c900 8 valve timing cover removal with engine in situ

Job - Remove timing cover with engine still in car whilst attending to everything else in the area (preventative maintenance)

Difficulty - 5/5 Time required - 6-10 hours

Parts that can be replaced - New endless timing chain, new guides, new tensioner (old to new style), new oil pump O ring, new front crank seal, new water pump + gasket, + water pump to ports gasket, new alternator mounting and support arm bushes, new crank pulley, new belts

Doing a job in this fashion produces risks of breaking/damaging components that may not have been broken/damaged if the engine was removed due to clearance for tools. It requires a lot of patience and good quality tools, you may run into rounded bolt heads from previous work, seized bolts (water pump) or other snags - you will knock your hands up! If you do it be prepared for worst case scenario - hiring a hoist and doubling your work to fix something you may mess up in saying that it's obvious you MUST be careful. You CAN NOT afford to slip whilst trying to loosen bolts, you CAN NOT cut corners. if something doesn't work first time you probably need a better tool. :)

Advantages over engine removal (the annoying bits)
- Doable without a hoist
- Doesn't require removal/partial removal of drive shafts
- Doesn't require loosening of engine mounts (except right side)
- Doesn't require removal of gearshift linkage
- Doesn't require disconnection of starter motor and various components of loom

Difficult or time consuming parts of job
- Removing A/C pulley from crank pulley - minimal clearance - 3/5 20 mins
- Removing the stud at the bottom of the timing cover that screws into the transmission - minimal clearance 5/5 30 minutes
- Removing the 13mm bolt that bolts the right arm of the right engine mount to the transmission (under the exhaust manifold - minimal clearance) 5/5 - 20-30 mins

Overview of job
- A/C compressor + mount must be removed (if your power lead to your A/C doesn't have a bullet connector you will have to cut and solder a bullet or similar connector) A/C pulley on crank must be removed, A/C idler pulley + bracket must be removed
- Alternator must be removed + alternator stay bracket (can sit on intake manifold with all wires still connected)
- Water pump must be removed
- crank pulley must be removed
- belts must be removed
- right side engine mount must be partially undone (engine/transmission supported on jack)
- oil pump + housing must be removed
- P/S pump must be loosened (lifted clear of engine mount whilst getting timing cover clear)


I will continue this thread into detailed disassembly, I apologise for lack of photos I have an iphone that produces atrocious excuses for photos (no flash). I will do my best to take some photos and count fasteners etc. :lol:

Detailed disassembly – Apologies if I have 12/13mm mixed up in places, ensure you have the right size socket as not to damage the heads of fasteners (I’m doing all this off memory)

Instructions in order I did them

Remove A/C components
- 1 13mm bolt at top of alternator stay bracket, it is down underneath/behind the alternator
- 1x 13mm bolt in intake manifold
- 1x 13mm bolt going into cylinder head
- Remove A/C idler – remove the entire bracket that holds the A/C idler and P/S pump adjuster
- Remove the A/C pulley from the crank pulley – 3x 10mm bolts
- You may have to cut the power line to A/C compressor – use bullet connectors

Remove alternator
- Remove all electrical connections to alternator
- Remove alternator support arm from timing cover via 13mm bolt
- Remove 17mm nut on adjuster arm at top of alternator
- Remove adjuster bolt mechanism from alternator
- Remove alternator stay bracket by removing 2x torq or allen bolts (left and underneath alternator)
- Remove alternator
- (this is a good time to do alternator bushes [FONT=Wingdings]J[/FONT])

Remove crank pulley & all belts

Timing cover bolts
- Remove all 13mm bolts on timing cover – feel around for them
- Remove 2x 13mm bolts going up into cylinder head from timing cover
- Remove 1x 13mm bolt going up from transmission into bottom of timing cover
- The tricky part – down the bottom of the timing cover there is recess where there is a stud with a nut on it. The stud screws down into the transmission, you need to remove the stud to remove the timing cover. You need another nut at this stage – tighten it down on top of the current nut (to create a locknut) then you simply undo the bottom nut to remove the stud. You may need to retighten the bottom nut and then tighten the top nut down again as the stud moves out you may run out of clearance [FONT=Wingdings]J[/FONT] - This took me about 30 minutes just because there isn’t much space

The right engine mount
- Follow the left arm of the right engine mount to it’s bolt – 13mm in timing cover – remove
- Follow right arm of right engine mount to its’ bolt under exhaust manifold 13mm bolt – remove – this is tricky, minimal clearance, you need a short flat ring spanner, it took me about 30 minutes if I had a ratchet ring spanner it would have been easy
- Jack the engine up to take the load off the mount, use a block of wood between the jack and transmission. I jack at the transmission drain plug as there is another lip of metal which creates a large surface area, also because the right engine mount is at the back of the engine
- Remove the 17mm through bolt that screws through towards the firewall
- Remove the 2 12mm bolts with spacers going into the head
- The engine mount should now be able to be rotated – to flop down and away so the left arm of the mount is no longer in front of the timing cover

Oil pump housing
- I leave this until last to reduce stuff getting into sump etc. you can do it earlier if you like
- Remove the 8x 10mm bolts
- Remove the 2 13mm bolts on the left side – Take note of their length and location as they are different. The top one is longer and the bottom one is shorter. The bottom may seem similar to the rest of the Timing cover bolts – it’s not, it’s slightly longer, don’t get them mixed up
- Use the pry point to tap or lever away the oil pump housing, be careful not to lose the locating dowels, I had one in the timing cover and one in the housing.
- This is where you replace the oil pump O ring and front crank seal as per Bentley’s instructions

Triple check and feel with your hands that you haven’t missed any bolts on the timing cover, ensure the engine mount is out of the way – feel for the pry points and use a large flat blade and a mallet to tap away evenly, and that’s it you’re about 1/3 to ½ way through!

Now the timing cover is off you can replace the timing chain – before doing anything set engine to TDC, you can also replace guides with better ones (new ones are NLA)

Preparation for reassembly - Time 1-2 hours – Difficulty 2/5

- Clean all mating surfaces with a razor blade on the engine block and on the timing cover – this is time consuming but the old paper gasket may either come off nicely or be an absolute pain.
- With the timing cover off you can remove the water pump and clean up the gasket surfaces (you can buy both water pump and water pump to block gaskets if you want or use a sealant) I left the waterpump off when I installed the timing cover because it adds weight and the hole where the water pump goes makes a good holding point whilst aligning everything
- Install new crank seal and oil pump O ring in oil pump cover – make note of the outer gear of the oil pump having a punch mark in it, this must be visible to you (don’t flip the gear) – pack the oil pump with fresh Vaseline.
- Last step after cleaning everything and making sure you have all the parts etc to finish the job apply Loctite 518 to all mating surfaces of the TC in a continuous bead. Before you do this you may want to practice getting the timing cover into place (it is tricky! – a dry run is ideal)

Reassembly – Time 3.5-5 hours – Difficulty 4/5

- Aligning the timing cover is tricky, but I found the best way to do it was to put my little finger in the hole where the oil pickup goes to help guide and align it at the bottom,
- Be careful and watch and feel the bottom transmission gasket and the top head gasket, you do not want to bend or distort these or you will be in trouble. If the cover doesn’t want to slip into place then you have a problem, bear in mind the locating studs are a tight fit and the oil pickup makes it hard for you to align everything – Be patient – take it slow –
- You will know when its on right, get a small hammer or a mallet and tap the timing cover on all the while being worried about the transmission gasket which is in two parts (and so you can clear the 1^st but get stuck on the 2^nd) tap the cover on evenly (don’t hit the oil pump or water pump mating surfaces!)

Timing cover once installed -
- Torque up all the timing cover bolts to get the 518 gasket to form
- Install the oil pump housing onto the timing cover, lubricate the crankshaft with engine oil to prevent damaging the front seal, slide it on, the key on the oil pump gear has to fit the crankshaft – it takes some lining up.
- Torque oil pump cover bolts to 8nm – install longer oil pump bolt at top and shorter at bottom

Water pump
- Install old/new water pump with gaskets or gasket maker/sealant
- Look carefully at the housing, it will be obvious where the longer bolts should go and where the shorter bolts should go – use new bolts if you can buy them from a local fasteners store, they corrode and can seize/break as mine did.

Alternator
- Basically reverse of removal

A/C
- Basically reverse of removal

Engine mount
- Line up the engine mount and put the bolt through the mount into the timing cover do up loosely
- Start the 13mm bolt under the exhaust manifold by hand, it’s hard but it is doable, then continue with a spanner
- Install tighten 17mm through bolt
- Install 2 13mm bolts with spacers into cylinder head
- Remove jack

- Install crank pulley – torque to 190 nm (IIRC)
- Install belts and tension – from what I know you want 2cm of flex when you depress them otherwise they’re too tight

The rest is pretty obvious and simple, check and double check everything you have touched, whilst sitting here writing this I have realized I forgot to check the engine mount bolts for tightness!

Add coolant before starting and bleed the system, I’d recommend replacing the coolant entirely

Change oil and oil filter for good measure – dust and all sorts of rubbish may have fallen into sump whilst doing the job. Best to get rid of it!

Disconnect hall sensor or lead to coil and remove spark plugs – crank car over until oil light goes out- reconnect and start engine

Check for leaks, continue to methodically check over everything you did and didn’t touch, take it for a drive, check for leaks, be vigilant for anything you may have missed you have after all completed a mammoth job in your own backyard without a hoist!

Enjoy your new chain, elimination of oil leaks, and generally good feeling of tackling a number of things as preventative maintenance. Front seal, alternator bushes – oil pump o ring, gaskets and belts are cheap insurance so get the lot! don’t replace the crank pulley unless the rubber looks badly damaged or you can afford $100. Water pump replacement is your choice, if there is play or it doesn’t turn nicely or there Is no resistance (turns really freely) then it’s probably toast. At $55 for a good quality replacement, you may as well do it while you’re there! Timing chain – it’s probably never been done, so good time to do it now!

Good luck if you take the challenge, it is definitely doable, just give yourself plenty of time!