Exhausted and annoyed
Discussion
After using TVRbob's excellent method for finding exhaust leak [nice one bob] I found I still have that bloody annoying leak at the manifold to bin clamps. Had exhausts off previous cars before and they went back on with no real problem. Since having my mainifolds back with pre-cats taken out and cones put in earlier this year, I just cant seem to get them to seal properly and my MOT is up end of month.
I have used loading straps to pull manifolds together on to main cat' and even undone manifold to head bolts to help, but still can't get proper seal. Any ideas?
PS. previous cars and latest are Rv8.
I have used loading straps to pull manifolds together on to main cat' and even undone manifold to head bolts to help, but still can't get proper seal. Any ideas?
PS. previous cars and latest are Rv8.
happy to be of service. Did you have a willing wife happy to blow to her hearts content?It's a sod of a joint to seal, tell me about it. Although way outside its 'proper' applications and temperatures, I have had success with silicone RTV sealant here (and on other exhaust joints)... the very high temps seem to set it off into a hard but breakable/removeable form that gap-fills, seals and stays put. I've not tried the cargo strap method and had to resort to backing off the manifold fasteners to get the thing to line up as you describe...worth making sure all the scale and rust etc is off the joint faces to give it the best chance of self-aligning. And judicious use of soft-faced hammer around the v-bands made me feel better even if it did no good (think it does assist). Good luck
Wish I had a wife like that ..... 
The manifolds have come back bowed after the welding?
I'm wary of slackening the bolts to the head because the gasket here can be problematic too. Get it clamped down with a little external load as possible and then try not to apply any more load to the manifold than you have to when you connect the Y piece.
When you offer the joint up without the clamps fitted (cargo strap if necessary to pull the joint closed) you can see if the sealing faces are actually lined up and parallel. If they aren't, you're wasting your time. If it's only a little way out then loosen the clamp between the Y piece and the rest of the exhaust so that the Y piece can align itself with the manifolds and see if that lets you get the sealing faces lined up. If it still won't, you need to get physical with the manifold.
I'm wary of slackening the bolts to the head because the gasket here can be problematic too. Get it clamped down with a little external load as possible and then try not to apply any more load to the manifold than you have to when you connect the Y piece.
When you offer the joint up without the clamps fitted (cargo strap if necessary to pull the joint closed) you can see if the sealing faces are actually lined up and parallel. If they aren't, you're wasting your time. If it's only a little way out then loosen the clamp between the Y piece and the rest of the exhaust so that the Y piece can align itself with the manifolds and see if that lets you get the sealing faces lined up. If it still won't, you need to get physical with the manifold.
macdeb said:
Thanks Peter. I do fear about the manifolds as I have to use considerable force to get them anywhere near, of which I never did on previous cars. Mike [mongoose] on another thread said something about [if I understand it though not heard of it] that there are different sizes?
Mac,its the exhaust,not the manifolds,that were talking about on the griff forum.I would think that all the cat manifolds and 'y' piece are supposed to be the same?I had the same problem on my old Chim 450. I used a pure graphite based pipe thread / flange face sealant which is rated to 900 deg C. This is available from any industrial pipe and fittings merchant such as Pipeline Center, BSS, etc and goes by the name of Foliac Graphite jointing paste. I just call it black shite.
ntel said:
I had the same problem on my old Chim 450. I used a pure graphite based pipe thread / flange face sealant which is rated to 900 deg C. This is available from any industrial pipe and fittings merchant such as Pipeline Center, BSS, etc and goes by the name of Foliac Graphite jointing paste. I just call it black shite.
Can't be... that's Sikaflex
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