Where'd the Woodruff Key Go? - PeachParts Mercedes-Benz Forum

gmog220d · #1 06-02-2015, 07:24 PM

616.916, '74 240D.

In typical fashion for me a simple job turns into something more. I was installing a offset woodruff key between the cam and gear and it popped out when I was placing the gear back on the cam for a momentary break. For the moment the whereabouts of the key are unknown.

The key wasn't all the way down in the slot - needed my small brass hammer to tap it down. I wanted to hang the gear on the end of the cam shaft without pushing it all the way home, just so I could go across the shop to get the small brass hammer, leaving the key wedged into the top of the slot. Of course, the gear slid all the way back and in the process pushed the key up and out of its slot. I had a bunch of paper towels stuffed into the opening to prevent stuff from falling into the engine . . .

When the key popped out it appeared to go back and fall between the #1 and #2 intake runners, down over the exhaust runners. AC compressor and bracket are out, so I can see pretty well on that side of the engine. It ain't on the floor. It ain't anywhere on the engine that I can find after about 3 hours of searching. I can't find it on top of the sub frame or any suspension parts. I blew air around seeing if I could blow it out - nada. I swiped the magnet on a stick around various places - nada.

So I'm wondering if it fell into the engine. Before pulling the paper towels out I looked around them to see if there was a way the key could have gone down into it. On the RH side, LH looking rear, there was a bit of a gap between the towels and the opening down into the engine behind the cam gear, right above the top of the tensioner and its rail. Hmm . . .

I pulled the gear again and held it off to the side opposite the tension rail and pulled the rail over to provide a view down the backside - nada but I can't see all the way down. After putting the gear back on I looked down the middle, all the way down to the crank gear and inner slide rail. No key visible down there. I ran the magnet on a stick down all the places I could get it and nada.

I pulled the lower oil pan to see if it had fallen in there - nada. I fished around with some wire up in the area around the crank gear and got nothing.

Engine cranks by hand (socket on crank pulley nut) 360 degrees at the cam without binding.

So where could it be? Best I can think is that if it fell down into the engine it would be on the back side of the tensioner rail, down where I can't see it or get to it with the magnet. Could also have bounced along the floor and ended up under something way off to the side of the car, though that seems unlikely. Sitting on top of something in the engine bay, on the manifold side, somewhere still?

Has anyone else dropped a woodruff key or similar sized object down there? Where did it get caught? What'd you do to extract it?

At this point I ain't cranking the engine without knowing where the damned key went. Curious to get other ideas/opinions.

EDIT: Looks like I need to pull the tension rail to get into the area behind it, if I don't find the key laying on the ground in the morning. Shop floor is clean all around the car, BTW. I've looked high and low to no avail.

TnBob · #2 06-03-2015, 09:40 AM

Maybe get a 2nd key and intentionally replicate your prior actions, this time watching where it goes. Maybe paint it brightly too !!

gmog220d · #3 06-03-2015, 11:03 AM

Thanks for the suggestion, TnBob. I could do that with the straight key I still know the location of (installed between the cam and gear).

I've played it all back best I can many times. Funny how unclear memory and perception can both be when you're not expecting something to happen a certain way. Only clear thing for me is that I didn't hear it hit the floor. Primary lesson learned is to use the bungee to hold the gear and chain back so I have both hands to putz with other stuff. That would have prevented this situation.

So enough time wasted looking around the floor and engine bay. Today I will use a more methodical approach, and eliminate the engine as the woodruff key's hiding place first. Seems like there are fewer places it can hide in there, and is thus easier to eliminate. And if I don't find it in the engine I ain't wasting anymore time looking for the lost key, which will probably show up in the middle of the floor after I've got the car back together and running. :-)

I've decided to go ahead and pull the tension rail out right off to verify that the key didn't fall down into the space behind it. This seems the most likely area for it to have ended up in if it went into the engine on the side I last saw the key on. With the rail out I should be able to see down and probe into that lower corner just fine.

If it had fallen down in the space by the crank gear and inner slide rail it would have been caught between the chain and gear when I cranked the engine over, or picked up by the magnet on a stick. As for it getting into the space outside the outer slide rail, seems unlikely. It would have to have been forced past the edge of the chain to get out into that area.

Onward . . .

gmog220d · #4 06-03-2015, 05:42 PM

First, mis-described where I think I saw the key fall. It went between the thermostat and intake, down over the #1 exhaust runner. At least that's where I think it went. Still haven't found it.

But after spending time with the engine today I am almost certain that the key is not in the front of the engine. I didn't have to remove the tension rail after all. With better light and fresh perspective I was able to see up into the lower portions of the galley and probe more with some wire. There's really no way a key could stick up there as all the surfaces are sloped. I was able to check pretty good on both sides of the crank gear/chain. Also with better light, looking from above, I can see that the key isn't in there either, down in the middle nor on the backside of the tension rail. I hear nothing odd when I crank it over by hand.

I was tempted to pull the front main seal to have a look in there, but I felt like I could see in there good enough from below without doing that. There's really only so much room in there and something the size of a woodruff key would get pushed around and spit out, I think.

Where is it? Who knows. I spent a little more time looking around the engine and the bay. Looked around on the floor again. Nada.

Anybody have anything to add? Something else to consider before I put it back together and fire it up?

Parts to order, and then on from there.

gmog220d · #5 06-03-2015, 10:33 PM

Anyone with more experience dare comment on whether or not there's a woodruff key down the front of this engine of mine? I can't be the only person who's dug around looking for things dropped down the hole, or not . . .

Did that "simulated drop" test, BTW, as best I could TnBob. Used a woodruff key I found laying around, one from a VW generator that's about the same size. I did it five or six times. The key either landed on the top of the head or fell out down to the floor. Huh.

funola · #6 06-03-2015, 10:58 PM

It could have bounced and land much further away than you think. Or it could have bounced up and landed on some horizontal surface you wouldn't expect. Did you try fishing the ground with a big magnet? (car speaker works good).

Stretch · #7 06-04-2015, 06:03 AM

I'm sorry but I can't help but to smile

The simulated drop test is pure suicide - I used to suggest that (as a joke) to newbies working on the top of Chinook helicopters!

cho · #8 06-04-2015, 09:37 AM

.

one word......MAGNET

.

gmog220d · #9 06-04-2015, 10:17 AM

Oh yeah, I've got a magnet, and I know how to use it!

It's an old Craftsman, what I've always called the "magnet on a stick", that's got a long cylindrical magnet that's pretty strong, strong enough to pull steel objects to it from a small distance. I've swiped this thing all over the engine on the side I think the key flew. I've swiped it over the subframe and suspension, the IP side of the engine, around the starter and alternator, under the air cleaner, around the front of the engine. There's actually a fair amount of space that I can see and feel with my hands, and I've gone over it multiple times by now from above and below. At this point I've got the radiator out too since during all this I noticed it was leaking from the top seam. That's going to a rebuild shop today . . .

So I can see around the engine and floor pretty good at this point, and feel like I've just about exhausted the search there. The concrete shop floor under and around the car is clean and clear, and was when the thing flew into hyperspace (I keep my space pretty tidy). I've swept a large portion of the floor into a pile and didn't find it.

My main concern is if it's down in the front of the engine, and that's where I'm fishing for opinions. Do you guys think, after all the digging around and looking I've done in the front of the engine from above and below, that it's clear for reassembly and running? I feel like I've seen and "felt" almost every nook and cranny in there and it seems clear. As for the key, screw it - if it's not in the engine I'm not concerned and will get another. And it WILL show up in the middle of the floor at some point . . .

Yeah, I chuckled at the "simulation" myself. I was standing there, scratching my head, just came across the VW woddruff key, and asked myself, "WTF? Why not?"

Stretch · #10 06-04-2015, 10:34 AM

Nobody here on this forum sitting in their armchairs can say where that pesky key has gone. I think there's a really good chance it has gone down the front of the engine in the dark hole where the timing chain lives.

To be 100% safe you have to find the key.

But you're in charge of what you do!

gmog220d · #11 06-04-2015, 10:56 AM

What else can one do to inspect the interior of the engine front?

The things I still could do:

- Pull balancer plate and oil seal; and
- Pull vacuum pump.

I'm less inclined to mess with the balancer plate because I believe I am seeing pretty much all around the crank sprocket/chain from above and below. A woodruff in there would:

- Bind between the sprocket and chain if on top, inside the chain loop; or
- Get spit into the oil pan if underneath, outside the chain loop.

The only area I can't really get into is outside the chain loop, above the outer slide rail, under and out a little from the IP timer. Pulling the vac. pump would show me that space. Might also be able to probe through the chain retaining screw hole.

What would satisfy you, Stretch, were you in my shoes?

Simpler=Better · #12 06-04-2015, 10:59 AM

The last time this happened it ot me this was a valve keeper. It wound up inside the cylinder (eeek). Car ran for another 2 years, although with a knock.

gmog220d · #13 06-04-2015, 11:05 AM

Quote:

Originally Posted by Simpler=Better

The last time this happened it ot me this was a valve keeper. It wound up inside the cylinder (eeek). Car ran for another 2 years, although with a knock.

How did the keeper get inside the cylinder?

Stretch · #14 06-04-2015, 12:33 PM

Quote:

Originally Posted by gmog220d

...

What would satisfy you, Stretch, were you in my shoes?

To be honest it would probably go like this =>

I'd remove the vacuum pump - and then check the intermediate shaft bearing (getting side tracked as usual) and then perhaps decide the bearings on the pump could do with a renewal...

...as you can see I'm not really the best person to ask "what would you do" to...

...After much more undisclosed dismantling and general fun I'd then drain the oil and remove the lower oil pan.

I'd then use engine oil gallery "bottle" brushes to scrub up and down the front of the engine until I found the pesky thing.

In the likely event that I didn't find it I'd stamp about the place like a petulant school child singing the 'uckety 'uck 'uck 'uck song and probably kick some things until I hurt myself.

Only when I reached a stage of total hopeless depression would I reluctantly put it all back together and tell myself I have done all I can to solve the problem.

Letting go doesn't always come so easy!

(Then as you say if I found the effing thing on the garage floor or worse still stuck to the teeth of a pair of pliers I'd then perform a ritual dance of destruction of the offending item with an effing big hammer)

mespe · #15 06-04-2015, 01:19 PM

It's resting on the left front wheel, at least that's where I found something small that I dropped.