Lower oil pan was the first thing to come off when I started looking for the key. It wasn't in there. I though about wheels, and it's not on or in either front wheel (front end is off the ground, easy to spin the wheels).

I went ahead and removed the balance plate and vac. pump (decided the engine could use the new seal and gasket, and a good cleaning while I have it apart). It's not down in the bottom near the crank sprocket. Looking into the space around the IP timer I can see it ain't in there, either on the outside above the outer slide rail, nor in the space behind the timer where the oil pump drive shaft resides.

I lit the scene with some good light. I probed or looked down everywhere I could get to, which at this point seems like everywhere. For probes I used steel wire and the magnet on a stick. I also blew air from above and below into the various spaces - nothing moving around. I'm betting it isn't in there!

I'll give the IP timer some side-to-side pressure to see if the bushing shows slack. I guess it would wear downward, due to the chain pulling it that way. For now I'll leave it on there.

Incidentally, Pelican doesn't even list upper/lower radiator hoses for this car ('74 W115 240D). Decided the German lower hose still has life in it. NAPA's upper hose by application appears to be for '73 or earlier. Guess I'm going to Benz for that one.

Attached Thumbnails

 

I dropped it in there while changing the valve stem seals in situ. It was a crazy long night.

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

One kind of out of the box idea is to get a USB borescope and use that to actually look at some of those nooks and crannies both in and out of the engine. I can't vouch for their effectiveness (at least yet) as I've got one on order to try to look at the head and cylinders for damage on my spare engine that had 4 out of 5 prechamber balls "burnt" up. Some come with a mirror attachment that allows for "looking sideways" which I think would be helpful in your situation.

Just search for USB borescope or endoscope on eBay.

Kind of a wierd idea but who knows, it might just work.

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Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

You must have dropped the valve first, then dropped the keeper? Does a keeper even fit into a valve guide?

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Thanks for the suggestion Mach4. It's not a weird idea at all. I've been keeping up with your thread about the worn out pre-chambers missing their balls. Now THAT'S weird.

As for the camera I'm not sure I need it, though. I can see pretty much everywhere in there now with the lower oil pan, balance plate, and vac. pump off. Engine spins free and there are no signs of that key in it. I've ordered another and will be pushing forward form here.

But, while I wait for parts I will be doing a brake job on the Mom-In-Law's 2007 CRV. I'll be pulling the 240D out for the day, and that'll give me easy access to the entire shop floor for a more thorough search. I will also be looking in the tread grooves on the front tires in case it got jammed in there.

If you pulled the injection pump timer, which is now just that one bolt and then push the timing chain back out of the way, then you would be able to see a lot more of the timing case area.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Reading your first post again, you had paper towels stuffed into the opening to prevent it from falling into the engine. It sounds like you were watchin as the gear slipped and the key popped and you saw where it fell, which is down the intake/exhaust runners? If you did indeed see it fall there, then it did not fall into the engine. If you didn't, different story. You had paper towels stuffed into the cam gear opening. Are there other openings in the head like oil drain holes where it could have fallen into?

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Yes, I had towels stuffed but there was that small gap on the side behind the cam gear I noticed right after the key warped outa the shop. If it had gone down there it would gone into the space backside of the tension rail, or maybe down into the very bottom on top of the crank sprocket. I can clearly see in those areas now and there's no key.

The top of the head has drain slots on the very rear edge, and they don't look large enough unless the key hit them at just the right approach and angle. It would have had to go waaayyy back there which doesn't seem likely. I've looked all over the top of the head, inside the valve springs, etc. Just for grins I'll climb up on top of the engine again and look down those drain slots more carefully.

I recall it going down and sounding like it got stuck and didn't hit the floor. It stopped bouncing and making noise before I thought it would. For it to have fallen into the engine through that small gap in the paper towels it would have had to bounce backwards from the direction of travel I remember. Not impossible given the shape, though.

This is all so silly! Such a small job turns into a crap fest yet again!

Thanks for the ideas.

That would be an excellent way to see inside the timing area. I'm going to measure the timer/shaft end play and let that guide the decision of whether or not to pull the timing device. If it checks out and I don't feel any side-to-side play I'll most likely leave it alone.

For now I'll stick to probing spaces with magnet and wire. I can see into some of the space on the backside of the timing device as it is. A key in there would tumble around or slide on the inside surface as the assembly rotates. I might hear it and I'd see it. Plus, if it was tumbling around in there I'd think it would try to fall out the back as the engine is tilted that way, especially with the front end up on stands.

I will at least look more closely down the backside of the timer while rotating the engine. It's not a space I've concentrated heavily on, though I have looked into the space around the timer's edge and can see there's no key between the timer and engine block front or rear. I'll run the wire back there for sure. Shoot, maybe the front bushing needs to be replaced and it's moot.

I appreciate the suggestions. If anyone has a similar enough engine in a similar state of dis-assembly and can take a look around the timing galley I'd like to hear your thoughts on how well you think you can see everything. I think I can see well enough, and the few places left I can't put my eyes on I can easily reach in with the wire probe and feel around and drag stuff out. I've got some bright ass lights and have shined them up from below while looking down and the reverse. I've got good light coming from my direction too.

I might just drop another key down there intentionally to verify that I can find and extract it no matter where it falls.

Cheap video inspection camera?

http://www.amazon.com/Vividia-Portable-Digital-Flexible-Inspection/dp/B00AIFSSUG/ref=sr_1_5?ie=UTF8&qid=1433523306&sr=8-5&keywords=borescope

Rgds,
Chris W.
'95 E300D, 443K
who has spent much time with magnets on flexible arms

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Objects in closer are mirror than they appear.

Had time to measure timing device end play and I get about .0045"/0.114mm. So it's right on the edge of the outer limit of .012mm. I'll replace the bushing at a later date, but I still might pull the device to get a better look inside the engine.

A pal has a camera like the one you linked to, Chris W. I'm going to borrow it for a day.

Might have a little more time later today to fool around with it.

Thanks again for the suggestions.

Spent a little more time on it this afternoon. I dropped another woodruff down the timing galley multiple times. If I dropped it on the outside of the tension rail it fell out all the way to the floor every time, through where the lower oil pan would normally be. If dropped in the middle or even more over the top of the IP timer it would fall down on top of the crank sprocket and end up coming out the space right behind the front main oil seal area. Not once did it get stuck in there.

Also turned the engine over while watching the space behind the timing device. No sign of the key in there. Couldn't see or hear or feel anything with the wire probe. Anybody got a pic of the backside of a timing device?

And I looked in that drain slot at the back of the head's top - no key in there. Not sure one would fit through anyway.

I'll have the wand camera tomorrow, but I bet I won't see that missing key in there.

Gonna go over the floor again with the car out of the shop tomorrow.

Yep (and some)

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Thanks Stretch. Nice pics of the guts of the timing device. Looks pretty similar to the mechanism in a centrifugal advance distributor.

Got another of the device simply flipped over so I can see what it looks like on the side that faces the rear of the vehicle? Just curious to see what that space looks like with my eyes, since I've only "seen" it with the wire probe thus far.

Picked up the camera but didn't have time to mess with it yesterday.

Thanks again, Stretch. I appreciate your time/replies.

Oh bugger that's the wrong side isn't it? !

I'm away on a short trip at the moment and won't be back to my HDD back ups for the other pictures until later on in the week.

The closest I can get is this one =>

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!