Exhaust fumes question?

olddog · #1 (**permalink**) 07-15-2007, 08:35 AM

Before buying, I had ridden in a couple cobras. Short and fast rides. Now after logging a few miles in my own car, I noticed that the exhaust fumes can come into the car. It seems to me that how you adjust the wind wings does make a differance. The more you try to turn the wind out of the car the more the fumes come in. Not that it is real bad, but noticable. Is this normal? The car has side pipes, like most. It do think it is burning a little on the rich side.

Ron61 · #2 (**permalink**) 07-15-2007, 09:51 AM

When I had my Cobra Roadster, I never noticed any exhaust fumes at all at any speed. I did notice the noise and wore ear plugs when going very far. Could you have an exhaust leak in the headers or up front that is letting some fumes come back into the car? Mine ran on the rich side until it was warmed up as it had a racing set up and no choke on the carb.

Ron

MaSnaka · #3 (**permalink**) 07-15-2007, 03:55 PM

I have noticed when the exhaust leaks at the collectors it makes for a more noticable smell on my shirt. I can smell it after my drive. When there is no leak I cannot smell the fumes on my shirt. I have never noticed a connection with the wind wings. You might double check your collectors for leaks as the bolt fasteners are known to work themselves loose and fall off. John

Bob In Ct · #4 (**permalink**) 07-15-2007, 04:53 PM

No odors in my SPF. Check for leaks. CO is very unhealthy.

Bob

olddog · #5 (**permalink**) 07-15-2007, 06:39 PM

Thanks all.

A leak had not dawned on me and it should have.

I haven't heard anything sounding like a leak, but that may well be the case. I will check it out one night this week after work. Supposed to rain so it will be sitting.

h2oman · #6 (**permalink**) 07-15-2007, 07:49 PM

Headers and pipes flanged or slip fit?
Had the same problem until I flanged them.

Tinker51 · #7 (**permalink**) 07-15-2007, 09:47 PM

If I am moving I get no odor. When I sit in traffic I don't get an odor in the car but at the end of the day you can smell it on the clothes. My car does run slightly rich.

olddog · #8 (**permalink**) 07-16-2007, 03:16 PM

Ok. Yes the pipes are a slip fit. There is some leakage as there is a black sooty film on the pipes near the junction. Odds are that is where the fumes are coming from.

I'm surprised to see that there is nothing in the design to tighten the pipe diameters to each other. There are two bolts that are designed to keep the side pipes from slipping off of the header pipes.

Certainly welding a flange plate on each piece would be the ultimate solution, but then the ceramic coating will need redone to keep it corrosion resistant. That seems like a winter prodject to me. So what is the best idea on a temporary quick and dirty fix, to get by until winter?

MaSnaka · #9 (**permalink**) 07-16-2007, 03:29 PM

Olddog I'm sure someone with slip fit will chime in for you but I'm sure one way to seal them is to use the silicone sealer with copper. It's called Permatex Ultra Copper RTV. I don't think it's a permanent solution but it should work for a good while. I have the flange on my headers and side pipe and this stuff works great. Good luck, John

Ibr8k4vetts · #10 (**permalink**) 07-16-2007, 06:03 PM

silicone sealer with copper, that is what I use and it will last for about 1,000mi.

Burnd · #11 (**permalink**) 07-16-2007, 06:23 PM

Olddog:

The copper RTV is a temp solution but buys you time in a clutch. It'll cook away after a while. Been to that show.

I had the fumes problem on the passenger side of the car when i had a 351C in the car. The headers mated with a flange and I couldn't keep gaskets in the flange joint. It sucked fumes in on the passenger side; to the point where eyes watered.

I blew up the pictures of your sidepipes but i can't see where the slip fit joins. It "appears" it may be about 2" in front of the step-down pipe from the muffler. If it's not there, then I assume it's inside the 1/4 panel. That said; if its joined just in front of the muffler, I'd weld that SOB all the way around at that point and then recut the pipe at the center of the step down. You can have it slipped into an expander at the cut and make a new single 4" slip joint. Then you can buy 4" bands that bolt up tighter than a knats fanny, and the joints won't leak. The bolts on the bands face towards the frame rails and you can't see them tucked underneath. Mine are done that way and it allows me to change side pipe mufflers or run "shorty turnouts" too. Tubular Automotive Headers, Rockland, MA 781-878-9875 sells the bands and they're dirt cheap. Winter project though, but it would make life a lot simpler and the bands don't leak.

Bernie

h2oman · #12 (**permalink**) 07-16-2007, 07:41 PM

Quote:

Originally Posted by olddog

So what is the best idea on a temporary quick and dirty fix, to get by until winter?

Do what I use to do at the lights, hold your breath or breath shallow.

The sooner you flange it the happier you'll be, and the better she'll sound.

olddog · #13 (**permalink**) 07-16-2007, 08:11 PM

The header pipes end about 8" from the fender, as individual pipes in a square pattern like so ::

The side pipe slips onto the header, as four individual tubes inside the fender. From that point on the side pipes are welded as one piece.

The leakage at the slip joint is minimal. I was wondering if some type of fiberglass cloth could be wrapped at the joint and a stainless steel band could be clamped over it. Of course it would require 8 bands. I was thinking on the line of something similar to a hose clamp only wider.

h2oman · #14 (**permalink**) 07-17-2007, 05:28 AM

The way mine were sounds like yours. There was no way to get a complete seal without it blowing out.
Check out my flange install.

www.clubcobra.com/forums/showthread.php?t=78790

olddog · #15 (**permalink**) 07-17-2007, 05:47 PM

h2oman - thanks for the info. Did you use 1/4" or 3/8" plate for the flanges?

I have Jet Hot coating, as it looked like you did too. Did you have everything recoated? Can they spot in an area of damage or do you have to have the entire system recoated?

Come to think of it, the exhaust does pop if you back off at high rpm. I remember thinking at the time it had to be sucking in air, but it slipped my mind later.

Dirty Harry · #16 (**permalink**) 07-17-2007, 06:54 PM

That Permatex Ultra Copper has worked very well on my slip-fit headers and side pipes.

h2oman · #17 (**permalink**) 07-17-2007, 07:40 PM

Quote:

Originally Posted by olddog

h2oman - thanks for the info. Did you use 1/4" or 3/8" plate for the flanges?

I have Jet Hot coating, as it looked like you did too. Did you have everything recoated? Can they spot in an area of damage or do you have to have the entire system recoated?

Come to think of it, the exhaust does pop if you back off at high rpm. I remember thinking at the time it had to be sucking in air, but it slipped my mind later.

I believe the flanges are 3/8". I bought the flange kit from Bill Littleton at www.gcperf.com/, for about $140. However, I think all of the Backdraft Dealers carry the kits now.

As far as the coated headers, sparks when welding but cleans up nice. Didn't disturb any part except the end of the tubes. Looks good and no problems so far. Well worth the time and money!

olddog · #18 (**permalink**) 07-17-2007, 08:27 PM

Quote:

Originally Posted by Dirty Harry

That Permatex Ultra Copper has worked very well on my slip-fit headers and side pipes.

I'm going to check with a local muffler shop to see if they have anything any better. If not I'm going to use the Ultra Copper, for now. I will likely do the flanges this winter.

How many miles have you gotten out of the Ultra Copper? If it works good enough and long enough, I may leave it at that, but the flange would obviously be the most reliable fix.