Conference terri::cars_uk

    Mitz,
    
    I used to have a 1973 Nissan Sunny estate, and did approx 24,000 miles
    with no filter.
    
    The engine actually seemed to run better without it, and when you're
    young, the engine sounds great! The reason I had no filter was because
    I was a poor student existing on a meagre grant at the time (1979) and
    there were more important things to buy... like beer ;*)
    
    Britain is not exactly a dusty country however, so perhaps the filter
    is not as critical here?
    
    I'm surprised that your Honda dealer made such an obvious mistake, my
    wife has a Prelude and before that 2 Accords, which get serviced by
    Honda and we've never had a problem...
    
    As for long term damage, well, I bow to others knowledge, but I always
    thought the real reason for a filter was to stop dirt and dust blocking
    carburettor jets and injectors, I would have thougt anything big
    enough to get into the cylinders, say a fly, would get vapourized!

    >>I would have thougt anything big enough to get into the cylinders,
    >>say a fly, would get vapourized!
    
    A stone?
    
    ;-)))
    
    Cheers,
    Dan

    The answer to .0 is obviously - it depends.  Couldn't resist answering,
    though, I lived in Oregon when Mount Saint Helens blew her top.  There
    were people trying to drive through all the ash which was blowing
    around like a sand storm.  Their air filters soon became clogged and
    the engine would quit from starvation.  So the ones who decided they
    NEEDED to get somewhere removed their air filters.  That got them
    another 20 to 500 miles, whereupon the engine seized.
    
    In your case, the air in and air out were dirty, meaning that the
    filter was turned upside-down during the service and seems to have
    sealed well enough to force incoming air through the filter.  Doesn't
    sound too bad.
    
    grins,
    Bob

    Thanks for the replies...
    
    RE: .1 >>The engine actually seemed to run better without it, and when
           >>you're young, the engine sounds great!
    
    I noticed it too, after the 48,000Km maintenance the engine started
    soundlouder and I liked it that way.
    Another difference I noticed was gas mileage, it improved by about
    10% for some reason.....???
    
           >>Honda and we've never had a problem...
    
    Lucky you!!!   
    This is the 2nd Honda dealer I had problems.
    The first one is where I bought this car as new.
    It had almost a foot long dent on the driver's side door. The sales 
    mamager at Honda dealer pretended that he couldn't see it.
    It took four visits to actually fix it, their very first attempt was
    quite funny, they just sand papered over the dent and scratch.
    The first 3000Km maintenance was done at the same place and car came
    back with dented engine hood this time.
    I switched dealer after that but seems same to me.
    
    	   
    RE .3 >>In your case, the air in and air out were dirty, meaning that
          >>the ilter was turned upside-down during the service and seems 
    	  >>to have sealed well enough to force incoming air through the
    	  >>filter. Doesn't sound too bad.
    
    I hope so, but what if the mechanic just turned the ORIGINAL dirty
    filter upside down and left it there? 
    All dirt collected in last 48,000Km is now air out side and it could
    sucked into the engine.
    
    May be I've seen too many RP04 disk drive head crashes caused by 
    dirty filters.......?????
    
    Mitz 
    
    

    Ahhhhhhhhhhhhh Induction noise, sighhhhh how I just used to Lurrrrvve	
    the sweet sound of induction noise.......................
    
    Matt (going back to his youth)
    8^)
    

    Me, I'm deaf because of it.
    
    :-(
    
    Dan

    Stick a K&N on an 1 3/4" SU on a head with big valves, and a Janspeed
    exhaust manifold, and then tell me about induction noise! :^)
    
    Laurie.

    Errm, funny, but that's exactly what I did!
    
    The Lozza & me, we are the induction-roar boys!
    
    (errm, well, boy & old fart, but you know what I mean...)
    
    ;-)
    
    Dan

    Almost connected.... Any body in the Edinburgh area got a carb balancer
    I could borrow at the weekend. My ears are all blown out from induction
    noise too...phone no is 0131-331-8108.
    				cheers,
    					brian.

    As long as your ears aren't too shot, you can balance carbs by ear.
    Simply use a small piece of tube, and stick one end in yer ear, and the
    other just in the intake. Balance the carbs by making the induction
    noise the same; it's amazing how easy it is to get it pretty well
    right.
    
    Laurie.

    << wot e' said.
    
    ;-)
    
    Cheers,
    Dan

    So....
    
    I learnt a lesson.
    
    If the 48,000Km major maintenance was done at the Honda dealer near
    my office and noticed POSITIVE difference such as louder induction
    noise (which I liked) or a little torque improvement at low rpm
    then the air filter must be upside-down and the housing is loose.
    
    I paid a little over CDN$ 500.00 for it and certainly worth it...NOT.
    
    Mitz
    

    
    I have had motorcycles/cars with no air filter & no problems, but...
    
    I was bunkered on a beach a couple of years ago (Oh no, of course it
    wasnt a company car) & at the next service the air filter revealed
    enough sand to build a dune. I hate to think what would happen if I
    hadnt had a filter then. So, no air filters seems ok until you
    do something abnormal.
    
    Tony

   Reminds me of my old Hoda 400/4. Lovely machine but too quiet by half - used 
   to get pedestrians stepping in front of me with a "didn't hear you coming" 
   plea of mitigation...
 
   So I ripped out the air filter gubbins, jetted-up the carbs a tad and put 
   some fancy bell-mouths with fine wire mesh over the ends. Great ! I had a 
   bike which made nicer noises and walleys on foot could hear me before I had 
   a chance to mow them down.
 
   Strange thing I noticed that my petrol economy improved significantly and 
   the engine's response curve straightened out. The 400/4 was known for being 
   a pussy-cat until you hit 5000-6000 RPM when it picked up after a bit of a 
   tail-off of power just before this band. These changes made the thing go 
   from 1000-10000+ RPM with no step in the middle. NICE.
 
   Heaven knows what effect the ingress of dust had on the engine but it was 
   good fun in the meantime...
 
   I also remember a mate of mine with a Ducati Hailwood Replica. Air filters ? 
   For wimps only. This beast had bell-mouths like trombones with "mesh" over 
   the ends. I use the term mesh loosely as the gaps were @ � inch square and I 
   believe they were there to prevent parts of the rider's anatomy from being 
   sucked into the carbs !!   MMM... sounds kinda kinky put like that.. ;^)
 
   Ahh those were the days.
 
   Nostalgically... Rog

    Filters are a mixed blessing.
    
    Certainly they keep an amazing amount of crud out of the engine - crud
    which will wear away at the turbo (if fitted), valve stems, valve
    seats, cylinder walls and will even find its way into the oilways to
    cause havoc in the multitude of bearings around the engine.
    
    However they also reduce the mass flow by an appreciable unless they're
    very well designed.  Even when they're well designed the mass flow will
    be reduced a little bit.
    
    When I worked on helicopter engines in a previous life we could get
    everything significant out of the intake, from small rocks to talcum
    sized dust, by clever design and a <2.5% air bleed.  Without it engine
    life in Saudi was 15 minutes - all down to dust ingestion.  With it we
    were getting 2,000 hours.
    
    In all cases you trade performance against engine life.

   Not being personal Nick...  I just wondered if making a filter on a large 
   scale would increase the air flow available to the engine thus improving its 
   performance...
 
   I can now picture cars fitted with filter housings like those on 
   Early-Warning Boeings (sp?) !   8^)
 
   Rog

    Rog
    
    As with other things, size doesn't matter...
    
    The problem with an air filter is that it also causes a pressure drop.
    The only design that could overcome this is to use a ram intake, but
    even so you're going to get a pressure drop with a filter when compared
    to without.
    
    We couldn't put a ram intake on the aero engines I was reffering to as
    they were for helicopters.  Generally a helicopter needs max. power
    when it's hovering, i.e. no forward movement through the air to get the
    ram effect.
    
    Nick

    re .17
    
    Surely, if you double the area of the filter then you will only need to
    get half as much air through each square inch of filter. This will
    result in a smaller pressure drop through the filter.
    
    While a helicopter is hovering it doesn't have any forwards motion.
    However it does have a considerable downwards flow of air from the
    rotor blades. Couldn't some of this airstream be fed into the air
    intakes (maybe via some kind of opening door arangement to direct the
    air where it's wanted) ?
    
    Andrew

Hello,

ahead of the old discussion about cylinders and valve protection, I experienced
 recently an immediate effect of the air filters suppression.
I own an 86 Ford Sierra (130000Km and working well, thank you) and a few month 
ago, I got some sand bit in the gas main stream, in the carburettor. (with the 
usual effects...) 
It appeared that the filter cover was misplaced and let some dust pass between
 it and the filter.
On this car (is it the only one?), the carburettor's design is rather peculiar:
 the gas pool is open that means there is a 1cm2 wide aperture in the carb cap
(to prevent percolation or pressure problems?)
So the air filter prevents dust from getting down to the intake, but from the 
gas pool too.
So, before removing the air filter, look at the configuration!

Alain

PS: (RE .18) Andrew, may I suggest the usage of a supercharger?   

    I think it is normal for the air space above the gas in a carburettor
    to be connected to the airstream somewhere between the filter and the
    choke. The air pressure above the gas needs to be related to the
    pressure in the venturi, without any extra pressure caused by the
    filter (otherwise, the richness of the mixture would depend on how
    clean the filter was !).
    
    Andrew

Andrew,

I am OK with the fact that there must be no pressure difference between the gas 
level and the venturi, and so there must be some free air interconnection 
between them, but it is the first time (I worked on a lot of cars at this time)
I see this design of carb cover.
Usually, the interconnexion is a little "bendy".
On this car (Sierra 1.6L), there is obviously a hole, you may see the gas from 
above. Do you know other cars with this kind of design?

Actually, my concern was I hardly understood how the sand bit could get into 
the gas pool and then to the gas circuit and had to open the carb three times 
before getting definitely rid of it.

Alain

PS: I read above in the note (.4)that someone discovered that running without 
an air filter may lower the gas consumption, we all know that running with a 
dirty increases it a lot...