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My exhaust kills small animals. Normal?

Discussion in 'Technical Q&A' started by Birdman, Sep 9, 2004.

  1. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,687
    North shore, MA
    Full Name:
    THE Birdman
    Hi Everyone,
    I have gotten used to the stinky exhaust from my '77 308 but my wife wants to know if it's "normal." Basically, anyone driving behind me has to stay back quite a distance or they will asphyxiate from the toxic fumes. I pull the car out of the garage as soon as it starts so I don't fume up the place. I don't think I have ever actually killed small animals with it, but I'm sure it would!

    The PO took off the air pumps, and I put in .60 idle jets to make it stop popping (although the exhaust was just as toxic with .55 jets). It has an Ansa exhaust and everything else (including the other jets, emulsion tubes, etc) is stock. Is this normal or could we surmise that when I do my valve adjustment and timing belt replacement this winter I will find that my exhaust valve timing is off a tooth or something? Will that raise the emissions a lot? The car only made 165 RWHP on the dyno a few months ago. That was before I got the idle jetting so it would actually run well, but since I didn't touch the main jets, I can't imagine the thing would make a significantly different amount of top end power now. I'm wondering if you think the HP and emissions might be a function of bad exhaust valve timing and I'm wondering if anyone else out there has toxic fumes that will kill small animals.

    Thanks!

    Birdman
     
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  3. FasterIsBetter

    FasterIsBetter F1 Veteran

    Jul 22, 2004
    5,844
    NoNJ/Jupiter FL
    Full Name:
    Steve W.
    When you say bad smell, do you mean "rotten egg" smell (or the stench of a sulfur pit)? That's usually a sign of defective catalytic converters. But does your '77 have cats? Bad cats can also adversely effect performance as well as making everyone with 100 yards sick to their stomach.

    A nauseatingly sweet sort of smell, with black smoke on acceleration, is usually a mixture that is way too rich. But it can also mean you're not burning fuel properly. Have you gone through all the basics -- plugs, wires, distributors, rotors, coils, engine ground, timing, etc. -- to make sure that everything is working right? You can't effectively set the mixture unless everything else is working properly.
     
  4. 1975gt4don

    1975gt4don Formula Junior

    Nov 5, 2003
    662
    Peoples Rep of CA
    Full Name:
    Smog Exempt
    birdman, mine smells the same---very very rich. It stings my eyes if I am standing behind it within 5 feet or so with it idling. It has been that way every since the thermoreactor muffler and air pumps fell off the car right after I bought it.
     
  5. jimangle

    jimangle Formula 3

    Nov 5, 2003
    2,438
    Haverford
    Full Name:
    James
    Jon,
    Does your car consume an abnormal amount of oil?
     
  6. 1975gt4don

    1975gt4don Formula Junior

    Nov 5, 2003
    662
    Peoples Rep of CA
    Full Name:
    Smog Exempt
    Mine doesn't. about a quart every 1500 miles, way above the allowed 650 miles spec'd in the O.M. Getting around 10-12 MPG combined however.

     
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  8. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,220
    TN
    My carb 308 is the same way also. I have no cats, air pumps, etc. It will have a strong gas odor in the air. I have 135 main jets. It will sting my eyes also if I am in a garage with it for a while. I just rebuilt my carbs, and went through my entire ignition, plus I have electronic ignition. I think when you remove the cats and air pumps this is the nature of the beast.
     
  9. Sean F.

    Sean F. F1 Rookie

    Feb 4, 2003
    3,003
    Kansas
    Full Name:
    Sean F
    The smell should not be THAT strong. You're running too rich at idle. Bad smell sure, but not "stay 100-feet back" kind of odor.

    You should be getting around 10-12mpg depending on how heavy your foot is.
     
  10. jimangle

    jimangle Formula 3

    Nov 5, 2003
    2,438
    Haverford
    Full Name:
    James
    Now that I think about it, it could be an exhaust cam timing issue. When I had the intake cam timing issue, it was almost impossible to sync the carbs. The unburnt fuel mist coming from the carbs was like pepper spray. I could see the reverse happening with incorrect exhaust valve timing and excess unburned fuel is coming from the exhaust. By the way, my car has 60 idle jets, and 130 mains. After the cam timing was corrected the car runs like a beast now. My exhaust though a little rich, doesn't burn my eyes.
     
  11. ham308

    ham308 Formula Junior

    Nov 3, 2003
    358
    NE Switzerland
    Full Name:
    Richard Ham
    I found that fitting hotter plugs and getting the idle mixture to sort of within spec helped a lot in getting rid of the oil-fuel smell on my carb 308 and also stopped the rear panel getting a black covering. The plugs recommended in the manual are probably fine for high power driving but maybe not so good for travelling around in a country full of speed cameras, with the occasional spirited burst up to full revs.
     
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  13. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    27,086
    Austin TX
    Full Name:
    Brian Crall
    Smell=Hydrocarbons, Hydrocarbons=Lost horsepower. There are many variables, but that is the basic equation.
     
  14. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    7,000
    Groton, MA
    Full Name:
    Verell Boaen
    Jonathan,
    I've got an exhaust gas analyzer the John Wise borrowed from a friend. Haven't had a chance to try it out, but we could see how your car compares to my 308 & Rx7.

    John will be over working on his engine Sunday, but it wouldn't take long to see what we can figure out about your engine.
     
  15. 1975gt4don

    1975gt4don Formula Junior

    Nov 5, 2003
    662
    Peoples Rep of CA
    Full Name:
    Smog Exempt
    Yes I probably am running rich. I was born with a birth defect---my right foot is made of lead. I should check the size of my jets, I rejetted the carbs when I changed exhaust system many years ago. However, I did not do the work. That was the last time anyone other than myself touched my engine.


     
  16. Dom

    Dom F1 Veteran
    Rossa Subscribed Owner

    Nov 5, 2002
    7,941
    Southern California
    Full Name:
    Dom V.
    My car's smell kills small animals too. I have no cats (car didn't have one to begin with), and replaced original thermoreactor exhaust with Stebro exhaust. I still have my air-pumps connected and functional.

    Dom
     
  17. Spasso

    Spasso F1 World Champ
    Silver Subscribed

    Feb 16, 2003
    14,612
    Land of Slugs & Moss
    Full Name:
    Han Solo
    Stinging eyes is the sign of lean burn.
     
  18. zan

    zan Formula Junior

    Nov 15, 2002
    537
    Boston
    Full Name:
    Mark M
    birdman, when following you last month in addition to stinging eyes, I also got the occasional smell of raw gas.

    Mark
     
  19. 1975gt4don

    1975gt4don Formula Junior

    Nov 5, 2003
    662
    Peoples Rep of CA
    Full Name:
    Smog Exempt
    The raw gas smell is very very evident AFTER I shut it off and it being in the garage.

    DOM: with air pumps on mine, I had zero odor. Little to none brown soot/film on the tailights area. But that was a very long time ago in a universe far far away.

     
  20. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,687
    North shore, MA
    Full Name:
    THE Birdman
    Everyone,
    This has been very enlightening. I have not noticed a burning eyes thing, although maybe people behind me have. I get "soot" on the rear bumper and it smells very "hydrocarbon-like". It smells like motorcycles and lawnmowers (i.e. the no cat smell) but stronger. In idling, I don't detect an unburned fuel smell from the exhaust. (That comes from the intake vent leading to the airbox). Zan, it was your complaint about about the stench following me that got me thinking about it. And once my wife followed me home from someplace in her car and said she had to back off a hundred yards because she was going to die from it! My car seems to get the same fuel economy that most of the carb 308 owners report (around 12 MPG on average, although sometimes I get as high as 17 MPG if I am on the highway going the speed limit. Too slow or too fast and the MPG drops.)

    I have been thinking that it has been running too rich therefore producing this noxious cloud, but my car was clearly running too LEAN before I re-jetted. The bigger jets completely fixed all the popping through the carbs and bad idle (along with a carb sync). I couldn't get it to run well enough with the .55 jets to even sync it. Since it made the same noxious cloud before it was rejetted, I just don't know. I'm thinking there is an exhaust timing thing going on, bad combustion, or something. (It has hotter plugs in it to reduce fouling in the mostly around town driving I do, and has stock coils and points). Other than producing 30 HP too little, it runs exceptionally well, accelerates well, idles like a clock, gets up and goes, lots of fun to drive and very little of the hesitation I had before it was jetted and synched. I can't expect that it will produce the HP it did when it was new, but 30 HP seems a little low to just be the result of age. I guess I should do a leakdown test.

    Alas, once I do a valve adjustment, timing belt replacement, etc. this winter I'll be able to make a comparison.

    Verell, thank you kindly for your offer. I would LOVE to come over Sunday, but I'm afraid I'm a slave to building this garage for a while. If you guys are working on the car one NIGHT sometime, I would love to come over, join the rebuilding of John's engine, and hang out. I'll even bring the hard cider!

    Thanks to all.

    Birdman
     
  21. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    4,366
    NY
    My 77 does the same. No pumps and Ansa exhaust. Stock jets with NGK 5's . I run it rich but get 17mpg at 70mph on the road and about 12mpg around town. Getting about 1200 miles on a quart . Not to concerned , will do wires and plugs this winter and maybe new caps and rotors. Running Pertronix's ignition.
     
  22. Aircon

    Aircon Eight Time F1 World Champ

    Jun 23, 2003
    87,205
    Melbourne, Australia
    Full Name:
    Peter
    If it's any help, and i doubt that it is, my old carbed boxer AND my non cat 355 do the same thing. They stink like hell and burn the eyes very quickly. I can adjust the mixture to anything I like with the 355 and it still does it.
     
  23. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
    2,149
    way north california
    Full Name:
    chris morse
    Birdman,

    My wife threatened to not ride with me, said it made her sick. My 77 has the thermal reactor removed, (for those not familir with the smog trash foisted on the 308, let me say that the 76 and 77 308 used a HEAVY, aprox 100 pound, muffler filled with concrete or metal or who knows what to encourage the oxidation of unburned gas. In '78, Ferrari went to a real Catalytic Converter.

    When i replaced the ineffective stone with a Flowmaster, I had all kinds of backfiring through the carbs, out the exhauset on over run and on shut off. This problem almost vanished with the 140 mains and 200 AC jets. Things got even better with the 40 idle jets.

    The car still stinks but runs tolerably at low speed. We took a trip to santa barbara to give the dealer another chance to smog the car, failed twice more, had the hc meter pegged at 2000 at idle. Reinstalled stock thermal reactor, jets, installed smog pump belt, still failed, the points had almost closed up, fixed that, still failed, adjusted the valves, result unknown. Suspect the carb still have an internal problem, (float setting??, cold enrichment device gas leak???)

    Is idle speed richness a chronic problem with the old carbureted engines???

    Stupified but still loving to drive it.
    chris
     
  24. Jdubbya

    Jdubbya Two Time F1 World Champ
    Silver Subscribed

    Dec 28, 2003
    24,052
    PNW
    Full Name:
    John
    Maybe I'm a little twisted, but I like the smell mine makes! I've had mine on stands for over a month now and actually went out and started it the other day just to get the smell back in my garage! Then again I used to like pumping gas in the family car when I was young because I liked the smell of that too. Maybe it's just me??
     
  25. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    Chris
    Wow - 40 Idles are the leanest I have ever heard of in a 40dcnf.
    For comparison from my 308 Weber charts:
    74 Euro: .45
    75 Euro: .50
    77 Euro: .50
    74 - 78 USA: .55

    As we've all noted before, changes in exhaust systems cause changes in jet requirements and yours is certainly a change from the original! We've also discussed in previous threads how sl richer idle jets will aid transition hole leanness in some applications, and you do carry the richness of the idles in an additive fashion with the mains and A/Cs all the way through the range. As well, many modern FI cars actually idle a bit lean at around A/F 15 (no load) from what my dyno tech told me. Looking over the archives, it seems one of the most popular 308 combos is .55/140s.
    My carbs A/F with 45/145s idles around 14 and runs in the high 12s and low 13 AF (best power) with some smell noted by family travelling behind, even with 36 mm venturis (stock is 32).
    In short - would look at A/F.
    Verell's gracious offer of an A/F meter would really give you an answer or might be worth $60 for a dyno run or two with A/F measuring, as well as a comparing plugs to see if all are seeing the same mixture; a color-tune device would be even better (see Fchat archives and other boards).
    Disclaimer: **cannot exactly compare many carb cars as they all have sl different optimal jetting**.

    Looking forward to hearing about everyone's experiences!
    best, and good luck!
    rt
     
  26. Sean F.

    Sean F. F1 Rookie

    Feb 4, 2003
    3,003
    Kansas
    Full Name:
    Sean F
    Age will not make your car develop 30 less HP. Most owners with cars in proper tune report close to correct HP depending on year (76/77~240BHP, 78/79~205BHP).

    165RWHP with the normal 17% loss most report would give you ~195BHP. You should have closer too 199RWHP in a '77 with no CATS. Check the cam timing (as you've noted), then check your carbs, valves etc.

    And what is all this oil usage everone reports? My oil level has stayed fairly constant since I bought the car. I'm running Valvoline Synthetic Racing 20W50 and the car has used very little if any use. 1qt per 1000-miles seems like a lot.

    '77GTB with 25,000 miles (I'm the 2nd owner).
     
  27. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
    2,149
    way north california
    Full Name:
    chris morse
    Russ,

    My idle jets are 60 not the 40's I mentioned - shouldn't post when tired.

    chris
     
  28. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,687
    North shore, MA
    Full Name:
    THE Birdman
    Sean,
    Have you ever actually dyno'd yours? On our dyno day in the spring, we tested a few 308's including 2 Qv's. The QV's posted 170 and 190 RWHP respectively. Mine was the only carb and we had no 2V injected ones to compare. Maybe the dyno we used reads a little low, or more likely, maybe the figures Ferrari puts out are very optimistic!

    I would love to hear from people who have actually dyno'd their carb cars for what I should realistically expect.

    Birdman
     

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