Air filter popped out in flight

[John Tierney]

May have happened on startup, from excess priming. Not a backfire but a front fire.

[Bavafa]

Originally Posted by John Tierney

May have happened on startup, from excess priming. Not a backfire but a front fire.

Plus one for this...

[wcalvert]

I can predictably trash a filter like this with one false start backfire. Most always I can tell it happened, but it does happen on start, usually when everything is cold.

Just like the previous post said, over rich on start and the flow reverses thru the intake, deforming the filter upward. Mine is a little more secured than yours (mine is not exactly per plans, added some retention not called for), but the shape of the filter folds are almost the same.

My new technique (you learn faster after $45 penalties) is to prime less and feed the mixture in during the start. Not 100% but it's working pretty well to avoid this issue.

BTW The filter will hang in there and do the job for a long time after this happens, but seeing a waffled filter in my intake path gives me the heebies thinking about where the trash might end up if it comes apart ...

Cheers

[lr172]

Originally Posted by John Tierney

May have happened on startup, from excess priming. Not a backfire but a front fire.

well aware of what a backfire is, but you are going to have to explain what a "front fire" is. Not in the mechanical vocabulary I learned from.

[wirejock]

Ryan
Would you post the Auto Parts part number please.
I like to keep a backup and can't find the original box.
Thanks

[Draker]

Originally Posted by wirejock

Ryan
Would you post the Auto Parts part number please.
I like to keep a backup and can't find the original box.
Thanks

Larry,

The part number on the one that came with my snorkel kit is K&N 33-2060. The best price I found online was at the actual K&N store if you don't need it the next day. All the local autoparts stores I called needed to transfer it from another store. https://www.knfilters.com/33-2060-re...ent-air-filter

[chrisskymaster]

No way this is a backfire. During my phase I on an RV-14A, I had something similar....not exact but similar. I had squeezing that deformed the air filter bracket hold down. The problem was with the RV-14, you build up the cowl to add a rubber flange to seal off the air box. My build up was a little excessive and it created a squeezing effect on the air box. I inspected everything carefully and removed some of the flox build up and re-positioned the rubber flange and it relieved the "squeeze" and I've had another 50 hours on the airframe without any more squeezing. I am confident that you will find this has nothing to do with a backfire and everything to do with cowl fitting and such. good luck

[wirejock]

Originally Posted by Draker

Larry,

The part number on the one that came with my snorkel kit is K&N 33-2060. The best price I found online was at the actual K&N store if you don't need it the next day. All the local autoparts stores I called needed to transfer it from another store. https://www.knfilters.com/33-2060-re...ent-air-filter

Thanks Ryan

[rzbill]

Originally Posted by lr172

well aware of what a backfire is, but you are going to have to explain what a "front fire" is. Not in the mechanical vocabulary I learned from.

Larry,
Before I learned and practiced the mixture sweep method of hot starting a Bendix injected Lycoming, I got a "pop" or explosion in the intake on a couple of occasions due to igniting fuel in the intake of an overly flooded engine. The filter looked exactly like the OPs image. Replaced it once, bent it back once.

Never had an another issue since using mixture sweeping.

[Bill Boyd]

There is no front-fire. There is backfire, and there is after-fire.

Choose one, you must.