Leaking header?

Are you getting any extra noise or is is louder than before??

Jerry

Yes it is. I will be taking off the SC today to have a look.

Leon

I had a noise a few years ago that sounds similar. It ended up being a crack in the exhaust manifold (e.g., sounds like it might be the header). Best of luck.

Gus (91 BRG)

I saw no problems with the header, but I found that one of the three nuts holding the header to the piece of pipe with the oxygen sensor was missing. I wonder whether some shop that installed an exhaust for me took it off to create more clearance? Anyway, I put on a new nut, with considerable difficulty (it is tight there,) and we will see.

I also put the FM cat back, which gives the humongous JR exhaust tip some clearance (the finishline has it against the fender,) but I am afraid that now the tip will again scrape against the bumper on throttling down, making another terrible racket. I may go for the bumper with a utility knife if it does not shut up. ;)

Leon

Now was that an FM *cat* or a *dog*?

I used vice grips and a BFH to "maneuver" the lip away from the pipe. Don't forget to replace any paint that chips away.

Leon,

The exhaust tip won't make noise from hitting the bumper, it will hit the frame first where the rear teeth are attached and that will create a godawful vibration. You'll need your 4" grinder to take away a little material from the frame to give it sufficient clearance. I think it's time for a "new" Miata for you :)

godawful vibration is exactly my symptoms. :)

I'll try that first, not having a grinder.

Thanks all, Leon

I ran out of time, but getting a grinder seems like an increasingly good idea. That lip is though. Double thickness, and steel hard as hell. Having no time left to put the rear on stands and take off the muffler, I tried a file on the lip. Not a dust particle came off. May try a dremel with cutting wheel if I cannot find a grinder.

For the time being, I wrapped some duct tape around it. :))

Meanwhile, with the nut I restored preventing an air gap to form between header and down pipe, the silence is deafening. No longer does Bozo sound like an AutoX special on starting the engine.

I now believe that the shop that installed my HKS exhaust is the one that came up with the neat little idea of removing the nut to create some "clearance." The HKS, and the JR after that, both heavily burned in the exhaust on coming back on the gas, as the movement of the engine in the engine bay would apparently open up the hole, allowing air to come in.

I must say also, that while the Flying Miata cat is more expensive than the others, it is the best made and has the most precise dimensions. With my earlier cats the exhaust tip was stuck so solidly in the cut-out that it did not rub.

Leon

Your FH isn't B enough. Drop the pipe and beat it to a pulp. I used an old lead-headed knock-off hammer from my MG days--must weigh 3+ lb.

If you're like me and seldom have a use for a grinder, buy the $9.99 drillmaster one from Harbor Freight. SOB wails like a banshee and took care of that material in two or three minutes (fits right in there without removing anything)and has come in handy for other "corrective" measures. I'm sure it would never stand up to everyday use but their Chinese tools work well for occasionally use and are about as cheap as you could want. Or, like Lanny said, BFH but that starts to seem like real work!

Tom