What are the signs that you have dirt in your nitro engine?

Usually flameouts, burnt glowplugs, erratic running characteristics........rapid tune changes, poor idle...

easiest way to know for sure is to pull the engine apart and inspect the internals, paying specific attention to the crankshaft...As the crankshaft doesn't lie...if dirt passed thru the engine the crankshaft will show it... doesn't matter how good your filter maintenance is, or what brand of air filter you use, if you see these marks it means dirt got in there.....

anyways here is what your crankshaft will look like if your engine has ingested dirt....... Any sort of marking of this nature means foreign material has passed between the crank and the case and been hard enough to scratch the hardened tool steel crankshaft..

here is another example

and here is another example

Those pics make me cringe ouch

Damn, those pictures are horrible, I can't imagine how I would feel if I pulled my engine a part and saw that

Wow.....just plain sad. It's like he poured dirt in the carb and glow plug hole intentionally.

Unfortunately it happens for more often then you would expect.....Most times when it happens guys just assume the engine is being picky to tune, and instead of stopping and cleaning the engine and possibly saving it , they persist on trying to tune the engine back to normal....Which unfortunately doesn't work and usually ends up working the damage deeper into the engine and eventually damaging the engine beyond repair.............

I can't stress enough to people that if your engines tune all of a sudden make a rapid change for no reason, starts flaming out and running poorly the chances are good you have ingested dirt and it would be quite wise to stop and clean out the internals of the engine, the quicker you clean it, the less damage will be done to the internals........... and unfortunately most guys don't stop , instead most will continue to fight with the engine for hours and sometimes days , turning the needles one way then the other hoping to solve the problem, some guys will even go seek advice of the local tuning experts, but in the end its usually inevitable the engine is beyond repair.....the more a dirty engine is run, the more damage is done inside.....

I challenge everyone to inspect their crankshafts, see how good their air filters are really doing...... It is my belief that many here would be shocked by how much dirt actually passes right thru their air filters...I know so many guys who have religious air filter maintenance practices and they still manage to suck piles of dirt into their engines....Some airfilters do a far better job then other airfilters, check your crankshafts and see for yourself how good your airfilters are doing,....

That would be a VERY extreme case , Neals scaring ya ,

Very true on the air filter thing , i see guys who thought there was no possible way there could have been dirt ingested through there carb and they have even tried to get me to warranty an engine because of this

Butttt the underside of the carb and the scratches on the crank tell all

Once in a while a motor that sucks dirt is fixable. If it wears out the crank it usually is too expensive to fix. It really depends the type of dirt, size of the particles and how long it ran like that. I have had some that all they needed is a pinch and a bearing or rod. Almost always the compression will go first and it wont idle. Like said earlier, if it all of a sudden changes tune stop running it.

Rex