|Changing cams on a Falcon 6|
|A special thankyou to Scott Carden who wrote this documentation and who was kind enough to offer it for publication on fordmods.com
Howdy all. If your car is lacking in performance and after idling at the lights she blows a puff of smoke, then it sounds like you could use a new cam and valve stem seals. No matter what you've heard this can be accomplished by most back yard hacks and it can all be done without removing the head. Yay!
Now if your cam looks like this then you have some serious problems. At all times and on all faces, the cam should be nice and smooth with no scratches at all. This cam is severely worn and requires replacement. Not sure if this cam could be reground, but we picked up one from the wreckers for $33 which we were happy with.
If you've noticed that when you first start the car, or if when you are idling at the lights and then take off that there is a nice puff of smoke, then this points to your valve stem seals being cactus. Generally after a while they become brittle and/or lose the metal expansion spring that helps them to seal. They are not expensive and can be gotten from ford for around $30-40 a set, I can't remember exactly. I have been told that the ones for Clevos will fit and they cost next to nothing (like $8 bucks a set) but I am yet to verify this. Either way it's not much money.
So if you're ready to do both, I should probably run through the equipment you will need. For the cam you will need nothing more fancy than a basic socket set, that's it. Most other items I use can be pinched from around the house and returned when finished. For the valve stem seals, you will need to fabricate a few items and also have and air compressor and patient friend on hand. A few beers here doesn't go astray either.
I'll deal with the valve stem seals first because if you are doing both, you need to finish the valve stem seals before the cam gets installed.
First pop the hood. Crack open a beer, Toheeys Old is a good choice, then stand back and admire the beauty that is the Ford inline 6. Ok, enough daydreaming, time for some real work. Depending on what series you have, you will need to remove the intake, throttle cable, etc that clutters the top of the engine. We want everything out of the way so that we have easy access to the engine. Once all that stuff is gone you can remove the tappet cover. This car we are working on is a CFI EA. The arrow shows the tappet cover to those less mechanically minded.
Once the tappet cover is removed you should be able to see the cam under the lifters and their attachments. You can also see the valve springs, and the valves. Now the valve stem seals are down where the valve meets the head. So to start making our way towards them we need to remove the lifters and rocker assembly. Simply undo the bolts (12 from memory), you really can't miss them. Carefully remove the rocker assembly and place in a nice clean area, remembering which way they were taken off.
Now we have the cam sitting out in the open and the valves and springs revealed in all their glory. What we want to do now is to remove the cam so we wont damage it while we change the valve stem seals. First we need to remove the timing chain and sprocket from the front of the cam. Now you can spend lots of money getting special tools that hold the timing chain in place (cause if it slips a tooth, it's a big pain in the butt) but the cheapest and easiest method by far involves a broom and a brick!
So off you go and pinch ya mums broom and the brick that is holding the neighbors fence up and we can start. Ready? First make sure the engine is at top dead center just to make life easy in case you screw up. To do this first crack the bolt that secures the sprocket to the cam. Now remove the spark plugs as this will make it about a million times easier to turn the engine over. Then simply grab hold of the bottom pulley and spin it until the little dot on the sprocket that represents tdc is at 12 noon. Now you can undo that bolt completely. If it doesn't want to move it's because there is a lock washer on there. You need to bent the tab back a bit first.
Now for the clever bit. I'm sure you were wondering what to do with the broom and brick. Well it wasn't to beat me with if things stuff up. What you do is slide the brick onto the broom all the way down to the broom head (so it wont fall off). Next stick the broom into one of the four holes in the sprocket. The weight of the brick and the fulcrum effect it applies to the sprocket will keep it nice and tight. You can now gently remove the sprocket from the cam in the knowledge that it wont slip, unless you let the broom handle slide out of the socket. See picture for full explanation.
Now you can easily lift the cam from the head and once again place it on a nice clean surface.
I should probably talk about the tools you will need to make to do the valve stem seals. You will need one tool to allow you to force compressed air into the combustion chambers to force the valves to stay up when the springs are removed. What I found is that if you get an old spark plug, remove the guts out of it, you will have a nice little item that will screw into the spark plug hole. Next you need a small piece of pipe to attach to this (be careful that the pipe isn't too long otherwise you might find that it wont be able to fit to all the plug holes). You will also need an attachment to suit your compressor. Weld all these together and you have your first tool made. Congratulations if you did it all your self! (sorry for the bad pic)
The next tool is used to get the leverage required to compress the valve spring. What I have used is the same piping that was used to make the other tool, cut into three sections and welded together. The dimension will relate to the spacing of the mounting holes for the rocker gear. Hope fully this picture explains what I'm on about. As you can see you use the bolts from the rocker gear to hold this tool in place and use something similar to a large, strong spanner to force the spring down around the valve tip. Here is another view.
Now that the tools are made, we can continue. Lets just make sure we have everything ready. We have the cam out, tools made, spark plugs out, beer in hand, air compressor on and patient mate standing by. Right, lets get to work! Install the first tool into the number one spark plug hole, hook up the compressor and watch the motor spin a bit as the cylinder gets charged with air. Next give the top of the spring, not the valve itself, a tap to loosen the collets (two little semi circles that lock the valve to the spring. They only go back in one way as they are tapered). Install your second tool so that it spans around the spring and valve in question as above picture shows. Now while the compressor is keeping the valve up, have your mate lever the spring down. If the valve moves too, stop and give the spring a few more good taps to loosen everything up. As the spring is forced down, remove the collets. My best advice here is only lower the spring as much as it takes to get to the collets otherwise you risk losing more than a few into the depths of the engine. Once the collets are remove you can then lift the spring away and you should see the valve stem seal sitting down there flush with the head. Grab that little feller off and replace with the new one. Place the spring back over the valve and have your mate compress it again. Carefully place the collets back into position and gently release the pressure on the spring. If the collets are in the right way, everything should go back the way it should. Woohoo! First one done. Sit back have a nice cold beer and admire how far man kind has come. Then you'll remember there are 11 more to go!
Repeat the procedure along the line, remembering that there are two valves per cylinder and you're all done.
Now that your arms are aching and you've downed a few too many beers it's time to put in the new cam. Basically it is the reversal of the removal procedure adhering to the following points. Make sure you follow the manufacturer's instructions with regard to the new cam (ie, any shims required if it's a regrind, etc). Make sure you keep the tension on the timing chain when installing it back onto the cam. Make sure that the rocker gear goes on the same way it came off. Use the correct tightening procedure for the rockers (work from the middle out, alternating sides). And lastly when you place the rocker gear back on, make sure all the lifters are sitting on their respective valves.
All done. Put the rocker cover back on, hook up all your other stuff that you took off and make sure you put the right leads on the right plugs (always good to mark them first). If you've installed an aftermarket cam, the computer may take around 200k's for everything to settle down.
If you're game to give it a go, but don't feel confident in making the tools, or you just don't have the equipment, I can supply them to you for $30 a set plus shipping.
|Document description:||Information on changing camshafts for Falcon sixes|
|Document written by:||Waggin on 25 2005>, Copyright © 2005 Waggin, all rights reserved.|
|Document revised:||25 2005 - Revision 1.0|
|Document views:||16593 since 25 2005|