THIS is why you dont use RTV
 

TL;DR Dont use RTV for header to TP/HFC connection, it WILL leak.


So I got some Resonated Test Pipes from someone on the forum, brought them to my favorite shop (at the time) to have them installed (I didnt want to deal with the demon bolt). The shop calls me a few hours later to ask if I brought gaskets for the header flange, and I said that the RTPs didnt come with them. The guy from the shop said that they would use either RTV or fabricate a gasket, and I told them either one would be fine as long as it doesnt ever leak.

I picked the car up and loved the new louder, deeper sound and extra HP. However, I began to notice that my car had a loud HISS whenever I was decelerating. I rode in a friends Z who had Long Tube Headers, and his had a similar, albeit less loud hiss. It got louder and more frequent until I finally got under the car to see that the shop had used only RTV, and that it was completely blown out. They have only been on for 3 months.

I ordered Z1's metal gaskets on Black Friday (see here: Z1 Metal HR/VHR Manifold 3 Bolt Gaskets) and finally got the chance to install them today.

Here is the obivous leakage:
http://www.the370z.com/members/losts...214-111452.jpg
http://www.the370z.com/members/losts...214-105808.jpg

So at the end of the day, if you are going to do anything with headers, test pipes, or HFC's, dont be cheap, spend the extra $40 and get gaskets so you only have to do it once.

that no where near enough RTV to seal the header and i bet the shop didnt let the RTV dry properly before giving it back to you(it needs 2-3 hours to dry properly)

im using RTV to replace a gasket that burnt up and im not leaking

at the end of the day, don't let someone else work on your car, you're just asking for something to go wrong

Metal gaskets are best.
 

Nissan uses metal exhaust gaskets on the car from the factory because they work best. Using RTV or a metallic cardboard style gasket does not provide the same heat resistance or durability as the OEM style metal gaskets.

luigi - You can tell they used a good amount, but it had all blown out, and most of it was stuck on the header side hence why this pic looks like there is none

verda - the factory components use a donut style gasket, which most aftermarket ones dont. I was just sharing an experience with a shop as well as giving a word of advice for those who might try to save a few bucks.

OEM dont have gaskets at all on the cats, just FIY



it looks like it was globbed on in some places and it wasnt spread evenly throughout the header
do you know which RTV they used? and do you know if they allowed it to dry properly before letting you drive it away?

like i said i have no problems with RTV on my header and test pipe(i used RTV ultra copper)

I only have a cat back on mine so far so I know that all of the factory gaskets for CBE are flat stamped metal gaskets for all of the 2 bolt flanges. But I haven't yet had the front of the cats disconnected. So next year when I get Motordyne ART test pipes I'll also be ordering the metal 3 bolt flange gaskets from Z1 to connect the test pipes to the exhaust manifold with no leaks.

Funny my car says other wise.

I purchased these from Z1 Motorsports for my HFC install. They worked as expected. Ahh ... just read the last sentence on your post. These will work great!

Z1 Metal HR/VHR Manifold 3 Bolt Gaskets

http://www.the370z.com/members/stino...4-img-0636.jpg

the factory cat has a stamped two bolt gasket on the bottom, and a stainless o-ring on the front. to anyone who says they didn't have rear gaskets, either they were removed already or were stuck to the pipe and you didn't notice.

The colour of that RTV tells me it's a high temp for water or oil. If it was the correct stuff, if would look copper coloured, not red. Still, I agree with the OP, use a gasket!

I have had no issues with red RTV when it comes to sealing exhaust flanges, even on boosted cars where the exhaust back pressure before the turbo can reach 20+psi. I do however let it sit overnight every time I use it. I think this is very important.

With the turbo kits I use Berk Technologies gaskets, rated to 2000 deg F. These have worked great when installed properly.

Ummmmmm... Yeah they do... How else does it seal?



And my bet is that the RTV didn't have time to harden. Red RTV sets stronger than the copper stuff too from what I've been told

Regardless of if RTV "can" work, the metal gaskets from Z1 WILL work and aren't so expensive that people should cheap out. Just my 2 cents.

I agree, but before Z1 had theirs out, RTV was a good second choice

Aren't the directions put in on, tighten only a little, wait a few hours, then tighten to spec. After 24hrs its gtg. I can't see a shop doing this!

Depends on the quality of the shop......

even the best silicone is only good up to 500F so it will fail eventualy on manifolds and cats that can reach temps well above that.

Doesn't matter. No ones gonna pay 3 hours additional labor for a TP job.

RTV copper is 700*. It never failed me on a 1600* turbo, but I use a gasket with RTV on both sides.

That's what I've seen on the back of every tube I've ever bought. Every time I followed directions it worked flawlessly. The only time RTV didn't work for me was when I was using it to redneck-engineer something and it was the wrong tool for the job.

My high temp copper rtv gaskets are working, but I wouldn't mind adding those z1 gaskets to my wishlist :) Thx for the idea

No they don't. The cat flandges are offset and the pipe physically sticks into the header. I'll upload a pic later today but when I took my cats off. No gasket

http://i.imgur.com/9IQIwYeh.jpg

Didn't you buy used? Looks like someone modded your car before haha. Looks like a crush gasket to me on that. But what do you think 9 and 18 are?

Yeah, that pic shows a metal gasket squished around the pipe.

Here's the 09 PDF, same as the 13 pic above, gasket at every location.

I have been using the COPPER as others have said the COPPER RTV for years. Both mating surfaces must be clean, real clean. Place a good sized bead on the TP flange, then tighten it up, but not torqued down. I let it sit for an hour, then torque it down, done. NO leaks long after gaskets start leaking. 8 bucks at advance for a tube enough to do a whole exhaust.

OK so there is a metal crush gasket that only fits on the cat. There isn't anything like the pic you posted on there. I bought my car used but it was bone stock down to the air filter.

This is a donut style gasket. If you want a leak-proof design, this is the route to go. Unfortunately, I can only think of one company that makes aftermarket test pipes where the piping protrudes the flange to allow this type of gasket to be used, Motordyne ART pipes (newer version).

I've used RTV sealant by itself, with gaskets, I've tried Z1 metal gaskets (which are still on the car). They all have leaked on me, on the passenger side where the manifold bolts to the upper flange on the test pipe. This is on two different sets of aftermarket test pipes - as I thought it could be the way the pipes were produced and not allowing them to sit flat on the flanges to bolt down, causing them to leak.

The Z1 metal gaskets held up the best and the only way to actually tell it's leaking is by listening through a stethoscope, pretty minor. You can't see much black soot around the flanges as you could with the other gaskets and just using RTV sealant, so from the naked eye it looks fine.

I finally got a hold of a set of newer ART pipes that will go on the car once the weather gets warmer.

Now its bone stock, wasn't before. :tup:

Sounds like an over tightening problem. Without cheating and looking, tell me the torque spec? I bet you bent the header flange. You'll need a straight edge and you'll have to check the surface of it. In the manual for example it says the header flange to the head is out of spec if there is like 0.028" gap.

http://www.nicoclub.com/FSM/370Z/Coupe/2013/EM.pdf. Page 41 and 145

That's what I thought too until I ran the stock cats after the fact without any problems / leaks whatsoever.

However, thinking about it, it would be pretty hard to bend the flange if you're using just a socket wrench and not an air impact wrench. Plus it wasn't gorilla torqued whatsoever.

I've done it before with a wrench and socket. Only way to check is to check.

lol doubtful, but ill bite

i can say safely nothing to the exhaust side was messed with, not too sure about the intake side although it was a pita to get off when i had my short rams installed there

I used the metal gaskets and put a thin coat of the copper stuff on both sides of the gasket before installation. Helps it stick in place when lining up the bolt holes anyways, and hasn't leaked :)

i did this when i was doing the valve cover gasket on my eclipse, probably one of the best uses for RTV out there

I bought a set of gtm resonated tp's. There was no header to to gasket supplied. Gtm said to reuse the stock crush ring. I purchased 2 brand new crush rings for the tp's and discovered that the rings do not fit on male part of the tp flange. I've been tossing up whether to just use rtv copper. Other ideas have been to cut the new crush rings and stretch them around the male part of the tp flange. Then use rtv copper in the gap area. Any thoughts?