Help!! Something bad happened! - PeachParts Mercedes-Benz Forum

244brick · #1 01-22-2013, 06:17 PM

1989 300e
Im changing the crankshaft vibration damper or harmonic balancer, whatever its called, and when I go to put the new one on, which seems impossible, the little metal pin (which is by far the stupidest design) pushed in and fell into the crankcase.
I guess my only option would be to drain the oil and HOPE it comes out. If not, rather than dropping the pan to retrieve it, i might run to the JY and see if I can find the one off the donor car I got the part from. Would I looking at any danger by leaving that little piece in there at the bottom of the pan?

So whats the trick to putting this thing back on, im a bit steamed at the moment, everything was going smooth until now.

Cheers in advance.

lorainfurniture · #2 01-22-2013, 07:00 PM

It should be fine. The oil pickup has a fine mesh screen. You can probably get it out by using a magnet and bring it closer to the drain.

Put a dab of grease or gasket maker to keep the key in place

Gilly · #3 01-23-2013, 07:35 AM

Copy and paste:

Curse you, W. N. Woodruff!

Late in the nineteenth century, a Connecticut inventor named W.N. Woodruff invented the Woodruff Key, a way to mate parts to rotating shafts. Mr. Woodruff came up with the ingenious idea of inserting a semi-circular key into a keyway cut longitudinally into a shaft so that a portion of the key protrudes as a tab from the keyway. The tab fits into a notch on a part placed over the shaft and prevents the part slipped over the shaft from freely rotating about the shaft.

Another benefit of this setup is it eliminates the need for expensive milling of an integrated tab into the shaft which concentrates stress. This configuration also helps to concentrically align the shaft and mated part which is critical to reducing wear and vibration in high speed applications. According to Wikipedia, the woodruff key is widely used in machine tools, automotive applications, snowblowers (but how widely used could that be?), and marine propellers.

How ingenious was this idea? Well…Mr. Woodruff’s invention was SO ingenious that in 1888 he was presented with the John Scott Medal by the prestigious Franklin Institute, where over the years many famous scientists have demonstrated groundbreaking new technology. For example Nikola Tesla demonstrated wireless telegraphy at the Institute in 1893, and in 1934, Philo Taylor Farnsworth gave the world’s first public demonstration of an all-electronic television system.

(end copy and paste)
So stop slamming the Woodruff key. IT has been around a lot longer than you! LOL.
If you drain the oil you could also use a magnet on a long flexible wand to try to fish it out. I don't think it would come out with the oil. You could also put in a magnet drain plug if you can't fish it out.
I find that by keeping the forward part of the the key a little low (angled slightly towards the front of the car) it might stay in place better.

daddi · #4 01-23-2013, 08:04 AM

Drain the oil and use a telescopic magnet to retrieve the key.

RPM55 · #5 01-23-2013, 10:57 AM

You need to do whatever it takes to find that key. You don't want to leave it in the engine thinking it won't cause any harm. Like a previous reply mentioned there is a fine screen on the oil pump pick up, but after that key swirls around and bounces against that screen it will eventually get sucked through the screen and cause the oil pump to self destruct. It may not happen tomorrow or next week but it will happen eventually.

I have seen this happen several times over the years and it is not pretty.

Good luck, Robert

244brick · #6 01-23-2013, 01:39 PM

My frustration was the culprit for the shunning of the woodruff key haha. Fact noted, I had assumed it was designed like that for a reason lol.
Anyway thanks guys for the helpful advice and wisdom. Im going to go buy some magnets.

whunter · #7 01-23-2013, 02:58 PM

Quote:

Originally Posted by 244brick

1989 300e
I'm changing the crankshaft vibration damper or harmonic balancer, whatever its called, and when I go to put the new one on, which seems impossible, the little metal pin (which is by far the stupidest design) pushed in and fell into the crankcase.
I guess my only option would be to drain the oil and HOPE it comes out. If not, rather than dropping the pan to retrieve it, i might run to the JY and see if I can find the one off the donor car I got the part from. Would I looking at any danger by leaving that little piece in there at the bottom of the pan?

So whats the trick to putting this thing back on, im a bit steamed at the moment, everything was going smooth until now.

Cheers in advance.

The slot needs to be on the top position.
Yes, you must retrieve the woodruff key.
The danger of leaving this key in the oil pan is the oil pump CHAIN, if it gets between chain and sprocket = the torque will BREAK the oil pump.

Here is what happens
http://www.peachparts.com/shopforum/3020702-post49.html

http://www.peachparts.com/shopforum/diesel-discussion/324783-1992-300d-2-5-vacuum-pump-failure-ball-bearings-fell-into-timing-chain.html

.

Rob Pruijt · #8 01-23-2013, 06:35 PM

I use a little drop of Locktite to fix it.

Clean the slot, put a drop of locktite in it and press the key down and hold in position.
Apply the locktite with a small screwdriver to prevent using to much.

Rob

244brick · #9 01-27-2013, 04:05 PM

I have retrieved the woodruff key!

After dropping the pan because my drain plug is seized! IMPOSSIBLE TO REMOVE.
Anyway...
Locktite was an excellent idea. I just have one question, I cant seem to find my torque wrench... I know its something like 220lbs but can I get away with using a breaker bar until it feels tight enough to function properly?

Rob Pruijt · #10 01-27-2013, 05:38 PM

If you mean the hub (big central bold) it is 300Nm /220lb ft.
This is a lot, nearly 3 times the torque of a wheel bold.

If you can do it without a torque wrench depents on your skills.
Torque wreches should be checked regulary, most are not very accurate.

Rob

compress ignite · #11 01-27-2013, 07:25 PM

That I'd Not Even try to "Non Georgia Tech approved Engineer it".

If the FSM calls for 220FtLbs ...That's what you should give it!

whunter · #12 01-27-2013, 09:30 PM

Quote:

Originally Posted by 244brick

I have retrieved the woodruff key!

After dropping the pan because my drain plug is seized! IMPOSSIBLE TO REMOVE.
Anyway...
Locktite was an excellent idea. I just have one question, I cant seem to find my torque wrench... I know its something like 220lbs but can I get away with using a breaker bar until it feels tight enough to function properly?

Glad you got it out.

The bolt torque is critical.

.

244brick · #13 01-27-2013, 09:37 PM

I used a breaker bar with a jack handle on the end and cranked it til it couldnt go anymore.

The tensioner tighted the belt, but i cant get the 19mm bolt to thread... i think its shot.