Leaky china rail

Hey all,

I had to use some .120 gaskets for my Indy intake on my W2 econo heads and I sprung a bad leak at the front china rail. I used The Right Stuff RTV and thought I used a pretty big bead but apparently it wasn't enough.

Just wondering, have you guys ever had any success trying to seal a china rail up without harming the intake gaskets? How did you do it? I ask because I have custom gaskets from FlatOut and I was hoping to get this back on the road for some tuning and break in oil change this weekend, I likely wouldn't get the new gaskets in time.

Second, when it comes time to replace, should I maybe try a cork gaskets for the china rails instead of just silicon? Or just build the silicon up higher and try again?

thanks!

Go to your local good auto parts store and see if they have any RTV that says "Adhesive sealer or Adhesive silicone on the label, if they do buy it and use a small thin bladed screw drivers to pack that silicone in the leaking area after cleaning it thoroughly with either laquer thinner or brake cleaner solution
Make sure it is clean and dry before using the sealer

I always test fit my intake on my block and measure how big of a bead of silicon I need. I have Permatex black silicon in the big tubes on my caucking gun so then I can lay down the needed bead. I also take a black magic marker and trace a line around the intake during my test fitting so I know exactly where to lay the bead.

Cab's fix should be fine for a temporary fix. I haven't used a gasket on intake end rails for decades. Next time the intake comes off, put the side gaskets on, sit the clean intake on it and look at the gap to get an idea of what is needed. The silicon bead needs to be a bit thicker than the gap to get a squish effect. Use something with some body to it like the gray Permatex. If the gap is wide, multiple passes can be used to build height. Blend the ends up into the gaskets. I usually allow it to sit for a few minutes, before dropping the intake on it, to allow the silicone to skin and tighten up some so it doesn't just ooze out when compressed. Clean everything with lacquer thinner before assembly.

A shop vac plays heavily into my leak sealing methods

I use a shop vac and stethoscope to locate the leak.
I use a shop vac to draw cleaner into the leak.
I use a shop vac to help dry out the leak.
I use a shop vac to draw some sealer into the freshly cleaned leak.

After removing the shop vac, smooth the outside without vacuum applied to seal any holes drawn by the vacuum.
Let it cure overnite.

To make the leak easier to hear, you can cover the shop vac with a couple heavy blankets to reduce it's noise. Another solution is to buy more hose and place the shop vac outside.

Grant

Shop Vac - choice of the experts. Never fails when done correctly.

I agree the shop vac method is great, I have seen it used for all kinds of stuff, even changing drain plug gaskets while the engine is full of oil.

Thanks guys! it looks like it's seeping across the whole front of the china rail then dripping badly out from the corner down the head. I ordered new gaskets from Flatout with 2nd day air but I think I am going to give the shop vac idea in conjunction with what Cab said first. Might as well give it a shot, fingers crossed as I'll need all the time I can get this weekend to adjust the valves and continue trying to tune this FITECH 1200 on E85 to make it at least somewhat drivable.

I have nothing productive to add but, I do want to say that if you would have started out with an American rail, you'd probably not be having this issue.

I will probably get push back on this.. but the right stuff sucks.. install a healthy beat let it sit for a few days and cut it open with a razor blade it's full of hollow Pockets from the aerosol that used to push it out of the can.. I think it should only be used in a pinch because it dries very quickly.. however I have had numerous issues using the right stuff.. especially when trying to use a vacuum pump.. my Motors never leak oil only air.. I would tape everything up and use a heavy grade window silicone.. you can get it at your local hardware store.. and you apply it with a caulking gun.

I've used Permatex Ultra Copper on my last three small blocks (china walls) and had no leaks.

Permatex 82194 Ultra Grey

Agree, Ultra grey or black RTV.
Clean both surfaces with alcohol, apply a film to both intake and wall with your finger(to verify/assure adhesion). Then lay out 3/16 bead on the wall and install intake. Wait 24 hrs. if you can.

Parksr5, very true! LOL

I've probably done almost 100 intake jobs and never once have I had a leak. This is the first time I have used The Right Stuff, always used to use ultra gray. Maybe it really is just poor silicon, but it's also probably the biggest gap I've had to fill so might have just been me not being careful in building the bead high enough. I'll let you guys know how the fix goes when I can get out there to work on it. Thanks for the help!