleaner. I should've bought some.
It took me a few hours to clean the lower can housing. I used mainly Acetone on the mating surface, a "sharp" 5-in-1 Home Depot scraper to clean the sides (it's my go to tool for gasket material removing. I'm familiar with it, and I can control the pressure accurately).
Still, near the timing chain cover legs, I had some silicon left on the lower cam housing. Arg! I used a new sheet of 2000 grit sandpaper - do not "spot sand", sand over a long wide area.


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