Falcon Head Gasket

Head Gasket Replacement Falcon 4.0 – Part Two

This article is the follow-on of Falcon Head Gasket Replacement Part One.

We’ll start the reassembly by getting the cylinder head ready to go back on. First up if you have removed the cam and rocker gear now is the time to bolt it back on.

Lube the camshaft journals with a bit of engine oil and carefully drop it into place. To make life easier when it comes time to fit the camshaft sprocket ensure that the notch on the camshaft snout is in the correct position like so –

falcon head gasket replacement 35

To ensure that the lash adjusters don’t fall out when you go to fit the rocker gear use some masking or electrical tape to temporarily hold them in place. If you have one come apart on you see the pic in Part One for the component breakdown.

falcon rocker gear

Loosely fit all of the 10mm bolts and then remove the tape. The bolts MUST BE tightened gradually up to a torque of 25Nm, starting from the middle and working you’re way out a few turns at a time. You must also support the ends of the head as a couple of the valves will be protruding once everything is tightened up.

Once that’s done, roll the head onto it’s side and give the face a wipe with a clean, petrol soaked rag followed by a dry clean rag.

At this stage I suggest taking out the new head bolts and lightly oiling the threads and under the head of the bolts so that they are ready to go when you drop the head on.

falcon head bolts

Now for the block. After making sure that it’s as clean as it’s going to get fit both dowels to their respective holes (one front and one rear) and give them a gentle tap with a hammer to make sure they are all the way home.

falcon head gasket dowels

We can then fit the head gasket ensuring that it fits over the dowels and lines up with the bolt holes, cooling jackets etc. The top of the timing cover gasket can now be fitted also. Have your helping hand standing by as we need to work quick once we put the sealant down. At the very least I suggest some silicone sealant (Ultra Blue or similar) where the timing cover and block meet, and to be honest on most models I usually run a bead of silicone right around the top of the timing cover and ‘sit’ the gasket into it so it doesn’t move, and doesn’t leak.

Now we can carefully lower the head down evenly onto the block, making sure that the timing chain sprocket and guide don’t get caught up and once it’s down make sure the it locates in both dowels. Start fitting the bolts as soon as possible and just run them down ‘just tight’ for a start.

The next steps are important to get right, we first have to torque all the head bolts to 40Nm (30ft. lbs) and then take them a further 90 degrees. So first take the bolts to 40Nm in the sequence shown below.

falcon head bolt tightening sequence

And then a further 90 degrees. A Torque Angle Gauge is a good investment here, however 90 degrees is obviously a quarter of a turn so if you’re careful you can line up the breaker bar with the rocker shaft for example, and then turn it to be perpendicular with the side of the head and you have 90 degrees. A good trick for not loosing where you’re up to is grab a white marker pen and make one mark on the bolt head when you’ve torqued them to 40Nm and add another mark when you’ve done the 90 degrees, that way you end up with a ‘X’ on the ones you’ve done and if you get distracted it’s not hard to pick up where you left off.

using torque angle gaugeUsing A Torque Angle Gauge

Next on the list is to fit the timing chain sprocket to the camshaft. Hopefully you’ve lined the camshaft up nice when you’ve fitted it back to the head and it will simply be a matter of lifting the sprocket up a bit, sliding it onto the cam and the locator will fit right into the cutout. If you didn’t quite get it right, as I didn’t, you will probably find it easier to slightly rotate the crankshaft until it lines up, rather than trying to move the camshaft.

DON’T FORGET to fit the bolt and washer, a little bit of Loctite doesn’t go astray on the thread, and then TIGHTEN IT by locking the cam up with a socket extension or something similar onto a headbolt.

falcon timing chain repair 8
Smear some thread sealant on the upper chain guide bolt and fit and tighten it also.

falcon head gasket

Next up we can reset the timing chain tensioner as per the FALCON TIMING CHAIN TENSIONER article and cut the zip ties off. The thread on the timing chain tensioner ‘plug’ should have some sealant put on it before fitting also.

At the point I always turn the engine over by hand to make sure that there are no issues that we need to deal with before going any further. You can either do this by using a 24mm socket and ratchet on the harmonic balancer bolt or by using a large screwdriver through the bolts on the waterpump pulley. Chances are you won’t have any spark plugs fitted, but if you do I suggest removing them for this step. It makes life so much easier!

Also, please don’t skip this step, you don’t want to find out you have problems after putting everything back together, or worse you hit the key and something like the valve timing isn’t right and a couple of pistons turn some valves into spaghetti – not nice.

falcon head gasket 1 falcon head gasket 2

Make sure you rotate the crankshaft two full turns (one full turn for the camshaft). Now we are into the home stretch and can start bolting the manifolds on using new gaskets and I suggest using a Permatex Aviation Form-A-Gasket on the inlet gasket (around the ports is enough) and the thermostat housing gasket. Also it’s a good habit with manifold’s to tighten the middle bolts first and work you’re way out (as you would with head bolts). There is a few hints on getting to those pesky inlet manifold bolts in PART ONE.

Don’t forget to refit the engine lifting hook and refit the two electrical connectors.

falcon head gasket replacement 5

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On the exhaust side we also have the power steering pump bracket to fit.

falcon head gasket replacement 22

And pump and belt…

falcon head gasket replacement 27

falcon head gasket replacement 23

replacing timing chain 22

The next step is to refit the bottom and top radiator hoses and the expansion tank hose at the thermostat housing and then start on the tapper cover.

A new gasket should be fitted to the head for the tappet cover and be careful when fitting the cover not to push the gasket out, particularly at the back because the tappet cover’s are a bugger to fit at the best of times. Once you have the cover in place and bolted up (don’t forget the bracket for the brake booster hose on the back stud) the PCV valve/hose and back breather hose can be fitted and the brake booster hose refitted to the booster.

Then we can wind in some spark plugs, bring the plug leads over and put them on and then refit the accelerator and cruise control/kickdown (if fitted) cables.

Now it’s time to refill the coolant, change the engine oil and filter if you’ve had water in the oil, reconnect the battery and turn the key. Just as a precaution, keep an eye on the oil pressure light on that first start, always good to know the engine has adequate oil pressure!

Don’t be alarmed by very noisy tappets/lash adjusters. As soon as they get air in them they will be as noisy as hell on startup and may take some time to quieten down. I’ve had instances where it’s literally taken a day or two before all of the noise is gone.

Obviously keep a good eye out for any leaks and recheck the coolant level several times as the engine is warming up. If all looks good take the car for a drive and recheck for leaks and coolant level. I also suggest checking these again when the engine has cooled down.

Now it’s time to enjoy the fact that you’ve accomplished something awesome and just saved yourself a shipload of cash in the process, well done!!

8 thoughts on “Head Gasket Replacement Falcon 4.0 – Part Two

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  5. G’day. I recently cooked the head gasket (blew one) in my XH ute. 6CYL. There’s no water in the oil and it does still run smooth and doesn’t cough/fart or backfire…but of course I don’t/cant run it too long. Any chance of putting an online tutorial up for that? Or turning me on to a good one? I checked this one out..very clear and helpful stuff..but not 100% relevant of course.

    Many thanks!

  6. I have just replaced head gasket/bolts and a 2nd hand head assembly. After torquing it all down I went to fit the chain sprocket but it doesn’t align up, it is about 180deg away from the locating hole it has to go into.
    What do I need to do to fix this?

  7. I have just done the head gasket on my XG ute. There are some minor variations, but nothing of significance.

    To lift the head off, I placed two large cable ties under the overhead gear. This gives you convenient handles to grab, or put two bars through so you can lift from both sides without having to stretch over the guards.

    Thanks for your help

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