M110 valve spring compressor

jodyone1

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1984 280CE W123 (garage queen); 1991 300SE (going); C207 E220 (daily)
I'm considering changing the timing chain and tensioner on my '84 280CE (M110), myself. It seems the MB spring compressor is very expensive, and many people seem to use home fabricated versions. I've found this Sealey device online:

Sealey VS168 Valve Spring Compressor Lever Type OHV/OHC

media.nl


Does anybody know if it will work, or at least be modifiable to fit?

I've done a fair amount of research online, but any other advice about this job would be most welcome! Many thanks, all.
 
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jodyone1

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Thanks for the link. That's the first I've heard of a tool like that being used- if it works it could make this job a lot more feasible. If anybody else has experience using something similar, I may just get it on spec and see.
 

Druk

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That tool compresses the valve springs to remove the rocker arms. I have one and it works OK. However you shouldn't need to do this to replace the timing chain and tensioner. The recommended way is to split the old chain at the top, join the new chain to the old, and wind the new chain around keeping tension on the old chain as it comes out. Removing the spark plugs removes the compression and the engine turns easily.
 
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jodyone1

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That tool compresses the valve springs to remove the rocker arms. I have one and it works OK. However you shouldn't need to do this to replace the timing chain and tensioner. The recommended way is to split the old chain at the top, join the new chain to the old, and wind the new chain around keeping tension on the old chain as it comes out. Removing the spark plugs removes the compression and the engine turns easily.

Thanks Druk. By "that tool"- which do you mean? the Sealey one I pictured, or the one jaymanek referenced?

I'd heard that people had tried replacing the chain without removing the rocker arms, but it seemed a bit hit-and-miss. The FSM certainly calls for removal of the rocker arms, and all the accounts online seem to cite that removal as the hardest bit of the whole process... but I'd love to avoid it if it's really do-able.

Can you confirm that removing the spark plugs is enough on an M110, to fit the new chain with decent control? I'm starting to feel more confident about this job, which I was halfway towards sending to the nearest Merc independent.
 
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Druk

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Thanks Druk. By "that tool"- which do you mean? the Sealey one I pictured, or the one jaymanek referenced?

Yes...the Sealey one you pictured. The only real difference in the 110 engine to the one featured in Grobers 'How To' is the chain passes under one of the camwheels instead of over. Haynes manual 677 gives a how-to on the 110 engine and does say that it may assist the engine turning smoothly if the followers are removed. Quite how that can be escapes me but it's your choice. Slightly easier maybe: but smoother?????
 
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jodyone1

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Yes...the Sealey one you pictured. The only real difference in the 110 engine to the one featured in Grobers 'How To' is the chain passes under one of the camwheels instead of over. Haynes manual 677 gives a how-to on the 110 engine and does say that it may assist the engine turning smoothly if the followers are removed. Quite how that can be escapes me but it's your choice. Slightly easier maybe: but smoother?????

On that basis, I think I'll get it anyway. I found it for 20 quid elsewhere, in any case. I'll pull the plugs, see how easy it is to turn the engine, and only use the valve spring tool if I feel I need to.

I'll keep this thread updated as I do the job. Between the FSM, the Peachparts howto posted, and various reports elsewhere on the web, I feel a little bit confident. At least, it may help others to learn from my -potentially magnificent- mistakes...
 
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jodyone1

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I have one more query about this before I get in up to my elbows: the FSM calls for removing the tensioner- then replacing it with a rigid one, screwed hand-tight, before changing the chain. The accounts I've read online seem to have skipped this... do I risk the chain becoming too sloppy (and potentially skipping a tooth) if I change it with the tensioner entirely removed, and nothing in its place?

If so, does anybody know the dimensions if the rigid tensioner? It looks pretty much like a long bolt, which could be pre-fabbed (or even bodged together from the old tensioner, no?!)
 
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jodyone1

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Well, I went ahead and changed the timing chain and tensioner. I found it a little less fearsome than I anticipated, perhaps partly because I'd researched it pretty heavily. There are good resources online: I relied on the following write-ups and how-to's (apart from the service manual itself):

PeachPartsWiki: M116/117 Timing Chain Replacement

M110 timing chain renewal

I'm on the fence with the timing chain - Benzworld.org - Mercedes-Benz Discussion Forum

There's another very helpful account which I can't remember, but will add when I find it..!



Following, are my notes on the job. In general, the links above provide enough guidance- but this may fill in the gaps.

I didn't remove the rocker arms. I found (as advised) that removing the plugs alone made rotating the engine easy enough. It still has to pull the exhaust camshaft against the valvetrain load, but because I ensured the chain was permanently strapped down, that wasn't a problem.

The tensioner frightened me, in anticipation, but turned out to be declawed, so to speak. I just managed to remove the old one as per the service manual, with a canted hex key. It helped that I had an old, low quality hex key to hand, with burred edges which added a little purchase. If you cannot, you will need an M18 bolt (which you probably won't have- it's big!), and a compact slide hammer or some other method of bearing on the bolt. It may be worth sourcing one beforehand, to save delays.

Once the old tensioner was out, I was concerned about the temporary tensioner the FSM specifies, which I didn't have. However, it became obvious that this is nothing more than a prop to hold the tensioning rail in place. I used a succession of socket adapters to make a stubby rod of about 3 inches, and put that loosely into the tensioner aperture. That assembly was hand-tightened with the original cover plug, until snug.

I removed the second version of tensioner, and replaced it with a new one, of the same type. I could probably have reused the original, in retrospect, but I'm happy to be sure with a replacement. To be clear, the M110 tensioner is a ratcheting type (both styles). I think this is the most invaluable section from the service manual: that is available online, in the usual places. Without it, I would have struggled to deal with the tensioner.

I used the "bag of zip-ties" method of retaining the chain, during replacement. I couldn't find small mole-wrenches locally, and besides, I wasn't too happy about biting into the camshaft sprocket with wrench jaws. Initially I was ridiculously cautious, securing nearly every tooth, and inching slowly into the new chain. Eventually I settled into a rhythm, and the entire replacement took about an hour, and about 50-80 zip-ties. I was determined not to slip a tooth!

P1020870.jpg


I ordered both chain and tensioner from my local MB dealer. Total cost was about £120. The chain came riveted into a loop, with no master link: I had to grind off one link to split it, and order a master link seperately. I wrongly assumed that the master link would be included. Be warned- and check with your parts desk. I attached the tiny c-clips on the master link to thread before fitting and removing. I drop things. Know thyself.

P1020868.jpg


Below, is the old tensioner and new. The cap and spring in the middle are re-used. On the far right, is my "hand-tensioner" assembly.

P1020871.jpg


After fitting, I checked the timing, and rotated the engine a couple of times to be sure of clearance everywhere. Then I did the valve clearance, since I had the rocker cover off. Of course, I despaired when the engine didn't start. It took most of a battery's worth of cranking and worrying before I remembered to refit the coil lead.

I hope these notes are useful to anybody considering doing this job on the venerable old M110. I'm happy to understand my engine better now.
 

AusGreg

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On that basis, I think I'll get it anyway. I found it for 20 quid elsewhere, in any case. I'll pull the plugs, see how easy it is to turn the engine, and only use the valve spring tool if I feel I need to.

I'll keep this thread updated as I do the job. Between the FSM, the Peachparts howto posted, and various reports elsewhere on the web, I feel a little bit confident. At least, it may help others to learn from my -potentially magnificent- mistakes...
Hi jodyone1
Do you still have valve spring tool? Would you resell it?
 

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