I was thinking about what Bill (WGB) said when S class mentioned only the camshaft turns and the cam cog does not when adjusting the cam to get as close to TDC.
My reading suggests that cam timing can be done independently (one cam or two, not necessarily needing to be done to both cams) and the pulley is aligned at TDC and from there the decision to shift the cams not in alignment with the marks can then proceed which is my thinking, that aside i will say the following...
• The best way to approach the alignment of the camshaft mark to the mark on the bearing tower is to pull off the sprocket and look through the hole of the sprocket.
• The crank pulley will be at TDC for this operation as that is desirable but not always possible with the aim to get as close to TDC as practical (ideally 0 or 2 to 3 degrees advanced which is read to the left of the timing marker pin as you look at the engine)
• In my example as you look through the sprocket (at the right cam) you will see that the notch on the camshaft is to the left of the mark on the cam bearing tower and we want to get the notch on the camshaft as close as possible to the mark on the cam bearing tower
• move the camshaft with some grips in a clockwise direction to align the notch mark as close as possible to the cam bearing tower mark
• you will now notice that the slot on the cam sprocket for the woodruff key is no longer in line (this is where the offset woodruffs come into their own)
• remove the first woodruff key only at the front of the right cam and replace it with the replacement off set woodruff key to get as close as possible to alignment with the slot in the sprocket and the woodruff key (I used a 0.9mm offset which = 3.5 degrees on the on the cam and 7 degrees at the crank)
• If the chain does not have enough slack you may need to rotate the crank pulley slightly until the slot on the sprocket and the new key aligns then replace the sprocket (I did not need to do this as the chain had enough slack)
• check the crank pulley timing mark and it should be close to TDC by 2 to 3 degrees ATDC or if the operation has gone well with the right woodruff key size it will be at TDC (all things being equal) and the cam mark and cam bearing tower are both aligned
• It can be assumed that the reason the cam washer has a relatively wide 'U' compared to the thin line on the cam bearing tower is to say that as long as both cams align within the 'U' all is sweet
Things to note is there is no need to adjust the left cam when doing the right cam (the individual cam rotates relative to the slot in the sprocket with the new key)
The key for the thin washer in the right cam (that contains the ‘U’ section) remains the same as this denotes the factory setting of the cam shaft only and would only need adjusting if Cam Shaft timing is altered due to a re grind or aftermarket cam by use of the measuring gauge specialised tool used to get back to factory spec; therefore only one key would normally be used.
UNLESS SPECIFIED RIGHT & LEFT SIDE(S) ARE TAKEN FROM THE DRIVING POSITION (LOOKING FORWARD OVER THE BONNET)
Timing positioned at TDC after new chain, cam sprockets and sliders. When i aligned the right cam to the mark on the cam tower the pulley was 7 degrees ATDC
Position of Left hand cam relative to marking on cam bearing tower (fixed position)…
Position of right cam shaft relative to mark on cam bearing tower (fixed position) this equates to approximately 7 degrees ATDC on the pulley which is disappointing considering people with high mileage engines get to around 2 or 3 degrees ATDC with a new chain and sprockets…
Chain well secured to prevent dropping into engine, sprocket on right cam removed along with large spacer washer that slides off easily (caution note – thin washer behind large spacer will stick together as shown so keep an eye on that or will disappear into engine) now see both woodruff revealed.
Knocking out front woodruff key (these are the originals so they fit in perfect with no overlap, if you see the overlap on a woodruff someone has been here before) place a long thin edge (large flathead screwdriver) at one end and lightly tap, key will either slowly come out (as happened to me) or fly out (as reported elseware) so if a spare pair of fingers are available use them!
New woodruff placed (0.9mm to get 3.5 degree offset at cam) in first slot at front, as can be seen the woodruff is off set to the left (as you look at it from the front of the engine) this means the cam will need to be rotated in direction of engine operation hence ‘cam shaft advancement’ in order for sprocket slot to fit over it (the sprocket does not move, only the cam)
Can anyone see the error made here? Woodruff in place before spacers put back in (Grrrrrr) you will be unable to slide on if you have done this due to difference in alignment of the two keys) Fortunately I filled recess for woodruff with Inox ‘just in case’, easy to pry out.
With thin and thick spacer in place I discovered that the large spacer is about 2mm over the 2nd woodruff at the front, bugger.
Now for the purists do not read further but if you do…. this is how I got around this issue….
I cut 2mm off the overlap part of the woodruff key, fortunately the steel is very mild (soft) and was easy to do. Not sure from an engineering point of view how this will affect integrity but considering the sprocket only sits on the exposed part anyway and the shaft fit is tight I do not expect any issue, certainly will report back if it does (in tears)
Sprocket put back on right cam and the chain tensioner put back in place. Engine rotated a lot of times (enough to get oil through the cam oiler passage) the following is the result….
Left cam shaft alignment to cam bearing tower marking, still in same position as before…
Right cam shaft alignment to cam bearing tower marking…
Pulley position at TDC (still the same, cams do all the work here)
Very happy with result
After replacing the following –
• Warm Up Regulator (WUR) $290 performed by MBSpares + postage
• Crank pulley – painted pot belly black
• Battery tray – painted pot belly black
• Both large hoses into and out of the Auxiliary Air Valve and most of the vacuum lines replaced with new
• Two new fuel lines from the CIS body to the WUR courtesy of Tom Hanson and TJ450 (Tim)
• New spark plugs NGK BP6ES
• Oil change (Valvaline Plus 20/50) and oil filter
• New coolant ‘Flow Kleen’ + de ionized water
After some trepidation I cranked her over on the 12 September 2010 and she fired up almost immediately. A growling noise was a lack of fluid in the Power Steering Pump (thank god, got pretty worried there for a mo) and heaps of smoke from the manifolds that were covered in oil.
She idled well and the timing was adjusted back to TDC, idle was just short of smooth as glass (big improvement) and only other adjustment was the idle screw and she now idles sitting on 750rpm.
No leaks of any sort and warmed up to operating temperature quickly
Many thanks Bill and Tim and the guys on the M100 forum who seemed to be the only online citizens covering this in detail.
(21-DEC-2010 edit) On advice from TJ450 i rechecked the ignition timing as there will be some adjustment as the chain and cogs settle in and after 3000klm the timing was 1 degree ATDC so moved back to TDC.