Replacing new gasket on CHC

[airjoc]

1985 911 W/127k miles, I'm a bit mechanical incline and tackling this issue myself with some expert advice. I have a bad oil leak seem to be coming from chain housing cover; "Is this common"? My question on replacing new gasket on CHC, do you recommend that I should put any sealants with the gasket; at same time I plan to also replace valve cover gasket, the new gasket has a small beads of sealant on the new gasket, do I add anymore sealant with the new gasket to valve cover. Last thing, need torque spec. if anyone have one...Thanks

[KTL]

First make sure it is indeed from the chain housing cover. Those covers do sometimes leak, and so does the "box" the cover is attached to- both at the inboard side along the crankcase and worse yet, behind the box where the camshaft enters the chain box. So the question is, is the leak coming from the front or the rear of the chain box? A picture would be VERY helpful

Without seeing a picture, i'm going to bet your leak is unfortunately the cam seal behind the box because this is a fairly common leak point. This one is kind of a pain because you have to remove the timing chain tensioner and the cam sprocket in order to get at the gasket and rubber o-ring at the back of the chain box. Then you have to retime the cam....

If it is indeed your chain box cover, that's easy. Use NO silicone sealant on the gasket. The only sealant that some people recommended is a spray sealant like Permatex copper gasket sealant or something similar which helps prevent weeping from the thick paper gaskets. But you can install the gasket dry and not have a problem, so long as your box cover and box surfaces are very clean- use a gasket removing spray and avoid doing too much scraping. The key is of course to get all old gasket material off so you have a clean, flat surface for a tight seal against the new gasket. Don't forget that you should use new tensioner oil feed line crush washers and also a new o-ring for the seal between the chain box cover and the tensioner oil supply port.

Chain box cover nuts are M6 nylock nuts (usually good to replace with new nuts and washers to avoid leakage) and are torqued to only 6-8 ft-lbs. If you don't have an inch-pound torque wrench, snug is good enough.

Valve cover gaskets also go on dry, clean with no silicone sealant like RTV or any goop like that. Torque those in a center-outward-diagonal manner to 18 ft-lbs. New M8 nylock nuts and aluminum washers are a very good idea to reduce leakage. That lower valve cover is a pain and they love to leak very easily. A lot of cars, mine included, like to leak THROUGH the nylon locking ring inside the nut.......

[airjoc]

I was afraid of this, someone is going to tell me something else is wrong thinking its just a simple thing to fix, its like going to the doctor and afraid to hear the bad news that he's going to tell you. Leak behind the cam seal and removing the timing chain tensioner and reset the timing, oh man....I dint hear that, I hope that not the case, have no tools to remove all that..going to keep my figure cross hopping that not the case. Thanks for advice KTL