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Thread: Exhaust fumes in cabin solved!!!

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    Registered User Derek's Avatar
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    Default Exhaust fumes in cabin solved!!!

    For me that is.
    I've been battling with this problem for years. In Florida I mainly run with the windows up and the air on so it hasn't been too much of a problem. But with the windows down and during down shifts it was getting pretty bad. I had made all the usual repairs. New weatherstripping, sealed the tail ights, checked for holes with a flashlight, etcetera etcetera. All to no avail. I then came across this post by
    Zs-ondabrain http://www.classiczcars.com/forums/s...=exhaust+fumes

    Here is one thing you can do. Get a smoke machine, a shop vacuum and some cardboard.

    Cut the card board to fit in the window opening with the window 1/4 of the way down. Cut a hole the size of the vacuum hose into the card board and slide the card board into the felt groove in the upper part of the window frame. Then tape the lower part of the cardboard to the upper part of the open window.

    Turn on the vacuum. Start the smoke machine and blow the smoke to the suspected areas and there ya go. Or have someone on the inside watching for the exact spot that the smoke comes in, while you're out side with the machine
    .”

    The only thing I changed was I was on the inside of the car and my buddy was on the outside working the smoke machine.

    As I laid in the back of of the car my thoughts quickly switched from wondering if I wasted $45.00 on the smoke machine to “ I hope I can get out of here alive” as I was immediately engulfed by smoke. Okay I know the smokes non toxic but it was a bit freaky! We aired out the car and decided to go for a more measured approach. This time I was able to spot the areas where the smoke was coming in. In my case it was the body seams between the rear body panel and the inner floor that were leaking.
    I had put a new rear body panel on the car years ago and didn't do a good enough job of sealing the seams. The biggest culprit was the very bottom seam. This is the one you see if you look under the car and follow the inside of the panel upward. This is also where the bumper brackets mount. Although this channel doesn't directly lead into the cabin, the ends are open and spill into the ¼ panels under the tail lights.
    It then became a game of sealing leaks and the re smoking the car. All told I found 3 minor and 1 major leaks that I probably never would have located without the smoke machine. Now's the time to buy one because of Halloween. The party stores all stock these things.



    This really works!

    Derek

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    Back in the saddle again. Poindexter's Avatar
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    Great idea. I have heard that a chunk of dry ice in a pail of water (carefully insulated from any surface inside of the car) works well also- although I have yet to try it.

    2/71 240Z, HLS30-23788. 920 Gold/Black. California car. 5-speed, otherwise all original/paint, stickers & matching #'s. Driven almost daily over my local "road course" along a river. Performing thorough mechanical restoration, using only OEM parts to not ruin the provenance as an "original" car. Please check out my Flickr photostream!
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    Registered User cunniwj's Avatar
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    Derek, What were you smokin? I had the same problem with the windows up but when I replaced my tailghts with new ones and gaskets and sealed up the back panel most of it went away. I still get some smell with the windows down when I'm decelerating I guess it's areo effect. If you still got the stuff maybe I can come down and we can smoke my car.
    How's your car coming along and that manifold. Take care Bill

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    Registered User Derek's Avatar
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    Quote Originally Posted by cunniwj View Post
    Derek, What were you smokin? I had the same problem with the windows up but when I replaced my tailghts with new ones and gaskets and sealed up the back panel most of it went away. I still get some smell with the windows down when I'm decelerating I guess it's areo effect. If you still got the stuff maybe I can come down and we can smoke my car.
    How's your car coming along and that manifold. Take care Bill
    Man my car hasn't been that smokey inside for a lot of years! But that's another story.
    I bought one of the smoke machines and plan on keeping it. Your welcome to bring your Z over and we'll have a smoke out.

    The wife and I took the car out to dinner last night and drove home with the windows down. Not the slightest bit of exhaust fumes were in the car. She's more sensitive to the smell than I am and she didn't smell a thing.

    When I get a little more time I'm going to smoke the rest of the car and get the rest of it sealed up.

    The manifold is on hold right now as I'm really busy with paying pattern work. Although I'm carving an intake pattern right now for a Desoto Hemi. So I am working on an intake just not mine!

    Shoot me an email and let me know when you want to come over.

    Derek

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    Hi Derek:
    Thanks for posting the info. It's interesting to know that the seams were actually leaking.

    FWIW,
    Carl B.

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    Registered User Derek's Avatar
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    Quote Originally Posted by Carl Beck View Post
    Hi Derek:
    Thanks for posting the info. It's interesting to know that the seams were actually leaking.

    FWIW,
    Carl B.
    Hi Carl
    Yea it was really freaky. Ultimately it was my poor job of sealing when I put the rear body panel on but three of the seams were really tight but smoke still came pouring through. It's probably debatable whether these were leaking exhaust or not. The large seam along the bottom was probably the main culprit but as the many posts can attest no two cars are the same when it comes to exhaust leaks. I really went over the inside of the car with a fine toothed comb and never spotted these problems.
    You have to wonder about the condition of some of the seam sealer on these older cars though. I'm convinced that this is probably the only way you can truly solve the leak problem in a methodical way.

    One thing is that the lower seam is part of the rear bumper mounts so if there's been any kind of damage to this area there is the potential for exhaust leakage. I didn't bother trying to seal the seam. I shot some spray foam into the ends of the tubes and this sealed it right off. I removed the rear marker lights and this gave me a pretty straight shot into the tube.

    Things like spoilers and long tail pipes are just band aids that mask the problem.

    I've had this car since 1980 and I can't remember the last time I could drive it with the windows down and not get some sort of exhaust smell.
    I'm really psyched!!

    Derek

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    AZ Z Fan duffman's Avatar
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    Default Smoke or Fog Machine?

    Just for clarification, would a fog machine work for this, or is a smoke machine the only way to do this? I found fog machines are easier to find around here ...
    January 1970 240Z
    HLS3001399

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    Registered User Jeff G 78's Avatar
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    I never thought of using a Halloween smoke machine.

    I tried something very similar to this last summer, but I removed the C pillar air extractor emblems and taped the shop vac hose to one side of the car and taped off the other side. Unfortunately, I didn't have a helper, so I tried to do it simply by looking through the hatch glass with a flashlight for a smoke trail with no luck. I didn't feel comfortable getting inside the car during the test since I was using a chemical reaction HVAC smoke bomb rather than a Halloween smoke machine. I think I will try again this spring while inside the car.

    I did extend the tailpipe which greatly reduced the fumes in my car, but I'd like to completely eliminate the problem like Derek did.
    Jeff
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    I"ve been fighting the fumes in the car issue too since I got my car. I extended the tip and replaced the door and trunk seals and I no longer smell it with the windows up, but as soon as the windows come down, its smoke-out season. Once the weather gets better, I plan to try the smoke machine approach and see if I can fix it.

    Greg

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    beandip beandip's Avatar
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    Derek, like many of us, I have been fighting this same thing for a long time . I shot POR in the same channel on my Z through the marker light holes in the fender. However I still get a little fumes . I am going to try the foam in the ends of the square channel and see if this takes care of it. Thanks for the heads up.
    Gary
    I'd rather die while I am living than live while I am dieing. CZC 1887 IZCC 12602 Member of NorthWest Z Car Club

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    I put masking tape over the tail light area (inside of the Z) and covered the hatch vents too (I have a '70 with hatch vents, not the 71 with vents on the pillar) and the car went from undriveable (due to fumes) to now, very little fumes and none with the windows open.

    So now I will replace the tail light gaskets. I went to try to rempve the assembly and found that the bolts rotate freely but do not come out. What gives? Any advice?

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    Sounds like the plastic housing has been broken where the nuts are fitted. If you haven't removed your tail light cover/valance/surround, you'll need to do that (it's the 3 black or gray pieces that surround your taillights and license plate on the outside).
    First & Third owner of HLS30-00721
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    Frank in Houston, Texas

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    Great post.
    We just got plates on the kid's Z and are having fume issues.
    At first i thought it was the evap tank, but after reading this it's got to be exhaust.
    The car is fine with the windows rolled up, soon as you roll them down, she starts to get stinky!

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    Default exhaust smell

    I too have exhaust smells in my z when I sit at a stop light with the windows down. I have done all the work that has been discussed on this forum, and the car has no smell inside with the windows up. My question is why do our cars smell so bad in the first place. Is it a common thing with SU carburated vehicles. I have been around old cars and hotrods all my life and have not had one that smells like my 260z. We all spend a lot of time on sealing up our drivers compartments. I wonder if anybody has thoughts, opinions or ideas how to reduce the smell at the source
    Bob

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    Registered User olzed's Avatar
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    More on exhaust smell entering the cabin. On my 72 240 I had done all I could think of to try to remedy this, but it still persisted with the window down. Looking further, I noticed the area where the hatch compresses against the rubber along where the two hinges are, is two different profiles. The hatch rim is straight trying to seal against the rubber thats attached to the flange where the hinges are. At this area the body and the rubber takes a dip down to accomodate the hinges.There was a gap of quater inch wide and five inches long. I stuck on to the hatch sealing area at this point two pieces of self adhesive sponge strip about 6 inches long, at each hinge point.
    The gassing with the window down has ceased.
    Surely the vehicle wasn't made new like this with a hatch that did not conform to the body shape. I know this hatch is not origional to the car, as it had the rear vents from an earlier model. It fits perfectly apart from the sealing area where the hinges are. Are the early hatches different in this area?
    Last edited by olzed; 10-01-2010 at 08:20 PM.

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    I also wonder why the cars smell so bad. Mine isn't running rich, judging by the nice clean plugs. It still stinks, though. Is this an SU carb thing? Do 4-barrel converted Zs smell better?

    Man, you should have seen me charging the AC in my garage, with the garage doors open. Had to slightly rev the engine to get the compressor to suck in the freon, for like 15 minutes. Stank up the garage horribly. Note, the PO removed ALL the smog devices on my 73 car, so maybe that's why it stinks so bad? I also think I need to do a complete tuneup, including valve adjustment, as I haven't done it in about 18 months, or 10k miles. Maybe I should quit my rambling complaining and get to work....

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    Registered User Derek's Avatar
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    I was thinking about this this morning as I was driving in to the shop. It's starting to cool off here enough to have the windows down and the A/C off. Now I still don't have any fumes when I'm moving but when I come to a stop I can smell a little bit of exhaust. If I'm driving 40 mph and there is a cloud of exhaust gas trapped in the low pressure area behind the car and I come to a stop does the gas come to a stop as well. Or does it keep moving forward.

    Also when I drive the speed of light and I turn my headlights on should I be able to see anything?

    Thanks
    Derek

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    Registered User jaltman's Avatar
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    Quote Originally Posted by Derek View Post
    Also when I drive the speed of light and I turn my headlights on should I be able to see anything?
    That depends on whether your car has inertial dampeners to survive the acceleration.
    Jim Altman
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    if u drive the speed of light, your car will stop aging. Maybe even stop rusting.

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    Registered User doradox's Avatar
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    Quote Originally Posted by Derek View Post


    Also when I drive the speed of light and I turn my headlights on should I be able to see anything?

    Thanks
    Derek
    HID or halogen?

    Steve

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    Chillin Inf's Avatar
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    Quote Originally Posted by Derek View Post
    Also when I drive the speed of light and I turn my headlights on should I be able to see anything?
    I think you should be more worried about what kind of tires you're gonna use!
    -Andrew

    03/72 240Z HLS30-70xxx - R.I.P. 2011/01/04

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    Merchant of Cool Z train's Avatar
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    This topic started off with sopme great info & "how-to" advice but it is starting to take a "diverging route".Below you can see where my muffler ends.I have ZERO fumes in the cabin issues.Translation:Length of your tail pipe is NOT the problem.

    Faster than anyone in Oceanside

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    Registered User Derek's Avatar
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    My take on this is if you smell exhaust in the cabin you have a leak. Spoilers, tailpipes, bumper/no bumper all play a part in how bad but the bottom line is you have a leak. Find it and fix it. I'm pretty sure I still have one small leak but I need to pull the gas tank to fix it.
    When I first did the smoke test I had previously gone over everything with a fine toothed comb. I was so sure I had everything covered. I wish I had a video of how much smoke and how fast it filled the cabin. It really doesn't take much of a crack to be a problem.

    And a little thread levity never hurt anyone!

    Derek

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    Merchant of Cool Z train's Avatar
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    Quote Originally Posted by Derek View Post
    It really doesn't take much of a crack to be a problem.

    And a little thread levity never hurt anyone!

    Derek
    How true!

    Faster than anyone in Oceanside

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    Supporting Member EScanlon's Avatar
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    Quote Originally Posted by Z train View Post
    ...Below you can see where my muffler ends.I have ZERO fumes in the cabin issues.Translation:Length of your tail pipe is NOT the problem.

    I suppose if you choose to ignore the effect of that ice scraper you're using for a spoiler AND the increased diameter of your tailpipe in your hypothesis regarding length of tailpipe NOT having an effect on fumes in the cabin then the theory might be .... naah... the translation is off.

    That spoiler changes the air flow behind the car considerably. I believe that that is the PRIMARY reason for putting them on, to change the air flow. I'll bet that the spoiler is more likely the reason you're not getting fumes than the length of your tail-pipe.

    The discussions regarding exhaust fumes in the cabin, the causes and solutions have been going on for years. Spoilers AND / OR length of tail-pipe have been tried all with moderate success. So have louvers, both side and rear window, as well as front/rear/side skirts, all to some measure of success... or at least that's what's been reported.

    Of all the ones that have been written about, and you can do a search here, the downward pointing tail-pipe that's been extended just a couple of inches (just to knee scraping protrusion) is the one that's (purportedly) worked for more people.


    E

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    Merchant of Cool Z train's Avatar
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    Quote Originally Posted by EScanlon View Post
    I suppose1) if you choose to ignore the effect of that ice scraper you're using for a spoiler AND the increased diameter of your tailpipe in your hypothesis regarding length of tailpipe NOT having an effect on fumes in the cabin then the theory might be .... naah... the translation is off.

    2)That spoiler changes the air flow behind the car considerably. 3)I believe that that is the PRIMARY reason for putting them on, to change the air flow. 4)I'll bet that the spoiler is more likely the reason you're not getting fumes than the length of your tail-pipe.


    5)Of all the ones that have been written about, and you can do a search here, the downward pointing tail-pipe that's been extended just a couple of inches (just to knee scraping protrusion) is the one that's (purportedly) worked for more people.


    E
    1)I'm not ignoring anything.Diameter has zero effect.My muffler/pipe(however you want to call it)ends in just about the same(or shorter) location as the stock one.
    2)Yes it does.In fact it creates MORE negative pressure behind the car.which shoots YOUR theory in the ass.
    3)The primary reason for spoilers is downforce over the rear tires.
    4)This defies logic.
    5)This is nothing more than a band-aid solution.The cause is still there.Now if some don't have the skills or inclination to re-seal everything,it is understandable for them to go the "extended pipe route".

    This is my 4th Z dating back to 1977.I have NEVER had any fume issue that wasn't attributed to a leaking cabin.
    Last edited by Z train; 10-02-2010 at 06:40 PM.
    Faster than anyone in Oceanside

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    Supporting Member EScanlon's Avatar
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    Quote Originally Posted by Z train View Post
    1)I'm not ignoring anything.Diameter has zero effect.My muffler/pipe(however you want to call it)ends in just about the same(or shorter) location as the stock one.
    2)Yes it does.In fact it creates MORE negative pressure behind the car.which shoots YOUR theory in the ass.
    3)The primary reason for spoilers is downforce over the rear tires.
    4)This defies logic.
    5)This is nothing more than a band-aid solution.The cause is still there.Now if some don't have the skills or inclination to re-seal everything,it is understandable for them to go the "extended pipe route".

    This is my 4th Z dating back to 1977.I have NEVER had any fume issue that wasn't attributed to a leaking cabin.
    Ahh... you're an enlightened scientist... that is, if it doesn't match your idea of what it's supposed to mean then it's inconsequential. That is, ignore the facts if it contradicts your hypothesis.

    1) Different diameter exhaust tubing is used to allow for less back pressure. Less back pressure means that the exhaust isn't being pushed out with as much force towards the air turbulence behind the car.

    2) My theory as you put it, is that your translation is off ... which it is. YOUR theory is that the length of the pipe in your non-stock diameter exhaust pipe in a STOCK location has no effect and therefore that's why you don't smell fumes. But your theory is based on your ignoring the effect of the spoiler, which by your admission creates more negative pressure behind the car. More negative pressure and less exhaust pressure and you have the reason you're NOT smelling fumes. They're being blown away by the shear forces behind the car.

    3) Yes, you're right... by disrupting the air flow over the car.

    4) Not if you are capable of logical thought.

    5) I'll agree with you there. That is the main reason that so many people do have a problem with this. But, the extended pipe still proves to alleviate the problem for many.

    The design of the car is such that there is a vortex of turbulence behind the car. That turbulence traps the exhaust behind the car so that at certain speeds the vortex actually engulfs the rear section of the car. Any opening into the cabin (which is at a lower air pressure than the vortex) is literally sucking that exhaust rich air into the car. The extended and downward pipe puts the exhaust on the lower and outer portion of the vortex, allowing it to dissipate more than if it's positioned near the middle of the vortex.

    Congratulations on being a long time Z owner. Have you been Arizona the whole time? Maybe the reason you've not noticed the fumes is that you're mostly running with the A/C on, and the windows closed. Which would explain why you only notice the fumes when the car has a leaky cabin.

    If the cause could be effectively pinpointed and the solution(s) documented then maybe this wouldn't be such a divisive subject. As it is, it's mostly conjecture based on individual, non-reproducible results.

    I've never smelt the fumes in my Z, with a straight stock length tailpipe, without a spoiler, air dam or skirts, window(s) open but with both hatch and side window louvers... could they be the proper fix?

    You can choose to argue it, but the theory is far from being properly phrased, let alone solved.

    I will agree that properly sealing the cabin is of the utmost importance, and probably the single most important preventative measure to avoiding the fume problem. But some supposedly still encounter problems, so go figure.

    Let's not get this thread closed. We can agree to disagree, but insults or expletives are not required.

    E

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    Merchant of Cool Z train's Avatar
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    Bottom line:If a Z(1st gen) is in perfect order(perfect order meaning in as "left the factory condition",then how does adding a spoiler introduce exhaust fumes to the cabin?

    By the way,i have used no expletives or insults.
    Faster than anyone in Oceanside

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    Registered User olzed's Avatar
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    Does anyone know if all the rear hatches on an early and later 240 are the same. My 72 has an earlier hatch which fits the body perfectly, but where the hinges are there is a gap caused by a dip in the body to accomodate the hinges. This results is a gap between the hatch and the rubber about quater inch wide at this point.

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    Quote Originally Posted by olzed View Post
    Does anyone know if all the rear hatches on an early and later 240 are the same. My 72 has an earlier hatch which fits the body perfectly, but where the hinges are there is a gap caused by a dip in the body to accomodate the hinges. This results is a gap between the hatch and the rubber about quater inch wide at this point.
    I think I have the same hinge dip that you describe with my 1973 with the original hatch. I spent a few hours getting the rubber to fit tightly in that location.

    For me cabin fumes were 95% related to the hatch panel. I put plastic behind it and It didn't look like it was leaking but it was.

    I found my leaks with temporary bits of tape and plastic. I simply taped up areas of the car until the fumes went away. Great way of narrowing this down.
    Steve

    1973 240Z (daily driver)
    1971 240Z (track car)

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    A spoiler could both cause or stop a leak from allowing fumes into the cabin. (notice that I am not talking about a well sealed Z)

    A spoiler spoils lift. It does so by changing the air pressure distribution on the outside of the car. There is also to some extent a conservation of momentum effect when you change the direction of airflow but I'll not go into that. So generally speaking adding a spoiler means increasing pressure on the top of the car and decreasing it on the bottom. So depending on where the leak is it could begin letting in fumes if it were in an area that experienced a pressure increase or stop leaking in an area that experienced a pressure decrease.

    Since there are so many places that can leak there is no one magic bullet that "solves" the fume problem. That's why you see so many different solutions and why one persons solution may not work for another. Unless, of course, that solution is to seal the car properly.

    Steve
    Last edited by doradox; 10-03-2010 at 08:54 AM. Reason: spelling

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    Attached is a write up with some pics of how to do the smoke testing, and a method of using a hose to pinpoint the exact source of the leak. It also shows and notes areas where I found leaks...

    http://www.classiczcars.com/forums/s...ad.php?t=34205

    Good Luck,

    Bob
    Thanks,

    Bob

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    Some fun tests could be done by someone with the time and interest...

    You could mount something emitting a colored smoke in your exhaust pipe and drive along a track or something at various speeds while video taping the flow patterns. Could be interesting.

    We have a small scale wind tunnel in my building on campus. I wish I had been interested in this topic back then, I could have bought a 240Z model and done some testing for my undergraduate fluid mechanics lab. Would have been a fun project.

    Of course, testing this in a wind tunnel may not be accurate in two ways that immediately come to mind:

    1) The air would be moving relative to any static "ground" you installed in the test section (unlike in real life, where it could just be sitting above the road on a windless day). This could be important because air flow under the car would be very different.

    2) You couldn't effectively explore what happens when you slow down for a stop sign or stop light. The smoke-filled air lingering behind your car would have some forward momentum in the real world, which may carry it forward around your car as you slow down. This would not occur in a wind tunnel when you ramp the speed down.

    Anyway, I'm getting off track. The real world testing would be superior (and a lot more fun!).

    Caveat emptor: fluid mechanics is not my technical area
    -Andrew

    03/72 240Z HLS30-70xxx - R.I.P. 2011/01/04

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    Default fumes

    I am not sure if this is the right thread for this, but why do our cars smell that bad in the first place. Anybody got any ideas. My engine is a fresh rebuid, the carbs are perfect, the plugs look great and it still has a certain amount of smell???????
    Bob

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    Quote Originally Posted by Inf View Post
    Some fun tests could be done by someone with the time and interest...

    You could mount something emitting a colored smoke in your exhaust pipe and drive along a track or something at various speeds while video taping the flow patterns. Could be interesting.

    We have a small scale wind tunnel in my building on campus. I wish I had been interested in this topic back then, I could have bought a 240Z model and done some testing for my undergraduate fluid mechanics lab. Would have been a fun project.

    Of course, testing this in a wind tunnel may not be accurate in two ways that immediately come to mind:

    1) The air would be moving relative to any static "ground" you installed in the test section (unlike in real life, where it could just be sitting above the road on a windless day). This could be important because air flow under the car would be very different.

    2) You couldn't effectively explore what happens when you slow down for a stop sign or stop light. The smoke-filled air lingering behind your car would have some forward momentum in the real world, which may carry it forward around your car as you slow down. This would not occur in a wind tunnel when you ramp the speed down.

    Anyway, I'm getting off track. The real world testing would be superior (and a lot more fun!).

    Caveat emptor: fluid mechanics is not my technical area
    That would be really neat to see done.

    Quote Originally Posted by racer88 View Post
    I am not sure if this is the right thread for this, but why do our cars smell that bad in the first place. Anybody got any ideas. My engine is a fresh rebuid, the carbs are perfect, the plugs look great and it still has a certain amount of smell???????
    Bob
    You have a leak in the cabin somewhere.At the age of these cars,seam sealant has dried and cracked and other gasket types have become porous.
    Faster than anyone in Oceanside

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    Quote Originally Posted by Z train View Post
    You have a leak in the cabin somewhere.At the age of these cars,seam sealant has dried and cracked and other gasket types have become porous.
    My leak between the exhaust manifold and downpipe doesn't help either, but that's being fixed as I type. Hopefully that will make some difference.
    '78 280Z - HLS30-456750

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    Default Effect of reduced back pressure due tio larger diameter exhaust tip

    Does this reduced back pressure have any negative effects on the engine life/performance?
    Brad 73 240Z

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    My son and I started working on the back of his Z.
    We took the tail lights out of the car, I thought maybe the seals were dried up and no good.
    To my surprise I found the driver's side reverse light wire looped between the seal and the body.
    The backside of the tail light housing was all black, you could see exactly where exhaust was being sucked in.
    It was litteraly the smoking gun!
    We also found a small rust hole where the drain plug is on the antenna side.
    The seals are good, so a little rust repair and careful re-installation of the tail lights, fingers crossed most of the fumes should be gone.

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    Quote Originally Posted by Rocket88 View Post
    My son and I started working on the back of his Z.
    We took the tail lights out of the car, I thought maybe the seals were dried up and no good.
    To my surprise I found the driver's side reverse light wire looped between the seal and the body.
    The backside of the tail light housing was all black, you could see exactly where exhaust was being sucked in.
    It was litteraly the smoking gun!
    We also found a small rust hole where the drain plug is on the antenna side.
    The seals are good, so a little rust repair and careful re-installation of the tail lights, fingers crossed most of the fumes should be gone.
    Rarely do you find a "Fuming gun" like that.But don't stop there,make sure every thing on the back of the cabin is"tight".
    Faster than anyone in Oceanside

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    lol...fuming gun
    The hatch seal seems good, I've been taking a sheet of paper and closing the hatch on it.
    Went all around the hatch like that and it is very difficult to slide the paper out so I'm keeping my fingers crossed.
    We've got the fual tank out as well.
    The evap tank is going and we are sealing up all the holes left over as well as replacing all the grommets in the back of the car.

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    I am glad I found this thread too. Now its added to my long list of things to do. I find it very interesting (as mentioned above) that even a good running engine, still can produce this exhaust smell in the car. Because that is my main complaint about driving my z car. When I rolled down the windows... I get an exhaust smell building up in the car. In fact if I had a coat on it, I could take it off, and walk inside and the coat actually *stinks*

    I saw the thread about using the fog machine. I have one. So I will be doing that too. I really hope I can eliminate this problem once and for all. I never smelled exhaust on any other car I have owned. At least I am not the only one with this problem.

    I cant imagine that new Z cars had this problem. I suppose it just started happening once they got *old*.

    I dont have a stock exhaust on it. Previous owner changed it. I think its a monza? exhaust. It has dual tips on it and it sticks out maybe just a little past the back bumper. And I have back window louver, and side window louvers that I added. I may very well take them all off, and drive the car and see if the smell changes or is better or worse. The back louvers have been on car since 1978 (I see them on the original sales reciept that I have for the car). The side louvers I added myself. It just makes me think that the back louvers didnt cause this effect on the car. Its probably just bad seals all over the place.

    It seems to me that Previous owner replaced some of the seals. I also checked various grommets and fixed/replaced a few of them.
    Last edited by argniest; 01-29-2011 at 09:12 AM.

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    Quote Originally Posted by argniest View Post
    I cant imagine that new Z cars had this problem. I suppose it just started happening once they got *old*.
    That is part of the problem, but the other part is that we are running unleaded gasoline in cars without a catalytic converter. The anti-knock compounds that are in unleaded gasoline apparently smell horrible, and without a converter to burn them off you get that characteristic stench. I have the same problem with my 1967 garden tractor. It didn't smell bad back in the 60's and 70's, but today you have to take a shower after using it for any length of time at all.
    '71 240Z, Because any fool can drive fast in a straight line.

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    Wow that is really interesting about the unleaded gas, and the old tractor. From what I know, only the California cars have the catalytic converter on them?

    But does that mean every person on here (non california) with a decent running Z car, has a fumy stinky exhausty kind of a smell coming out of their tailpipes?

    My two 99 chevys dont have any abormal kind of smell to them. But I suppose they both have catalytic convertors since they are 20 years newer almost.

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    Well I'm going to tag on to this older thread because I think Derek had the best idea for trouble shooting this issue. I had actually bought a fog machine over a year ago when they were cheap(after the hallowen holiday). It really is a cheap, fast clean way to diagnose the exhaust fumes.
    I tried the "suck" method first, but it left too much to question. Inside the car with not much room to move around and it being dark, it was too hard to tell where the fumes originated from.
    Now the "blow" method was much better. It really only takes a couple of minutes to set things up and start trouble shooting.
    What I found and yet to be fixed, is that I have a lot of air moving thru the latch assembly. It looked like a steam engine coming out of there. Perfect spot to suck up those swirling fumes around the back. I haven't finished examining everything yet, but the only way fumes have access thru this point is by leaking around the vinyl panel on the hatch. The low pressure in the cabin must be sucking air around this panel(which is NOT air tight-mine anyway) and thru the hatch assembly. It would seem to me that the easiest fix here would be to seal the hatch panel by sealing some plastic sheet behind it-agree?
    I also noticed smoke around the left tail light , where some previous bodywork was done. Also noticed a lot of smoke out the pillar vents, but I think they are too far from the exhaust to be sucking anything in.
    I will update as I try to fix these
    Steve
    71 240z,bw-5sp 2.4-40 over,balanced,e-88,big valves,ported&polished, stage2,header, triple Mikuni's 40's
    3.90 Subaru STI LSD

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    So all this time the majority of my issue has been the interior hatch panel not be sealed . It is night an day difference now that I have put plastic underneath the panel and sealed things off. It's not perfect but 99% better. So I am going to go along with all those folks that say it's nothing to do with exhaust tip length or lack of spoiler - it's an exhaust leak.
    Steve
    71 240z,bw-5sp 2.4-40 over,balanced,e-88,big valves,ported&polished, stage2,header, triple Mikuni's 40's
    3.90 Subaru STI LSD

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    Did you use a shower liner? Got any pics?
    Life's a journey; enjoy the ride!

    Mitchell
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    1972 Datsun 240z
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    Just had some thick black plastic laying around and RTV'd it to the opening under the panel.
    Steve
    71 240z,bw-5sp 2.4-40 over,balanced,e-88,big valves,ported&polished, stage2,header, triple Mikuni's 40's
    3.90 Subaru STI LSD

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    Still enjoying clean air!!! This really has enhanced my Z driving experience. Windows down and 70mph is a joy. I did also find some small exhaust leaks in my exhaust system around some band clamps, which I removed and welded solid. I think I was smelling this when I was rolling up to a stop.
    Though my hatch seal still shows leaks using the fog test, they are very minimal and I can't smell them. The remedy there might be an actual Nissan seal;0
    So if you are dealing with smells, there is hope. first thing I would check is the hatch panel. Think about it, it's been there for 40 years and very possibly been removed at least once-probably by you---so seal it up!!
    Steve
    71 240z,bw-5sp 2.4-40 over,balanced,e-88,big valves,ported&polished, stage2,header, triple Mikuni's 40's
    3.90 Subaru STI LSD

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    Happy 43rd Anniversary!!

    Had the Z out for a run to celebrate. What was most remarkable was that there were no comments/complaints about exhaust fumes from my wife...no smelly clothes and/or burning eyes...ALL GONE...Period!!

    Why the disappearance? It has to be a secondary benefit from refurbishing the rear tail lights which was carried out over the past winter. Specifically, better sealing around the light fixtures.

    Cheers,

    George
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    Original owner of: HLS3018859 (Jan./71) ZCOOR Member # 178

    'Storms Never Last'

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