sealing exhaust

[dave wheeler]

ok new big bore s2 pipe,cant get a seal on the manifold/barrel joint, doesnt appear to be weak in any way but there is an oily weep on the exhaust nuts, so 1/ does it matter if its weeping a bit but not showing any signs of weakness, 2/ will it go away if i ignore it, ie it will eventually seal itself up ,and 3/ i was given a heat mate sealant, remains rubbery and good for 300 degrees c, should i use?

[wack 63]

Take U pipe off and file/linish flat, then a smear of the heat proof silicone on both sides of the gasket, then loctite the nuts.

[coaster]

I agree with Wack, that'll be the problem but make sure you don't over tighten the nuts on re-assembly as the flange will bend slightly, maybe no straight away but over time it will and then it'll start to blow again. I notice that MB are selling thicker flanges for you get welded on to cure this problem.

[Yanker]

ok new big bore s2 pipe,

What pipe is it? Not 100% convinced about this 'Silicone' deployment reccomended here on both temperature and pressure grounds....

[dave wheeler]

its a casa s2 big bore.re-annealed gasket, used the sealant as per instructions, fired it up and within 5 mins could see black oily deposit starting to form on threads of exhaust stud, however yet again no increase in tickover or carburetion, so it cant be drawing any significant amount of air, so am inclined to moniter over a longish run and see if any changes, have also ordered an mb big bore gasket that isnt copper as i am not happy about the use of sealant, so may try that if it arrives in time

[dapper]

I always linnish the exhaust manifold on glass covered with wet 'n dry and also do the solid copper gasket (which I prefer) so that all surfaces are perfectly flat and then use Hi temp silicone to aid sealing.