9000 Head Gasket & Timing Chain Replacement



FAQ by Ben Thompson - Email Contact
Prologue

Head gasket, timing chain replacement - in sitiu - on a 1994 Saab 9000 Aero

I've owned my '94 Aero for about five years now. It's the Saab I've always wanted, and I drove to freakin' Idaho to get it. The previous owner lived a good 3 hours from the nearest Saab mechanic, so I spent the first several years re-doing a variety of JB Weld and bailing wire repairs.

The entire time I've had it, the engine was always a little rattly on the serpentine belt side. I checked the pulleys, changed the top chain guide under the valve cover, and toyed around with different weight oils. Every time I took the car to my indy mechanic, Charlie, for something that I felt was out of my league, I'd ask him about the rattle. He told me some Saabs just are a bit louder than others, so for a while I was comfortable with that. Last month, I had the car into Charlie's to get the drain plug unstuck. I'd successfully made a circle of a hexagon again. He told me that I had a metal on metal sound coming from the chain, and that I should do something about that.

In addition to the persistent chain noise, I'd noticed the car weeping coolant from the right front (when standing in front of the open hood) part of the engine, right at the corner. I'd very slowly loose coolant, needing a top-up every couple of months. I knew I had a hairline fracture in my radiator where the top hose attached, so I figured that accounted for the loss, but I also knew the gasket was on it's way out.


So I did a little research, and decided I should check the extension on the timing chain tensioner. If it was out of limits (over 11mm), I'd pull the head and do the chains. If it were 11mm or less, then I'd leave it be for a while.

Now, one detail is critically important; that is, that I have a tiny garage. Actually, given the urban location of my house, it's lucky to have a garage at all (and in fact, it has a garage plus two carports). Though I have a crane and an engine stand (currently housed at my mother in law's house - that's another project), there simply isn't enough room for the car and the crane in front of it. That meant that whatever procedure I'd be doing, it's happening with the engine still in the car.

 

  1. Check the timing chain tensioner
    1. First up, I had to pull out the timing chain tensioner. To do this, I removed the upper engine (‘dogbone’) mount by removing the 14mm bolt at the firewall, and the 15mm bolt and 17mm nut from the rubber doughnut attached to the engine via a big, chunky aluminum bracket. I also removed the 3 13mm bolts from the bracket by the firewall and got that out of the way.



    2. Belt removal : Next, I had to take off the belt. I made a belt tensioner tool with a flat piece of aluminum and some screws. I can't say it worked great, but it did it's job (initially).



      To get to the belt tensioner, you can't realistically do this from above, so you have to pull the passenger side front fender liner. Besides, after the belt, I had to loosen the alternator, and that for certain has to happen through the passenger side wheel well. Taking out the liner requires removing a number of 8mm nuts from the arch of the wheel well, plus a few assorted other screws underneath and elsewhere. The fender liner comes in 2 halves, and you need only remove the front half.



      With the liner out, you can now have a clear view of the belt end of the engine. I put a 19mm socket on the tensioner pulley, and pulled on it counter-clockwise to relieve the tension, and slipped the belt off. Desperately trying to maintain balance and composure, I also grabbed the home-made tool and fit that over the tensioner, so that it wouldn't explode into two halves, when I released the tension. These two halves would repel each other like the same poles of two magnets if you ever try to reassemble them.
    3. Moving the alternator out of the way
      Now that the belt is off, I could loosen the top bolt on the alternator. It's an 8mm hex socket cap bolt. It doesn't need to come all the way out, which is good because there isn't room to pull it all the way out.
      The bottom bolt (also 8mm hex socket cap), however, does need to come out. Then lever the alternator until it comes loose, and push it back against the firewall to get it out of the way.



    4. Removing the upper engine mount bracket
      That done, you can now proceed to removing that big chunky aluminum bracket with the rubber doughnut at the end. There are 4 13mm bolts which attach this to the back of the cylinder head and the engine block. It's tough, because they are hard to see, but with a couple of short extensions, I was able to do it.



    5. Checking the extension of the tension
      Now, you can get at the tensioner. It takes a 27mm socket to remove, preferably a fairly deep one. But hold on, there buster! We want to know about the extension, and if we pull it out, it'll just zip on out to full extension and you won't know anything more than when you started. So first, remove the 12mm bolt that's on the end of the tensioner. There's a spring and a small plastic plunger under this bolt - if you can, grab those so you don't loose them. Now use the 27mm socket and turn it until it feels like you are just a week from retiring from what has become your life's work, and it'll come out. Measure the distance between the foot of the tensioner and the body, and you'll have the extension length. Saab's spec is a maximum of 11mm, and then they start talking chain and guides replacement. I understand that's a pretty conservative number (how Swedish!), and it must've been because I had full extension on my tensioner (22mm). There literally wasn't another fraction of a millimeter that it could come out.



      Given the state of the chain tensioner, I was certain now that I had to do the timing chains. From what I've read, it seemed like having the head off at the same time might make pulling the timing cover easier, so I decided to double down and take care of the head gasket as well.

  2. Removing the head
    To proceed from here and remove both the head and the timing cover requires the removal of an unholy number of bolts in really difficult places, but it's not impossible, and you don't have to be Harry Houdini to get at them. In short, to get the head off, you've got to remove the intake manifold, the exhaust manifold (and turbo), the heater hoses, upper radiator hose, DI cassette, and A/C compressor and bracket. Simple, right? Yeah... I thought so too.
    1. Drain the coolant
      But before you dig in on all that, you have to drain the coolant. There's a small plastic plug in the bottom of the radiator, on the passenger side. On my car, there is a cut out in the plastic splash panels where I could reach up with a good long pair of pliers and grab ahold of this plug and turn it. Be sure to drain the coolant into a container and keep it safely out of the way. I won't advocate being an environmental hooligan, and this stuff is poison to animals who are wont to drink it - so be responsible!



    2. Drain the oil
      I’ll assume you know how to do this. 13mm bolt on the back of the oil pan. You know the drill. Don’t forget to recycle your oil!
    3. Get your A/C out of the way
      Starting with the A/C compressor - this is held on with 3 impossibly long 12mm bolts. They should be relatively easy to turn. Unclip the connector for the electric clutch, and heave it up onto the front cross beam (above the passenger side headlight), and use some bungee cords to keep it there, safely out of your way. Next, remove the three 13mm bolts which hold the A/C compressor bracket to the front of the engine. Now put that somewhere you won't lose it, and leave the bolts in their respective holes (some are different lengths).



    4. Ditch the exhaust manifold
      Next, remove the exhaust manifold and/or turbo. I actually left the turbo nominally attached to the car, but you may find it's easier to remove it completely for extra working room. To remove the manifold, there are in theory seven 13mm nuts which attach the thing to studs coming out of the cylinder head. I say in theory, because every 9000 I have ever owned was missing at least one stud, usually more. They snap off - usually inside the head. If you are turning one, and find that it's far easier than you ever expected for a rusty exhaust bolt, don't be surprised if you pull it out and it only has about two turns of thread on the end of it, and the rest of the stud is still buried inside the head. A penetrating lubricant is your friend here. Soak the entire exhaust system and let it sit for a good while. There are also four13mm nuts that attach the exhaust manifold to the turbo. I find that having a variety of 13mm box and open ended wrenches (spanners, for you Brits out there) is useful. I have one box end wrench that I ground down to make it a bit thinner that works well on the back 2 nuts on the turbo flange.
      Remember to unbolt the water line (15mm banjo bolt - don't lose the washers!) that goes up the side of the engine and connects to the cylinder head right above where the heater hose goes in. Undo the other water line from the back of the water pump (also a 15 mm banjo bolt), and the bolt attaching the bracket underneath the turbo, and there should be enough play to push the turbo down a bit and wriggle the exhaust manifold free of the car.



    5. Remove a bunch of hoses
      Continuing counter-clockwise, make sure you remove the upper radiator hose, heater hose, and unbolt the metal coolant tube from the back side of the thermostat housing. On my car, this was held on by 2 very stubborn T-30 torx screws - may you not be so cursed.



      If you haven't done so already, unplug the DI cassette and remove it from the car. If you need to know how this is done, your next step should be to purchase a Toyota.
    6. Outtake the intake manifold
      Now, this is what I'd consider the second toughest part of the whole job - removing the intake manifold. It's held on by 8 12mm bolts. 2 on the ends, three on top, and vexingly, 3 underneath. I started by unclipping the fuel injectors (label these first!), and removing the ground wires. I pushed these wires through the holes inbetween the intake runners to gain a little more working room - especially for the lower bolts. I also removed the fuel rail and injectors completely be unscrewing the 2 T-30 bolts, but that's optional. With those out of the way, I worked my way through all 8 of the 12mm bolts, using a 6-inch extension and a small (1/4 inch drive) ratchet to reach the ones underneath. Once all the bolts were out, I could push that back against the firewall. Note that there may be a few extra coolant lines to the throttle body that are still tethering this Rube-Goldberg contraption to the head, you'll have to undo these too.



    7. Open the valve cover
      Continuing on around, you'll need to remove the two bolts which attach the head to the timing cover. Then you need to remove all 15 of the T-40 bolts which keep the valve cover securely clamped on top of the engine.



      The valve cover may be rather stuck (despite the fact that the seal around it is leaking), for this I recommend carefully tapping it with a rubber mallet until it comes loose. Now would be a good time to pull the PCV hose out of the back of the valve cover, and remove the hose entirely to get it out of the way.
    8. Time to set the timing
      Now, before proceeding, it’s a good idea to set the engine so that the #1 piston is at top dead center (TDC). This is relatively easy. Grab a ½-inch breaker bar with a 24-inch handle, and get an 18 or 24 inch extension and the 27mm socket you used on the timing chain tensioner. Use this on the bolt that secures the crank pulley to turn the engine clockwise until the notch on the back side of the pulley lines up with the ridge on the timing cover.



      If you then look at the cams, you should see that the timing marks on the cams also line up. If they don’t, you are off by 180 degrees, and you should rotate the crank through one more turn and they should show up.





      If the timing is correct, there should be 16 links between the marks on the cam gears at this point.
      EDIT: Raymond Foote points out "Actually there should be 15 pins or rollers (7 1/2 links). His photos show it correctly, 15 pins between marks, but it would be bad if someone followed the words and set engine timing wrong."



      The engine is now set up with the #1 cylinder at TDC. You’ll want to follow the same procedure to set the timing when you put everything back together.

      NOTE : since I was going to replace the timing chain and the gears, I made no real attempt to mark the timing of the gears during my process. If you're just doing the head, I strongly urge you to set the engine at TDC for the #1 cylinder and mark everything with something indelable so that you can line everything back up upon reassembly.
    9. Remove the camshaft gears
      Now that you can see the valves, and have everything lined up, it's time to remove the timing gears. I used a 19mm open ended wrench on the far end to hold the camshaft in place, and then used a 14mm socket with an electric impact wrench to get the sprockets off. In my experience, I have never been able to remove these with hand tools, only the impact driver will do.



    10. Off with the head
      Now that the sprockets were off, I could remove the 10 ET-16 head bolts. The socket I had is a 1/2-inch drive, and I used a 6-inch extension with it. I was able to break these loose by hand and turn them out.



      Once all the head bolts are spun loose, you can pull the head straight up and off the engine. It's moderately heavy (30 lbs or so), so make sure you're well balanced before pulling it. Set it on it's side, or stand it on end, and let the oil drain out of it into a pan. Don't lay the think flat on it's bottom - some of the valves may be sticking out far enough that you may bend them if you just throw it on the floor or a table, right side up.



      In my case, I suspected that I had leaky valve stem seals. The car would smoke a little on start up if it sat for a week or so. A look inside the combustion chamber lent further support to this theory, as the #1 and #4 cylinders had a lot of carbonized gunk in them. The tops of the combustion chambers were pretty cruddy too, so I took the head over to a local shop to have it checked, cleaned, and the valve stem seals installed. It was relatively inexpensive - $120 for the basic job + another $40 if they needed to re-grind the valves, and I felt better having an experienced hand tackle that part of the process.



      I also had a look at the gasket. It was in sorry shape. A couple of the coolant passages had become blocked, and the rubber in the front corner, where it had been leaking, was completely gone.




  3. Time to remove the timing cover

    Now, with the head off to the shop, I turned to removing the timing cover. This is not a terrible job, but there are a few pain points that I'll highlight as I go through it. In general, though, you'll need to remove the power steering pump and bracket, the water pump, the water feed line that runs from the pump to the thermostat, the crank pulley, and last, but not least the nine hundred and seventy two T-40 bolts which hold the timing cover on, plus the two that come up from the oil pan.
    1. Loose the power steering pump
      To remove the power steering pump, rotate the pulley so that the holes in the wheel expose each of the two 12mm bolts which hold it into the bracket. Use a socket on a 6-inch extension to get these out, then push the pump back against the firewall to get it out of the way. Given that the alternator is in that vicintiy, you may need to juggle the two of them until they co-exist happily. Then remove the four 13mm bolts which attach the pump bracket to the engine. Two bolts go into the block, and the two closest to you go into the timing cover. Pull the bracket out, and you'll now have enough room to retrieve the alternator (remember to disconnect it first).





    2. Dunk the water pump
      Next, you'll want to tackle the water pump. My pump had some play in it, so I planned on replacing it. On my '94, the pump is bolted onto the timing cover with 3 more of those T-40 bolts. The problem with that is there is no good way to get the bottom one out without stripping it. Newer cars ('95 on up) have traditional bolts here, which should make that easier. If you have the newer style bolts, undo those 3 and pull the pump out. If you are again smote with the dreaded torx bolts, you may have to do what I did.



      First, I used a prybar to hold the back of the pump's pulley in place while I removed the 4 T-30 screws that held the pulley wheel on. Then I removed the 6 12mm bolts (4 short, 1 medum, and one long length bolt) and took the back off the pump. It can be tight, but wiggle it around until it comes loose. I left the front half attached to the timing cover and separated the two it once the whole assembly was outside the car.



      Next I removed the T-30 screw (later models have a regular bolt) that attached the coolant transfer line to the front of the timing cover, and wiggled it out of the pump, then pushed it out of the way.
    3. Yank the crank pulley
      Then there is the big, tough job of removing the crank pulley bolt. It's a 27mm, and it's a tough looking hombre. Again, I turned to my electric impact driver. I put the car in gear to lock the crankshaft in place (otherwise, I would have just turned the engine over many times), and hit the switch on the electric wrench. Moments later, and with very little sweat on my part, the big, bad bolt was on the garage floor, and the crank pulley slides off easily.



    4. Turning Torx – or – how I removed the timing cover
      Now you can turn your attention to the 15 T-40 torx bolts which hold the timing cover to the engine block. I grabbed a flat cardboard box, drew an outline of the timing cover on it, and stuck the bolts in their relative position as I removed them. With all of them out, I couldn't quite get the cover off by pulling alone. I got out my rubber mallet and carefully tapped at the back side of it at the water pump and on the back side of the engine. That got me a crack of an opening between the timing cover and the block, and I was able to pull it off by hand after that.







    5. Oil pump cover recovery
      The timing cover has a few components to it which will need your attention. First, it may have a ginormous circlup holding inthe oil pump cover (the oil pump fits around the hole where the crankshaft pokes through). Many people swear by the OTC 16-inch circlip pliers. But these cost upwards of $70, so I made my own. I bought a pair of 10" right angle needle-nose pliers at the local automotive store, and then took the dremmel to it to grind down the tips of the pliers so that they'll fit in the snap ring. Did the trick, and cost me just $9. I will say the OTC ones (which I did end up buying anyway), with their ratcheting mechanism, make installation of the circlip much easier than with my home-made tool.



      Mounted on the front of the oil pump cover is the front crank seal. I'd replace this (cheap insurance). Be careful when driving in the new seal that it goes in square and isn't cocked or uneven in it's fitting. I've also been told to drive the new one in to a slightly different depth than the old one. It seems the seal can minutely wear a groove in the crankshaft, and if you put the new one in exactly the same spot as the old one, you'll just be in that same groove, and won't get a good seal.

      Behind the oil pump cover (shockingly) are the oil pump gears. You'll want to check these for damage, missing teeth, or scoring, and clean the inside of oil pump casing thoroughly. Opinions are divided if the oil pump gears are better replaced as a standard procedure or not, but I elected to replace mine. After 180,000 miles, I figured the original pump gears had earned their retirement.
    6. Gears, chains and guides
      With the timing cover out of the way, you should be faced with an assortment of sprockets, chains, and chain guides that would have made the Wright brothers blush. Sitting on top (closest to you) is the balance chain. Behind it is the timing chain and guides. So to change the timing chain, you have to remove the balance chain. In the top right corner of the timing area is the balance chain idler gear.



      It has a countersunk T-40 screw holding it on. You are supposed to remove that, along with the balance chain tensioner, to gain enough slack to remove it. This proved to be the most painful part of the whole job. Given it's position in the car, there was no way I could get my electric impact driver square on it. The inside member of the fender was in the way. Turning it by hand also was ineffective. There isn't sufficient room to use the 'tap and turn' method that I'd employed so successfully on the other stubborn T-40 bolts. Add to this that on my car, this bolt was seriously stuck. It would not budge, and yeah, I ended up stripping it.

      Screw extractor to the rescue! I drilled a pilot hole with a 1/8th inch bit, and then proceeded to get the screw extracter firmly stuck in the bolt. My mgihty Makita drill didn't have the torque to turn it. I had to go get a 10-inch adjustable crescent wrench and clamp that onto the end of extractor bit, and was finally able to break the screw loose. Once you remove the screw, the idler sprocket falls right off the engine, and promptly rolls into the darkests, greasiest corner of your engine bay (for me, this was underneath the oil cooler).




      You can then remove the balance chain, and it's lower drive sprocket - which just slides off the crankshaft. The tensioner is held on with 2 T-30 bolts (or 8mm bolts on newer cars), and can be cleaned out and re-used. Pull the plastic guide that it pushes on straight off it's hinge pin, and remove the 2 T-30 bolts holding the top balance guide to get down to the next level - the timing chain.

      The right chain guide is held on by 2 more T-30 bolts, while the left one can be pulled straight off the same hinge pin it shares with the balance chain guide. There is also a lower chain guide under the crankshaft held in place with 2 short T-30 screws.

      Remove the timing chain, and slide the drive gear (which is smaller than the one for the balance chain) off the crankshaft. You car should now be berift of both valve train and timing components.



  4. Cleaning up your mess

    It's time to clean everything thoroughly. As I mentioned previously, I sent the head off to be cleaned at a professional shop. It was a job I didn't feel the need to risk messing up. Cleaning the top of the block, though, that was left to me. I used a razor blade scraper to remove all the chunks of gasket that had become one with the block, and then sprayed the whole thing liberally with brake cleaner.

    Then I spend an inordiant amount of time blocking up the coolant passages, oil feeds, and bolt holes with cotton balls. I got a couple of nylon scouring pads that are mounted into a roloc backing plate, and put that in my drill. It's important to note that these nylon pads don't have any additional abrasives, like aluminum oxide (present in your kitchen variety green scotch-brite pads). I've heard plenty of people use the plain old scotch-brite pads, and other people poo-poo this idea, so I decided to err on the safe side. I figured if I were careful in avoiding the abrasive dust, while it might make for more work on my part, it certainly won't be a detriment to the engine. I cranked the pistons halfway down so that I wouldn't hit them with the abrasive pad, and stuffed the cylinders with rags before hitting the top surface with the drill mounted pad. Once I had the top of the block to a suficient shine, all I had left to deal with was the carbonized crap on top of the pistons.

    To remove this, I found that a plastic scraper works best. I used a 2-inch plastic drywall putty knife from Lowes, and it did the trick nicely. I could scrape off the hard crusty stuff, then hit it with brake cleaner and a rag to polish it off. Keep in mind, I still had the cotton balls stuffed in all the openings in the top of the block, so I was careful not to get any of this crud down in the engine.



    Once the pistons were clean, I rotated the crankshaft so that each piston went down to bottom dead center, and observed that some of the crud had gotten into the cylinders. I'd wipe out the cylinder, rotate the crank, wipe again, rotate, wipe, until there were no more streaks of crud on the cylinder walls. By the way - for turning the crank over by hand, I simply slid the crank pulley back on the crankshaft and turned the pulley by hand - it should be easy enough.

    Next, I did the same kind of treatment to the timing galley area, paying particular attention to the mating surfaces for the timing cover, to make sure I got them as clean as possible without scratching or damaging the mating surface.
    For this, I used a pink scotch-brite pad. The package had it labeled as "delicate", which means it was just pure nylon, no additional abrasives. I took the timing cover outside, along with the valve cover and all the other greasy parts and applied liberal amounts of engine degreaser. There's no easy trick for these, it's simply engine degreaser, scouring pads, a hose, and lots and lots of scrubbing.

    Once I got them thoroughly cleaned, I inspected each for cracks and wear. I removed the 17mm bolt from the bottom of the timing cover and pulled out the oil thermostat spring and valve. I cleaned them all liberally with brake part cleaner and reassembled. I also cleaned the inside of the oil pump housing with brake cleaner, being extra careful to remove any contaminants.
  5. Assembly (with more than 1’s and 0’s)
    Now we have officially turned the corner, from tearing down to building back up.
    1. Rebuilding the oil pump cover
      For many people, the front crank seal pops right out of the oil pump cover. In the few engines I've taken apart, I've yet to have that happen. For me, I had to turn the oil pump cover and tap around the inside edges of the seal with a hammer and a large flat blade screwdriver to eventually drive it out and replace it with a new seal. I’ve been told that when putting the new seal in, drive it to a slightly different depth than the old seal. The theory is that grit trapped between the seal and the crank and grind an imperceptible groove in the crank, widening the gap and letting out oil. Having the seal in a slightly different position makes for a tighter seal. I used the old seal with a block of wood to drive the new one home. I also replaced the large O-ring around the perimeter of the oil pump cover.
    2. Time to gear up
      The next step is to install the new timing components. I know some people install the head before putting the timing cover on (there’s a trick with this that involves putting the timing cover in your freezer to shrink it slightly), but I couldn’t make that work, and ruined a head gasket. Therefore, I recommend you install the timing and balance components first, then get the timing cover all buttoned up before installing the head gasket and head.

      During this process, I find that it’s helpful to put the car in gear, as it will keep the engine from rotating while you are working on it.
      First, slide the lower crank gear on to the crankshaft. On the bottom of the sprocket, there should be a mark. On the new chain, there will be some shiny brass colored links. Two sets of links will be 16 links apart, and a third, solitary brass link will be halfway down the chain from them. Find this link and line it up with the notch in the gear.



      Drape the rest of the chain over the top of the engine block or use a bungee cord to apply a little tension by hanging it from the open hood. Then install the two timing chain guides. One of these guides (the fixed one) straddles the chain, and the other is hinged on a peg sticking out of the engine block.



      Next, slide the lower balance gear onto the crank. It will ride up against the timing gear. Then, on the same peg as the hinged timing guide, slide on the hinged balance guide. Then install the hydraulic balance chain tensioner (make sure the thumbtack stays in to lock it in the retracted position), fitting the slotted end of the tensioner into the notch on the balance chain guide. Once this is done, you can drape the balance chain over the balance gears.



      Next, grab the balance chain idler sprocket, thrust washer, etc. and put the new bolt through it.



      Now, check that both the balance shafts are lined up properly. There is a mark on the shaft, and a groove on the collar that bolts into the block, The way the balance shafts are weighted, they should rest in the lined up position.



      Then, hook the idler shaft into the chain and tighten the bolt to hold it fast to the block. It took me a couple of tries to get the idler gear in the right spot so that I didn’t pull the balance shafts out of alignment on install.
      Once the chain is on, install the upper guide balance chain guide and the lower guide and you are ready to close up the timing cover (don’t forget to pull the thumbtack out of the balance chain tensioner first).



      Here is how it should look…



      Make sure that all of the mating surfaces on both the timing cover and the engine are clean and smooth. Apply a thin bead of anaerobic sealant to the engine side, and the engine sealant to the timing cover (or vice versa, if you prefer), and slide the timing cover into place. It should go smoothly, and only take some gentle tapping with a rubber mallet to properly seat the cover.

      Then, using your cardboard organizer, re-install all the bolts in the timing cover. Wipe away any of the excess sealant that may have oozed out.
      Install the crankshaft key and oil pump gears. Pack the gears with vasoline or lubriplate to make sure it gains suction on startup. Then install the oil pump cover, lining up the arrow on the oil pump cover with the arrow on the timing cover. Insert the crank pulley, and tighten the crank pulley bolt.



    3. Add the power (steering)
      Next, re-install the power steering pump bracket, and install the power steering pump with it’s 2 long 12mm bolts. At this point, I also put the bottom bolt through the alternator.
    4. Cool it with the water pump
      Then re-install (or install a new) water pump. This is easier with the head off as there is less to have to work around. Be sure to refresh the o-rings on the pipe that sticks out of the engine block, and the coolant cross feed pipe that runs around the back of the engine. Be sure to refit the pipe into the water pump. I also took the opportunity to replace the three T-40 bolts that were originally on the car with equivalent 13mm bolts – just in case I ever had to remove the water pump again.
    5. Head games
      Now re-clean the top of the engine block with brake cleaner, and wipe down with a clean paper towel.
      Lay the new head gasket in place, locating it with the dowels.
      Clean the bottom of the head in the same manner as you did with the block.
      At this point, I turned the crank back by hand counter-clockwise just a few degrees. What this does is gives us a few mm of room between the pistons and the top of the block, so that if any of the valves from the head are protruding a little, they won’t make contact.
      Here’s where it helps to have another person, though I did do this part on my own. The head is just heavy enough, and the reach is far enough to throw a person off balance, so having two people handle this part will make it easier. Make sure the chain is threaded through the head, and the chain guides are out of the way, then lay the head on top of the new head gasket and begin inserting NEW head bolts. These are torque to yield, so they cannot be re-used.
      Use the ET16 socket with a torque wrench to tighten the head bolts in the following pattern :



      First, tighten all the bolts to 60 Nm or 44 lb-ft.
      Then go through all the bolts (following the above pattern) and tighten again to 80 Nm / 59 lb-ft.
      Finally, give each one a 90-degree turn.
    6. Make time for the timing chain
      Now it’s time to put the chain back on and set the timing.
      First, reinstall the cam gear on the exhaust cam. Use a 19mm open ended wrench to hold the cam in position. We’ll reinstall the intake cam gear in a minute.
      Then, using the wrench, turn the cams so that the timing marks line up for both cams
      Now turn the crank forward again (clockwise) and line up the timing marks, so now both the cams and the crank are positioned with cyl #1 at TDC.
      Loop the timing chain over the exhaust gear. The brass colored link should be over the timing mark on the front of the gear. You may have to turn the cam slightly with the 19mm wrench to make this happen.
      Now take the intake cam gear and fit it into the chain so that the timing mark is lined up between the remaining two brass links, then fit the gear to the end of the cam. Again, you may need to turn the cam slightly with the wrench to get everything lined up.



      Now check that the timing marks on the crank and both cams line up, and that there are 15 links between the marks on the cam gears. Install the timing chain tensioner in the back of the head. At this point, I like to turn the engine over by hand a couple of times and make sure everything is still lined up. The brass colored links won’t line up with the marks, but the marks on the cams and the crank pulley should stay in sync.
      If you are just replacing the head, also don’t expect the brass colored links to line up; just make sure that when the crank pulley is lined up for #1 TDC, both of the cam gears are lined up on their timing marks too.
    7. Finishing the job
      From here, it’s largely a matter of putting things back together the way that they came apart. Once you have everything back together, fill the engine with oil and coolant. Check for leaks. Then take out the fuse for the fuel pump and/or disconnect the DI cassette and turn the engine over with the starter for a few seconds. This should prime the oil pump.
      Replace the fuse and the DI cassette, and start it up. The tappets may be loud and rattly at first, but it should fire evenly and run without a problem. Let the engine come up to temp, and then shut it off. Check for leaks again. If everything looks OK, finish buttoning things up and enjoy!
    8. Parting thoughts
      For me, and I fully admit I may be paranoid, I like to do a quick oil change after doing any kind of major work like this. I drove the car for 150 miles and changed the oil. It was just starting to get a kind of gray murkishness to it. As careful as I was, I knew there was crud and contaminants that might have gotten down in the engine, plus all the gasket makers and such that wound up in the oil. In my opinion, it doesn’t hurt to get that stuff out by changing the oil.
      I also put a ZDDP additive in the oil. Most engine oils you can run out and buy today (at least in the US) have little to none of this Zinc/Phosphate additive that prevents wear. If I just spent good money and loads of time on new tappets, I’d want to protect them a little.

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