Exhaust leaks

[6SENSE]

Am I the only one that cant get rid of the exhaust leaks around my engine? This is really getting frustrating. Headers have been welded up and new gaskets. Always had ticking from passenger side (partly from ATR up-pipe never sealing at header), but now for some reason the crossover refuses to seal all the way and I have leaks from both sides now. I refuse to drive the car like this, sounds like crap, and I know it aint helping the performance either. Is there any trick to a good sealing exhaust, or should I just give up on the stock stuff and shell out the dough for aftermarket headers and crossover? It would be nice if I could get this stuff to seal though, the headers are ported and welded nicely. It would be really nice to have engine compartment exhaust leak free and just have all the noise coming out of the single shot in the back.
Thanks for any suggestions/comments.

P.S. whats the deal with going with no header gaskets? I know of some people that prefer to use no gaskets.

 

[FJM568]

The deal with no header gaskets is that Buick never had them on the motor from the factory...

As a matter of fact, I don't ever remember seeing them on any Buick motor that I have ever worked on...300, couple of 350's, couple of 455's, NA 3.8L, several turbo 3.8L's, etc...If all the mounting flanges are flat and true(heads and headers), you don't need header gaskets...

 

[TurboRegal84]

For the crossover pipe, Weld studs into the header flanges. I had a terrible leaking problem with my Poston headers leaking, but after I welded studs on it sealed up.


Another tip is to make a generious bead of Copper RTV around the inside of the Crossover pipe. Then slide the crossover flange over the studs you put in, and EVENLY tighten...no need to go bonzi on the torque, but nice and tight..."then some" is good.

Let the car sit for a solid 12-24 hours for the RTV to seal up, and you should be good to go.

(Method I used, and once you seal the crossover you will know it because spool should be VERY good)

Another thing that could be your problem is you put on header gaskets. Granted I have thought about how the heck GM got them to seal up so well from the factory, and I for one swear by the thick Poston Copper Header gaskets. Although using gaskets on the stock set up will set the headers further out from the engine, and this could create just enough room for the crossover not to seal up.


If you have the money buy the Poston Header set up, it is very nice, and gave me a decrease of .5 at the track.....The lifetime warrenty they offer with it is unbeatible!

 

[6SENSE]

Thanks for the tips. I was thinking off taking off the gasket on the driver's side header and see if it made a difference. The thought had crossed my mind about the headers sitting out further. If I dont have any luck with I will be thinking about the Poston set up. Did you get their crossover pipe too, or just the headers? Any reason to get all three pieces? What about the gaskets? Did they make the set up to be used with gaskets, or are they basically modeled after the stock and as long as the mounting surfaces are flat would be better without gaskets? You would think that by them being new the mounting surfaces would be true.

 

[TurboRegal84]

I can only suggest what I have used......

Get the Posten Driver Side, Passenger side, and Crossover pipe....take the mounting hardware they give you and put it aside....find the correct size stud, and thead it into the headers, and you should be good to go...

Go with the whole kit so that you start with brand new un warped flange sealing surfaces, and all of the peices can "move" together as they heat cycle.


While you are getting the system order the thick copper header gaskets from them...they require some slight attention after the install (re-tourqing a few times), but they will not blow out like a composite ones.

Good luck...the header system is a nice investment for our cars....unlike the 86/87 cars our car's really get a performance gain from engine exhaust modifications.