i was tramping bush with my d8h when suddenly the air filter burned. there were no fires around, nothing else burned. the filter just started burning. it didn't do any damage, but what the heck would cause this?
Does it have a siphon dust ejector tube to the muffler? Have heard of the exhaust going backwards if the muffler is damaged internally
no it doesn't.
no muffler either, just a straight pipe off the turbo
How did you first notice the filter was burning up, I would have thought any smoke from it would have been sucked into the engine ..?
\ it started running like crap so i shut it off. then smoke started coming out of the air cleaner. took the filter off and the paper was all burnt. once i got the filter out and fired it up it ran 100%
Are you running a pony motor to start the engine? I am really feeling my age thinking about that.
yes i am.. hmmmm
the dozer ran for two hours before the filter burned. so of the pup engine sent lames through the intake it would somehow have to travel through the turbo and to the filter and burn two hors later.
Is this a 235 HP? without a safety element?
it's the 235 hp. it has a canopy and engine shields.
I meant it only has one air cleaner element correct, no safety element
that's correct.
Has to be some kind of freak deal. Could you tell if the burned part started on the dirty or clean side of the element? I suppose the starting engine could spit a hot piece of carbon toward the intake and it smouldered until it lit but how remote is that? If the pony exhaust thru the intake manifold leaked same thing could happen I guess, though the main engine would have been getting dirt from the pony exhaust pipe. Don't know if you will ever find out.
Debris could of sat on the exhaust manifold or turbo long enough to catch fire or create a ember, That ember then could get sucked into the filter housing burning the filter element from the out side in under a vacuum.
the entire element burned out so i have no clue which side started first.
I have had my old 2U's running and they will sent up a nice hot chunk of soot/carbon/whatever once in a while when I am running them hard and every now and then I am lucky enough to have one land in the back of my neck, and I can tell you that it feels just like weld splatter.... so if you get just the right chunk sucked into the filter I can see where it would light up the element.
Sledge, wonder if you might have a hole rotted through the housing of the air filter? Then like everybody else said trash laying on the exhaust manifold got hot, ignited and sucked up into the filter?
Our D7F did the exact same ordeal this spring. Started running like crap, Bill shut it off, smoke poured out. Pulled the air filter covers off fast, filters engulfed. Filters had very low hrs on them. Ever run one at night? then you can see sparks sometimes come out of the exhaust. I would assume it to be red hot carbon bits? We believe our machine simply sucked in a spark and lit the filters up. Burned the right down to the metal mesh, no paper left at all.
Sledgehammer, Could it have backfired through the Carburetor? (if it has one, I did that on my mower ) Is the element the Cat radial seal one or does it need a filter oil or something? Just because filter oil does burn sometimes :tong
Zactly! Exactly. I don't even know what made me ask that (about the pony motor) but I was trying to find a schematic of the intake system. I think the pony motor feeds directly off the engine filter on some Cats but too far back to remember. I have a service manual around here somewhere. So is that making any sense to any one else or are we not firing on all cylinders (with or without air cleaner)?
the pup engine has it's own filter. the exhaust travels through the intake of the diesel engine, but a spark of flame would have to make it through the turbo and all the way back to the filter, and burn two hours later. i'm not seeing it. the only logical explanation i can see is the breather sucking in a spark.
I tend to go with the theory that it sucked in a lump of red hot carbon from the exhaust. Worth checking that the air filter housing isn't rotted though.