603 - tensioner re-install... I hope I didn't screw this up - PeachParts Mercedes-Benz Forum

MercFan · #1 11-01-2010, 06:52 PM

I was in the process of re-installing the new tensioner lever into my 300SDL. The big hex bolt that connects the tensioner to the block... I have used the big 1/2 drive to tighten the big hex bolt - I wanted it snug but it felt like it gave in at little at the end... I removed it and inspected the threads... don't seen anything bad but I'm afraid to tighten it again. I HOPE and PRAY I didn't strip those threads!

Can somebody plz provide a quick spec for tightening torque for this big bolt?! Again, it's the tensioner that has the idler pulley and shock absorber installed to each end of it.

Quick help will be appreciated.

James

W124 E300D · #2 11-01-2010, 07:06 PM

it's a 16 or 18 mm hex from memory, spring one side and damper the other, that one?

It *is* a nasty one, everyone thinks they either cracked the block or stripped the thread, I don't know the factory settings, did both of mine by hand with a proper hex key and a ring spanner to lever until it felt right. I do know one person who broke the block.... so on that data point alone it appears that the block will fail before the threads...

My advice is watch it, open the bonnet every day or two for 3 months, if it hasn't moved by then you'll be OK.

jt20 · #3 11-01-2010, 07:11 PM

100 nm

the "bearing pin" ?

MercFan · #4 11-01-2010, 08:42 PM

I'm talking about this bugger in the photo below:

W124 E300D · #5 11-01-2010, 08:55 PM

That's the one.

I *think* from memory it's around 55-60 ft/lb

babymog · #6 11-01-2010, 09:11 PM

You did remember the big flat washer that was between the tensioner and the chain cover?

MercFan · #7 11-01-2010, 11:47 PM

Quote:

Originally Posted by babymog

You did remember the big flat washer that was between the tensioner and the chain cover?

Yes sir, I did... I'm thinking of using thread lock on that big bolt?!

compress ignite · #8 11-02-2010, 02:19 AM

1.Thread lock on the portion of the Bolt that fits into the Aluminum Timing Cover.
('Careful,don't want any of that Loctite into the Engine Oil)

[And Yeah,they're calling for "Clean thread and coat with sealant."]

2. A Timesert insert into the Timing Cover [Would be a Permanent Fix]
BUT you'd wanna R+R the Timing Cover to do that.The threaded Bolt hole
is open to the Timing chain cavity on the Inside.

[I feel for you,I was the Over Torque champion in Jr. High."What's a Torque Wrench and why would you need one?]

1 N-m = 0.737561 lb-ft
100 N-m = 73.7561 Lb-Ft

MercFan · #9 11-02-2010, 10:59 AM

Quote:

Originally Posted by compress ignite

A Timesert insert into the Timing Cover [Would be a Permanent Fix]

Thanks - what is the 'Timesert' insert?!

vstech · #10 11-02-2010, 11:22 AM

Quote:

Originally Posted by MercFan

Thanks - what is the 'Timesert' insert?!

http://www.google.com/search?q=Timesert&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US

fficial&client=firefox-a
similar to helicoil...

dablk1 · #11 11-02-2010, 07:03 PM

I used lock-tight on mine also. Not much, but just a dab. I also torqued it by feel. It actually came loose once after I didn't tighten enough and caused the fan to start hitting the tensoner.

MercFan · #12 11-02-2010, 07:24 PM

Yep, think I'm f&&&ed... tried to re-tourque the bolt and it went slack on me... it turned all the way around on me - I must have stripped the threads for good!!!

That's how you make a 1 hr task into a 3 month project

Could I use JBWeld to weld that bolt into the block? I know JBWeld is good stuff and it can withstand temperature, but I'm not sure if there is any amount of tension on that big bolt from that spring - I know JBWeld doesn't tolerate twisting and torquing very well... dang it!

It's not a good fix - I won't be happy with it but it may be the only thing that will get me back on the road... opinions, please?!

dablk1 · #13 11-02-2010, 07:33 PM

OUCH!

MercFan · #14 11-02-2010, 08:09 PM

Now that I have royally hosed myself - I think I see three options:

1) Use JBWeld to fix the bolt to the block - not a great fix but it MAY work temporarily

2) Remove the timing chain cover, drill and insert the 'Timesert' solution with proper thread into the damaged hole.

3) Buy and install a new timing chain cover... which reminds me - my buddy has a dead engine that he just removed from his 1991 2.5L 300D (602 engine). Will that timing chain cover fit my 603?!

Not a happy camper...

Billybob · #15 11-02-2010, 09:58 PM

Quote:

Originally Posted by MercFan

Now that I have royally hosed myself - I think I see three options:

1) Use JBWeld to fix the bolt to the block - not a great fix but it MAY work temporarily

2) Remove the timing chain cover, drill and insert the 'Timesert' solution with proper thread into the damaged hole.

3) Buy and install a new timing chain cover... which reminds me - my buddy has a dead engine that he just removed from his 1991 2.5L 300D (602 engine). Will that timing chain cover fit my 603?!

Not a happy camper...

The fourth option could be to drill and install the Timesert with the timing cover in place after either taking the valve cover off and putting a small cup down from above or removing the vacuum pump and timing device and putting a small cup from the side behind the hole to be drilled out and inside the timing chain chase to catch any drilling/tapping debris. From above you might have to separate the chain and take the sprocket off the cam to get as straight as possible shot down below. In reality any drilling debris will be aluminum and much less concern that if was steel. After drilling out the hole for the Timesert and tapping that, carefully pull the cup you installed to catch anything, with the side extension cover off the oil pan lay a clean rag onto the bottom of the sump, then you can use some kerosene or diesel to wash off anything that might have missed the catch cup from above and down into the sump where it can be removed as you pull the rag out after folding it over itself. After rinse the area down with the diesel or kero onto the rag, remove the drain plug and let that lighter viscosity fluid drain through the rag and out the sump drain, then you can reach in and fold the rag over itself to capture any debris between the top and bottom layers of the rag.

You'll still have to pull the radiator and probably the condenser, but you won't have to pull the balancer and the hub, or worry about the gaskets at the top and bottom of the timing case cover.

But if you do pull the cover you might as well change the guides, the oil pump chain/guide/spring, a new front seal as there'll be no better time!