Author Topic: M110 timing chain renewal  (Read 16631 times)

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
M110 timing chain renewal
« on: 23 March 2009, 05:34 AM »
The plan is to not only change the chain but put some offset woodruff keys in as well to give POVO some extra top end power.  I'm still planning on what to do exactly.  Basically, retarding valve timing gives more top end power and I might mix in 2 and 3 degree offset keys to play with the Lobe Separation Angle as well but I can't make my mind up which way to go.  LSA measured in degrees is the angle between the maximum lift of the intake and exhaust lobes.  There's trade offs regardless which way you adjust it.

Anyway, since POVO will spend all of its time above 4000rpm it matters not what it does below that, so long as it can start and runs I'll be happy.  Idle and low down torque aren't important.

It's only small steps at this stage.  Part of me wants to do a full 5 degrees retard on both cams but after getting some maths wrong earlier and misjudging the overlap I need to study my cam specs more.  But on to the chain.

From the looks of it the chain is original (no master link and it appears there's about 6-7 degrees of chain stretch.

Exhaust


Intake





Always one to take shortcuts against better judgement, I read someone stating that valves could be depressed with a screwdriver.  Tried it and couldn't budge the valve enough.  It became apparent after a while that I needed a valve compressor tool.  Compared to WGB's and Koan's home made valve compressor mine is a joke.

First attempt, MarkI, was rushed to get an idea of what might work. 
The flat bar was what some mechanic years ago rigged up to hold the front registration plate on my 350. 
The hook was part of a three pronged garden hand tool.  I left the middle prong and grabbed the "U" that made the outer prongs and bashed it into the shape you see. 
The underwhelming, yet well shaped compressor part is a surplus disc changing tool for an angle grinder.  Basically it bent fairly quickly and failed.  So since I was running out of time to buy some real steel it was time for MarkII





MarkII involved just coming up with a better, stronger compressor part.  I bought a couple of angled galvanised steel bars and basically cut em and welded them and ground them to come up with this.


I had planned to hinge it off the bar but when I put this part onto a valve and the bar into the slot it worked perfectly.  The back of the compressor slides against the cam cover and doesn't seem to do any harm.  Worked a treat and takes only a few seconds to set it up on the valve springs and to remove a rocker.


Typically I encountered a few clearance issues, especially the exhaust valve on #6 and the intake on #1 but #6 exhaust produced the biggest headache.  My half decent unrefined compressor now became this.......  but it still worked.





Now the rockers were off I don't have to worry about valves contacting pistons whilst I muck round with the sprockets and chain.
I had already taken the covers off for the expansion bolts at the end of the cam shafts, next thing to do was the tensioner.    A 10, 17 and 19mm inhex is needed.  My set only went to 17mm so I spent a good part of the day driving around town trying to find someone with a 19mm socket in stock.  In the end an engineering shop cracked open a set and gave me the 19mm socket.


Even though it's pretty simple I thought the manual made it look a bit daunting.  To summarise, the 17mm is used to undo the plug, the 10mm socket loosens the tensioner by two turns, the 19mm undoes the locking ring (visible on the 19mm socket above).  The 10mm is put back in the tensioner, angle it a bit so the socket binds and pull it out.




Sliding rails.  I should replace them, poor planning on my part.  The lining on the one under the intake sprocket looks pretty thick but it is chocolate brown like the rest of the inside of the engine.  Anyway the bottom stud of that slide has to be removed before replacing the chain.  It took me a while, trying out a few different bolt and washer and nut combinations to extract the pin.  Because the cam housing is unexpectedly uneven around this stud I couldn't just butt washers up to the housing like I hoped.  In the end I settled for an 11mm socket with a 2.5 inch M6 screw threaded through it, plus the washers and 10mm nut visible below.  It worked but was very stubborn.



BTW, some keen observers might note the grey/milky colours on the exhaust side there below.  It's all good.  That was just me and carelessly not drying the compressor tool after I doused it in water post grinding and filing.
But that's it so far.  Lifters look fairly worn I have to say.  Cam housing innards look crappy even though mechanically I can't see any defects in the camshafts or rockers.  Very minimal sludge accumulating in pooling areas like in the top of head and cam housing bolts.  I'm just not sure if I should try and clean it or leave it.   I'm not sure I'd know how to clean it and what to use and in the end, is it really going to be of any benefit.  The last thing I want to do is dislodge some crud that might get stuck somewhere in an oil duct.


1973 350SE, my first & fave

TJ 450

  • W116 Addict
  • ****
  • Posts: 4,264
  • Location: Rockingham, Western Australia
    • Tim's Insulators Downunder
Re: M110 timing chain renewal
« Reply #1 on: 23 March 2009, 06:21 AM »
Nice work Oscar. 8)

It's good to see an M110 receiving this sort of attention. 8)
The tensioner on an M110 is ratcheting isn't it? It would be interesting to see how it compares to the M100 version.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

koan

  • W116 Addict
  • ****
  • Posts: 3,316
  • Location: Melbourne
Re: M110 timing chain renewal
« Reply #2 on: 23 March 2009, 06:52 AM »
You've been very busy oscar.

The valve spring compressor is good but I'm sure you want to refine the design and build Mark III just as I do with mine to solve a minor inconvenience with it - it'll never happen!

Good luck with the valve timing, late intake closing is the go but no idea on what to do with the exhaust timing.

koan
Boogity, Boogity, Boogity, Amen!

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: M110 timing chain renewal
« Reply #3 on: 23 March 2009, 07:44 AM »
Thanks guys,

Yeah I don't know about the tensioner TJ.  I've read that others have called it a ratcheting type but looking at the diagrams and the how to in the manual to pull it apart it seems to me it's purely controlled by oil pressure but I can't work out if it can go slack.  There are two versions but they operate the same from what I can gather and to my mind they seem similar to the M116 and m117.  But I don't know how racheting tensioners work.  It looks a bit fiddly to pull it apart so I wasn't going to do it but down the track I might grab one of the donors and take it apart. 

I don't know when koan but there has to be a MarkIII.  I'll install the rockers this time round using what I've got but apart from refinement of the arm and a little more angle on the foot, I think it's possible to get away with this two piece arrangement so long as a pin of some kind is used in the lever to stop the compressor arm from sliding against the cam housing.  Also the lever has to be either angled up or the compressor arm longer.   Things like the carburettor and brake booster got in the way of pulling the lever down.  In both instances I had to use a thick screw driver in between the compressor arm and the cam housing in order to change the position where the arm meets the lever.  The effect was that the arm started from a higher position.  Interesting stuff though.  I've been promising to make one ever since you and WGB built some but I was expecting to bring out something a little more polished instead of what I made.  But  I suppose that's the result of leaving things till the last minute. ::)
« Last Edit: 23 March 2009, 07:47 AM by oscar »
1973 350SE, my first & fave

s class

  • W116 Addict
  • ****
  • Posts: 4,171
  • I'll keep the 116's, the rest can go
  • Location: Squeezing 3 W116's into a double garage
Re: M110 timing chain renewal
« Reply #4 on: 23 March 2009, 02:46 PM »
Well done Oscar.  You've become really quite the intrepid mechanic. 

I agree, the manual makes it look like a major project.  I need to do this on my 280SE, though it appears I am approaching a state of sufficient bore wear to consider a more extensive rebuild. 

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

koan

  • W116 Addict
  • ****
  • Posts: 3,316
  • Location: Melbourne
Re: M110 timing chain renewal
« Reply #5 on: 23 March 2009, 03:15 PM »
Yeah I don't know about the tensioner TJ.

If it's like the 6.9 tensioner it has to be pulled apart and reset to the first ratchet before reinstalling.
Quote
I don't know when koan but there has to be a MarkIII.

I have an "adjustment" in my compressor where I can pivot the lever 90 degrees to get at the rear cylinders but still have to remove brake booster. Don't know if the same would work with your design because it/you would end up pulling sideways.

Which part of the compressor touches the cam housing?

Is it because because the claw hook to presser foot spacing is too big?

My first attempt was similar to yours but didn't work because the angles, lengths and spacing were wrong. When pulled on it just wanted to fall off the valve.

koan
Boogity, Boogity, Boogity, Amen!

WGB

  • W116 Addict
  • ****
  • Posts: 3,280
  • And on the eighth day he made the 116
  • Location: Perth - Western Australia
Re: M110 timing chain renewal
« Reply #6 on: 23 March 2009, 03:18 PM »
Great day's work  and thanks for the photos which are priceless.

As far as the valve compressor goes I have seen pictures of an M110 compressor which use a shaped thick wire (well it looks lik that)  for the foot part - obviously clearance for working on the followers is a bit tighter than on a V8.

The tensioner is the same sort of design as the M100 one but I thought we had discussed in teh past that the M110 one was dimensionally smaller.

Keep up the great work and the great photography.

What camera are you using?

Bill


oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: M110 timing chain renewal
« Reply #7 on: 23 March 2009, 04:27 PM »
Thanks for the comments fellas. 8)

sclass, it makes me wonder just how long povo's got left before it needs a major overhaul too.  Especially as it appears to be a high mileage car.   There's too many anomalies like it appears to have an original timing chain without that much stretch but the speedo shows 434,000km.  It's possible the speedo has been swapped but I just don't know.  Some aspects make it look like it's covered that distance yet other aspects don't.  There is bottom end noise which has been there since the day I got it and hasn't changed since I've been racing it.  It's hard to capture the sound but I'll have Craigb look at it and get his thoughts if I get it started before Friday.

koan,  to answer both questions.  The distance between the fulcrum point of the claw and the lever in the arm slot is only limited by the arm resting against the inside of the cam housing.  Because the cam housing in the m110 is so tall it stops the arm from falling back which means there's no way I can use this compressor on a V8 unless the arm can be limited by a pin of some kind or an opposing slot or selection of opposing slots in the lever to give the arm something to hold on to.  At the moment the arm is free to travel up or down the lever.

I'll have to read the tensioner detail prior to installing.  I vaguely remembering reading something about audible click/s when reassembling it if it's been disassembled.

WGB, the camera's just an entry level DSLR.  Pentax ist DSLR, usually set on auto.
When there's really good diffuse light which I get from this side of the garage, the camera is at it's best and has great depth of field but as soon as I use a flash it throws it off a bit.   I actually grabbed my son's tripod to use yesterday so I wouldn't have to use the flash but it was too cheap and wobbly to make a difference. 
1973 350SE, my first & fave

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: M110 timing chain renewal
« Reply #8 on: 23 March 2009, 06:09 PM »
I'm stuck on something simple but I need reinforcement.  The diagram and its legend below from the manual seems wrong.  It was clear in my mind but now I've been thinking about it for too long.

If I want to retard valve events do I place offset keys as per (A) or (B)? 


Edit, the manual's correct, I was wrong.



« Last Edit: 23 March 2009, 07:17 PM by oscar »
1973 350SE, my first & fave

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: M110 timing chain renewal
« Reply #9 on: 23 March 2009, 07:24 PM »
Have another question.  The crank and cams are all out of whack now and I'm about to put the new chain on. 

Now that there's 3deg retard on the exhaust and 2deg retard on the intake do I still line it all up so when the crank is at TDC the cams should be on their respective timing marks?

Also, if I've skipped a link or two on the distributor gear what should I do?  I'm thinking take it out and wait till the new chain is in, get everything at TDC then put the dizzy back in with the rotor at the number 1 mark.  Does that sound right?
1973 350SE, my first & fave

13B

  • Vintage
  • ***
  • Posts: 871
  • Location: Bonerland - I like big butts and I cannot lie!
Re: M110 timing chain renewal
« Reply #10 on: 23 March 2009, 08:03 PM »
Wouldn't you install new chain, tensioner, sprockets and rails, and then re-check timing error?  By then your 7 degrees should be back to 2-3 degrees or less.  You'd then use offset keys to get it back to 0 degrees, then to advance or retard the camshafts calculate how many degrees offset the keys need to be to compensate.

Say you got it 2 degrees advanced with standard flat keys, so putting in 2 degree  woodruff keys would bring it back to zero.  But if you wanted that camshaft to open 3 degrees retarded, then you'd need to replace the 2 degree woodruff keys with 5 degree ones... at least thats how I see it to be done anyway.

I.
450SEL 6.9 #5440 = V MB 690 , 450SE # 43094 = 02010 H , 190E/turbo # 31548 = AOH 68K

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: M110 timing chain renewal
« Reply #11 on: 23 March 2009, 08:45 PM »
What you say makes sense but since I put the offset keys in before the new chain I was just wondering how I should line up everything before the new chain went on.   

But, FWIW I did line it all up again and put the tensioner in.  The stretched chain looks like it retards the valve timing a bit further again.  I should've left it in.  Especially since now that I cut the chain without removing  the tensioner and without tethering the old chain to the exhaust sprocket. :-\   I  watched helplessly as that half of the chain snaked its way back down the front cover and is probably sitting in the bottom of the sump right now.  That's a hell of a lot of hex screws to undo again :'(

I've had enough for one day......Taxi!
1973 350SE, my first & fave

WGB

  • W116 Addict
  • ****
  • Posts: 3,280
  • And on the eighth day he made the 116
  • Location: Perth - Western Australia
Re: M110 timing chain renewal
« Reply #12 on: 23 March 2009, 10:48 PM »
A magnet and some positive thinking - plus next time put a fine length of wire through the chain  before cutting it.

Bill

P.S - for what it is worth here is a  picture of the M110 valve spring compressor as sold by  Sir Tools



Lots of luck and hope your fishing expedition is successful

P.P.S - You are probably aware but wear in the sprockets also adds to the "apparent" chain stretch.



« Last Edit: 23 March 2009, 11:51 PM by WGB »

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: M110 timing chain renewal
« Reply #13 on: 24 March 2009, 05:45 AM »
<a href="http://www.youtube.com/v/qW82OcrC6Ko&amp;hl=en&amp;fs=1" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">http://www.youtube.com/v/qW82OcrC6Ko&amp;hl=en&amp;fs=1</a>

Well it's running again and I have to take my hat off to mechanics.  Sure there's good and bad ones and we all have a go at labour costs but one car and two days to change a timing chain :P Geez! I'd go broke if I was a mechanic. 

My first ever timing chain replacement complete although I didn't have enough oil to take it for a test run but I got it started a couple of times to get it all lubed up but not long enough to get up to operating temp.  As long as valves were clear I was happy for the moment.  You might notice the whirr sound?  I can only deduce that it's from the new chain and the tensioner which I reckon might be too tight.  I ended up pulling apart the tensioner and inserting using torques as specified in the manual.  But tyring to turn the engine at the crank whilst reinserting rockers was very hard compared to what it was like before.  Loosen the tensioner locking ring and it's easy again.

Dropping the old chain wasn't as bad as I thought it would be.  In about half an hour I fished it out (twice) with two unravelled wire coat hangers.

That tool from Sir Tools Bill is pretty much waht's pictured in the manual.  My little gadget worked well but it defintiely needs refinement or rather a new approach.  Looking at the manual and the one pictured I'm sure you'll agree it can't be that hard to replicate.

Anyway, to pick up where I left off from yesterday......... I also did an oil change and thermostat change from a 70 something degees to an 80 something degrees.  Can't remember specifics.

Here's the selection of woodruff keys I had.  From left to right,a 1deg, 2, 2, 3, and 0.  Notice the 2degree one in the middle was a new one I bought and that's how it arrived with rust spots.   >:( It went into the intake cam but needed filing to fit.


As stated earlier I replaced the 0 woodruff keys with offset keys prior to changing the chain.  Woodruff keys can be changed without undoing the chain.  With the tensioner released or removed there's enough slack in the chain to remove either sprocket and once the expansion bolts are removed from the end of the camshafts, knocking off the sprockets and moving the camshafts towards the firewall is all done by hand, no tools needed.  I was disappointed to find out though that to replace camshafts you need to remove the cam housing.  There's another two expansion bolts holding the other end of the camshafts in place. I thought that I might one day put k-jet cams in which I believe have greater duration but I wont be doing that for a while given the big job that it would be.



Now sprockets are back on and I decided to cut the chain. Prior to this I put the crank at TDC, got the cams timing marks close to lining up, pushing the tensioner in by hand to make sure the chain's slack was taken up.  Then I screwed the locking ring in for the tensioner to keep it in place.

I ground pins for one link of the old chain.  This is where I should have been clamping the chain ends to the sprockets but I forgot and with the tensioner in place, well you know the rest, the chain fell down the exhaust side but stayed put on the inlet side.



So here it is, chain gathered up way down there. I seriously thought it was in the sump but after undoing the umpteen sump bolts I discovered that there's no way it can drop into the pan.  So I ended up fishing it out with unwound wire coathangers.  Worked well.




From that last photo I realised I needed to take the exhaust sprocket off again.  It was the only way I could see to get the chain to go to the left of the sprocket.


Now that I've removed that sprocket and pushed the exhaust cam back towards the firewall I sought to torque up those cam housing bolts that aren't ordinarily accessible without the proper bent 6mm hex tool.  When the camshaft bearings move out of their housings, the cam can move a little towads the middle and "normal" hex attachments can be used to retorque those bolts.  Most with an M110 would know of the oil leak that develops in time at the edge of the housing and sensor box.  You can see a blue line (Loctite Blue Maxx) as recommended by Craigb and I have to say it worked to stop the leak.  But I found the bolts on this side needed a full turn or more to get the tourque wrench to click.  One bolt was a bit damaged though and I could only do a 1/4 turn.  I hate inhex bolts.  they damage too easily.  But a word of advice, clean and dry any inhex bolt's head before undoing or tightening.  It'll help reduce the possibility of damaging the bolts' head.



Just to get the new chain attached I've attached it where shown rather than straight off the exhaust sprocket.  The old chain end on that side was tied off with cable ties to the steel lines visible but then the new chain and old chain was held together with my left hand whilst the right did the crank turning. I was moving my right hand to the left, dragging the old chain out whilst applying to tension to the new chain going in.  I didn't have the tensioner in but I did replace the pin that I removed earlier.  The one going into that slide below the inlet sprocket.




After completing that chain linkage I had to get the exhaust sprocket to jump a few teeth to get the timing marks aligned as near as possible. In the end all marks were close to spot on.


To the tensioner.  I found out that I had the earlier version.  Didn't get a pic of every little piece because my hands ended up very oily.  But what I did find was that there's ball valves at either end of the long spring that pushes against the tensioning pin.  The ball in the pic below is supposed to stop oil pressure leaking out of the tensioner.  Does this mean it's a ratchet type??  But I found that this ball is supposed to be in the ball cage, the little plastic yellow/orange cup.  Instead, this ball was rolling around in the spring so this ball valve wasn't working.  I put the ball back in the cage but I don't think it'll last there before it ends up in the spring again.  I ned to get a new tensioner.  Why didn't they make the ball cage out of metal >:(


How it should look from the outside looking in with ball in ball cage.


That's all!  Until I test run.
1973 350SE, my first & fave

WGB

  • W116 Addict
  • ****
  • Posts: 3,280
  • And on the eighth day he made the 116
  • Location: Perth - Western Australia
Re: M110 timing chain renewal
« Reply #14 on: 24 March 2009, 04:54 PM »
Wow - great achievement and thanks for going to all the trouble to document it as I know how long it takes to do that part alone.

I see you used the "Double cable tie" method - it is quicker with three small vice grips but cheaper with a packet of cable ties.

I don't know anything about the earlier timing chain tensioner other than it bears little resemblance to the 6.9 one unlike the latter type.

The 6.9 one has a definite serated surface that engages in a small circlip to provide the ratcheting with no balls and cups.

Pleased the chain end resurfaced.

Bill