Sealing hot pipe to HX40

[Woodenhead]

I finally have my 40/3B twins installed. When I close my exhaust brake and check for leaks I am getting a leak between the hot pipe and where it bolts onto the 40 with a copper gasket. Not a gushing leak but it's still there and I'm not sure how much effect it will have. I guess for those surfaces to seal air tight with the copper gasket they'll have to be flat within a few thou. which isn't the case.



Anyone ever used a thin coat of hi temp sealer on the gasket face to get a nice tight seal? Maybe some hi-temp RTV or ? I'm thinking about pulling the gasket, giving it a thin coat, put it together and snug the bolts, leave it over night and crank the bolts up the next day.



Mike

 

[Jetpilot]

Use the hi temp copper RTV, used it in the same location with excellent results.



Doug

 

[NPloysa]

Hi Doug!



Yes, what Doug said. I used a lot of combinations on my jet engine and found the RTV to be the best for a paste-type. I ended up using a "cork" gasket with it too.

 

[Woodenhead]

Nice! I was standing at NAPA today with a tube of copper RTV in my hand. It says it's good for intermittent temps of 700F. I was wondering if it'd hold up, looks like it's close enough. I might wait until I get my gauge in the manifold to check drive pressures just so I can see how much difference this leak really makes.



Thanks Fellas!

Mike

 

[Woodenhead]

Removed the bolts from the hot pipe, slid out the gasket, applies some copper RTV, slid it back in and cranked up the bolts. Sealed up tight now. Thanks,

Mike

 

[PToombs]

I love the "Ultra Copper". It's the only RTV I use anymore. Seals on oil, fuel, heat, water, my fingers... ... .

 

[CanadianCarGuy]

What about the other end of the hotpipe where it bolts to the top turbo with the V-clamp, what can a guy used to seal this? I tried muffler tape, but it doesn't quite completely seal it.

 

[Woodenhead]

That is the end that I used the RTV on. The end that bolts to the bottom turbo (3B) has a gasket with 4 bolts just like it would on an exhaust manifold. On my setup the exhaust flange on the 40 is removed and the hot pipe bolts on in place of the flange with 5 bolts and a copper gasket. This is where I had the leaks.



As far as you leaks go. I have found if a V-band clamp is leaking then either it's not tight enough or the pipes are being pulled on a bit so they won't come together. The flange faces should be able to sit flat against each other before the clamp goes on. I've fought with this situation on my exhaust before. I guess you could try running a bead of copper RTV around the inside of the clamp, put it on and tighten it most of the way. The next day crank up the clamp to compress the RTV a bit and see if it seals. Might work, might make a huge mess and take forever to clean up a pile of RTV. I'd be careful not to get a bunch of RTV inside the pipe to where it may go through a turbo.

 

[CanadianCarGuy]

The problem is the clamp's V has stretched slightly and with the exhaust mounted it pulls down the bottom turbo spreading the flange surfaces apart. I have the exhaust leak under control now I think, there is no more black soot covering anything anymore or any signs of smoke for the time being at least.

 

[BPonci]

If you still find that it leaks you can aneal the copper and then double back with some ultra copper. Anealing softens the gasket so it will bite better on uneven surfaces. Food for thought.

 

[NoSeeUm]

Use the hi temp copper RTV, used it in the same location with excellent results.



Doug

The s400 outlet flange leaked when I used the brake. So just like JP, the High Temp (copper) RTV is what I used.



In my case, I layed a bead in the V of the V-band clamp and just re-installed it. Knock on wood, it has not leaked since.



Jim