So for all of you considering the friction gear spring replacement, here are some photos of what we're talking about and some comments on what to watch out for.
First off is the part itself....
Friction Spring (65KB)
Next....all the parts of the rear camshaft friction spring assembly. Notice the shiny areas on the inside of the spring washer and the outer ring of the nut. These areas show much greater wear than the contact points of the spring washer and friction gear....meaning it probably spent more time spinning on the nut then on the gear like it's supposed to....which is why it was redesigned...which you'll see later below.
Friction Spring Mechanism (48KB)
Now where the fun begins. You can take the FGS apart without removing the timing belt. HOWEVER, this poses several problems. First, the end camshaft thrust journal that holds both cams down can not be fully removed because it's too large to pass by the timing sprocket and gear on the belt driven cam.
This is the part I am lifting to it's maximum here.....
Rear Cams Thrust Bearing (101KB)
Why a problem? 3 Reasons.
First, you have to seal the mating surfaces of the thrust bearing and cylinder head with silicone. There's about enough room for a small pinky finger between them at max. Remember, you have to clean out the old first and can't get any of the new silicone on the cam itself (yeah...sure Houdini).
Second, you're not supposed to clamp the cam seal between the two halfs...it should be pressed in once they're assembled (which requires removal of the timing belt and sprockets). If you end up going the route of not removing the timing belt...put a thin coat of silicone on the cam seal to prevent it from being snagged and pinched when assembling. Wave a dead chicken over it as well :razz:
Third....there are end plugs in the cams that don't protrude....same problem as above....pressed in after assembly usually and no room to press them in once you put the pieces together. Once again, clean and silicone or replace and silicone.
Here is another shot of the journals and thrust bearing. The cam end plug seals the end of the cam on the right. Keep in mind...you need to apply sealant between these two aluminum pieces and it only lifts maybe 1/2" at most..........
Rear Cams Thrust Bearing -Side View - Cam Out (162KB)
Now the serious fun and the begins.
You will notice that your replacement FGS has two little tangs where it's supposed to slip over the collar on the nut. Why? To keep the FGS sliding on the larger area of the spocket instead of just spinning on the nut side. Looks like this.....
Old & New Friction Springs Side By Side (39KB)
My first thoughts .....
How will this fit on the nut? Well, there is a newly designed nut with notches in it. One problem though......it's special order at Ford and Mazda (at least around here). Not the time to find this when the engine is apart
What now? Die grinder. Used a dial indicator to find the center of the sides of the nut and cut a "U" shaped notch in two places....looks like this....
Notched Friction Nut(10KB)
Fit just swell.
Other outstanding issues....
Hope you have a serious tool collection or a trusting mechanic friend. The nut and flats on the camshaft are bigger than 32mm and on really tight. I have nothing over 1-1/4" or 32mm. Had to use a plumbing wrench and towel.
Make SURE you have the Friction Gear...this thing.....
Friction Gear (32KB)
...and the cam gear teeth lined up with each other at the marking point for aligning the two cams together. You will not be able to install the cam if the teeth are misaligned and it's just about impossible to turn the FG with the new spring on. Look for the painted marks and punched circle in the cams to see the alignment point. Good luck holding the FG from turning while tightening the nut....you almost have to anticipate the amount it will move and misalign it that much before tightening.
Lastly, remember to rotate the engine so the cams are not under any spring pressure from the valve springs. It should be off all HLA's and you should be able to spin the HLA's in their holes...if not, it's still under pressure. When you loosen the bearings, you'll chance bending them this way.
That's all I can think of right now.
First off is the part itself....
Friction Spring (65KB)
Next....all the parts of the rear camshaft friction spring assembly. Notice the shiny areas on the inside of the spring washer and the outer ring of the nut. These areas show much greater wear than the contact points of the spring washer and friction gear....meaning it probably spent more time spinning on the nut then on the gear like it's supposed to....which is why it was redesigned...which you'll see later below.
Friction Spring Mechanism (48KB)
Now where the fun begins. You can take the FGS apart without removing the timing belt. HOWEVER, this poses several problems. First, the end camshaft thrust journal that holds both cams down can not be fully removed because it's too large to pass by the timing sprocket and gear on the belt driven cam.
This is the part I am lifting to it's maximum here.....
Rear Cams Thrust Bearing (101KB)
Why a problem? 3 Reasons.
First, you have to seal the mating surfaces of the thrust bearing and cylinder head with silicone. There's about enough room for a small pinky finger between them at max. Remember, you have to clean out the old first and can't get any of the new silicone on the cam itself (yeah...sure Houdini).
Second, you're not supposed to clamp the cam seal between the two halfs...it should be pressed in once they're assembled (which requires removal of the timing belt and sprockets). If you end up going the route of not removing the timing belt...put a thin coat of silicone on the cam seal to prevent it from being snagged and pinched when assembling. Wave a dead chicken over it as well :razz:
Third....there are end plugs in the cams that don't protrude....same problem as above....pressed in after assembly usually and no room to press them in once you put the pieces together. Once again, clean and silicone or replace and silicone.
Here is another shot of the journals and thrust bearing. The cam end plug seals the end of the cam on the right. Keep in mind...you need to apply sealant between these two aluminum pieces and it only lifts maybe 1/2" at most..........
Rear Cams Thrust Bearing -Side View - Cam Out (162KB)
Now the serious fun and the begins.
You will notice that your replacement FGS has two little tangs where it's supposed to slip over the collar on the nut. Why? To keep the FGS sliding on the larger area of the spocket instead of just spinning on the nut side. Looks like this.....
Old & New Friction Springs Side By Side (39KB)
My first thoughts .....
How will this fit on the nut? Well, there is a newly designed nut with notches in it. One problem though......it's special order at Ford and Mazda (at least around here). Not the time to find this when the engine is apart
What now? Die grinder. Used a dial indicator to find the center of the sides of the nut and cut a "U" shaped notch in two places....looks like this....
Notched Friction Nut(10KB)
Fit just swell.
Other outstanding issues....
Hope you have a serious tool collection or a trusting mechanic friend. The nut and flats on the camshaft are bigger than 32mm and on really tight. I have nothing over 1-1/4" or 32mm. Had to use a plumbing wrench and towel.
Make SURE you have the Friction Gear...this thing.....
Friction Gear (32KB)
...and the cam gear teeth lined up with each other at the marking point for aligning the two cams together. You will not be able to install the cam if the teeth are misaligned and it's just about impossible to turn the FG with the new spring on. Look for the painted marks and punched circle in the cams to see the alignment point. Good luck holding the FG from turning while tightening the nut....you almost have to anticipate the amount it will move and misalign it that much before tightening.
Lastly, remember to rotate the engine so the cams are not under any spring pressure from the valve springs. It should be off all HLA's and you should be able to spin the HLA's in their holes...if not, it's still under pressure. When you loosen the bearings, you'll chance bending them this way.
That's all I can think of right now.
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