V6 Friction Ring Replacement

By Ken

Introduction

Ok so we have that evil rattle from the left hand rear bank of cylinders. Don't like it? Here's how it can be sorted...

Instructions

1. First thing is to remove the inlet manifold and all them plug sockets and pipes. It's not so bad as it looks to be around an hour to do.




2. Now rotate the engine until you see the paint marks on the rear cams line up - the marks will be on the helical gears there also may be a punch mark as well. Now check that the rear exhaust cam HLA’s are all off the cam lobes - try to rotate each HLA to make sure. It’s possible on number 6 cylinder they may be a little tight but don’t worry.
   
   Now remove the cam thrust housing as shown




3. It will only lift about 25mm but just enough to get your finger in to apply new gasket compound. Now next is to remove the camshaft bearing caps. When you do this make sure you slowly work you way across, loosening from left to right now lift out the cam and take a look at the evil little friction spring .




4. The friction spring is just a big concave washer that loads up the friction gear, this gear is just one tooth bigger so when under load from the rotation of the engine it keeps the main helical gears under load so stopping gear rattle, because the friction gear is one tooth bigger it has to slip a little, so what we have is no more than a simple clutch.




5. OK now to remove that big nut, it’s 41mm and tight. I never had that size socket so I had to resort to using a plumbing wrench and a rag it came of just fine - I held the main gear in vice using some wooden blocks. So with the nut off we can now remove the friction spring and gear. Take a look at the gear - if it has a groove worn in from the spring you should replace that too but you may not have to for a while.




6. 0K clean up time now and fitting the new parts. Now the fun bit when you reassemble the new spring. You have to make sure that the friction gear is just past the main helical gear tooth at the point of our paint mark or dot - if you look close you can see that the friction gear and helical drive gear teeth flow together. Get his wrong and the cam wont go back in snug and you will run the risk of snapping the cam so get this right!!!
7. So with luck our cam is now sat back in the head and we can replace the bearing caps - remember what way they faced??? slowly work you way from left to right and do not tighten them right down at first, just do it in stages. Next we have to get some gasket compound under the thrust cover, I used silicone compound and could just get my finger in there. There is a cam shaft end plug that should realy be pushed in after bolting down but we have no room so coat this with silicone and sit in place first and bolt up the thrust housing, time for tea? You deserve it! Right, now rotate the engine and make sure all is well. Replace the the inlet manifold and and all them pipes and plugs.




8. Restart the engine and listen to the change in engine sound. It is well worth the effort take it from me, friction spring is around £9 it took me 4hrs in total