1966 230SL Head Removal

[Harry]

Hello.

I am trying to see how to manage the timing chain during my head removal and I would appreciate your advice.  I have removed the chain tensioner and the guide that mounts to the top of the head, but the cam pulley is still on as well as the roller sprocket/arm that the tensioner applies the load to.  It looks as though I need to remove the cam sprocket to be able to move the chain aside so that I can rotate the the roller sprocket/arm to get to the 6mm SHCS that lies directly beneath it?

Should/can I remove the roller sprocket/arm?  If so, how is that done?  I have the bolt out of the front of the engine that goes into the mounting shaft but the sprocket/arm seems captured by the head.  Is it spring loaded such that with the chain out of the way, I can depress it against the spring and then remove it?

Thanks,
Harry

[Harry]

Also, I guess the camshaft pulley has to be removed with a puller?

Thanks again,
Harry

[MikeSimon]

The sprocket does not need a puller to be removed. I think you need to thread a bolt into the roller arm shaft to pull it out. Be very carful that the spring does not disappear into a cavity somewhere. I secured it with a cable tie before I pulled the shaft out.

[merrill]

when i pulled the head on my 66 230 a few months ago (with Joe Alexanders guidance)  I did remove the
timing chain sprocket.

first make sure timing is at zero at crank and cam and sprocket are at their TDC mark.

next i applied a counter hold on the crank bolt and then removed the sprocket bolt.  then removed the timing chain tensioner.

from there i marked the position of the chain on the sproket and then carefully  (with rags in beneath the sprocket)  i pulled off the sprocket and chain.

from there you can let the chain go down , i tied some string on a link so i could pull the chain back up.

[Pawel66]

I cannot help much in technical/procedural topics, but from practical point of view:
- really fill the chain galleys with rags so that yo do not drop anything down there; I did drop a small clip - I was very lucky to fish for it just a couple of minutes with a magnet
- if you do not want to/need to detach chain from sprocket - you can tie chain to the sprocket with 3-4 loom ties (but then you will probably look at the sprocket teeth to decide if you want to replace it and may lose the timing anyway)
- i did not need a puller to remove the sprocket from camshaft - I tapped it gently off with a small hammer
- I ended up replacing the chain and the sprocket, so I lost the timing eventually, but it was not that difficult to set it back again

[Harry]

Thanks to all.  I should note that I am planning to check the engine over when I get the head off - mic the cylinders, remove/clean the pan and look at the bottom of the engine.  At this point, I was planning to replace the timing chain based on the recommendation of the Forum and the mileage of the car (which I believe to be accurate as shown at about 100K miles).

I am not planning to touch the vertical timing gear, and hopefully not remove the crankshaft - but I may lose timing totally in the process.  It seems it shouldn't be that difficult to restore the right timing on reassembly.  I just need to be sure that all of the marks are in the right positions at TDC - right?  (Fuel injection pump is off of the car.)

Is there a link somewhere on the Forum that describes how to re-establish timing, including installing the timing chain?  That would be most helpful.

Thanks again,
Harry

[Benz Dr.]

Set all of your timing marks to TDC number 1 piston then move your crank to 20 degrees ATDC and install your IP.   

[Harry]

Benz Dr. - thanks.  Here's my question, better stated.  If I remove the timing chain in the replacement process, the crank, cam and vertical timing gear/distributor may all need to be re-positioned for the new chain.  I would set the crank to TDC, and the cam to align the marks but I wonder about the vertical timing gear/distributor.  Is there a mark also on the VTG to set it to the correct position when everything else is aligned.  (Does that make sense?)

It would be as though all of the rotating elements were installed but not aligned together.

Or I could feed the new chain off of the old one, I suppose, keeping everything together.  I'd still like to know how to time everything from scratch. 

Thanks again,
Harry

[Benz Dr.]

Hook the new chain on to the old one and feed it through. Make sure the cam turns with it.

[Pawel66]

You have the procedure here: https://www.sl113.org/wiki/Engine/TimingChain

There was also one described in the forum, a similar one to the one quoted.

[Harry]

Another question, please.

Is it necessary to remove the coolant elbow from the head to send the head to a shop for machining?  This is the short elbow on the driver's side that is bent towards the firewall for the heater connection.  There is a 32mm fitting that secures it to a fitting on the head.

Thanks in advance,
Harry

[ja17]

Removal not needed.

[Harry]

Thanks very much!

[Harry]

So I looked at the thread on the timing chain replacement but it doesn’t roll me what I need to know.  I expect that I may have to disassemble the engine such that everything (cam, crank and vertical timing gear/distributor) all have to retired from zero - like when the engine was originally assembled.
The Ip was removed with timing set to20 degrees ATDC so if I get the other pieces back in time, I can reset to that setting and reinstall the IP.  What is the full procedure to set timing starting from scratch?
Thanks again,
Harry

[Benz Dr.]

I set the camshaft timing to the crankshaft. The crankshaft must be set at zero, number 1 piston TDC and then the cam can be set so that the timing marks line up. If I'm rebuilding an engine I leave all of the rockers off until I have the cam timing done so I can turn the engine over to check that everything turns freely. Once I have the cam and crank timed correctly, then I time the IP so that the marks on the pump drive line up and then I turn the crank to 20 degrees ATDC on number 1 piston. I usually oil the drive collar between the IP and the IP drive shaft. Where you start with the distributor drive gear and shaft isn't all that important but you should take care that all of the gears slide on and over the woodruff keys so that everything stays in line. I would also check the end play on the oil pump/tach drive gear shaft. There is quite a bit of info on this site about how to do this procedure. Don't over look this because it's important. 

[Harry]

Thank you Benz Dr.

This is a big help.  But I'm a little confused about the distributor drive gear and shaft since at TDC, the rotor button does have a position that it must align to on the distributor.  I suppose you are saying that if it is close, the distributor itself can be rotated such that this alignment is achieved - right?

And I recall the end play discussion so I'll have another look at that.

Harry

[ja17]

The distributor has a slash mark on the rim. Align with rotor at TDC #1.  Look at original photos in BBB or other to find original orientation of distributor. Sitting in driver's seat orient vacuum cell on #051 vacuum retard type distributor to approx. 1:00 o'clock to 2:00 o'clock.  230 SLs with vacuum advance distributors are oriented at about 5:30 o'clock for initial set-up. Loosen the distributor cinch collar to turn distributor for fine adjustment. Different distributor numbers may vary in orientation. The concept is to be able to move the distributor in in either direction without obstruction once the rotor is set on the slash mark. Some nice photos in the BBB if you have one.

[Harry]

Thanks Joe (and all),

I have the position of the distributor documented (it does lie as described in the 1 - 2 o'clock position).  I have had the dizzy out before and I seemed to recall that the "blade" at the bottom would actually only fit one way (not 180 degrees the other way).  So I wanted to be sure that I could get things lined up such that everything worked together.  I probably need to go a little further to better understand what is being described.

I don't have a BBB but I sure would like to find one!

Thanks again,
Harry

[Pawel66]

Sorry, maybe I will add a word to help clarify...

Harry - this distributor (or rather rotor) position at this stage is only to verify that the crankshaft at zero is the "0" with TDC of the first cylinder is when the POWER stroke begins. That is all. You will adjust distributor exactly later, when you adjust ignition timing.

It is a four stroke engine. The crankshaft passes zero either when the piston in the first cylinder is starting power stroke or when it is starting a suction stroke. When you set the crankshaft at zero to set timing in engine, engine has to be at "0", meaning TDC when the power stroke in cylinder 1 starts. This is verified (that it is this "0", not the suction stroke 0) either by first cylinder cams positions (they have to be up, meaning valves closed, meaning power stroke starts) or by rotor position - spark given to cylinder 1, which is the rotor pointing more or less at the cut in the distributor housing. More or less, because if crank is at 0 for suction stroke, the rotor is pointing completely to the other side of distributor.

So orientation of distributor needs to be verified as it is important, as the experienced Members are saying, and rotor needs to point to the cut in the housing with distributor fitted in the right way. But the exact rotor location, a couple of milimeters this or that way is not that important at this moment.

What is also important now is the crankshaft at "0" exactly and the marks lining up on camshaft. Then for IP - you just turn the engine 20 degrees as described and you need to have all three marks on IP aligned (refer to Technical Manual). Even I did not have an issue wih tthat.

What I found important and I got help from the forum was how to re-assemble the chain tensioner properly with priming it with oil. There are threads about it and also it is described in Tech Manual.

If in doubt, the oriention of distributor is described in detail in Technical Manual for advance and retard types.

[Benz Dr.]

I guess I should of added that the gear below the distributor can be moved into the basic position if your rotor isn't lined up. Use a large flat bladed screw driver and insert it into the slot on top of the drive gear. Give the screw driver a twist and the gear should rise and then fall down again as it slides into the next quadrant. Try your distributor and if it's not in the right orientation keep moving the drive gear until it points in the right direction. I should also point out that the engine should be turned to TDC on number 1 cylinder.

Not hard to do but not exactly intuitive if you are trying to figure it out on your own. 

[Harry]

 Very helpful - thanks.  Will hopefully get back onto it today!

[Harry]

I did get the head off today to get ready for a valve job.  I do have a question about the head though.  I expected that the cam towers might come away from the head when I removed the longer head bolts that went through them - but they did not, i.e. they appear to be still securely attached to the head.  It doesn't appear that they are integral to the head though.  How are they attached and how do I remove them?

The block is on the engine stand, bare except for the lower end and the distributor.  I want to remove the distributor (easy enough) and the distributor mount but I'm still a little uncertain about regaining the position of the horizontal timing gear.  I see  a timing mark on the spline collar that the IP slides over so I expect on reassembly, I need to find that position again.

I also need to look through the tech manual to see how to remove distributor mount (the the aluminum cover that holds the distributor and covers the opening to the sprocket on the horizontal timing gear).  It looks like that cover is secured with 6 socket head cap screws and has a large bolt in the center.  There's another large bolt on the perimeter at about the 8 0'clock position but I'm not sure yet whether either of the large bolts have to be removed?

Maybe the bigger question is should I check the end play of the vertical drive gear before I do any of that?  How much play is allowable?

Thanks,
Harry

[Pawel66]

On your first point: have you unscrewed those nuts on bolts marked on the picture?

I hope I marked them correct....

[Harry]

Nope.  I didn’t see those at all but I do this morning.  Looks like that will release the towers?  What about the timing chain idler sprocket in the offset of the head?  It appears as though it is removed similar to the tensioner sprocket, i.e. remove the large bolt to access the idler shaft.  Then insert a bolt into a threaded hole in the shaft to pull the shaft and release the sprocket?

Thank you (everyone),
Harry

[mbzse]

.../...remove the large bolt to access the idler shaft.  Then insert a bolt into a threaded hole in the shaft to pull the shaft and release the sprocket.../...

Yep, right on. There is a factory issue puller (see picture attached below), but you can make do with a M6 normal threaded bolt, plus nuts and washers and perhaps a suitable size socket to lever against (through)